Weeks 5-8 Flashcards
(348 cards)
1
Q
What are chromosomes?
A
Strands of genes that comes in pairs
2
Q
How do male mammal chromosomes differ from others?
A
They have unpaired X and Y chromosomes with different genes
3
Q
How are DNA and RNA (ribonucleic acid) related?
A
DNA serves as a template for the synthesis of RNA.
4
Q
What is messenger RNA?
A
A template for the synthesis of protein molecules
5
Q
What are the four bases in DNA?
A
Adenine
Guanine
Cytosine
Thymine
6
Q
How does the order of bases affect RNA and DNA?
A
Determines the order of corresponding bases along an RNA molecule, which in turn determines the order of amino acids that compose a protein.
E.g. Cytosine + adenine + guanine result in the protein adding glutamine
7
Q
What does homozygous mean?
What does heterozygous mean?
A
You have the same genes on your two copies of a chromosome.
You have an unmatched pair of genes.
8
Q
What’s an example of heterozygous genes?
A
A gene for blue eyes on one chromosome and a gene for brown eyes on the other.
9
Q
What are dominant, recessive, and intermediate genes?
A
Dominant
Strong effect in either the homozygous or heterozygous condition
Recessive
Shows its effects only in the homozygous condition
E.g. A gene for brown eyes is dominant and a gene for blue eyes is recessive. If you have one gene for brown eyes and one gene for blue, you will have brown eyes.
10
Q
Why can’t genes be used to make predictions?
A
Almost any characteristic depends on more than one gene.
Changes in environment can increase or decrease the expression of a gene.
11
Q
What are autosomal chromosomes and genes?
A
Chromosomes that are non sex-linked. Genes on autosomal chromosomes are called autosomal genes.
12
Q
How are chromosomes contributed during reproduction?
A
Female contributes an X.
Male contributes either an X or a Y.
13
Q
Which genes are scientists referring to when they refer to sex-linked genes?
A
X-linked genes.
Y chromosome is small with relatively few genes of its own.
14
Q
Why does red-green colourblindness occur?
A
A man may have the recessive form of the gene on his X chromosome because he has no other X chromosome.
A woman is colour deficient only when she has the gene on both of her chromosomes; it is thus more rare for women.
15
Q
What is a codon?
A
A sequence of 3 RNA bases
Represents a type of amino acid
16
Q
What are sex-linked genes?
A
Genes on the sex chromosomes (designated X and Y in mammals).
USUALLY referring to X-linked genes.
17
Q
What are autosomal genes?
A
Genes that are not sex-linked
18
Q
What causes a man to be colour blind?
What causes a woman to be colour blind?
A
Having recessive form of gene on his X chromosome (he has no other X chromosome that can see colour).
Affects 8% of population.
Having recessive form of gene on BOTH X chromosomes (if only one carries it, she can see colour).
Affects less that 1% of population.
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19
Q
- How does a sex-linked gene differ from a sex-limited gene?
A
- A sex-linked gene is on the X or Y chromosome.
A sex-limited gene is on an autosomal chromosome, but activated in one sex more than the other.
20
Q
Why are most gene mutations disadvantageous?
A
Evolution has had eons to select the best makeup of each gene
21
Q
What happens when a gene is duplicated or deleted?
What disorders might be related to duplications or deletions?
A
Part of a chromosome that usually appears once might appear twice or not at all.
It is possible for these to be helpful, but most are not.
Microduplications / microdeletions are responsible for several psychological or neurological disorders, probably including some cases of schizophrenia.
22
Q
What field deals with changes in gene expression?
A
Epigenetics
23
Q
Which cells are the only ones not to contain DNA?
A
Red blood cells
24
Q
How does gene activity change over time?
A
Genes may be more or less active during different stages of life, such as fetal, infancy, adolescence, adulthood etc.
A gene may be active in one person and not another.
Various experiences may turn a gene on or off, such as forming a new habit.
25
How do experiences modify genetic expression?
Proteins called histones bind DNA into a shape like string wound around a ball. Histone molecules in the ball have loose ends to which certain chemical groups can attach. To activate a gene, the DNA must partially unwind from the histones.
New experiences (such as maternal deprivation, exposure to drugs, new learning, etc) alter the chemical environment within the cell.
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What are some ways that identical twins may differ?
Handedness
| Mental health
27
5. How does an epigenetic change differ from a mutation?
5. A mutation is a permanent change in part of a chromosome.
An epigenetic change is an increase or decrease in the activity of a gene or group of genes.
28
6. How does adding a methyl or acetyl group to a histone protein alter gene activity?
6. Adding a methyl group turns genes off.
| An acetyl group loosens histone’s grip and increases gene activation.
29
Is singing ability depend on heredity or environment?
Both
30
How do we determine the heritability of a characteristic?
1. Monozygotic (from one egg) and dizygotic (from two eggs) twins
A stronger resemblance between monozygotic twins than dizygotic indicates a genetic contribution.
2. Studies of adopted children
Tendency for adopted children to resemble their biological parent indicates hereditary influence.
However bio mother contributes not just genes but also prenatal environment.
3. Identifying specific genes linked to some behaviour. There are two approaches:
"Candidate gene" approach - identified one gene with significant influence and other genes with moderate influence. However many studies have yielded small or uncertain effects.
"Genome wide association study" - examines all genes while comparing two groups, such as people with and without schizophrenia.
BUT this approach tests thousands of hypotheses at once (one for each gene) and there is risk of seeing an apparent effect by accident, especially in studies with a small sample.
Can also have misleading results when applied to ethnically diverse sample; what is a disorder is more common in one ethnic group than another? Then any other gene that is common in that ethnic group will appear to be a risk factor!
31
What behaviours have been found to have significant heritability?
Almost all, including loneliness, neuroticism, TV watching, childhood misbehaviour, social attitudes, cognitive performance, educational attainment, and speed of learning a second language.
Religious affiliation is NOT heritable.
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7. What are the main types of evidence to estimate the heritability of some behavior?
7. One type of evidence is greater similarity between monozygotic twins than dizygotic twins. Another is resemblance between adopted children and their biological
parents. A third is a demonstration that a particular gene is more common than average among people who show a particular behavior.
33
8. Suppose someone determines the heritability of IQ scores for a given population. Then society changes in a way that provides the best possible opportunity for everyone within that population. Will heritability of IQ increase, decrease, or stay
the same?
8. Heritability will increase. Heritability
estimates how much of the variation is due to differences in genes. If everyone has the same environment, then differences in environment cannot account for much
of the remaining differences in IQ scores. Therefore, the relative role of genetic differences will be greater.
34
9. What example illustrates the point that even if some characteristic is highly heritable, a change in the environment can alter it?
9. Keeping a child with the PKU gene on a strict lowphenylalanine diet prevents the mental retardation that the gene ordinarily causes. The general point is that sometimes a highly heritable condition can be modified environmentally.
35
How can evolution be described in terms of genetics?
A change over generations in the frequency of various genes in a population
36
Does the use or misuse of some structure or behaviour cause an evolutionary increase or decrease in that feature?
No - e.g. using your muscles will not result in your children having bigger muscles.
37
Have humans stopped evolving?
No - if people with certain genes have more than the average number of children, their genes will spread in the population.
38
Does evolution mean improvement?
Not necessarily. It improves "fitness", the number of copies of one's genes that endure in later generations. But it may promote features that become disadvantageous in new environments. E.g. Peacock tail feathers may attract predators in new environments.
39
Does evolution benefit the individual or the species?
Neither: It benefits the genes!
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10. Many people believe the human appendix is useless. Will it become smaller and smaller with each generation?
10. No. Failure to need a structure does not make it smaller in the next generation. The appendix will shrink only if people with a gene for a smaller appendix reproduce more successfully than other people do.
41
What evolutionary explanation might account for goose bumps in humans?
The behaviour involved in our remote furred ancestors to provide warmth or amplify size when threatened, and we inherited the mechanism.
42
How might natural selection promote altruism?
Kin selection - selection for a gene that benefits the individual's relatives.
Reciprocal altruism - individuals help those that will return the favour.
Group selection - altruistic groups thrive better than less cooperative ones
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43
1. What is a sex-linked gene?
A. A gene that influences sexual behavior
B. A gene that has greater effects on one sex than the other
C. A gene on either the X or Y chromosome
D. A gene that becomes activated during sexual behavior
C. A gene on either the X or Y chromosome
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2. What is a sex-limited gene?
A. A gene that influences sexual behavior
B. A gene that has greater effects on one sex than the other
C. A gene on either the X or Y chromosome
D. A gene that becomes activated during sexual behavior
B. A gene that has greater effects on one sex than the other
45
```
3. What does a microdeletion remove?
A. Part of a protein
B. Part of a brain wave
C. Part of a chromosome
D. Part of a neuron
```
C. Part of a chromosome
46
4. How does an epigenetic change differ from a mutation?
A. An epigenetic change is a duplication or deletion of part of a gene.
B. An epigenetic change alters gene activity without replacing any gene.
C. An epigenetic change alters more than one gene at a time.
D. An epigenetic change is beneficial, whereas a mutation is harmful.
B. An epigenetic change alters gene activity without replacing any gene.
47
5. How does adding a methyl or acetyl group to a histone protein alter gene activity?
A. A methyl group turns genes off. An acetyl group loosens histone’s grip and increases gene activation.
B. A methyl group turns genes on. An acetyl group tightens histone’s grip and decreases gene activation.
C. A methyl group increases the probability of a mutation, whereas an acetyl group decreases the probability.
D. A methyl group decreases the probability of a mutation, whereas an acetyl group increases the probability.
A. A methyl group turns genes off. An acetyl group loosens histone’s grip and increases gene activation.
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6. Most estimates of heritability of human behavior use what type(s) of evidence?
A. Studies of changes in behavior as people grow older
B. Studies of similarities between parents and children
C. Comparisons of twins and studies of adopted children
D. Comparisons of people living in different cultures
C. Comparisons of twins and studies of adopted children
49
7. What is the difference between monozygotic (MZ) and dizygotic (DZ) twins?
A. MZ twins develop from two eggs, whereas DZ twins develop from a single egg.
B. MZ twins develop from a single egg, whereas DZ twins develop from two eggs.
C. MZ twins are one male and one female, whereas DZ twins are of the same gender.
D. MZ twins are of the same gender, whereas DZ twins are one male and one female.
B. MZ twins develop from a single egg, whereas DZ twins develop from two eggs.
50
8. Which of the following offers strong evidence that environmental changes can largely counteract the effect of a gene?
A. The effects of temperature on children with autism spectrum disorder
B. The effects of diet on children with phenylketonuria (PKU)
C. The effects of muscle training on children who have suffered a concussion
D. The effects of sleep on children with malaria
B. The effects of diet on children with phenylketonuria (PKU)
51
9. Which of these is responsible for evolutionary changes in a species?
A. Using or failing to use part of the body increases or decreases its size for the next generation.
B. A gene that has long-term benefits to the species will become more common.
C. Individuals with certain genes reproduce more than average.
D. Evolutionary changes anticipate the adaptations that will be advantageous in the future.
C. Individuals with certain genes reproduce more than average.
52
10. What, if anything, can we predict about the future of human evolution?
A. People will get smarter, wiser, and more cooperative.
B. People will not change, because evolution no longer affects humans.
C. People will become more like whichever people tend to have the most children.
D. We cannot make any of these predictions.
C. People will become more like whichever people tend to have the most children.
53
11. Why do human infants show a grasp reflex?
A. The reflex is an accidental by-product of brain development.
B. The reflex is an imitation of actions the infant sees adults doing.
C. The reflex helps the infant develop motor skills that will be helpful later.
D. The reflex was advantageous to infants of our remote ancestors.
D. The reflex was advantageous to infants of our remote ancestors.
54
What genes regulate the expression of other genes and control the start of anatomical development?
