Exam 3 Flashcards
(119 cards)
1
Q
Describe each sensory receptor.
A
Vision: light energy -> chemical energy
Auditory: air pressure -> mechanical energy
Somatosensory: mechanical energy
Taste and Olfaction: chemical molecules
2
Q
What is the relationship between receptor density and sensitivity.
A
the more dense the receptors, the greater the sensitivity
3
Q
What is the topographic map?
A
a neural-spatial representation of the body or of the areas of the sensory world perceived by a sensory organ
4
Q
How do we perceive light?
A
Wavelengths differ from 400 nanometers to 700 nanometers
5
Q
What is the fovea?
A
region at the center of the retina that is specialized for high acuity; rod-free area
6
Q
How does acuity differ across the visual field?
A
Vision is best in the center and then weakens in the periphery
7
Q
What is the blind spot of the retina?
A
the optic disc (where axons forming the optic nerve leave the eye)
8
Q
Describe rod cells.
A
More numerous than cones
Sensitive to low levels of light
Used mainly for night vision
One type of pigment
9
Q
Describe cone cells.
A
Highly responsive to bright light
Specialized for color and high visual acuity
Located in the fovea only
Three types of pigment
10
Q
What three pigments do cones receive?
A
419nm - blue
531nm - green
559nm - red
11
Q
What is the least numerous color of cone receptor?
A
blue
12
Q
What are the retinal-neuron types?
A
Bipolar cell - input from photoreceptors
Horizontal cell - links photoreceptors and bipolar cells
Amacrine cell - links bipolar and ganglion cells
Retinal ganglion cell (RGC) - gives rise to optic nerve
13
Q
What are M cells? P cells?
A
M cells - receive input primarily from rods, sensitive to light and moving stimuli
P cells - receives input primarily from cones, sensitive to color
14
Q
Describe the geniculostriate system?
A
Projections from the retina to the lateral geniculate nucleus to the visual cortex; detailed visual system
15
Q
Describe the tectopulvinar system?
A
projections from the retina to the superior colliculus to the pulvinar (thalamus) to the parietal and temporal visual areas; less color vision based; involved in movement sensing, where objects are
16
Q
Describe the retinohypothalamic tract.
A
synapses in the tiny suprachiasmatic nucleus (SCN) in the hypothalamus; role in regulating circadian rhythms and in the pupillary reflex
17
Q
Describe the dorsal visual stream.
A
pathway that originates in the occipital cortex and projects to the parietal cortex; the “how” pathway (how action is to be guided toward objects)
18
Q
Describe the ventral visual stream.
A
pathway that originates in the occipital cortex and projects to the temporal cortex; the “what” pathway (identifies what an object is)
19
Q
Describe the four types of injuries to the pathway leading to the cortex.
A
Monocular blindness - destruction of the retina or optic nerve of one eye that produces loss of sight in that eye
Homonymous hemianopia - blindness of the entire left or right visual field
Quadrantanopia - blindness of one quadrant of the visual field
Scotoma - small blind spot in the visual field caused by a small lesion or migraines of the visual cortex
20
Q
What is optic ataxia?
A
deficit in the visual control of reaching and other movements; damage to parietal cortex; can recognize objects normally
21
Q
What is injury to the “what” pathway?
A
visual form - inability to recognize objects or drawings of objects
color - inability to recognize colors
face - inability to recognize faces
22
Q
Describe Broca’s area.
A
anterior speech area in the left hemisphere that functions with the motor cortex to produce the movements needed for speaking
23
Q
Describe Wernicke’s area.
A
posterior speech area at the rear of the left temporal lobe that regulates language comprehension; also called the posterior speech zone
24
Q
What is Broca’s aphasia?
