Exam 2 Flashcards
1
Q
What happens to rods in high light?
A
They get bleached
2
Q
Receptors found densely packed in the fovea are called
A
cones
3
Q
cones provide ____ % of vision input to the brain
A
90
4
Q
trichromatic theory
A
Also known as the Young-Helmholtz theory, the trichromatic theory suggests that we discriminate among wavelengths of light by the ratio of activity across the three types of cones (short-, medium-, and long-wavelength).
5
Q
opponent process theory
A
The opponent process theory suggests that we perceive color in terms of opposites (for example, yellow and blue) and can explain such visual artifacts as an afterimage.
6
Q
retinex theory
A
The retinex theory explains phenomenon such as color constancy and suggests that the cortex compares information from various parts of the retina to determine features such as brightness and color. Relies on cortex to gather memories
7
Q
Lateral inhibition
A
activity in one neuron reduces the activity in neighboring neurons. This allows for us to clearly see edges. This is why looking at very contrasting colors can make the edges defined.
8
Q
prosopagnosia
A
inability to recognize faces
9
Q
Gregor Mendel is responsible for:
A
introducing concept of genes
10
Q
T or F: part of a chromosome may alter the expression of another part without coding for any protein of its own
A
True
11
Q
what models messenger RNA
A
one strand of DNA
12
Q
what does messenger RNA do
A
synthesizes a protein
13
Q
Proteins consist of ____ amino acids, which are determined by ____ base pairs in the RNA strand.
A
20, 3
14
Q
What are the base pairs for tryptophan?
A
uracil, guanine, guanine
15
Q
homozygous v. heterozygous
A
matched genes on pairs of chromosomes v. unmatched
16
Q
alleles
A
variations in nucleotide sequence for the same gene between chromosome strands
17
Q
autosomal genes
A
not sex-linked
18
Q
Is the X or Y chromosome usually associated with sec-linked genes?
A
When biologists speak of sex-linked genes, they usually mean X-linked genes. The Y chromosome is small, with relatively few genes of its own, but it also has sites that influence the functioning of genes on other chromosomes.
19
Q
If a recessive form of a sex-linked gene produces color-blindness, will men or women be more likely to be color-blind?
A
men - they have no other X chromosome to even it out
20
Q
sex-limited genes
A
activated more in one sex due to hormones, typically during puberty
21
Q
A mutation is
A
a heritable change in DNA, typically just one base change, typically not advantageous
22
Q
T or F: epigenetics can be inherited
A
true
23
Q
how are genes activated?
A
partially unwinding from histones and chemical groups attaching to histone tails which helps loosen the grip.
24
Q
Steps of Development of Neurons
A
Proliferation, Migration, Differentiation, Synaptogenesis, myelination
25
Proliferation
production of new cells, most proliferation occurs within 28 weeks of gestation
26
Migration
immunoglobins and chemokines move primitive cells to more permanent locations in the brain
27
Differentiation
Primitive cells take their permanent shape. For ex: neurons begin to form axons and dendrites.
28
Synaptogensis
Formation of synapses (occurs throughout life)
29
Myelination
Myelin sheath forms first over spinal cord - hindbrain - midbrain - forebrain (occurs during motor development, too)
30
synaptic pruning
synapses, or connections, are depleted as we no longer need them from childhood to adulthood
31
What area of the brain undergoes synaptogensis relatively regularly after birth?
hippocampus
32
What did C14 help scientists discover?
cell turnover, neuron replacement. Skin cell turned over every year whereas skeletal muscles/heart every 15. Brain cells except the hippocampus remained from birth.
33
How to axons reach specific targets?
Chemical gradients, sometimes produced by concentrations of proteins where axons need to go to serve a certain function.
34
Neural Darwinism
Chemical gradients only steer axons to about the right location. Only advantageous connections in the right spot are kept, others are rejected.
35
T or F: the sympathetic nervous system originally forms far more neurons than it needs.
True
36
T or F: the sympathetic nervous system originally forms far more neurons than it needs.
True
37
T or F: The muscle sends messages to the ganglion to tell them which and how many axons to form.
False - Extra axons sprawl out to muscles and when the correct protein is formed, the remaining die out.
38
Nerve Growth Factor
A protein that promotes neuron survival when the axon projects onto the muscle.
39
Apoptosis
programmed mechanism of cell death (when NGF does not arrive, or due to other deadly mutations)
40
Teratogens
anything a person is exposed to or ingests during pregnancy that's known to cause fetal abnormalities
41
How does alcohol affect neuron development?
Alcohol promotes GABA, which inhibits/reduces excitation, and lessens glutamate, a primary inhibitory transmitter. This forces cells to receive not enough excitation to prevent them from undergoing apoptosis, which then thins necessary parts of the brain.