What effects do mutations of these genes have in humans?
Homeobox genes
Brain disorders and physical deformities
55
When does the human central nervous system begin to form?
When the embryo is about two weeks old
56
When do first muscle movements in fetuses occur?
7.5 weeks
57
Which brain areas are most likely to deteriorate in conditions such as Alzheimers?
Those that are slowest to develop, like the prefrontal cortex
58
Describe the growth and development of neurons.
1. Proliferation - production of new cells
2. Migration - cells move to different areas
3. Differentiation - cells become neurons or glia
4. Synaptogenesis - neurons form synapses. Continues throughout lifespan.
5. Myelination - process by which glia produce myelin sheath
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Which kinds of neurons can be formed new in adults?
Olfactory receptors
Hippocampus (2% per year)
Basal ganglia
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How could researchers determine whether new neurons form in the adult brain in humans?
Carbon dating using 14C.
Researchers have found 14C concentrations corresponding to the year of birth in various studies.
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15. What was Sperry’s evidence that axons grow to a specific target instead of attaching at random?
15. If he cut a newt’s eye and inverted it, axons grew back to their original targets, even though the connections were inappropriate to their new positions on the eye.
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16. If axons from the retina were prevented from showing spontaneous activity during early development, what would be the probable effect on development of the thalamus?
16. The axons would attach based on a chemical gradient but could not fine-tune their adjustment based on experience. Therefore, the connections would be less precise.
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What is neural Darwinism?
In the development of the nervous system, we start with more neurons and synapses than we can keep. The most successful combinations survive, and the others fail.
64
What did Rita Levi-Montalcini discover about the relationship between muscles and axons?
Muscles don't determine how many axons form; they determine how many survive.
65
What happens to cells that do not receive nerve growth factor (NGF) from a muscle?
It dies through a process called apoptosis.
66
What does loss of cells during the natural course of development in the brain indicate?
Maturation of successful cells is linked to simultaneous loss of less successful ones
67
What is a neurotrophin?
Chemical that promotes the survival and activity of neurons.
| Essential for growth of axons and dendrites, formation of new synapses, and learning.
68
What condition is linked to abnormalities in brain-derived neurotrophic factors (BDNF)?
Depression
69
17. What process assures that the spinal cord has the right number of axons to innervate all the muscle cells?
17. The nervous system builds more neurons than it needs and discards through apoptosis those that do not make lasting synapses.
70
18. What class of chemicals prevents apoptosis in the sympathetic nervous system?
18. Neurotrophins, such as nerve growth factor
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19. At what age does a person have the greatest number of neurons— early in life, during adolescence, or during adulthood?
19. The neuron number is greatest early in life.
72
What effect does a mother drinking during pregnancy have on the child?
- Thinning of the cerebral cortex
- Fetal alcohol syndrome
- Interferes with neuron proliferation
- Impairs neuron migration and differentiation
- Impairs synaptic transmission
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What effect does alcohol have on neurons?
Alcohol kills neurons by apoptosis by inhibiting receptors for glutamate, the brain's main excitatory transmitte and enhances receptors for GABA, the main inhibitory transmitter.
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20. Anesthetic drugs and anxiety-reducing drugs increase activity of GABA, decreasing brain excitation. Why would we predict that exposure to these drugs might be dangerous to the brain of a fetus?
20. Prolonged exposure to anesthetics or anxiety-reducing drugs might increase apoptosis of developing neurons. Increased GABA activity decreases excitation, and developing neurons undergo apoptosis if they do not receive enough excitation.
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21. In the ferret study, how did the experimenters determine that visual input to the auditory portions of the brain actually produced a visual sensation?
21. They trained the ferrets to respond to stimuli on the normal side, turning one direction in response to sounds and the other direction to lights. Then they presented light to the rewired side and saw that the ferret again turned in the direction it had associated with lights.
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How do dendrites change as we age?
The central structure becomes stable by adolescence, but the branches remain flexible throughout life.
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What accounts for enchanced neuronal changes of an enriched environment in rats?
Mostly physical activity, but also partially the interesting experiences and social interactions.
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What is far transfer?
The idea that training in a difficult subject will enhance intellect in other ways too. It has only a weak effect.
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22. An enriched environment promotes growth of axons and dendrites in laboratory rodents. What is known to be one important reason for this effect?
22. Animals in an enriched environment are more active, and their exercise enhances growth of axons and dendrites.
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Do blind people actually become better at other senses?
Sort of - rather they improve their attention to other senses. E.g. Blind people have greater than average touch sensitivity, especially those that read braille.
81
What surprising finding did researchers discover about brain activity in blind people?
Substantial activity in the occipital cortex, which is usually limited to visual information.
In people blind since birth, the occipital cortex also responds to auditory information.
A similar finding occurred in people deaf from birth; touch and vision come to activate what would be the auditory cortex in deaf people.
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23. Name two kinds of evidence indicating that touch information from the fingers activates the occipital cortex of people blind since birth.
23. First, brain scans indicate increased activity in the occipital cortex while blind people perform tasks such as feeling two objects and saying whether they are the same or different. Second, temporary inactivation of the occipital cortex blocks blind people’s ability to perform that task, without affecting the ability of sighted
people.
83
How do we know that brain differences in students are the results of training, not the cause of interest in a subject?
Longitudinal studies of students before and after training showed brain differences in those who took training, but no changes in those who didn't.
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24. Which brain area shows expanded representation of the left hand in people who began practicing stringed instruments in childhood and continued for many years?
24. Somatosensory cortex (postcentral gyrus) of the right hemisphere.
85
What is focal hand dystonia or "musician's cramp"?
25. Extensive practice of violin, piano, or other instruments causes expanded representation of the fingers in the somatosensory cortex, as well as displacement of representation of one or more fingers in the motor cortex.
If the sensory representation of two fingers overlaps too much, the person cannot feel them separately or move them separately.
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26. Why is immaturity of the prefrontal cortex not a satisfactory explanation for risky behaviors in adolescents?
26. As the teenage years progress, risky behavior tends to increase, even though the prefrontal cortex is becoming more mature.
87
Why might cognition in older people be underestimated? 3 reasons.
1. People deteriorate at different rates. Those who exercise more often maintain good cognitive function.
2. Those who may be slower in certain intellectual activities have developed a great base of knowledge and experience to draw on.
3. Older people find ways to compensate for losses, such as by activating more widespread brain areas to compensate for decreased arousal in one or two areas.
88
What procedures might help slow cognitive decline in old age?
Exercise!
| Potentially chemical interventions, such as blood transfusion, although this requires more research.
89
1. In early brain development, what is the relationship between the sensory systems and muscle movements?
A. The sensory systems develop before the first muscle movements.
B. The first muscle movements occur at the same time as when the sensory systems develop.
C. The first muscle movements occur before the sensory systems develop.
D. First vision develops, then movements, and then the other sensory systems.
C. The first muscle movements occur before the sensory systems develop.
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2. Which parts of the cerebral cortex are most likely to deteriorate in Alzheimer’s disease and other conditions?
A. The areas that mature at the earliest ages, such as the primary visual cortex.
B. The areas most distant from the heart, such as the parietal cortex.
C. The areas responsible for emotional processing, such as the amygdala.
D. The areas that mature at the latest age, such as the prefrontal cortex.
D. The areas that mature at the latest age, such as the prefrontal cortex.
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3. In which areas of the human brain do some new neurons develop during adulthood?
A. The primary visual cortex and the primary auditory cortex
B. The hippocampus and the basal ganglia
C. The olfactory bulbs and the areas responsible for speech
D. The corpus callosum and the cerebellum
B. The hippocampus and the basal ganglia
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4. When Sperry cut a newt’s optic nerve and turned the eye upside down, what happened?
A. Axons of the optic nerve grew randomly and attached diffusely to target cells.
B. Axons of the optic nerve grew back to their original targets.
C. Axons of the optic nerve grew back to targets appropriate to their new location in the eye.
D. At first the axons grew back randomly, but then they established appropriate connections by learning.
B. Axons of the optic nerve grew back to their original targets.
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```
5. In the sympathetic nervous system, which of the following prevents apoptosis?
A. Steroid hormones
B. Nerve growth factor
C. Physical exercise
D. Myelination
```
B. Nerve growth factor
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6. Why does the spinal cord have the right number of axons to innervate all the muscle cells?
A. Each muscle cell sends a chemical message telling the spinal cord to make a neuron.
B. The genes cause a certain number of neurons to form and the same number of muscles to form.
C. Immature cells divide, with one daughter cell becoming a neuron and the other becoming a muscle.
D. The spinal cord makes an excess of neurons, but those that fail to innervate a muscle die.
D. The spinal cord makes an excess of neurons, but those that fail to innervate a muscle die.
95
```
7. At what age does a person have the largest number of neurons?
A. Before or shortly after birth
B. Equally at all times of life
C. Adolescence
D. Adulthood
```
A. Before or shortly after birth
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8. If a pregnant woman drinks alcohol, alcohol harms the brain of the fetus not only while it is in the system, but also while it
is washing away after drinking. What is the danger while alcohol is washing away?
A. Temperature in the brain may decrease.
B. Blood pressure in the brain may decrease.
C. Excess inhibition at GABA synapses can lead to apoptosis.
D. Overstimulation at glutamate synapses can poison the mitochondria.
D. Overstimulation at glutamate synapses can poison the mitochondria.
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9. In the ferret study, what evidence indicated that visual input to the auditory portions of the brain actually produced a visual sensation?
A. Bright flashes of light to the rewired eye caused the ferrets to blink both eyes.
B. Recordings from individual cells of the rewired temporal cortex showed the same patterns usually seen in cells of the occipital cortex.
C. Ferrets could find their way around an unfamiliar room even with the normal eye closed.
D. Ferrets that learned to turn one way in response to light in the normal eye turned the same way to light in the rewired eye.
