Exam 2 Flashcards
(126 cards)
1
Q
sensory receptor
A
specialized neuron that detects a particular category of events
2
Q
Sensory transduction
A
process by which sensory stimuli are transduced into slow graded receptor poentials
3
Q
receptor potentials
A
slow graded electrical potential produced by a receptor cell in response to physical stimuli; affect the release of NT
4
Q
hue
A
the dominant wavelength
5
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brightness
A
intensity of visual stimuli
6
Q
saturation
A
purity of visual stimuli
7
Q
saccadic mov’ts
A
repid, jerky eye mov’ts used in scanning a visual scene
8
Q
pursuit mov’t
A
mov’t that the eyes make to maintain an image of a moving object on the fovea
9
Q
iris
A
pigmented ring of muscles situated behind the cornea; controls lens size
10
Q
lens
A
set immediately behind the iris, transparent
11
Q
accomodation
A
changes in the thickness of the lens of the eye, accomplished by ciliary muscles that focus near/distant objs on the retina
12
Q
retina
A
neural tissue & photo receptive cells located on the inner surface of the post. portion of the eye
13
Q
rods
A
sensitive to light of low intensity
good in dim light
good for global picture
14
Q
cones
A
maximally sensitive to 3 diff wavelengths of light & encode color vision; constitute the fovea
more acute than rods
info about small features
15
Q
photoreceptor
A
transduces photic E into electric potentials
Rod & cones
16
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fovea
A
region of the retina that mediates the most acute vision. Color sensitive cones only photoreceptors here.
17
Q
optic disk
A
location of the exit pt. from the retina to the fibers of the ganglion cells that form the optic nerve; responsible for blind spot
18
Q
why is there a blind spot on the optic disk
A
b/c there are no receptors located there
19
Q
bipolar cells
A
bipolar neuron located in the middles layer of the retina
conveys info from photo receptors to the ganglion cells
20
Q
ganglion cell
A
neuron located in the retina that receives visual info from bipolar cells
axons give rise to the optic nerve
21
Q
horizontal cells
A
neuron in the retina that interconnects adj. photoreceptors & other process of bipolar cells
22
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Amacrine cell
A
neuron in the retina that interconnects adj. ganglion cells & inner processes of bipolar cells
23
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lamelle
A
layer of membrane containing photopigments; found in rods and cones of retina
24
Q
photopigments
A
responsible for transduction of visual info.; respond to diff wavelengths
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2 parts of photopigments
1. opsin
| 2. retinal
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opsin
protein class that w/ retinal constitutes photopigments
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retinal
protein class that w/ opsin constitutes photopigments
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rhodopsin
particular opsin found in rods that produces a receptor potential
breaks into 2 components when exposed to light --> receptor potential
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Dorsal Lateral Geniculate nucleus (LGN)
group of cell bodies w/in the thalmus ; 6 layers
receives input from the retina and projects to primary visual cortex
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2 types of layers in the LGN
1. magnocellular
| 2. parvocellular
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magnocelluar layer of LGN
inner 2 layers
transmits info necessary for perception of form, mov't, depth & small diffs in brightness to primary visual cortex
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parvocellular layer of LGN
4 layers
transmits info necessary for perception of color & fine details to primary visual cortex
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koniocellular sublayers of LGN
found ventral to both magno & pervocellular layers
transmits info from short wavelength ("blue") cones to primary visual cortex
34
calcrine fissure
horizontal fissure on the inner surface of the post. cerebral cortex
location of primary visual cortex
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striate cortex
primary visual cortex
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optic chiasm
cross shaped connection b/t the optic nerves, located below the base of the brain
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Sensory processing Overview (4)
1. accessory structure (lens) modifies the stimulus
2. signal is transduced
3. output is transferred to cortex
4. info in primary sensory cortex goes to secondary and assoc. regions
38
receptive field
portion of visual field in which the presentation of visual stimuli will produce an alteration in the firing rate of a particular neuron
39
Why is foveal perception more precise that peripheral perception
fovea contains equal #s of ganglion cells & cones as the periphery of retina
40
Trichromatic theory
any color can be reproduced by mixing various quantities of 3 colors judiciously selected from diff pts along the spectrum
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bleaching
photorecpetor's photopigments are broken apart in presence of light (retinal & opsin)
42
Basic transduction process (3)
1. est. neural code (action potentials)
2. bleaching occurs
3. changes ultimately the firing rate of the ganglion layer
43
simple cells
responds to a particular orientation in a specific visual field (location)
specific orientation depends on the simple cell
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complex cells
responds to a particular orientation over a range of location (wider range than simple cells)
"motion detectors"
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hypercomplex cells
responds to a particular orientation- edge must be present to excite cells
"edge detectors"
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cytochromeoxidase (CO) blob
central region of a module of the primary visual cortex
contains wavelength sensitive neurons; parvo and koniocellulars
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extrastriate cortex (V2-V8)
region of the visual assoc. cortex
receives fibers from the striate cortex & from the sup colliculi & projects into the inf. temporal lobe
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Where are the outputs of V1 sent
directly to area V2 of extrastriate cortex
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dorsal stream
"where" pathway
involved in the perception of spatial location; terminates in post. parietal lobe
V5 and V7
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ventral stream
"what" pathway
involved in perception of form; terminates in inf. temporal cortex
V3, V4,VP.V8,LOC,FFA
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V3, VP, LOC, FFA purpose