A
inability to speak fluently
25
What is Wernicke's aphasia?
inability to understand or to produce meaningful language
26
Auditory Cortex mapping
Passively listening to noise bursts activates the primary auditory cortex; listening to words activates the posterior speech area; making a phonetic discrimination activates the frontal region (suggesting we run speech sounds through Broca's area to figure out what they are)
27
How do different kinds of sounds affect areas of the brain thought to be involved in audition and music perception?
passively listening to noise bursts activates Heschl's gyrus; perception of melody triggers activation in the right hemisphere auditory cortex lying in front of Heschl's gyrus; making relative pitch judgments about two notes of each melody activates a right frontal lobe area
28
How does music help those with Parkinson's?
listening to rhythm activates the motor and premotor cortex and can improve gait and arm training after a stroke
29
What are the three major components of the motor system?
Cerebrum - conscious control of movement
Brainstem - direct movements
Spinal cord - direct movements
30
Describe the motor sequence.
Prefrontal cortex: plans complex behavior
Premotor cortex: produces the appropriate complex movement sequences
Primary motor cortex: specifies how each movement is to be carried out
31
What is the relationship between the brainstem and species-specific behaviors?
Hess (1950s) stimulated different areas within the brainstem to produce different species-specific behaviors
32
What is cerebral palsy?
voluntary movements become difficult to make, caused by brainstem trauma, usually perinatally; movements can be clumsy, may see too much muscular rigidity, walking on toes or crouched gait
33
How did Penfield create the topographic map?
he used electrical stimulation to map to cortices
34
Which parts of the body are mapped disproportionately compared to the amount of space they occupy?
hands, fingers, lips, and tongue are disproportionately larger than parts of the motor cortex that control other areas
35
What are the three types of organization in the motor cortex?
the part of the body that is to be moved, the spatial location to which the movement is directed, and the movements function
36
Motor Cortex and Skilled Movement
Studies using human participants reveal a
number of situations in which motor-cortex
neurons are active at the same time that no
movement occurs.
37
Describe the plasticity in the motor cortex.
without rehab: the hand area of the motor cortex became smaller whereas the elbow and shoulder area became larger; lost ability to move hand
with rehab: hand area of the motor cortex retained its size; retained some ability to move hand
38
Describe the corticospinal tract.
main efferent (away) pathways from the motor cortex to the brainstem to the spinal cord; axons descend into the brainstem, sending collaterals to a few brainstem nuclei, and eventually emerge on the brainstem's ventral surface where they form a large bump on each side (pyramidal tracts)
39
What does the lateral corticospinal tract control?
branches at the brainstem level, crossing over to the opposite side of the brain and spinal cord; moves the digits and limbs on the opposite side of the body
40
What does the ventral corticospinal tract?
remains on the same side of the brain and spinal cord; moves the muscles of the midline body (trunk) on the same side of the body
41
How are limb muscles arranged?
in pairs
Extensor - moves the limb AWAY from the trunk
Flexor - moves the limb TOWARD the trunk
42
Describe the basal ganglia and the force of movement?
Receive input from all areas of the neocortex and allocortex, including motor cortex; project back to the motor cortex and substantia nigra; serve a wide range of functions including association or habit learning, motivation, emotion, and motor control
43
Describe hyperkinetic symptom.
when damage to the caudate putamen causes unwanted writhing and twitching movements called dyskinesias; Huntingtons and Tourette's
44
Describe hypokinetic symptom.
when damage to the basal ganglia results in a loss of motor ability, leading to rigidity and difficulty initiating and producing movement; Parkinsons
45
What is the volume hypothesis?
the internal globus pallidus (Gpi) acts like a volume control on the thalamus and motor cortex
46
What are the two pathways within the basal ganglia?
Direct: when activated the GPi is inhibited and the pathway is freed to produce movement
Indirect: when activated, the GPi is activated and it inhibits the thalamus, thus blocking movement
47
What are the anatomical parts of the cerebellum and what do they control?
Flocculus: small but dense lobe involved in eye movements and balance
Lateral Hemisphere: controls movement of limbs, hands, feet, and digits
Medial Hemisphere: controls movement of face and midline of body
48
How does the cerebellum improve movement control?
cerebellum has information about both versions of the movement (what you intended to do and what you actually did) and can calculate the error and tell the cortex how to correct the movement
49
What is the role of the somatosensory system?
tell us what the body is up to and what's going on in the environment by providing bodily sensations such as touch, temp, pain, position in space, and movement of the joints
50
What are the two types of skin?