D. Ferrets that learned to turn one way in response to light in the normal eye turned the same way to light in the rewired eye.
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```
10. An enriched environment including social interactions promotes growth of axons and dendrites in laboratory rodents.
What else can produce the same effect?
A. Improved diet
B. Physical activity
C. Exposure to music
D. Extra sleep
```
B. Physical activity
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11. According to most research, what are the effects of computerized programs to practice memory skills?
A. Temporary improvement of the skills that were practiced
B. Temporary improvement of both the practiced skills and general intelligence (“far transfer”)
C. Long-term improvement of both the practiced skills and general intelligence (“far transfer”)
D. No benefits, not even temporarily
A. Temporary improvement of the skills that were practiced
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12. If a person is born blind, what happens to the occipital (“visual”) cortex?
A. Its cells shrink and gradually die.
B. Its cells remain intact but forever inactive.
C. Its cells become responsive to touch or hearing.
D. Its cells become spontaneously active, producing hallucinations.
C. Its cells become responsive to touch or hearing.
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13. In people who practice violin or other stringed instruments for many years, what changes in the cerebral cortex?
A. Both hemispheres begin controlling speech equally.
B. Parts of the occipital cortex stop responding to vision and switch to hearing.
C. A larger than average portion of the cortex responds to the passage of time.
D. A larger than average portion of the cortex responds to fingers of the left hand.
D. A larger than average portion of the cortex responds to fingers of the left hand.
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14. What causes musician’s cramp?
A. Changes in the muscles and tendons of the hand
B. Rewiring of the cerebral cortex
C. Loss of myelin on the motor nerves to the hand
D. Changes in the touch receptors of the hand
B. Rewiring of the cerebral cortex
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15. What is the most likely biological explanation for increased risky behavior among adolescents?
A. Immaturity of the prefrontal cortex
B. Increased activity in brain areas that anticipate reward
C. Increased activity in brain areas responsible for depressed mood
D. Immaturity of the corpus callosum
B. Increased activity in brain areas that anticipate reward
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16. Why do many older people continue to hold important jobs in spite of the declines in memory and brain function that are known to occur in old age?
A. Laws prevent them from being fired.
B. Most of their jobs don’t require much brain activity.
C. Old people take the credit for work that younger people actually do.
D. The declines on average do not apply to all people.
D. The declines on average do not apply to all people.
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How do we know that we see light rays, and that we don't send out sight rays?
When we open our eyes, we can already see light - we don't have to wait for sight rays to reach their destination.
Ibn al-Haytham
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2. If someone electrically stimulated the auditory receptors in your ear, what would you perceive?
2. Because of the law of specific nerve energies, you would perceive it as sound, not as shock. (Of course, a strong enough shock might spread far enough to excite
pain receptors also.)
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3. If it were possible to flip your entire brain upside down, without breaking any of the connections to sense organs or muscles, what would happen to your perceptions of what you see, hear, and so forth?
3. Your perceptions would not
change. The way visual or auditory information is coded in the brain does not depend on the physical location within the brain. Seeing something as “on top” or “to the left” depends on which neurons are active but does not depend on the physical location of those neurons.
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Explain how the eye works.
See Page 149
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What cells does light pass through en route to the receptors?
Ganglion, amacrine and bipolar cells.
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Where is the blind spot and why?
The point at which the optic nerve exits through the back of the eye.
4. The blind spot has no receptors because it is occupied by exiting axons and blood vessels.
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How can we see properly despite the blind spot?
Everything the blind spot of one eye can't see, the other eye can see.
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What are the differences between foveal vision and peripheral vision?
Foveal - better acuity (sensitivity to detail)
Peripheral - better sensitivity to dim light
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What might interfere with peripheral vision?
Other nearby objects
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What are the two types of receptors and what are they good at?
Rods
Abundant in periphery of retina
Respond to faint light, but not useful in daylight
Cones
Abundant in and near fovea
More useful in bright light
Essential for colour vision
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5. You sometimes find that you can see a faint star on a dark night better if you look slightly to the side of the star instead of straight at it. Why?
5. If you look slightly to the side, the light falls on an area of the retina with more rods and more convergence of input.
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6. If you found a species with a high ratio of cones to rods in its retina, what would you predict about its way of life?
6. We should expect this species to be highly active during the day and seldom active at night.
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List colours in order of shortest to longest wavelengths.
```
Violet
Blue
Green
Yellow
Orange
Red
```
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Why do males and females of some birds look the same to us, but different to each other?
They can see ultraviolet light, and the males reflect more UV light.
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What is trichromatic theory or Young-Helmholtz theory?
We perceive colour through the relative rates of response by three kinds of cones, each one sensitive to a different set of wavelengths.
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Opponent-process theory
We perceive colour in terms of opposites. The brain has a mechanism that perceives colour on a continuum from red to green, another from yellow to blue, another from white to black. After you stare at one colour in one location for long enough you fatigue that response and swing to the opposite.
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7. Examine Figure 5.9. According to the trichromatic theory, what causes you to perceive red?
7. Activity of the long-wavelength cone is not sufficient. In fact, notice that the long-wavelength cone responds to what we call yellow more than to what we call red. A perception of red occurs only if the long-wavelength cone has a high ratio of response relative to the other two types of cone
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What is retinex theory?
The cortex compares information from various parts of the retina to determine the brightness and colour for each area.
Accounts for colour and brightness optical illusions.
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9. When a television set is off, its screen appears gray. When you watch a program, parts of the screen appear black, even though more light is actually showing on the screen than when the set was off. What accounts for the black perception?
9. The black experience arises by contrast with the brighter areas around it.
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10. Figure 5.9 shows light at about 510 nm as green. Why should we nevertheless not call it “green light”?
10. Color perception depends not just on the wavelength of light from a given spot but also the light from surrounding areas. As in Figure 5.13, the context can change
the color perception.
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11. Why is color vision deficiency a better term than color blindness?
11. Very few people see the world entirely in black and white. The more common condition is difficulty discriminating red from green.
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1. What happens when you see something?
A. You send out sight rays that strike the object.
B. Light rays reflect off the object and strike your retina.
C. You send out sight rays, and light reflecting off the object strikes your retina.
D. You neither send out sight rays nor receive light rays onto your retina.
B. Light rays reflect off the object and strike your retina.
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2. What is the route from retinal receptors to the brain?
A. Receptors send axons directly to the brain.
B. Receptors connect to bipolars, which connect to ganglion cells, which send axons to the brain.
C. Receptors connect to ganglion cells, which connect to bipolars, which send axons to the brain.
D. Receptors connect to amacrine cells, which send axons to the brain.
B. Receptors connect to bipolars, which connect to ganglion cells, which send axons to the brain.
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3. Where does the optic nerve exit from the retina?
A. At the blind spot
B. At the fovea
C. From the edge of the fovea
D. Diffusely from all parts of the retina
A. At the blind spot
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4. Why is vision most acute at the fovea?
A. The fovea is closest to the pupil.
B. The fovea has an equal ratio of cones to rods.
C. The cornea produces the least distortion of light at the fovea.
D. Each receptor in the fovea has a direct line to the brain.
D. Each receptor in the fovea has a direct line to the brain.
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5. Vision in the periphery of the retina has poor sensitivity to detail but great sensitivity to faint light. Why?
A. Toward the periphery, the retina has more midget ganglion cells.
B. Toward the periphery, the retina has more cones and fewer rods.
C. Toward the periphery, the retina has more convergence of input.
D. Toward the periphery, the light falls farther from the blind spot.
C. Toward the periphery, the retina has more convergence of input.
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6. Why do some people have greater than average sensitivity to brief, faint, or rapidly changing visual stimuli?
A. They do not have a blind spot in their retina.
B. The blind spot in their retina is smaller than average.
C. They have more axons from the retina to the brain.
D. They have four types of cones instead of three.
C. They have more axons from the retina to the brain.
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7. Suppose you perceive something as red. According to the trichromatic theory, what is the explanation?
A. Light from the object has excited your long-wavelength cones more strongly than your other cones.
B. Light from the object has excited your short-wavelength cones more strongly than your other cones.
C. Ganglion cells that increase response to red and decrease their response to green are firing strongly.
D. The cortex compares activity over all parts of the retina and computes that one area is red.
A. Light from the object has excited your long-wavelength cones more strongly than your other cones.
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8. If you stare at a white circle surrounded by a green background, and then look at a white surface, you perceive a green circle
surrounded by a red background. What does this observation imply about the opponent-process theory?
A. We perceive colors based on the pattern of input to the bipolar and ganglion cells of the retina.
B. The mechanisms of color vision vary from one species to another.
C. Opponent-process color perception depends on the visual cortex, not just the cells in the retina.
D. The opponent-process theory is wrong.
C. Opponent-process color perception depends on the visual cortex, not just the cells in the retina.
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9. An object that reflects all wavelengths equally ordinarily appears gray, but it may appear yellow, blue, or any other color,
depending on what?
A. Brightness of the light
B. Contrast with surrounding objects
C. The culture in which you grew up
D. The ratio of cones to rods in your retina
B. Contrast with surrounding objects
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10. Color vision deficiency demonstrates which fundamental point about perception?
A. Color is in the brain and not in the light itself.
B. Each sensory system depends on a different part of the cerebral cortex.
C. Color perception varies because of cultural influences.
D. Fatiguing a receptor can lead to a negative afterimage.
A. Color is in the brain and not in the light itself.
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What do rods and cones of the retina make synapses with?
Horizontal cells and bipolar cells
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What forms the optic nerve?
Axons of the ganglion cells
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Where do most ganglion cell axons go?
Where do some others go?
Lateral geniculate nucleus, part of the thalamus
Superior colliculus
Hypothalamus (that controls waking/sleeping schedule)
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12. Where does the optic nerve start and where does it end?
12. It starts with the ganglion cells in the retina. Most of its axons go to the lateral geniculate nucleus of the thalamus, but some go to the hypothalamus and superior colliculus.
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Define lateral inhibition
The retina's way of sharpening contrasts to emphasize the boreders of objects
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Why does visual receptors' output count as excitation of the bipolar cells?
1. Light striking rods and cones DECREASES their output.
2. Receptors make INHIBITORY synapses onto bipolar cells.
3. Therefore light on the rods or cones DECREASES their INHIBITORY output (double negative), resulting in excitation.
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How many bipolar cells does each cone attach to in the fovea?
Just one
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13. When light strikes a receptor, does the receptor excite or inhibit the bipolar cells? What effect does it have on horizontal cells? What effect does the horizontal cell have on bipolar cells?
13. The receptor excites both the bipolar cells and the horizontal cell. The horizontal cell inhibits the same bipolar cell that was excited plus additional bipolar cells in the
surround.