mainly form and shape recognition
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V4 & V8 purpose
color perception
V4= color constancy region
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Area V5 purpose
motion detection
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color constancy
relative constant appearance of the colors of objects viewed under varying light conditions
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cerebral achromatopsia
inability to discriminate among diff hues; caused by damage to area V8
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visual agnosia
deficits in visual form perception in the absence of blindness caused by brain damage
inability to perceive/ID stimulus by means of a particular sensory modallity
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lateral occipital complex (LOC)
region of the extrastriate cortex; involved in the perception of objects other than people's bodies & faces
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prosopagnesia
failure to recognize particular people by the sight of their faces; mostly caused by damage
common symptom of visual agnosia
know they are looking at a face but can't say who
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fusiform face area (FFA)
region of visual assoc. cortx located in the inf. temporal
involved in perception of faces
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extrastriate body area (EBA)
involved in perception of the human body and other body parts other than faces
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3 basic ways to recognize features
1. diff in features
2. diff in contour
3. diff in configurations of features (most difficult to detect)
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optic flow
provides info about relative distance of obj from observer & of relative direction of mov't; used to determine whether an object approaching us will hit/miss us
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akinetopsia
inability to perceive mov't caused by damage to V5
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intraparietal sulcus (IPS)
end of dorsal stream of visual assoc. cortex
involved in perception of location, visual attention & control of eye/hand mov'ts
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5 components of IPS
1. AIP
2. LIP
3. VIP
4. CIP
5. MIP
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ocular apraxia
impairments in visual scanning
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optic ataxia
impairments of reaching under visual guidance; eyes unable to direct reaching
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simultanagnosia
impairments in perceiving 2 objects when they are together
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Ballint's syndrome
1. ocular apraxia
2. optic ataxia
3. simultanagnosia
closely associated with bilateral dorsal stream damage
70
3 components of an emotional response
1. behavioral
2. autonomic
3. hormonal
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lateral nucleus
nucleus of the amygdala that receives sensory info from the:
1. neocortex
2. thalmus
3. hippocampus
send projections into central nucleus of amygdala.
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central nucleus
involved in emotional responses; single most important part of the brain for expressing emotional responses provoked by adverse stimuli
can learn that specific stimuli are dangerous/threatening
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Stimuli that activate the Central nucleus
1. loud unexpected noises
2. approach of large animals
3. heights
4. specific sounds/odors
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ventro-medial PFC
plays an inhibitory role in the expression of emotions
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Role of serotonin
increased serotonin decreases aggressive behavior
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Role of Ventromedial PFC
important role in control of emotional behavior
controls emotional responses organized by the amygdala
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Damage to the Ventromedial PFC
causes serious impairments of behavioral control and decision making (emotinal dysregulation)
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Role of amygdala in recognition
plays role in emotional recognition (visual)
esp. fear
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volitional facial paresis
difficulty in moving the facial muscles voluntarily; caused by damage to region of the primary motor cortex
cannot voluntarily move face muscles but can express emotion
80
emotional facial paresis
Can move facial muscle voluntarily but cannot express emotions on the affected side of the face
81
Role of right hemi (emotions)
involved in expressing emotions
Evidence: left side usually makes a more intense expression
82
schizophrenia definition
serious mental disorder characterized by disordered thoughts, delusions, hallucinations, or thought disorders
83
Schizophrenia 3 categories of symptoms
1. positive
2. negative
3. cognitive
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positive symptoms
symptom of schizophrenia evident by its presence
1. delusion
2. hallucinations
3. thought disorders
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though disorders
disorganized irrational thinking (most important symptom of schizophrenia)
difficulty to arrange thoughts logically
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delusions
belief that is clearly in contradiction to reality
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3 types of delusion
1. persecution
2. grandeur
3. control
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delusions of persecution
others are plotting/conspiring against them
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grandeur delusions
false beliefs of one's power/importance
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control delusions
being controlled by others
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hallucinations
perception of nonexistent objects/events
most commonly auditory
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Negative symptoms
symptoms of schizophrenia characterized by the absence of behaviors that are normally present; social withdraw, lack of affect, reduced motivation
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cognitive symptoms
symptom of schizophrenia characterized by cognitive difficulties; defecits in learning/memory, poor abstract thinking, difficulty with attention
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Dopamine hypothesis
suggests that positive symptoms of schizophrenia are caused by overactivity of synapses b/t dopaminergic neurons
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Drugs for schizophrenia....
