The brain and behaviour Flashcards
(129 cards)
1
Q
who was Phineas Gage?
A
he was a construction worker who got a steel pipe through his skull in 1848 and survived. however, his personality changed and therefore people started to assume that the brain was directly related to thoughts and behaviours.
2
Q
what are neurons?
A
the functional building blocks of the nervous system. cells which transmit the electrical activity which underlies psychological processes
3
Q
what is a glial cell?
A
from the greek for ‘glue’. cells surrounding neurons, holding them in place, providing nutrients neurons need and isolating toxins that would harm the neuron.
4
Q
what is a synapse?
A
a connection between neurons
5
Q
what is a sensory neuron?
A
neurons that carry input messages from the sensory organs to the spinal cord and brain
6
Q
what is a motor neuron?
A
neurons that transmit output impulses from the brain and spinal cord to the bodies muscles and organs
7
Q
what are interneurons?
A
neurons that perform connective or associative functions within the nervous system - they connect sensory neurons to motor neurons
8
Q
what is the peripheral nervous system?
A
contains the neurons outside the brain and spinal cord. it has two major divisions, the somatic and autonomic nervous systems
9
Q
what is the somatic nervous system?
A
a subdivision of the peripheral nervous system that controls voluntary movements
10
Q
what is the autonomic nervous system?
A
a subdivision of the peripheral nervous system that controls involuntary movement. it has two subdivisions, the sympathetic and parasympathetic nervous systems
11
Q
what is the sympathetic nervous system?
A
a division of the autonomic nervous system that controls activation and arousal. it is responsible for the ‘fight or flight’ reaction and tends to act as a ‘total unit’ (effects multiple different areas of the body.
12
Q
what is the parasympathetic nervous system?
A
a subdivision of the autonomic condition which opposes the sympathetic branch. it is generally responsible for the ‘rest and digest’ processes that reverse arousal.
13
Q
define homeostasis
A
a delicately balanced or constant internal state
14
Q
what is the central nervous system?
A
a system which contains the brain and spinal cord, it connects the peripheral nervous system with the brain.
15
Q
what are the dimensions of the spinal cord?
A
40.5-45.5 cm long and 2.5cm in diameter.
16
Q
what tissues does the spinal cord consist of?
A
white matter and grey matter
17
Q
what are spinal reflexes?
A
reflexes which do not require input from the brain. for example if you touch something hot your hand will immediately pull away as the message does not need to travel to the brain which would slow it down and increase the amount of damage done to the body.
18
Q
how does the make up of the brain and spinal cord differ?
A
spine = grey matter on the inside white on the outside brain = grey matter on the outside, white matter on the inside
19
Q
what is the difference between grey matter and white matter?
A
grey matter is made of up of the cell bodies of neurons
white matter is made up of the axons of neurons
20
Q
what is a neuron?
A
a specialised cell that forms the basic building blocks of the nervous system
21
Q
what is the structure of a neuron?
A
electrical impulses are conducted from the dendrites to the soma (cell body) this then sends messages down the axon (which is insulated by a myelin sheath).
22
Q
what are dendrites?
A
specialised receiving units like antennae that collect messages from neighbouring neurons and send them on to the cell body
23
Q
what is an axon?
A
conducts electrical impulses away from the cell body to other neurons, muscles or glands
24
Q
what are found at the end of axons?
A
axon terminals which are connections to other dendrites or muscles or glands etc.
25
what are the three stages of an electrical impulse travelling through a neuron?
1. the neuron maintains a resting potential through the distribution of positive and negatively charged ions inside and outside of the cell membrane
2. when stimulated the cell membrane depolarises (the charge reverses) which produces an action potential
3. the resting potential is recovered
26
what is a resting potential?
an internal difference of around -70mv
27
what is an action potential?
an electrical shift across the neural membrane, which lasts about a millisecond and propagates an electrical signal down an axon
28
how is an action potential created?
1. resting potential = the 10:1 ratio of sodium ions outside the neuron and the negative protein ions inside create a resting potential of -70mv
2. action potential created = if the neuron is stimulated, sodium channels open and sodium ions flood into the axon
3. resting potential restored = sodium channels close and potassium channels open so potassium ions exit the neuron and the resting potential is restored
29
what is the refractory period?
the period of time after an action potential where the balance of ions is being restored and so another action potential cannot be created.