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14. If light strikes only one receptor, what is the net effect (excitatory or inhibitory) on the nearest bipolar cell that is directly connected to that receptor? What is the effect on bipolar cells to the sides? What causes that effect?
14. It produces more excitation than inhibition for the nearest bipolar cell. For surrounding bipolar cells, it produces only inhibition. The reason is that the receptor
excites a horizontal cell, which inhibits all bipolar cells in the area.
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15. Examine Figure 5.17. You should see grayish diamonds at the crossroads among the black squares. Explain why.
15. In the parts of your retina that look at the long white arms, each neuron is inhibited by white input on two of its sides (either above and below or left and
right). In the crossroads, each neuron is in
hibited by input on all four sides. Therefore, the response in the crossroads is decreased compared to that in the arms.
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What are the three categories of primate ganglion cells?
```
Parvocellular neurons
Small cell bodies
Small receptive fields
Mostly in or near the fovea
Well-suited to detecting visual details, colour
```
```
Magnocellular neurons
Larger cell bodies
Larger receptive fields
Distributed evenly throughout the retina
Respond to movement, overall patterns
```
Koniocellular neurons
Small cell bodies
Throughout the retina
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16. As we progress from bipolar cells to ganglion cells to later cells in the visual system, are receptive fields ordinarily larger, smaller, or the same size? Why?
16. They become larger because each cell’s receptive field is made by inputs converging at an earlier level.
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What happens to people who have damage to their primary visual cortex (area V1)?
They report no conscious vision, no visual imagery, and no visuals in their dreams.
In contrast, those who lose vision because of eye damage continue to have visual imagery and visual dreams.
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What is blindsight?
Ability to respond to visual information without perceiving it consciously.
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150
18. If you were in a darkened room and researchers wanted to “read your mind” just enough to know whether you were having visual fantasies, what could they do?
18. Researchers could use fMRI, EEG, or other recording methods to see whether activity increased in your primary visual cortex.
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19. What is an example of an unconscious response to visual information?
19. In blindsight, someone can point toward an object or move the eyes toward the object, despite insisting that he or she sees nothing.
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What kind of cell has a receptive field with fixed excitatory and inhibitory zones?
Simple cell
Responds to a stimulus in only one location.
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153
What cells respond to patterns of light in a particular orientation, rather than the exact location of a stimulus?
Complex cells
Responds to stimuli equally throughout a large area.
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How do end-stopped or hypercomplex cells resemble complex cells?
Has a strong inhibitory area at one end of its bar-shaped receptive field
```
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```
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20. How could a researcher determine whether a given neuron in the visual cortex is simple or complex?
20. First identify a stimulus, such as a horizontal line, that stimulates the cell. Then present the stimulus in several locations. If the cell responds strongly in only one location, it is a simple cell. If it responds in several locations, it is a complex cell.
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How are cells grouped in the visual cortex?
Cells with similar properties group together in the visual cortex in columns perpendicular to the surface.
For example, cells within a given column
might respond to only the left eye, only the right eye, or both eyes about equally. Also, cells within a given column respond best to lines of a single orientation.
157
21. What do cells within a column of the visual cortex have in common?
21. They respond best to lines in the same orientation. Also, they are similar in their preference for one eye or the other, or both equally.
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Why do we consider visual cortex cells to be feature detectors?
Prolonged exposure to a given visual feature decreases sensitivity to that feature.
E.g. Looking at a forest after watching a waterfall for a while will make it appear that the trees are flowing upwards. This indicates that the neurons for downward motion are fatigued, leaving unopposed the detectors for the opposite motion.
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What evidence indicates that feature detectors don't account for all vision?
Abstract images (such as Mooney faces) that require interpretation to see a recognisable image indicate top-down processes in which other brain areas interpret visual stimulus and send message back to reorganise the activity in the primary visual cortex.
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22. What is a feature detector?
22. It is a neuron that detects the presence of a particular aspect of an object, such as
a shape or a direction of movement.
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23. What is the effect of closing one eye early in life?
What is the effect of closing both eyes?
23. If one eye is closed during early development, the cortex becomes unresponsive to it.
If both eyes are closed, cortical cells remain somewhat responsive for several weeks and then gradually become sluggish and unselective in their responses
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24. What early experience would cause a kitten or human child to lose stereoscopic depth perception?
24. If the eye muscles cannot keep both eyes focused in the same direction, the developing brain loses the ability for any neuron in the visual cortex to respond to input from both eyes. Instead, each neuron responds to one eye or the other. Stereoscopic depth perception requires cells that compare the input from the two eyes.
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25. What causes astigmatism?
25. Astigmatism results when the eyeball is not quite spherical. As a result, the person sees one direction of lines more clearly than the other.
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26. If an infant is born with dense cataracts on both eyes and they are surgically removed years later, how well does the child see at first?
26. The child sees well enough to identify whether two objects are the same or different, but the child doesn’t understand what the visual information means. In particular, the child cannot answer which visual display matches something the child touches. However, understanding of vision improves with practice
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```
1. What do horizontal cells in the retina do?
A. They inhibit neighboring receptors.
B. They inhibit bipolar cells.
C. They inhibit ganglion cells.
D. They stimulate ganglion cells.
```
B. They inhibit bipolar cells.
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2. In humans, what crosses to the contralateral hemisphere at the optic chiasm?
A. Half of each optic nerve, the part representing the nasal half of the retina
B. Half of each optic nerve, the part representing the temporal half of the retina
C. Half of each optic nerve, originating from random parts of the retina
D. All of each optic nerve
A. Half of each optic nerve, the part representing the nasal half of the retina
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```
3. What is the function of lateral inhibition in the retina?
A. To sharpen borders
B. To enhance colors
C. To recognize objects
D. To increase attention
```
A. To sharpen borders
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4. Suppose light strikes the retina in a circle, surrounded by dark. Which bipolar cells will show the greatest response, and
which will show the least?
A. Bipolars connected to receptors in the center of the circle respond the most. Those connected to receptors farthest from the circle respond the least.
B. Bipolars connected to the receptors just outside the circumference of the circle respond most. Those connected to receptors just inside the circumference respond least.
C. Bipolars connected to the receptors just inside the circumference of the circle respond most. Those connected to receptors just outside the circumference respond least.
D. All bipolars within the circle respond equally, and those outside the circle do not respond at all.
C. Bipolars connected to the receptors just inside the circumference of the circle respond most. Those connected to receptors just outside the circumference respond least.
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5. What is the shape of a receptive field of a ganglion cell?
A. Either a bar or an edge, in a fixed position
B. Either a bar or an edge, anywhere within a large area of the retina
C. Either a bar or an edge, with a strong inhibitory field at one end
D. A circle, with a surround that responds in the opposite way
D. A circle, with a surround that responds in the opposite way
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6. What is the shape of a receptive field of a simple cell in the primary visual cortex?
A. Either a bar or an edge, in a fixed position
B. Either a bar or an edge, anywhere within a large area of the retina
C. Either a bar or an edge, with a strong inhibitory field at one end
D. A circle, with a surround that responds in the opposite way
A. Either a bar or an edge, in a fixed position
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```
7. In contrast to parvocellular neurons, magnocellular neurons are more sensitive to ____.
A. color
B. small details
C. movement
D. the fovea
```
C. movement
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8. If you were in a darkened room and researchers wanted to know whether you were having visual fantasies (without asking
you), they could measure activity in which brain area?
A. The retina
B. The lateral geniculate nucleus of the thalamus
C. The primary visual cortex
D. The parietal cortex
C. The primary visual cortex
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9. In most cases, blindsight apparently depends on what connection?
A. From the thalamus to the temporal cortex
B. From the occipital cortex to the temporal cortex
C. From the thalamus to the frontal cortex
D. From the occipital cortex to the frontal cortex
A. From the thalamus to the temporal cortex
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10. What evidence suggests that certain types of feature detectors operate in the human visual cortex?
A. When you examine Mooney faces, at first you see only meaningless blobs, but with time and effort you start to perceive faces.
B. After you stare at a waterfall or other steadily moving display, you see stationary objects as moving in the opposite direction.
C. An electrode traveling through a section of the cortex may encounter one neuron after another with receptive fields in the same orientation.
D. Children who are deprived of input in one eye become attentive only to the other eye.
B. After you stare at a waterfall or other steadily moving display, you see stationary objects as moving in the opposite direction.
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11. If a kitten has one eye shut for its first few weeks of life, its visual cortex becomes insensitive to that eye. Why?
A. The receptors die.
B. Any axon that is not used for that long becomes unable to respond.
C. Activity from the active eye inhibits synapses from the inactive eye.
D. The visual cortex becomes responsive to sounds instead of light.
C. Activity from the active eye inhibits synapses from the inactive eye.
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12. What early experience, if any, is necessary to maintain binocular input to the neurons of the visual cortex?
A. Cortical cells will always maintain binocular responsiveness, regardless of their experience.
B. Cortical cells must receive some input to each eye every day.
C. Cortical cells must receive an equal amount of input from the two eyes.
D. Cortical cells must usually receive simultaneous input from the two eyes.
D. Cortical cells must usually receive simultaneous input from the two eyes.
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13. If someone is born with dense cataracts on both eyes, and the cataracts are removed years later, what happens?
A. The person remains permanently blind.
B. The person gradually recovers all aspects of vision.
C. The person gains some vision, but remains impaired on object recognition, motion vision, and depth perception.
D. The person gains almost all aspects of vision, but remains greatly impaired on color perception.
C. The person gains some vision, but remains impaired on object recognition, motion vision, and depth perception.
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What is the ventral stream?
Temporal cortex and its connections to the primary visual cortex
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What is the dorsal stream?
Pathway through the parietal cortex to the primary visual cortex
180
What are photopigments?
```
Photosensitive chemicals (sensitive to photons of light) - when exposed to light they change their chemical structure.
Flow of Na+ into photoreceptors is interfered with.
Flow of K+ out of the photoreceptors continues, resulting in change to resting membrane potential
Photoreceptor membranes become hyperpolarised
```
There's more! Refer Week 6 study guide for more info...
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Suppose someone can describe an object in detail but stumbles and fumbles when trying to walk toward it and pick it up. Which is probably damaged, the dorsal path or the ventral path?
27. The inability to guide movement based on vision implies damage to the dorsal path.
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What are newborns most likely to look at?
In order:
1. Faces (esp. right side up)
2. Circles
3. Newsprint
4. White
5. Yellow
6. Red
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Why are same people only able to detect motion, not the objects that are moving?
After damage to area V1 (enough to produce blindness), area MT may still have enough input to permit motion detection.
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30. When you move your eyes, why does it not seem as if the world is moving?
30. Neurons in areas MT and MST respond strongly when an object moves relative to the background, and not when the object and background move in the same direction and speed.
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31. Under what circumstance does someone with an intact brain become motion blind, and what accounts for the motion blindness?