Hair Skin
Glabrous Skin: no hair follicles but larger numbers of sensory receptors than other areas
51
What are the three types of somatosensory receptors?
Nocioception: perception of pain, temp, and itch; free nerve endings activated by chemicals
Hapsis: perceive fine touch and pressure, and identify objects that we touch and grasp; activated by mechanical stimulation of the hair, tissue, or capsule
Proprioception: perception of the location and movement of the body; sensitive to the stretch of muscles and tendons and the movement of joints
52
What is the difference between rapidly adapting receptors and slowly adapting receptors?
Rapid: responds briefly to the beginning and end of a stimulus on the body
Slow: responds as long as the sensory stimulus is on the body
53
Which of the somatosensory receptor types are slow vs fast?
Proprioceptive and Haptic: large, well-myelinated (fast)
Nocioceptive: small with little or no myelination (slow)
54
Describe the somatosensory pathway to the brain.
1. Dorsal-root ganglion neurons respond to the stimulus
2. the ventral spinothalamic tract receives input from pain and temp neurons and then joins the pathway called the medial lemniscus
3. The dorsal-column nuclei relay fine touch and pressure stimulus
4. The medial lemniscus contains axons that carry sensory information to the ventrolateral thalamus
5. The ventrolateral thalamus relays sensory information to the somatosensory cortex
6. The primary somatosensory cortex (areas 3-1-2) receives somatosensory information
55
How many neurons does it take haptic, proprioceptive, and nocioceptive information to reach the cortex?
3 neurons (2 synapses) to get from periphery to cortex
56
How do the different somatosensory neurons ascend the spinal cord?
Haptic and Proprioceptive: ipsilaterally
Nocioceptive: cross to the contralateral side
57
Describe how a cut affects the spinal cord and the somatosensory receptors.
Unilateral damage to the spinal cord:
loss of fine-touch and pressure sensation on the same side of the body below the cut
loss of pain and temperature sensation on the opposite side of the body below the cut
58
What is a spinal reflex (monosynaptic)?
reflex requiring one synapse between sensory input and movement
59
What is pain gate theory?
Activities in different sensory pathways play off against each other and so determine whether and how much pain is perceived as a result of an injury; Haptic-proprioceptive stimulation can reduce pain perception, whereas the absence of such
stimulation can increase pain perception through
interactions at a pain gate
60
What are the periaqueductal gray matter neurons?
produce pain-suppressing effect by exciting pathways in the brainstem that project to the spinal cord where they inhibit neurons that form the ascending pain pathways
61
What is referred pain?
neurons in the spinal cord that relay pain and temp messages to the brain receive two sets of signals (body surface and internal organs)
62
How the semicircular canals signal movement and balance?
when the head moves, fluid in the canals pushes against hair cells which causes bending of the cilia located on top of the hair cells; bending of the cilia leads to receptor potentials in the hair cells and action potentials in the cells forming the vestibular nerve
63
How do the otolith organs signal movement and balance?
The utricle and saccule also contain hair cells,
which are embedded within a gelatin-like
substance that contains small crystals of
calcium carbonate called otoconia; When the head is tilted, the gelatin and
otoconia push against the hair cells, which
alters the rate of action potentials in cells that
form the vestibular nerve
64
Describe the primary somatosensory cortex.
Receives porjections from the thalamus; Brodmann's areas 3-1-2; begins the process of constructing perceptions from somatosensory information
65
Describe the secondary somatosensory cortex.
located behind the primary somatosensory cortex; Brodmann's areas 5 and 7; refines the constructions of perceptions, projects to the frontal cortex
66
What are the four somatosensory homunculi?
Area 3a: Muscles
Area 3b: Skin (slow)
Area 1: Skin (fast)
Area 2: Joints, pressure
67
What does damage to the primary somatosensory cortex do?
impairs sensory thresholds, proprioception, hapsis, and simple movements
68
Just read this.