30
what are graded potentials?
changes in the negative resting potential that do not reach the -50mv action
31
what is a myelin sheath?
a whitish, fatty, insulation layer that covers axons. it is derived from glial cells. it is interrupted by nodes of ranvier which allow electrical activation to jump from one node to another and speed up the rate of transmission.
the myelin sheath develops throughout childhood and adolescence so explains why muscle control and coordination gets better with age.
32
what does damage to the myelin sheath do?
it can be caused by conditions such as MS resulting in jerky, uncoordinated movement or paralysis.
33
what is a synaptic cleft?
the tiny gap between one axon terminal and the next neuron
34
why is synaptic connectivity important for development?
changes in synaptic connection in early life leads to psychological development, synaptic connecting and pruning plays an important part in adult psychological functions
35
what are neurotransmitters?
chemical substances that carry messages across the synaptic cleft to other neurons, muscles or glands
36
what is a synaptic vesicle?
chambers within the axon terminal
37
what are receptor sites?
large protein molecules embedded in the receiving neurons cell membrane
38
outline the steps of synaptic transmission
1) the action potential triggers the presynaptic neuron to release neurotransmitter into the synaptic cleft
2) neurotransmitter defuses across the synaptic cleft
3) neurotransmitter molecules bind to the receptor sites on the postsynaptic neuron
4) this binding triggers an action potential in the postsynaptic neuron
39
what is meant by excitatory and inhibitory neurotransmitters?
```
excitatory = make the postsynaptic neuron more likely to fire an action potential
inhibitory = make the postsynaptic neuron less likely to fire an action potential
```
40
what is meant by re-uptake in the synapse?
the transmitter molecules are taken back into the presynaptic axon terminal
41
what are the two methods of deactivation?
1) re-uptake into the presynaptic neuron
| 2) breakdown by other chemicals found in the synaptic cleft
42
what is acetylcholine and what is it involved with?
it is a neurotransmitter found in the brain that is involved with memory and muscle activity
43
how is ACh involved with Alzheimers?
underproduction of ACh is thought to cause the memory problems and lack of muscle control in ALezheimers disease
44
what effect does ACh have on muscles?
it is excitatory
45
what is botulinum bacteria?
toxin forming bacteria, a mild form of which is town as botox. it blocks the action of ACh
46
what are neuromodulators?
neurotransmitters with a more widespread and generalised influence on synaptic transmission. they increase or decrease the sensitivity of many neurons. an example is endorphins
47
what is noradrenaline?
a neurotransmitter released from the adrenal medulla, it has both excitatory and inhibitory effects and is involved in learning, memory, wakefulness and eating. an undersupply causes depression
48
what is serotonin?
a neurotransmitter involved in mood, sleep, eating and arousal. may also play a key role in pleasure and pain. an undersupply can lead to depression, eating and sleeping disorders.
49
what is dopamine?
an excitatory neurotransmitter that is involved in emotional arousal, learning, memory, pleasure and pain. an undersupply can lead to Parkinson's disease.
50
what is GABA?
it is inhibitory in the motor system. lack of GABA leads to loss of motor control in Huntington's disease
51
what is an endorphin?
a neuromodulator that decreases sensitivity to pain
52
what is glutamate?
an excitatory neurotransmitter involved in most aspects of brain function
53
what is neuropsychology?
the study of the function of the brain by investigating the effects of brain damage on mental functions
54
what are neuropsychological tests?
tests designed to test the verbal and non-verbal abilities of people with brain damage.
55
what is a single dissociation?
a patient with brain damage is given two tasks and performance on each is compared
56
what is a double dissociation?
when a patient with brain damage is given two tasks and their performance on both is compared to one another and also compared to a healthy controls performance.
57
what is Wernicke's aphasia?
a condition which results from damage to Wernicke's area, located in the temporal lobe. it is primarily manifested as difficulties with speech comprehension
58
what is Broca's aphasia?
a condition which results from damage to Broca's area, located in the frontal lobe. it is primarily manifested as difficulties with the production of speech.
59
what are lesion studies?
studies where researchers produce specific lesions (areas of brain damage) in animals to see what effect this has on brain functioning
60
what is EEG?
electroencephalogram - measures the activity of large groups of neurons through a series of large electrodes placed on the scalp
61
what is MRI?
magnetic resonance imaging - creates images based on how atoms in living tissues respond to a magnetic pulse delivered by the device
62
what is DTI?
Diffusion tensor imaging - measures how water molecules diffuse on tissue (shows how white matter tissues are arranged in the brain)
63
what is fMRI?
functional magnetic resonance imaging - can produce pictures of blood flow in the brain taken less than a second apart.