31. People become motion blind shortly
| before and during a saccade (voluntary eye movement), because of suppressed activity in area MT.
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1. The ventral stream of the visual system is specialized for which of these?
A. Identifying locations
B. Coordinating vision with movement
C. Peripheral vision and vision under poor lighting
D. Detailed identification of objects
D. Detailed identification of objects
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```
2. If someone can identify objects, but does not seem to know where they are, what location of brain damage is likely?
A. Primary visual cortex (V1)
B. Middle temporal cortex (MT or V5)
C. Secondary visual cortex (V2)
D. Parietal cortex
```
D. Parietal cortex
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3. What is distinctive about visual perception in the inferior temporal cortex?
A. Cells respond only to objects that are symmetrical.
B. Cells respond in proportion to the brightness of light.
C. Cells respond only to objects that are moving at a particular speed.
D. Cells respond to an object regardless of the angle of view.
D. Cells respond to an object regardless of the angle of view.
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4. The fusiform gyrus is specialized for which of the following?
A. Recognizing faces and other highly familiar objects
B. Maintaining color recognition despite changes in room lighting
C. Identifying the direction and speed of a visual object
D. Coordinating vision with hearing and other senses
A. Recognizing faces and other highly familiar objects
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5. If someone has trouble recognizing faces, what pathway in the nervous system is probably deficient?
A. Connections between the primary visual cortex and area MT (V5)
B. Connections between the fusiform gyrus and part of the occipital cortex
C. Connections between the temporal cortex and the parietal cortex
D. Connections between the occipital cortex and the primary motor cortex
B. Connections between the fusiform gyrus and part of the occipital cortex
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```
6. What happens after damage limited to area MT?
A. Motion blindness
B. Face blindness
C. Color blindness
D. Night blindness
```
A. Motion blindness
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7. Why is it difficult to watch your own eyes move when looking in the mirror?
A. The eye movements are too fast to see.
B. The eye movements are too small to see.
C. During a saccadic eye movement, the eyes do not move relative to the background of the rest of the face.
D. During saccadic eye movements, activity decreases in area MT.
D. During saccadic eye movements, activity decreases in area MT.
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What are sound waves?
Periodic compressions of air, water, or other media
194
What is amplitude?
What is frequency?
Intensity - greater amplitude usually seems louder
Number of compressions per second (Hz) - pitch
195
What is place theory?
Each frequency activates hair cells at only one place along the basilar membrane, and the nervous system distinguishes among frequences based on which neurons respond.
Similar to tuning a piano with a tuning fork.
196
What is frequency theory?
The entire basilar membrane vibrates in synchrony with a sound, causing auditory nerves axons to produce action potentials at the same frequency. E.g. A sound at 50Hz would cause 50 action potentials per second in the auditory nerve.
However the refractory period of a neuron is 1/1000 second, far short of the highest frequencies we hear.
197
What is the current theory on hearing?
A combination of both:
For low frequency sounds up to 100 Hz the basilar membrane vibrates in synchrony and auditory nerve axons generate one action potential per wave.
For medium frequency sounds 100 Hz - 4000 Hz, a neuron might fire on some waves and not others. Action potentials are phase locked to the peaks of the sound waves
For high frequency sounds over 4000 Hz we use a mechanism similar to place theory. High frequency sounds vibrate hair cells near the base of the basilar membrane where it is stiffest. Low frequency sounds vibrate cells further along where it is floppier.
198
1. Through which mechanism do we perceive low-frequency sounds (up to about 100 Hz)?
1. At low frequencies, the basilar membrane vibrates in synchrony with the sound waves, and each responding axon in the auditory nerve sends one action potential per sound wave.
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2. How do we perceive middle-frequency sounds (100 to 4000 Hz)?
2. At intermediate frequencies, no single
axon fires an action potential for each sound wave, but different axons fire for different waves, and so a volley (group) of axons fires for each wave.
200
3. How do we perceive high-frequency sounds (above 4000 Hz)?
3. At high frequencies, the sound causes maximum vibration for the hair cells at one location along the basilar membrane.
201
How does damage to the primary auditory cortex differ from damage to the primary visual cortex?
Damage to PVC results in blindness.
Damage to PAC does not result in deafness - individuals can still identify individual sounds but have trouble with speech and music.
202
4. How is the auditory cortex like the visual cortex?
4. Any of the following:
(a) Both vision and hearing have “what” and “where” pathways.
(b) Areas in the superior temporal cortex analyze movement of both visual and auditory stimuli. Damage there can cause motion blindness or motion deafness.
(c) The visual cortex is essential for visual imagery, and the primary auditory cortex is essential for auditory imagery.
(d) Both the visual and auditory cortices need normal experience early in life to develop normal sensitivities.
203
5. What is one way in which the auditory and visual cortices differ?
5. Damage to the primary visual cortex leaves someone blind, but damage to the primary auditory cortex merely impairs perception of complex sounds without making the person deaf.
204
6. What evidence suggests that human concepts rely on activation of the relevant sensory or motor areas of the cortex?
6. People with damage to the auditory cortex regard many sound-related words, such as “thunder,” as if they were nonwords.
205
How do we localise (deterine direction and distance) of sounds?
By comparing the response rate between the two ears - difference in time of arrival of sound. If there is a larger difference, indicates sound is coming from one side. A Small difference indicates sound is coming from a more central location.
Good for sudden sounds.
Bad underwater - sound travels faster so response rate difference is imperceptible.
Comparing intensity between two ears - if sound is louder in one ear it means it's closer.
Best for high frequencies.
Phase difference - useful for localising sound up to 1500 Hz.
206
7. Which method of sound localization is more effective for an animal with a small head?
Which is more effective for an animal with a large head? Why?
7. An animal with a small head localizes sounds mainly by differences in loudness because the ears are not far enough apart for differences in onset time to be useful.
An animal with a large head localizes sounds mainly by differences in onset time because its ears are far apart and well suited to noting differences in phase or onset time.
207
Why do older people suffer from difficulty for understanding speech even with hearing aids, especially in noisy rooms?
The hearings aids make the sound louder, but the parts of the brain responsible for processing speech are declining in activity.
The elderly also experience a loss of inhibitory neurotransmitters in auditory portions of the brain, and therefore find it harder to focus attention or tune out unwanted stimuli.
208
8. What evidence suggests that absolute pitch depends on special experiences?
8. Absolute pitch occurs almost entirely among people
who had early musical training and is also more common
among people who speak tonal languages, which require
greater attention to pitch.
209
9. Which type of hearing loss—conductive deafness or nerve deafness—would be more common among members of rock bands and why?
9. Nerve deafness is common among rock band members because their frequent exposure to loud noises causes damage to the cells of the ear.
210
10. Why do many older people have trouble hearing speech in spite of wearing hearing aids
10. In some cases the language areas of the cortex have become less responsive. Also, auditory areas of the brain have decreased levels of inhibitory neurotransmitters, and the result is decreased ability to focus attention on one speaker in a noisy environment.
211
```
1. When ancient fish evolved into land animals, why did they need to evolve the elaborate mechanisms of the middle ear and inner ear?
A. To amplify sounds
B. To localize sounds
C. To remember sounds
D. To distinguish among pitches
```
A. To amplify sounds
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2. Where are the auditory receptors, known as hair cells?
A. In the auditory nerve
B. Along the basilar membrane of the cochlea
C. Between the incus and the stapes
D. In the pinna
B. Along the basilar membrane of the cochlea
213
3. How do we identify a low-pitched sound?
A. Low frequencies cause only weak vibrations of the basilar membrane.
B. Each frequency produces a peak response at one point along the basilar membrane.
C. The whole basilar membrane vibrates in synchrony with the sound frequency.
D. Each frequency vibrates a different part of the pinna.
C. The whole basilar membrane vibrates in synchrony with the sound frequency.
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4. How do we identify a high-pitched sound?
A. High frequencies cause only weak vibrations of the basilar membrane.
B. Each frequency produces a peak response at one point along the basilar membrane.
C. The whole basilar membrane vibrates in synchrony with the sound frequency.
D. Each frequency vibrates a different part of the pinna.
B. Each frequency produces a peak response at one point along the basilar membrane.
215
5. What is one way in which the auditory cortex is not analogous to the visual cortex?
A. The auditory cortex does not have separate pathways for identifying and localizing stimuli.
B. Damage to the primary auditory cortex does not cause deafness.
C. Just imagining a sound does not activate the auditory cortex.
D. Variations in early experience do not modify the auditory cortex.
B. Damage to the primary auditory cortex does not cause deafness.
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6. What is meant by a “tonotopic map”?
A. Each location in the auditory cortex responds to a preferred tone.
B. The auditory cortex has axons back and forth to every other part of the cortex.
C. Each neuron in the auditory cortex responds differently depending on the location of the source of sound in space.
D. Each cell in the auditory cortex has a “partner” cell in the visual cortex.
A. Each location in the auditory cortex responds to a preferred tone.
217
```
7. What type of sound do we localize by comparing the time of arrival at the two ears?
A. Slow-onset sounds
B. Sudden sounds
C. High-frequency sounds
D. Low-frequency sounds
```
B. Sudden sounds
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8. Absolute pitch is more common among what type of people?
A. People who had a period of auditory deprivation during early childhood
B. People with extensive musical training beginning in early childhood
C. People who learned two languages beginning in early childhood
D. People with many older brothers and sisters
B. People with extensive musical training beginning in early childhood
219
9. Why do many older people have trouble understanding speech despite using hearing aids?
A. Lack of inhibitory transmission in the auditory cortex
B. Gradual shrinkage of the cochlea
C. Decrease in social responsiveness
D. Inability to remember the meanings of common words
A. Lack of inhibitory transmission in the auditory cortex
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11. People with damage to the vestibular system have trouble reading street signs while walking. Why?
11. The vestibular system enables the brain to shift eye movements to compensate for changes in head position. Without feedback about head position, a person would not be able to correct the eye movements, and the experience would be like watching a jiggling book page.
221
1. Why do we move the eye muscles with greater precision than
the biceps muscles?
1. Each axon to the biceps muscles innervates about a hundred fibers; therefore, it is not possible to change the movement by a small amount. In contrast, an axon to the eye muscles innervates only about three fibers.
222
2. Which transmitter causes a skeletal muscle to contract?
2. Acetylcholine. And remember that a muscle’s only movement is to contract.
223
3. In what way are fish movements impaired in cold water?
3. Although a fish can move rapidly in cold water, it fatigues easily.
224
4. Duck breast muscles are red (“dark meat”), whereas chicken breast muscles are white. Which species probably can fly for a longer time before fatiguing?
4. Ducks can fly great distances, as
they often do during migration. The white muscle of a chicken breast has the power necessary to get a heavy body off the ground, but it fatigues rapidly. Chickens seldom fly far.