42
T or F: Sensory input has no effect on how the cortex develops.
False - in studies done on animals, lesioning typical visual areas leaving the optic nerve no place to connect as it usually does, vision was the result of new connections with the thalamus and auditory areas.
43
What is some evidence of learning in terms of neurons?
A stimulating environment enhances sprouting of axons and dendrites
44
What is some evidence of learning in terms of neurons?
A stimulating environment enhances sprouting of axons and dendrites
45
What is the far transfer effect?
Practicing one exercise may improve ability on an unrelated task. However, only practicing what you actually want to improve seems the best route to enhance learning (strengthening of synapses)
46
Agonist
mimics neurotransmitters and directly effects cells by fitting into a receptor or influencing more reuptake/more neurotransmitters to be released. Ex: nictone & acetlycholine receptors and morphine & opioid receptors
47
Antagonist
prevents neurotransmitters from having their effect (ex: narcan and naloxone on opiod receptors)
48
How do drugs work?
Affect transmission at the synapse
49
mixed agonist-antagonist
agonist for some effects and an antagonist for others, or an agonist at some doses and an antagonist at others.
50
affinity
strength between drug and receptor
51
efficacy
how well a drug activates a receptor
52
A person's _____ ___ _______ can influence how much a drug affects them.
number of receptors
53
How is alcohol metabolized?
ethyl alcohol - acetaldehyde - (via acetaldehyde dehydrogenase) - Acetic Acid
54
Why is a predisposition to low acetaldehyde dehydrogenase an indicator of low likelihood for alcohol abuse?
Without an ability to break down the toxic acetaldehyde from alcohol, it produces hangovers (a punishment for drinking). Acetic acid, on the other hand, produces energy.
55
nucleus accumbens
main dopamine release area in the brain, near septum, located in rostral ventral forebrain
56
Cravings are reminiscent of damage to the prefrontal cortex, because:
After users have learned a response or a preference, they are slow to update it in response to new information
57
craving
search for the substance
58
repeated cocaine use desensitizes what and sensitizes what?
desensitizes: the reinforcing quality of the drug
sensitizes: cues associated with the drug
59
During abstinence from drug use, what occurs in the NA?
craving increases then decreases slightly, partly due to glutamate synapses here (most abundant excitatory NT and important in memory and learning)
60
Tolerance
decrease of all but mostly pleasant affects tied to the use of a drug after repeated use
61
How does tolerance work?
Learned process by which cues are associated with the drug itself, counteracting the reward inherent in the drug
62
withdrawal
abstinence from drug after repeated usage
63
severe alcohol withdrawal problems
hallucinations, convulsions, fever, and cardiovascular problems.
64
Possible hypothesis for addiction
way to prevent stress (including stress of withdrawal) - avoid positive and negative punishments
65
Possible hypothesis for addiction
way to prevent stress (including stress of withdrawal) - avoid positive and negative punishments
drug relieves the distress caused by drug withdrawal. That learning can generalize to other situations, so that users crave the drug during other kinds of distress.
66
Effective substance abuse treatments
CBT, support groups, medication, contingency management (rewards for no drug use)
67
Antabuse
reduces enzyme that metabolizes alcohol
68
naltrexone
blocks opiate receptors which in turn makes alcohol less pleasurable
69
methadone
same effects as heroine and morphine and binds to same receptors, except it diffuses slowly reducing disrupting behaviors; withdrawal also gradual
70
NA role in MDD
becomes less active and stimulated by reward
71
Marked symptoms of MDD
- absence of happiness
-anhedonia
- loss of energy, appetite change
72
Main causes of depression
genetic, environmental, brain abnormality
73
Which side of the prefrontal cortex works stronger for people with depression?
right (during the gaze test when thinking of a word puzzle, these people tend to stare off to the left)
74
categories of antidepressants
tricyclics, selective serotonin reuptake inhibitors, monoamine oxidase inhibitors, and atypical antidepressants
75
tricyclics
any of a class of antidepressant drugs having molecules with 3 fused rings
76
relationship between alcohol and neurotransmitters
Alcohol in a person increases the inhibitory NT GABA, and decreases the effects of the excitatory NT Glutamate
77
Alcohol _____ stress for most, but even more so for children of alcoholics.
decreases
78
How many dopamine pathways exist
at least 4
79
SSRIs
they block reuptake of serotonin to increase availability in the cell (Prozac and Zoloft)
80
SNRIs
block reuptake of norepinephrine AND serotonin, positive relationship w memory and few side effects (ex: cymbalta)
81
MAOIs
Block the enzyme monoamine oxidase that metabolizes (rids of) catecholamines and serotonin into inactive forms
Results in more transmitters in the presynaptic terminal available for release
82
BDNF
- essential for brain plasticity (adapting, learning, memory), nerve survival and growth, NT modulation
-widely expressed in brain and gut
83
How may ECT work?