64
what is PET scanning?
positron-emission tomography scans - measure brain activity, including metabolism, blood flow and neurotransmitter activity by measuring how and where radioactive glucose is taken up by respiring (active) neurons.
65
what is fNRIS?
functional near-infrared spectroscopy - by shining near-infrared light into the brain and measuring the ways in which is reflected, fNRIS can tell us which parts of the brain are using more oxygen. this is because oxygenated and deoxygenated blood absorb different amounts of infrared light.
66
what is TMS?
transcranial magnetic stimulation - an electromagnet coil is placed over an area of the brain. the electrical field created causes a temporary legion in that part of the brain. therefore tasks can be done without one area of the brain functioning, temporarily mimicking brain damage.
67
what is TDCS?
transcranial direct current stimulation - a low current is applied to the scalp which stimulates specific areas of the brain
68
what is the hindbrain?
the lowest and most primitive level of the brain.
69
parts of the hindbrain:
| what is the brain stem?
it supports vital life functions. it consists of the medulla and the pons
70
parts of the hindbrain:
| what is the medulla?
part of the brain stem that controls vital body functions such as heart rate and respiration. damage to it often results in death.
crossover of motor and sensory control also occurs in the medulla so the right side of the brain controls the left side of the body etc.
71
parts of the hindbrain:
| what is the pons?
part of the brain stem that relays sensory information between the cerebral cortex and the cerebellum. it also helps to control respiration and so damage often results in death.
72
parts of the hindbrain:
| what is the cerebellum?
area of the brain concerned primarily with muscular movement coordination , but it also plays a role in learning and memory.
it is especially involved with movements that require precise timing and coordination.
73
what is the midbrain?
contains clusters of sensory and motor neurons. it is concerned with sensory perception, eye movement etc.
74
parts of the midbrain:
| what is the reticular formation?
a finger shaped formation extending from the hindbrain to the lower portions of the forebrain. it acts as a kind of sentry, both alerting the higher centres of the brain that messages are coming and then either blocking those messages (descending portion) or allowing them to go forwards (ascending portion) to higher functioning parts of the brain.
it plays a central role in consciousness, sleep and attention. damage can result in a severe coma.
75
parts of the midbrain:
| what is in the midbrain apart from the reticular formation?
the tectum (including superior and inferior conniculi) and the substantia nigra
76
what is the forebrain?
the brains most recently evolved portion
77
parts of the forebrain:
| what is the cerebrum?
the most superior part of the forebrain consisting of the cerebral cortex. it is split into two hemispheres, left and right.
78
parts of the forebrain:
| what is the thalamus?
a sensory switchboard that organises inputs from sensory organs and routes them to the appropriate areas of the brain
damage can result in schizophrenic like symptoms as it disrupts sensory perception
79
parts of the forebrain:
| what is the hypothalamus?
plays a major role in many aspects of motivation and emotion, including sexual behaviour, temperature regulation, sleeping, eating, drinking and aggression. the hypothalamus controls the pituitary gland (master gland) and so is also vital in hormone regulation around the body. it also has a key role in reward and punishment
80
parts of the forebrain:
| what is the limbic system?
it helps coordinate behaviours needed to satisfy motivational and emotional urges that arise in the hypothalamus. it is also involved in memory. it contains the hippocampus and amygdala.
81
parts of the forebrain:
| what is the hippocampus?
key structure involved in the forming and retrieving of memories
82
parts of the forebrain:
| what is the amygdala?
structure that underlies emotional behaviours, particularly those linked to aggression and fear.
83
parts of the forebrain:
| what is the cerebral cortex?
a 0.63cm thick layer on the outside of the brain consisting primarily of grey matter
84
what is a fissure?
a fold in the brain surface
85
what are the three notable brain fissures?
the medial longitudinal fissure = divides the left and right hemisphere
the central fissure = divides the cerebrum into front and back halves.
the sylvian fissure = runs from front to back along the sides of the brain
86
what are the four lobes?
frontal
occipital
parietal
temporal
87
what is the motor cortex?
controls the 600 or more muscles involved in voluntary body movements
88
what is the somatosensory cortex?
receives sensory input that gives rise to our sensations of heat, touch and cold, and to our senses of balance and body movement
89
how are the motor and somatosensory cortices arranged?
motor cortex is a band in front, somatosensory is a band in just behind it
90
where are the primary auditory and visual cortices?
primary auditory cortex is in the temporal lobe
| primary visual cortex is in the occipital lobe
91
what is the association cortex?
involved in higher, important mental functions including perception, language and thought
92
what is the prefrontal cortex?
located just behind the forehead, is the seat of so called executive functions such as strategic planning and impulse control
93
what is the corpus collosum?
a neural bridge consisting of white matter tracts that acts as a major communication link between the two hemispheres and allows them to function together.