225
5. If you hold your arm straight out and someone pulls it down slightly, it quickly bounces back. Which proprioceptor is responsible?
5. The muscle spindle
226
6. What is the function of Golgi tendon organs?
6. Golgi tendon organs respond to
muscle tension and thereby prevent excessively
strong muscle contractions.
227
1. After acetylcholine causes a flexor muscle to move your hand toward your shoulder, what would move it the other direction?
A. A different transmitter causes the muscle to relax.
B. A different transmitter causes the muscle to move the other direction.
C. Acetylcholine causes the extensor muscle to contract.
D. A different transmitter causes the extensor muscle to contract.
C. Acetylcholine causes the extensor muscle to contract.
228
2. What happens to a fish’s movement speed in colder water?
A. The fish swims more slowly.
B. The fish swims at the same speed by making each muscle contract more strongly.
C. The fish swims at the same speed by recruiting more muscle fibers.
D. The fish swims faster.
C. The fish swims at the same speed by recruiting more muscle fibers.
229
3. Which of the following is true of mammals’ slow-twitch muscle fibers?
A. Because they are aerobic, they are subject to rapid fatigue.
B. Because they are anaerobic, they are subject to rapid fatigue.
C. Because they are aerobic, they do not fatigue rapidly.
D. Because they are anaerobic, they do not fatigue rapidly.
C. Because they are aerobic, they do not fatigue rapidly.
230
4. Which of the following describes a stretch reflex?
A. The receptor detects that a muscle is stretched, and sends a signal to contract it reflexively.
B. The receptor detects that a muscle is contracted, and sends a signal to stretch it reflexively.
A. The receptor detects that a muscle is stretched, and sends a signal to contract it reflexively.
231
```
5. A muscle spindle and a Golgi tendon organ are both described as what?
A. Optic receptors
B. Metabolic receptors
C. Proprioceptors
D. Chemoreceptors
```
C. Proprioceptors
232
6. What determines the rhythm of a cat’s scratching movements, or the wet dog shakes?
A. The rhythm of activity produced by the stimulus itself
B. The structure of the muscles
C. Commands from the prefrontal cortex
D. A set of neurons in the spinal cord
D. A set of neurons in the spinal cord
233
7. What aspect of brain anatomy facilitates communication between body sensations and body movements?
7. The motor cortex and the somatosensory cortex are adjacent, and the area of motor cortex devoted to a particular body structure is aligned with the somatosensory cortex area responsive to the same structure.
234
8. What evidence indicates that cortical activity represents the “idea” of the movement and not just the muscle contractions?
8. Activity in the motor cortex leads to a particular outcome, such as movement of the hand to the mouth, regardless of what muscle contractions are necessary given the hand’s current location.
235
9. How does the posterior parietal cortex contribute to movement?
The premotor cortex?
The supplementary motor cortex?
The prefrontal cortex?
9. The posterior parietal cortex is important for perceiving the location of objects and the position of the body relative to the environment. It is also active for planning of a movement.
The premotor cortex and supplementary motor cortex are also active in preparing a movement shortly before it occurs.
The supplementary motor cortex inhibits a habitual action when it is inappropriate.
The prefrontal cortex stores sensory information relevant to a movement and considers possible outcomes of a movement.
236
10. When expert pianists listen to familiar, well-practiced music, they imagine the finger movements, and the finger area of their motor cortex becomes active, even if they are not moving their fingers (Haueisen & Knösche, 2001). If we regard those neurons as another kind of mirror neuron, what do these results imply about the origin of mirror neurons?
10. These neurons must have acquired these properties through experience. That is, they did not enable pianists to copy what they hear. They developed as pianists learned to copy what they hear.
237
11. What kinds of movements does the lateral tract control? The
medial tract?
11. The lateral tract controls detailed movements in the periphery on the contralateral side of the body. For example, the lateral tract from the left hemisphere controls the right side of the body. The medial tract controls trunk movements bilaterally.
238
How might you test the cerebellum?
Ask someone to look at one spot and then to move the eyes quickly to focus on another spot. Saccades (sa-KAHDS), voluntary eye movements from one fixation point to another, depend on impulses from the cerebellum and the frontal cortex to the cranial nerves. Someone with cerebellar damage has difficulty programming the angle and distance of eye movements (Dichgans, 1984). The eyes make many short movements until, by trial and error, they eventually find the intended spot.
239
12. What kind of perceptual task would be most impaired by damage to the cerebellum?
12. Damage to the cerebellum impairs perceptual tasks that depend on accurate timing.
240
13. How are the parallel fibers arranged relative to one another
and to the Purkinje cells?
13. The parallel fibers are parallel to one another and
| perpendicular to the planes of the Purkinje cells.
241
14. If a larger number of parallel fibers are active, what is the
effect on the collective output of the Purkinje cells?
14. As a
larger number of parallel fibers become active,
the Purkinje cells increase their duration
of response.
242
Which behaviours are faster; self-initiated, or stimulus-elicited?
Stimulus-elicited
| I.e. Responsive actions such as avoiding an accident
243
15. In general, do the basal ganglia have more effect on
| responses to a stimulus or on self-initiated movements?
15. The basal ganglia have more influence on selfinitiated
| movements, which are generally slower.
244
16. Which aspect of movement do the basal ganglia control?
16. The basal ganglia control the vigor of movements.
245
17. What kind of learning depends most heavily on the basal ganglia?
17. The basal ganglia are essential for learning motor habits that are difficult to describe in words.
246
18. Explain the evidence suggesting that a conscious decision to
move does not cause the movement.
18. Researchers recorded responses in people’s cortex
that predicted the upcoming response. Those brain
responses occurred earlier than the time people reported
as “when they made the decision.”
247
19. Why are some researchers skeptical of this evidence?
19. The studies
assume that people accurately report the times of their
intentions. However, people’s reports are influenced by
events after the movement, and therefore we cannot be
confident of their accuracy. Furthermore, a decision to
make a voluntary movement is a gradual process
that cannot be pinpointed to a single instant.
248
1. What is the route from the motor cortex to the muscles?
A. Axons from the motor cortex go directly to the muscles.
B. Axons from the motor cortex go to the thalamus, which has axons to the muscles.
C. Axons from the motor cortex go to the cerebellum, which has axons to the muscles.
D. Axons from the motor cortex go to the brainstem and spinal cord, which have axons to the muscles.
D. Axons from the motor cortex go to the brainstem and spinal cord, which have axons to the muscles.
249
2. A half-second stimulation in the motor cortex produces what kind of result?
A. Isolated muscle twitches
B. Contraction of a particular combination of muscles
C. Contraction of whatever muscles are necessary to produce a particular outcome
D. Contractions of different muscles that vary unpredictably from one trial to another
C. Contraction of whatever muscles are necessary to produce a particular outcome
250
```
3. When a movement occurs, which of the following brain areas is the last one to reach its peak of activity?
A. The primary motor cortex
B. The posterior parietal cortex
C. The premotor cortex
D. The prefrontal cortex
```
A. The primary motor cortex
251
4. What does the antisaccade task measure?
A. The ability to inhibit a movement
B. The ability to vary the strength of a movement
C. The ability to control the speed of a movement
D. The ability to alternate between antagonistic muscles
A. The ability to inhibit a movement
252
5. Before we conclude that mirror neurons help people imitate, which of the following should research demonstrate?
A. Mirror neurons respond to both seeing and hearing someone else’s movement.
B. Mirror neurons occur in the same brain areas of humans as in monkeys.
C. Mirror neurons have different properties for people from different cultures.
D. Mirror neurons develop their properties before children start to imitate.
D. Mirror neurons develop their properties before children start to imitate.
253
6. What does the medial corticospinal tract control?
A. Bilateral movements of the trunk of the body
B. Contralateral movements of the trunk of the body
C. Bilateral movements of the arms, hands, and feet
D. Contralateral movements of the arms, hands, and feet
A. Bilateral movements of the trunk of the body
254
7. What does the finger-to-nose test measure?
A. Possible dysfunction of the basal ganglia
B. Possible dysfunction of the cerebellum
C. Possible dysfunction of the prefrontal cortex
D. Possible dysfunction of the primary motor cortex
B. Possible dysfunction of the cerebellum
255
```
8. The cerebellum is most important for which aspect of movement?
A. Strength
B. Timing
C. Direction
D. Inhibition
```
B. Timing
256
9. How are the parallel fibers arranged relative to the Purkinje cells?
A. They are parallel to them.
B. They are perpendicular to them.
C. They are arranged at random angles.
D. They circle around each Purkinje cell.
B. They are perpendicular to them.
257
10. Which of the following characterizes the movements that depend heavily on the basal ganglia?
A. Stimulus-triggered, and generally faster than selfinitiated movements
B. Stimulus-triggered, and generally slower than selfinitiated movements
C. Self-initiated, and generally faster than responses that
D. Self-initiated, and generally slower than responses that a stimulus triggers
D. Self-initiated, and generally slower than responses that a stimulus triggers
258
11. In what way, if at all, does basal ganglia activity relate to motivation?
A. The basal ganglia increase vigor of response depending on expected reward value.
B. The basal ganglia help to maintain constant behavior even when motivation is low.
C. The basal ganglia become active only when you are competing against someone else.
D. Basal ganglia activity has nothing to do with motivation.
A. The basal ganglia increase vigor of response depending on expected reward value.
259
12. What kind of learning depends most heavily on the basal ganglia?
A. Learned movements that depend on precise timing
B. Motor habits that are difficult to describe in words
C. Learning to recall specific life events
D. Learning what foods to eat
B. Motor habits that are difficult to describe in words
260
13. According to Libet’s study, what is the order of events in a voluntary movement?
A. People form an intention, then activity begins in the premotor cortex, and finally the movement starts.
B. People form an intention at the same time that activity begins in the premotor cortex, and a bit later, the movement starts.
C. Activity begins in the premotor cortex, and a bit later, people are aware of forming an intention, and finally the movement starts.
D. Activity begins in the premotor cortex, and a bit later, people are aware of forming an intention, and simultaneously
C. Activity begins in the premotor cortex, and a bit later, people are aware of forming an intention, and finally the movement starts.
261
What causes Parkinson's?
Damage to substantia nigra
Gene variants that increase risk
Exposure to toxins - drugs, pesticides, etc.
Cigarettes and coffee REDUCE risk of Parkinson's
262
20. How does MPTP exposure influence the likelihood of Parkinson’s
disease? What are the effects of cigarette smoking?
20. Exposure to MPTP can induce symptoms of Parkinson’s
disease. Cigarette smoking is correlated
with decreased risk of the disease.
263
Why would a dopamine pill be ineffective at treating Parkinson's?
Dopamine does not cross the blood-brain barrier
264
21. How does L-dopa relieve the symptoms of Parkinson’s
| disease?
21. L-dopa enters the brain, where neurons convert it
to dopamine, thus increasing the supply of a depleted
neurotransmitter.