The dorsal stream projects to the second somatosensory cortex to generate movements appropriate to objects in space
69
What did we learn from the sensory deprivation study on monkeys?
the idea that the brain needs constant stimulation
70
What role does evolution play in behavior?
Evolution has created brain circuits and corresponding behaviors that historically contributed to reproductive fitness
71
What are innate releasing mechanisms?
hypothetical mechanism that detects specific sensory stimuli and directs an organism to take a particular action; can be modified with experience
72
What was B.F. Skinner's main idea?
Operant conditioning; suggested a strong role of learning in behavior
73
What is a reinforcer?
any event that strengthens the behavior that it follows
74
Describe the basic idea of preparedness.
predisposition to respond to certain stimuli differently than to other; learn associations between flavors and nausea but not between lights/sounds and nausea; associations between lights/sound and pain, but only with difficulty learn associations between flavor and pain
75
How does the olfactory system differ from the other senses in terms of sensory processing?
olfactory input goes straight to olfactory bulbs and then the pyriform cortex instead of going to the brainstem and thalamus like other senses
76
What is the lifetime of an olfactory receptor neuron?
about 60 days
77
How many olfactory receptor genes do we have?
about 800
78
What are pheromones?
biochemicals released by one animal that act as chemosignals and can affect physiology or behavior of another animal
79
How are pheromones detected?
a special olfactory receptor system known as the vomeronasal organ (connected to the amygdala and hypothalamus)
80
Describe humans ability of behavioral related scents.
humans can identify their own odor and the odor of kin versus a stranger; body odors activate brain regions involved in emotional processing
81
What are the five different taste receptors?
bitter, sweet, sour, salty, umami
82
What nerves form the gustatory nerve, or, solitary tract?
Cranial nerves 7, 9, 10
83
Where is the primary gustatory cortex?
Insula, near primary somatosensory cortex
84
What is the funnel idea of the hypothalamus?
Inputs from the frontal lobes and limbic system funnel through the hypothalamus
85
What is the difference between regulatory and nonregulatory behavior?
Regulatory behavior is motivated to meet the survival needs of the animal; nonregulatory is not necessary to meet basic survival
86
Describe the lateral region of the hypothalamus.
contains nuclei and nerve tracts that connect the lower brainstem to the forebrain
87
Describe the medial forebrain bundle.
tract that connects structures in the brainstem with various parts of the limbic system; dopamine-containing fibers; forms the activating projections from brainstem to the basal ganglia and frontal cortex
88
What are the two aspects of the pituitary gland?
Posterior - neural tissue; continuation of the hypothalamus
Anterior - glandular; synthesizes hormones
89
Describe the hypothalamus's involvement in hormone secretions.
Hypothalamus makes peptides that are transported down axons to terminals in the posterior pituitary; capillaries in the posterior pituitary pick up the peptides
90
What lesion leads to aphagia? Hyperphagia?
lateral hypothalamus; ventromedial hypothalamus
91
How do other brain regions affect eating?
Amygdala - damage alters food preferences and abolishes taste aversion learning
Orbital prefrontal cortex - received input from olfactory bulb; damage may result in decreased eating because of diminished sensory responses to food oder and perhaps taste
92
Osmotic thirst vs hypovolemic thirst?
Osmotic - due to increased concentration of chemicals known as solutes in body fluids; drink water; receptors in third ventricle of hypothalamus
Hypovolemic - due to loss of overall fluid volume from the body; fluids other than water; kidneys release angiotensin
93
Hormone effects of organize vs activate?
During development, gonadal hormones organize the brain; in adulthood, they activate many sex specific behaviors
94
What are the sex behavior differences?
Female advantage in verbal fluency
Male advantage in spatial behavior
95
Estradiol affect in male brain?
masculinizes the brain; aromatase converts testosterone to estradiol; alpha-fetoprotein prevents estrogen from entering neurons
96
Which area of the hypothalamus is five times as large in males than in females?
Preoptic area
97
What are the activating effects of sex hormones?
high estrogen levels are associated with sexual receptivity; in males, testosterone levels influence the motivation to seek sexual behavior and the production of copulatory behavior
98
What are the three components of emotion?