94
what is lateralisation?
refers to the relatively greater localisation of a function in one hemisphere or the other.
95
what is aphasia?
the partial or total loss of the ability to communicate
96
what are the functions of each hemisphere?
right hemisphere = spatial relations, musical and artistic ability
left hemisphere = language deficits
97
explain Sperry's experiments
he worked with patients who had been severely epileptic and had had their corpus collosum severed in order to cure this. they could not report seeing objects in their left visual field as the right hemisphere has no language. however, a series of experiments revealed that they were aware of what the objects were.
98
what is neural plasticity?
the ability of neurons and brain areas and networks to change structure and function
99
what is neurogenesis?
the production of new neurons in the nervous system
100
what are neural stem cells?
immature 'uncommitted' cells that can mature into any type of neuron or glial cell needed by the brain
101
what is the endocrine system?
consists of numerous hormone-secreting glands distributed throughout the body
102
what are hormones?
chemical messengers that are secreted from its glands into the bloodstream
103
what are some glands in the body and what do they do?
pituitary gland = regulates growth
pancreas = insulin and glucagon control to regulate blood sugar levels
testes = produce testosterone to affect sexual behaviour
ovaries = produce oestrogen and progesterone to affect sexual behaviour
adrenal medulla = prepares the body for action by secreting stress hormones
adrenal cortex = regulates carbohydrate metabolism
thyroid = controls metabolic rate
hypothalamus = controls the pituitary gland
104
what are antigens?
foreign substances that trigger a biochemical response from the immune system.
105
approximately how much does the brain weigh?
1400g
106
what are the two functions of neurons?
1) generate electrical nerve impulses
| 2) release chemicals (neurotransmitters) which communicate with other neurones, glands or muscles
107
what is botulism?
food poisoning causing paralysis of muscles through blocking the action of ACh
108
what are the different types of method for studying the brain?
- neuropsychological tests
- destruction and stimulation techniques
- electrical recording
(imaging methods do not study the function of the brain, rather they just take images of its structure)
109
what are the four brain imaging techniques and what are the two categories they fall into?
CT, MRI, PET and fMRI
CT and MRI measure structure alone
PET and fMRI measure structure and function
110
what are some issues with brain imaging?
- its easy to localise brain ares, but for higher functions especially, interconnectivity is important
- not precise enough at present
- knowing the location of a function doesn't tell us what why or how.
111
what are gyri and fissures?
```
gyri = bulges of the brain
fisures = grooves of the brain that separate it into four lobes
```
112
how is the somatosensory cortex organised?
the amount of space allocated to each organ/body part is proportional to sensitivity
113
what effect does stimulation of the association cortex have?
no effect
114
what is the corpus collosum?
a large band of myelinated nerve fibres that connects the two hemispheres of the brain
115
Around how many neurons are there in the body?
100 billion
116
How much does the brain weigh?
1400g
117
How fast can action potentials occur?
300 per second
118
How do antidepressants work?
Seratonin - antidepressants stop re uptake of seratonin to increase positive emotions so more activation of the post synaptic neuron occurs
119
What’s the most common type of neuron?
Interneurons
120
How are spinal reflexes inhibited?
Signals reach the brain and inhibit the motor neuron that causes the muscle to move to stop the spinal reflex
121
What shows structure and what shows function of the brain?
CT and MRI = structure
| PET and fMRI = structure and function
122
What are some issues with brain imaging?
- easy to localise brain areas but inter connectivity is also important
- not precise enough at the moment
- knowing where doesn’t tell us why what or how
123
How does general anaesthetic work?
Blocks the ascending limb of the reticular formation so pain signals are not received by the brain
124
What does damage to the thalamus do?
Produces hallucinations and confusion
125
What determines cognitive complexity?
Not brain size but volume of cortex - number of fissures increases surface area
126
How much of the cortex does the association cortex fill?
75%
127
How much of the brain is frontal lobes?
29% - more than any other animal
128
How does language differ in men and women?
Language is more balanced across the hemispheres in women than men
129
What are the two ways that neurons can modify themselves?
Structurally - sprouting more dendrite or axons
| Biochemically - increasing neurotransmitter volume