265
22. In what ways is L-dopa treatment disappointing?
21. L-dopa enters the brain, where neurons convert it
to dopamine, thus increasing the supply of a depleted
neurotransmitter. 22. L-dopa increases dopamine activity
in spurts and in all neurons, not steadily and not just in
those that need help. It does not stop the loss of neurons.
It has unpleasant side effects.
266
23. What procedure has improved the effectiveness of brain
| grafts for treatment of Parkinson’s disease?
23. Results improved
somewhat after physicians began giving drugs to
suppress the immune response.
267
24. Why does damage to the basal ganglia lead to involuntary
| movements?
24. Output from the basal ganglia to the thalamus is
inhibitory. After damage to the basal ganglia, the thalamus,
and therefore the cortex, receive less inhibition.
Thus, they produce unwanted actions.
268
25. What procedure enables physicians to predict who will or will not get Huntington’s disease and to estimate the age of onset?
25. Physicians can count the number of consecutive
repeats of the combination C-A-G on one gene on chromosome 4. If the number is fewer than 36, the person will not develop Huntington’s disease. For repeats of 36 or more, the larger the number, the more certain the person is to develop the disease and the earlier the probable age of onset.
269
1. Deterioration of which axons leads to Parkinson’s disease?
A. Axons from the primary motor cortex to the spinal
cord
B. Axons from the basal forebrain to the prefrontal cortex
C. Axons from the substantia nigra to the striatum
D. Axons from the basal ganglia to the cerebellum
C. Axons from the substantia nigra to the striatum
270
2. People with Parkinson’s disease show the greatest impairment with which type of movement?
A. Reflexes
B. Spontaneous voluntary movements
C. Movements in response to a stimulus
D. Movements when other people are around
B. Spontaneous voluntary movements
271
```
3. Which of these chemicals damages the brain in a way that resembles Parkinson’s disease?
A. Capsaicin
B. L-dopa
C. Cannabinol
D. MPTP
```
D. MPTP
272
4. In what way is L-dopa treatment for Parkinson’s disease unusual?
A. It produces behavioral benefits without entering the
brain.
B. Unlike most drugs, it produces no unpleasant side
effects.
C. The treatment becomes more and more effective over time.
D. It was based on a theory instead of trial and error.
D. It was based on a theory instead of trial and error.
273
```
5. What is the most common age of onset for Huntington’s disease?
A. Early childhood (3 to 7 years old)
B. The teenage years (13 to 19)
C. Middle age (30 to 50)
D. Old age (65 to 80)
```
C. Middle age (30 to 50)
274
6. Why does damage to the basal ganglia lead to involuntary movements in Huntington’s disease?
A. The damage interrupts inhibitory axons from the
primary motor cortex to the spinal cord.
B. The cerebellum takes over the functions of the basal
ganglia, and overcompensates.
C. The person voluntarily tries to overcome the lack of
coordination.
D. Basal ganglia damage reduces inhibition of the
thalamus.
D. Basal ganglia damage reduces inhibition of the
| thalamus.
275
7. An examination of C-A-G repeats on one gene enables physicians to predict who will develop Huntington’s disease. What else does it help them predict?
A. What other diseases the person will get
B. The individual’s personality
C. The effectiveness of treatment
D. The age of onset of symptoms
D. The age of onset of symptoms
276
What time of day is the body warmest?
Half a degree warmer in mid-afternoon compared to middle of night
277
1. How does the idea of allostasis differ from homeostasis?
1. Homeostasis keeps certain body variables within a
fixed range by reacting to changes. Allostasis acts in
advance to prevent or minimize changes.
278
7. If you lacked vasopressin, would you drink like a beaver or like
a gerbil? Why?
7. If you lacked vasopressin, you would have to drink
more like a beaver. You would excrete much fluid, so you
would need to drink an equal amount to replace it.
279
8. Would adding salt to the body’s extracellular fluids increase or decrease osmotic thirst?
8. Adding salt to the extracellular fluids would increase
| osmotic thirst because it would draw water from the cells into the extracellular spaces.
280
9. Why are you likely to feel thirst just before bedtime?
Would you feel just as thirsty if you went to sleep at an unusual time?
9. At bedtime, your body secretes vasopressin, which helps conserve water and also stimulates thirst. Both responses help you get through the night while you cannot drink.
Your circadian rhythm triggers the increased vasopressin, so you would not feel as thirsty before going to sleep at an unusual time.
281
10. Who would drink more pure water—someone with osmotic thirst or someone with hypovolemic thirst?
10. Someone with osmotic thirst would drink more water. Someone with hypovolemic thirst would drink more of a solution containing salts.
282
11. What are the contributions of angiotensin II and
| aldosterone?
11. Angiotensin II constricts
the blood vessels, and stimulates neurons that produce
hypovolemic thirst. Aldosterone causes the body to retain salt, at times when blood volume is low.
283
1. Which of these happens after you eat something salty?
A. The sodium-potassium pump becomes less active.
B. The sodium-potassium pump becomes more active.
C. Salt flows into the cells.
D. Water flows out of the cells.
D. Water flows out of the cells.
284
```
2. What would happen as a result of adding salt to the body’s extracellular fluids?
A. Increased osmotic thirst
B. Decreased osmotic thirst
C. Increased hypovolemic thirst
D. Decreased hypovolemic thirs
```
A. Increased osmotic thirst
285
3. What does vasopressin do?
A. It increases both urination and thirst.
B. It decreases both urination and thirst.
C. It decreases urination and increases thirst.
D. It increases urination and decreases thirst.
C. It decreases urination and increases thirst.
286
4. Why do you stop drinking before water reaches the cells that need it?
A. Your throat is no longer dry.
B. Your stomach is full.
C. Drinking inhibits neurons responsible for thirst.
D. Drinking stimulates vasopressin release.
C. Drinking inhibits neurons responsible for thirst.
287
5. What is the most effective way to satisfy hypovolemic thirst?
A. Drink pure water slowly.
B. Drink pure water rapidly.
C. Drink water containing some salt or other solutes.
D. Alternate between drinking water and drinking
alcohol.
C. Drink water containing some salt or other solutes.
288
How might a territorial animal behave if its territory is threatened when it is extremely hungry?
It would probably run away - need for food overpowers other instincts.
289
19. Name three hormones that increase satiety and one that increases hunger.
19. Insulin, CCK, and leptin increase satiety. Ghrelin
| increases hunger.
290
20. Which neuropeptide from the arcuate nucleus to the paraventricular nucleus is most important for satiety?
20. Melanocortin
291
21. In what ways does the lateral hypothalamus facilitate feeding?
21. Activity of the lateral hypothalamus improves taste,
| enhances cortical responses to food, and increases secretions of insulin and digestive juices.
292
22. In what way does eating increase after damage in and
around the ventromedial hypothalamus? After damage to
the paraventricular nucleus?
22. Animals with damage to the ventromedial hypothalamus
eat more frequent meals. Animals with damage to the paraventricular
nucleus of the hypothalamus eat larger meals.
293
How might botox affect our emotions?
Freezes our muscles, and people have reported feeling emotions less intensely as a result - feeling physical response may be important to feeling emotions (see James-Lange theory)
294
1. What is the relevance of pure autonomic failure to the study of emotions?
1. People with pure autonomic failure do not react to
events with changes in heart rate or other autonomic
functions. They report still having emotional experiences but they do not feel them as strongly.
295
2. In what physiological way, if any, does one type of emotion differ from another?
2. No type of emotion has a unique pattern of physiological activity, either in the autonomic nervous system or in the brain.
296
Why is there no strong evidence for basic 'elemental' emotions?
If we found that each emotion was identified with its own brain area, we would regard that as strong evidence for basic emotions, but research has found no evidence for that idea.
297
3. What evidence challenges the idea that we identify people’s
emotions by their facial expressions?
3. Given a photo of a spontaneous facial expression,
people usually see more than one emotion and often
don’t see the emotion described by the person whose face
was shown. People recognize expressions from their own
culture better than those from other cultures. Also, in
everyday life we identify someone’s emotion by a
combination of cues, including posture, context,
gestures, and tone of voice.
298
In what way is action in either hemisphere related to personality?
Higher right brain activity - more socially withdrawn, less satisfied with life, prone to unpleasant emotions
Higher left brain activity - activity in frontal cortex tend to be happier, more outgoing, more fun loving
299
How might emotions be adaptive for our ancestors?
Fear alerts us to escape danger.
Anger directs us to attack an intruder.
Disgust tells us to avoid something that might cause sillness.
Adaptive value of some emotions is less clear - happiness, sadness, embarrassment, etc - perhaps they help us communicate our needs to others and understand others needs, or make quick decisions.
300
4. After damage to the ventromedial prefrontal cortex, what
| happens to people’s moral reasoning and concern for others?
4. Such people become more likely to endorse the utilitarian
option, even in situations where most people would
find it emotionally unacceptable. They show
decreased concern for others.
301
```
1. The parasympathetic nervous system is most active during which of the following?
A. Fight-or-flight activities
B. Digesting food
C. Intense emotions
D. Conversations
```
B. Digesting food
302
```
2. According to the James-Lange theory, feedback from the body’s actions is responsible for which aspect of emotion?
A. Appraisal
B. Feeling
C. Coping
D. Compassion
```
B. Feeling
303
3. When researchers looked for brain areas associated with particular emotions, what did they find?
A. Each emotion is centered in a different brain area.
B. Anger is easy to localize in one brain area, but other
emotions are not.
C. Happiness depends on one brain area, but other emotionsdo not.
D. No brain area is responsible for one and only one
emotion.
D. No brain area is responsible for one and only one
| emotion.
304
4. Several lines of evidence argue against the idea that facial expressions demonstrate the existence of six basic emotions. Which of the following is NOT one of those lines of evidence?
A. Asking people to match six faces to six labels interferes with accuracy.
B. People’s guesses about someone’s emotion do not
always match what the person reported.
C. Depending on someone’s posture, a given facial
expression can have several meanings.
D. People can recognize expressions from their own
culture better than those of others.
A. Asking people to match six faces to six labels interferes with accuracy.
305
```
5. Which brain area is associated with the behavioral activation system and a tendency to approach?
A. The right hemisphere
B. The left hemisphere
C. The amygdala
D. The hippocamp
```
B. The left hemisphere
306
6. Damage to the ventromedial prefrontal cortex increases which tendency in making decisions?
A. Greater conformity to the majority opinion
B. Longer delays in making decisions
C. More choices based on emotional feelings
D. More utilitarian choices
D. More utilitarian choices
307
How does heritability of violence difference between middle and lower socioeconomic demographics?