increasing BDNF and encourages cell division in hippocampus (though could also impair memory if not at right voltage)
84
SAD
due to dysfunction of endogenous clock and melatonin, light therapy and CBT seem effective
genetic mutations in PER3 gene linked to circadian rhythms
85
schizophrenia
genetic: DISC1 gene responsible for neurogenesis mutated through micro depletion
environmental: season of birth effect (winter/far from equator may be linked to higher rates due to infection)
brain abnormalities: small hippocampus and PFC, large ventricles, reduced matter
86
negative symptom examples
low social drive, apathy, anhedonia, poverty of speech
87
Schizophrenia treatments
Chlorpromazine (Thorazine)
relieves positive symptoms
88
Dopamine Hypothesis of schizophrenia
Schizophrenia results from excess activity at dopamine synapses in certain areas of the brain
89
Substance-induced psychotic disorder
Hallucinations and delusions resulting from repeated large doses of amphetamines, methamphetamines, or cocaine
Each prolongs activity at dopamine synapses
90
The Glutamate Hypothesis of schizophrenia
deficient activity at glutamate synapses, especially in the prefrontal cortex
In many brain areas, dopamine inhibits glutamate release
Alternately, glutamate stimulates neurons that inhibit dopamine release
Increased dopamine thus produces the same effects as decreased glutamate
91
BPD and lithium
Lithium stabilizes mood, preventing a relapse into either mania or depression. The dose must be regulated carefully, as a low dose is ineffective and a high dose is toxic. The mechanism of effect evidently has something to do with cells in the hippocampus. The hippocampus forms new neurons throughout life, and some of those that form in bipolar patients are hyperexcitable. Lithium relieves bipolar disorder only if it alleviates the hyperexcitability
92
Law of Specific Nerve Energies (Müller)
Action potentials from visual nerves interpret what we know as vision and particular energy from some neurons determines our perception of vision
93
Blind spot is also:
optic disc
94
Small opening which light passes in the eye
pupil
95
contains photoreceptors, sends cells out through optic nerve
retina
96
Visual info goes from the optic nerve to _________ then _____.
the thalamus, v1 (striate cortex of occipital lobe)
97
Visual info goes from the optic nerve to _________ then _____.
the thalamus, v1 (striate cortex of occipital lobe)
98
the LGN is in the
thalamus
99
Order of cell communication to send light info to the brain
Receptors – Bipolar Cells – (amacrine) - Ganglion Cells
100
the optic nerve is a bundle of ________ of ______ ________.
axons, ganglion cells
101
characteristics of the fovea
-high number of receptors
- free of ganglion axons
- acute vision
- 1:1:1 ratio of cells (midget ganglion cells) so cones each have direct access to the brain
102
Peripheral vision is good in low light why?
cells converge onto each other funneling down from rods to amacrine cells to ganglion cells
103
photopigments
release energy and enact second messenger (in photoreceptors)
- 11-cis-retinal wrapped around opsin proteins turns into all - transretinal due to light
104
short wavelength
blue
105
long wavelength
red
106
medium wavelength
green
107
receptive fields
whatever excites or inhibits the cell - for receptors it is light striking it
108
Parvocellular Neurons
Have smaller cell bodies and small receptive fields
Highly sensitive to detect color and visual detail
(fovea)
109
Magnocellular Neurons
Distributed evenly throughout the retina
Have larger cell bodies and visual fields
Highly sensitive to large overall pattern and moving stimuli
110
koniocellular Neurons
Have small cell bodies
Found throughout the retina
Have several functions, and their axons terminate in many different places
Help to with brightness contrast, color contrast, relays short waves
111
Blindsight results in damage to
v1
112
Simple cells
- v1
-small receptive field
-fixed ex and in zones
-edges in certain orientaion
113
complex and end-stopped
both v1 and v2, large receptive fields, but end-stopped have strong in zones
- bars of light
114
critical periods
periods of time during the lifespan when experiences have a particularly strong/enduring effect
115
stereoscopic depth perception
A method of perceiving distance, Relies on retinal disparity
116
lazy eye
starbismus
117
limited exposure during critical periods
Leads to nearly all of the visual cortex cells becoming responsive to only that pattern, leads to recognition problems
118
ventral stream
temporal cortex, what, identifying objects
119
dorsal stream
parietal cortex, where, where things are located
120
visual agnosia
The inability to recognize objects
121
MST
expansion, contraction, or rotation of a visual stimulus
122
MT/v5
responds to movement in specific directions