Autonomic (hypothalamus and ENS)
Subjective (amygdala and parts of frontal)
Cognitions (cerebral cortex)
99
What is the James-Lange view of emotion?
physiological changes produced by the autonomic nervous system come first, and the brain interprets these changes as an emotion; cortex produces cognitive responses; evidence is the intensity of emotions with spinal cord damage
100
What is the Appraisal theory of emotion?
defines emotion as processes rather than states, and view emotional episodes as the activity of several biological subsystems or components: appraisal component, somatic components, behavioral component, feeling component
101
What does the limbic cortex include?
cingulate gyrus, hippocampus, parahippocampal cortex
102
Describe the amygdala.
almond-shaped collection of nuclei in the limbic system, plays a role in emotional and species-specific behaviors, receives input from all sensory systems, sends projections primarily to the hypothalamus and brainstem, influences autonomic and hormonal responses via hypothalamus, influences conscious awareness of positive and negative consequences via prefrontal cortex
103
What does damage to the prefrontal cortex do?
inability to experience and express their own emotions and to recognize the emotional expression of others, apathy and loss of initiative or drive, inability to plan and organize, leading to poor decision-making
104
Describe prefrontal cortex and dopaminergic input.
abnormalities in dopaminergic projections may account for some disorders, including schizophrenia
105
What were the effects of a transorbital lobotomy?
widely practiced in 1950s, permanently altered the behavior of many people, popularized by Walter Freeman
106
What were the results of Olds and Milner's experiment?
Rats will press a bar to self-administer electrical stimulation to specific sites in the brain
107
What is the relationship between reward and dopamine?
amount of dopamine released somehow determines how rewarding an event is, increases in the nucleus accumbens
108
What is a biorhythm?
inherent timing mechanism that controls or initiates various biological processes, linked to the cycle of days and seasons produced by the Earth's rotation around the sun
109
What is a free-running rhythm?
rhythm of the body's own devising (endogenous) in the absence of all external cues; endogenous rhythm is 25 to 27 hours
110
Nocturnal and diurnal free-running rhythms?
Nocturnal: in constant darkness, free-running periods are shorter than 24 hours; in constant light, free-running periods are longer than 24 hours
Diurnal: in constant darkness, free-running periods are longer than 24 hours; in constant light, free running periods are shorter than 24 hours
111
What is a Zeitgeber?
environmental event that entrains biological rhythms; a "time giver" (light); jet-lag
112
What is seasonal affective disorder?
depression that occurs seasonally every winter in higher latitudes; may be caused by loss of entrainment to external cycle and consequent free running; treatments include seasonal use of antidepressants and light therapy
113
What is the suprachiasmatic nucleus?
main pacemaker of circadian rhythms located just above the optic chiasm
114
Describe suprachiasmatic rhythms.
If SCN is damaged, daily activities occur haphazardly; SCN cells are more metabolically active during light period; cells more electrically active in light period; SCN neurons maintain rhythmic activity in absence of input and output; cells in a dish retain periodic rhythm
115
What are the separate groups of circadian neurons?
M-cells: control morning activity and need light for entrainment
E-cells: control evening activity and need darkness for entrainment
116
Pacemaking circadian rhythms?
SCN connects with pituitary endocrine neurons to control hormone release to entrain many body tissues and organs; SCN instructs autonomic neurons in the spinal cord to inhibit the pineal gland from producing melatonin
117
Relationship between SCN and hormones?
SCN controls melatonin release from the pineal gland so that melatonin circulates during the dark phase of the circadian cycle; SCN controls the release of glucocorticoids from the adrenal glands so that they circulate during the light phase of the circadian cycle
118
Describe melatonin.
hormone secreted by the pineal gland during the dark phase of the day-night cycle; influences daily and seasonal biorhythms
119
Describe how melatonin affects hamster breeding.
In winter: melatonin levels increase, gonads shrink, testosterone levels decrease, and sexual behavior decreases
In summer: melatonin levels decrease, gonads grow, testosterone levels increase, and sexual behavior increases