Middle - high heritability
| Lower - low heritability, but higher environmental elicitations of violence
308
5. What relationship did Caspi et al. (2002) report between the enzyme MAOA and antisocial behavior?
5. Overall, people with genes for high or low production of MAOA do not differ significantly in their probability of antisocial behavior. However, among those who suffered serious maltreatment during childhood, people with lower levels of the enzyme showed higher rates of antisocial behavior.
309
Why are correlational studies not effective at studying testosterone?
People with high testosterone may be unusual in other regards too
310
6. Why did researchers test the effects of testosterone on women?
6. Studying the correlation between men’s testosterone
and their aggressive behavior does not demonstrate cause and effect. Administering testosterone to women is more likely to produce demonstrable effects because women start with a lower level.
311
7. If we want to know how much serotonin the brain has been releasing, what should we measure?
7. We can measure the concentration of 5-HIAA, a serotonin metabolite, in the cerebrospinal fluid or other body fluids. The more 5-HIAA, the more serotonin has been released and presumably resynthesized.
312
8. What is the relationship between cortisol and aggressive behavior?
8. Cortisol tends to inhibit impulsive behaviors, including aggression.
313
Why is the startle mechanism a valuable tool for emotional mechanism?
It is very difficult to measure emotions like happiness without self-report. The startle reflex correlates strongly with anxiety, and can thus be used to measure that emotion in an experimental setting.
314
9. What brain mechanism enables the startle reflex to be so
| fast?
9. Loud noises activate a path from the cochlea to cells in the pons that trigger a tensing of neck muscles.
315
10. How could a researcher use the startle reflex to determine whether some stimulus causes fear?
10. Present the stimulus before giving a loud noise. If the stimulus increases the startle reflex beyond its usual level, then the stimulus produced fear.
316
11. Given that the amygdala becomes more active when an expression is harder to interpret, can you explain why it does not respond strongly to happy faces?
11. Smiling faces are easy to interpret! The amygdala responds more strongly to expressions that are difficult to interpret.
317
12. If you wanted to predict which soldiers might have the
greatest difficulty dealing with combat stress, what brain
measurement might be worth trying?
12. Examine amygdala responses to disturbing pictures. In one study, soldiers with the greatest amygdala responses were the most likely to report great combat stress. Determining the strength of connections between prefrontal cortex and amygdala might be helpful also.
318
13. Why do people with amygdala damage have trouble recognizing expressions of fear?
13. They focus their vision on the nose and mouth.
| Expressions of fear depend almost entirely on the eyes.
319
14. What evidence indicates that a smaller than average hippocampus makes people more vulnerable to PTSD?
14. For victims of PTSD who have a monozygotic twin,
the twin also has a smaller than average hippocampus,
even if he or she does not have PTSD. Also, people with a smaller hippocampus are less likely to recover easily from PTSD.
320
15. What would be the effect of benzodiazepines on someone who had no GABA?
15. Benzodiazepines facilitate the effects of GABA,
so a person without GABA would not respond to
benzodiazepines.
321
```
1. Heritability of a tendency toward antisocial behavior is lowest for which of the following?
A. Males
B. Females
C. People in impoverished neighborhoods
D. People in middle-class neighborhoods
```
C. People in impoverished neighborhoods
322
2. How does the gene for the less active form of the enzyme MAOa affect the probability for aggressive behavior?
A. Increased probability, regardless of environment
B. Decreased probability, regardless of environment
C. Increased probability for someone who was abused in childhood
D. Increased probability for someone who lived in a
middle-class neighborhood
C. Increased probability for someone who was abused in childhood
323
```
3. Aggressive behavior correlates with low turnover of which neurotransmitter?
A. Serotonin
B. Norepinephrine
C. Dopamine
D. Glutamate
```
A. Serotonin
324
```
4. Which of the following hormones tends to inhibit aggressive behavior?
A. Cortisol
B. Testosterone
C. Estradiol
D. Insulin
```
A. Cortisol
325
5. Why do we know more about the brain mechanisms of fear and anxiety than we do about other emotions?
A. Clinical psychologists have greater interest in anxiety
than in other emotions.
B. Anxiety depends on brain areas that are easier to
reach surgically.
C. Unlike other emotions, anxiety depends on only a
single neurotransmitter.
D. Researchers can more satisfactorily measure anxiety
than other emotions in laboratory animals.
D. Researchers can more satisfactorily measure anxiety
| than other emotions in laboratory animals.
326
6. After damage to the amygdala, what happens to the startle reflex?
A. It becomes stronger than before.
B. It becomes weaker than before.
C. It disappears altogether.
D. It becomes more consistent from one time or situation to another
D. It becomes more consistent from one time or situation to another
327
7. Suppose a researcher wants to determine whether someone is afraid of cats. Of the following, which would be the most reasonable approach?
A. Present a photo of a cat and see whether it elicits a
startle reflex.
B. Present a photo of a cat and then a loud sound.
See whether the photo enhances the usual startle
reflex.
C. Present a loud sound and then show a photo of a cat. See whether the photo calms the person after the
startle reflex.
D. Present a loud sound to both a person and a cat and see which one shows the greater startle reflex.
B. Present a photo of a cat and then a loud sound.
See whether the photo enhances the usual startle
reflex.
328
8. Research on the amygdala supports which of these psychological conclusions?
A. People who experience great fear also tend to experience a great amount of anger.
B. Sigmund Freud’s insights provide the best method
for treating anxiety disorders.
C. What we call fear is a combination of several components, not an indivisible entity.
D. People have six basic types of emotion.
C. What we call fear is a combination of several components, not an indivisible entity.
329
9. What role does the bed nucleus of the stria terminalis play in fear or anxiety?
A. It affects fear of the environment in general.
B. It mediates reappraisal that reduces the response of
the amygdala.
C. It relays information from the amygdala to the
midbrain.
D. It is responsible for the extinction of learned fears.
A. It affects fear of the environment in general.
330
10. The amygdala responds most strongly to which type of facial expressions?
A. Expressions by infants and children
B. Expressions that require some effort to understand
C. Expressions that are directed away from the viewer
D. Expressions of sadness
B. Expressions that require some effort to understand
331
11. What, if anything, can we predict from measuring the strength of amygdala response to frightening stimuli or faces showing fear?
A. We can predict changes in personality, as measured
by questionnaires.
B. We can predict probability of criminal behavior.
C. We can predict probability of strong emotional
responses to stressful experiences.
D. We cannot predict anything.
C. We can predict probability of strong emotional
| responses to stressful experiences.
332
```
12. After Urbach-Wiethe disease damaged their amygdala, two people showed no fear under most circumstances. Which of the following did, nevertheless, evoke fear?
A. Breathing concentrated carbon dioxide
B. Holding a snake
C. Standing too close to a stranger
D. Watching a horror movie
```
A. Breathing concentrated carbon dioxide
333
13. Which of the following types of people would be more likely than average to develop PTSD?
A. People who have suffered damage to the amygdala
B. People with higher than average levels of serotonin
turnover
C. People with lower than average levels of cortisol
D. People with a smaller than average hippocampus
D. People with a smaller than average hippocampus
334
```
14. What do benzodiazepines do?
A. They decrease cortisol secretion.
B. They increase secretion of orexin.
C. They facilitate GABA synapses.
D. They inhibit serotonin synapses.
```
C. They facilitate GABA synapses.
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16. What function does cortisol play in the initial response to stress?
16. Cortisol increases blood levels of glucose and therefore makes more energy available.
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17. How does McEwen’s definition of stress differ from Selye’s?
17. Selye’s definition treated favorable and unfavorable changes as equally stressful. McEwen’s definition focuses on events that an individual considers threatening.
337
18. What kind of cell releases cytokines?
18. Leukocytes (white blood cells) release cytokines.
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19. What changes do prostaglandins stimulate?
19. Prostaglandins stimulate the hypothalamus to produce fever, decrease hunger, decrease sex
drive, and increase sleepiness.
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20. How do the effects of stress mimic the effects of illness?
20. Stress increases release of cytokines, which communicate with the hypothalamus via prostaglandins. The hypothalamus reacts with the same responses it uses to combat illness, such as inactivity and loss of appetite.
340
21. How does prolonged stress damage the hippocampus?
21. Stress increases the release of cortisol, which
enhances metabolic activity throughout the body. When neurons in the hippocampus have high metabolic activity, they become more vulnerable to damage by toxins or overstimulation.
341
```
1. Which hormone does the alarm stage release, but the resistance stage does not?
A. Cortisol
B. ACTH
C. Epinephrine
D. Testosterone
```
C. Epinephrine
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2. How do the functions of the HPA axis compare to those of the sympathetic nervous system?
A. The sympathetic nervous system readies the body
for brief, vigorous action, and the HPA axis controls
digestion and other vegetative activities.
B. The sympathetic nervous system activates the brain,
and the HPA axis activates the rest of the body.
C. The sympathetic nervous system readies the body for brief, vigorous action, and the HPA axis prepares the body for prolonged coping with a persistent stressor.
D. The sympathetic nervous system is active during a
stressful situation, and the HPA axis becomes active at
the end of the stressful situation.
C. The sympathetic nervous system readies the body for brief, vigorous action, and the HPA axis prepares the body for prolonged coping with a persistent stressor.
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3. How does McEwen’s definition of stress differ from Selye’s?
A. Selye’s definition applied only to severe stress.
B. Selye’s definition applied equally to favorable or unfavorable events.
C. Selye’s definition applied only to laboratory animals.
D. Selye’s definition applied only to humans.
B. Selye’s definition applied equally to favorable or unfavorable events.
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4. Which cells of the immune system secrete antibodies?
A. Natural killer cells only
B. T cells only
C. B cells only
D. Natural killer cells, T cells, and B cells equally
C. B cells only
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5. Why do nearly all infections produce similar symptoms, such as fever, sleepiness, and loss of energy?
A. Every infection damages the body’s ability to maintain body temperature and overall activity.
B. “Sickness behaviors” are an effective way for a sick
person to gain sympathy and help.
C. Infectious particles clog the arteries, making it difficult for other chemicals to reach their targets.
D. The immune system sends prostaglandins to the
brain, where they stimulate the hypothalamus to
produce these effects.
D. The immune system sends prostaglandins to the
brain, where they stimulate the hypothalamus to
produce these effects.
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6. What are the effects of stress on the immune system?
A. All stressful experiences impair the immune
system.
B. Brief stress activates the immune system, but prolonged stress weakens it.
C. Brief stress weakens the immune system, but prolonged stress strengthens it.
D. All stressful experiences strengthen the immune
system.
B. Brief stress activates the immune system, but prolonged stress weakens it.
347
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7. Prolonged stress is known to damage which brain area?
A. The visual cortex
B. The hippocampus
C. The cerebellum
D. The corpus callosum
```
B. The hippocampus
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```
8. Which of these increases resilience?
A. Unpredictability of events
B. Social support
C. Previous severely stressful experiences
D. Breathing carbon dioxide
```
B. Social support