block dopamine receptors
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seasonality effects
increase incidence of schizophrenia in people born during late winter/early spring
pregnant women more likely to develop viral illnesses
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hypofrontality
decreased activity of the DLPFC; believed to be responsible for the negative symptoms of schizophrenia
caused by decrease in dopamine release in PFC
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what are the negative/cognitive symptoms of schizophrenia caused by
decrease in the metabolic activity of the frontal lobes; NDMA receptors inhibited
99
PFC hypoactivity cause...
hyperactivity of mesolimbic dompaminergic cortex; increase in release of dopamine in nucleus accumbens
100
clozapine
alleviates +/- & cognitive symptoms of schizophrenia
causes increase in dopamine in PFC
Causes decrease in dopamine in nucleus accumbens
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What causes hypofrontality
synaptic pruning that occurs during adolescence; causes decreased activity of NDMA
102
major affective disorders
serious mood disorder (depression & bipolar disorder)
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bipolar disorder
serious mood disorder characterized by cyclical period of mania/depression
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major depressive disorder
serious mood disorder that consists of unremitting depression or periods of depression that do not alter with mania
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tricyclic antidepressant
used to treat depression; inhibits reuptake of norepinephrine and serotonin
106
Specific serotonin reuptake inhibtor (SSRI)
antidepressant drug that specifically inhibits the reuptake of serotonin w/o affecting the reuptake of other neurotransmitters (Prozac, Celexa, Paxil)
107
Specific serotonoin/norepinephrine reuptake inhibitor (SSNRI)
antidepressant drug that specifically inhibits the reuptake of norepinephrine & serotonin w/o affecting the reuptake of other NT
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ECT
brief electrical shock applied to the head that results in an electrical seizure; used to alleviate severe depression
MOST RAPID EFFECTS
109
lithium
chem element used to treat bipolar disorder, specifically the manic episodes
+ response in 1-2 weeks
110
monoamine hypothesis
depression is caused by a low lvl of activity of 1+ monoamine synapses (norepinephrine/serotonin)
hypothesis may be TOO simple
111
evidence for monoamine hypothesis
monoamine antagonists can produce symptoms of depression and monoamine agonists reduce the symptoms
112
tryptophan depletion procedure
low tryptophan diet that decreases the synthesis of 5HT- causes relapse into depression
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REM sleep deprivation
antidepressant treatment; wake patients as they enter REM sleep to alleviate depression over several weeks
can show long term effects
114
Total Sleep deprevation
produces immediate effects- not longterm- to alleviate depression
115
Seasonal Affective disorder
mood disorder characterized by depression, lethargy, sleep distrubances, and craving for CHOs during winter
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phototherapy
RX of seasonal affective disorder by daily exposure to bright lights- found to be effective for depression as well
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MAO inhibtors
blocks monamine oxidase and interferes with breakdown of monoamines, increasing availability
118
TMS
similar to ECT; induces elec, activity in the brain (usually in the left PFC); relatively new
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DBS
Deep Brain Stimulation
subgenual ACC stimulated- leads to reduced activity and causes decrease in depression
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subgenual ACC and depression
subgenual ACC usually HYPERACTIVE during depression
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Ventricular size in schizophrenic patients
ventricles larger- causes a decrease in gray matter
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Gray matter in schizophrenic patients
gray matter volume is lower in schizophrenic patients; rate of loss of gray matter neurons in schizophrenics is higher
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Dorsolateral PFC
responsible for executive fcns; decreased activity in this area results in hypofrontality
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Hypofrontality linked to...
1. decreased activity of DLPFC
2. decreased activity of glutamate receptors in DLPFC
3. decreased dopamine in DLPFC (mesocortical area)
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decreased activity in the DLPFC is related to...
increased activity in mesolimbic dopamine system
126
the mesolimbic and mesocortical systems are ________________ related
INVERSELY; specificall the GABA circut
