ch 13 occipital lobe Flashcards Preview

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Flashcards in ch 13 occipital lobe Deck (40):
1

anatomy

no clear subdivisions on lateral surface
medial surface-parietooccipital surface, calcarine sulcus (has primary visual cortex, separates upper and lower visual fields)
ventral surface-lingual gyrus (V2&VP), fusiform gyrus (V4)

2

color vision

V4, distributed throughout
detects movement, depth, and position (shadows)

3

primary visual cortex (V1) connections

input of lateral geniculate nucleus of thalamus, output to all other levels

4

secondary visual cortex (V2) connections

output to all other levels

5

connections after V2

output to parietal lobe-dorsal (where) stream
output to inferior temporal lobe-ventral (what) stream
output to superior temporal sulcus (STS)

6

visual pathways-dorsal stream

visual guidance of movements

7

visual pathways-ventral stream

object perception

8

visual pathways-STS

visuospatial functions and perception of certain movements

9

theory of function

vision begins in V1 and travels to more specialized zones, selective lesions up hierarchy produce specific deficits, lesions to V1 not aware of seeing

10

vision for action

see in order to act, parietal visual areas in dorsal stream (reach, duck, catch)

11

action for vision

move to see it all, visual scanning-move eyes and selective attention, saccades and pursuit problems

12

visual recognition

temporal lobes, object recognition

13

visual space

knowing where you are in space, parietal and temporal lobes, spatial location-egocentric (relation to self) and allocentric (relation to other objects)

14

visual attention

selective attention for specific visual input, parietal lobes guide movements and temporal lobes help in object recognition

15

dorsal stream is set of systems for online visual control of action

know because visual neurons in parietal corext only active when brain acts on visual info

16

STS stream characterized by

polysensory neurons, neurons responsive to both auditory and visual input or both visual and somatosensory input
originates from structures in parietal and temporal cortex

17

monocular blindness

destroy retina, optic nerve at bundles, loss of sight in 1 eye

18

bitemporal hemianopia

loss of vision from both temporal fields, lesion to optic chiasm, peripheral vision on both sides lost

19

nasal hemianopia

loss of vision to 1 nasal field, lesion of lateral chiasm

20

homonymous hemianopia

blindness of entire visual field, results from complete cut of optic tract, lateral geniculate body, or area V1

21

macular sparing

sparing of central or macular region of visual field, lesion to occipital lobe

22

hemianopia, quadrantoanopia

complete loss of vision in 1/2 or 1/4 of fovea, lesion to occipital lobe

23

scotoma

field defects, small blind spots, small occipital lobe lesions

24

conclusions to be made from case studies

distinct syndromes of visual disturbance, some provide evidence for fundamental dissociation between dorsal and ventral streams, visual experience not unified, asymmetry in functions

25

apperceptive agnosia

type of object agnosia, inability to perceive structure of objects
simultagnosia-inability to see multiple objects at a time
bilateral damage to lateral occipital lobe

26

associative agnosia

object agnosia, perceive objects but not identify them, anterior temporal lobe lesions

27

prosopagnosia

can't recognize faces, facial features or expressions, or tell human from nonhuman face

28

alexia, dyslexia

cant read, form of object agnosia-can't construct wholes from parts, form of associative agnosia-word memory damaged/inaccessible, damage to left fusiform and lingual areas

29

visual imagery

neural structures mediate perception and visualization not completely independent, R hemisphere usually does mental rotation, L hemisphere for image generation

30

V1 features

complex laminar organization, appears anatomically homogeneous but can be heterogeneous when stained with cytochrome oxidase-blobs
lesions in V1 can still get to V2, but must function so brain can make sense of whats happening

31

V2 features

can also be hererogeneous when stained with cytochrome oxidase, reveals stripes

32

3 pathways from V1&V2

v1->v4-color aread
v1->v2->v5-middle temporal, motion
v1&v2->v3-shape of objects in motion, form perception

33

V1 to temp lobe in ventral stream

knowing what an object is

34

V1 to pari lobe in dorsal stream

controlling visual guidance of movements

35

visual field organization

left half of each retina sends projections to R brain, R half of each retina sends projections to L brain

36

infarct

dead tissue

37

angioma

collection of abnormal blood vessels

38

optic ataxia

deficit in visually guided hand movements

39

prosopagnosia

facial recognition deficits

40

visuospatial agnosia

can't find way around, spatial perception/orientation