LEC 8: Obj Recognition

Question 1

what’s the end of the retino-geniculate-striate pathway?

Answer 1

primary visual cortex - that when higher processing begins!

Question 2

magnocellular cells

Answer 2

info from RODS but some cones
position and motion /large and fast things/colorblind

Question 3

parvocellular cells

Answer 3

primarily CONES
detail and texture, small cells,
more layers in LGN than m-cells
small/slow/colorful things

Question 4

what are the 2 retinoganglion cells

Answer 4

p and m cells

Question 5

how are you able to see left and right sides of space w one eye?

Answer 5

each eye synapses on both LGNs depending on L and R visual field,
allowing one eye to present both hemispheres w info on L and R visual field
R visual field for each eye maps on L hemisphere
L visual field for each eye maps onto R hemisphere

Question 6

where is primary visual cortex located?

Answer 6

occipital lobe

Question 7

indirect pathway

Answer 7

stops btwn LGN and MT

Question 8

direct pathway

Answer 8

LGN straight to MT
mostly associated w magnocellular pathway (fast to detect motion)

Question 9

dorsal pathway

Answer 9

the where pathway
- where
- top

Question 10

ventral pathway

Answer 10

the what pathway
- what
- bottom

Question 11

obj cue + damage implication

Answer 11

monkeys associate shape of obj w treat (ex: raisins under cube evry time)
damage to temporal lobe causes impairment here

Question 12

landmark cue + damage implication

Answer 12

monkey finds raisin near wherever certain landmark is
damage to parietal lobe causes impairment here

Question 13

dual stream hypothesis

Answer 13

as visual info exits occiptal lobe, it follows 2 streams (dorsal and ventral)

Question 14

receptive fields become ______ further along the ventral stream

Answer 14

larger

Question 15

ventral pathway steps

Answer 15

retina - LGN - V1- (V2-V3-V4) - PIT - CIT - AIT

Question 16

visual agnosia

Answer 16

modality specific
gnosis - knowledge
A - without

Question 17

apperceptive agnosia

Answer 17

cannot copy, cannot recognize objs by shape
can sometimes recognize by other features (texture, color)
some patients have deficit only when noise in pic or non-standard viewpt

Question 18

associative agnosia

Answer 18

can copy but unaware of what obj is
difficult to read cannot transfer visual inputs into words
can be category specific (ex: prosopagnosia)
normal sensory functions but striped of meaning

Question 19

apperceptive damage

Answer 19

occipital lobe

Question 20

associative damage

Answer 20

occipitotemporal cortex damage on both hemisphere

Question 21

prosopagnosia

Answer 21

inability to recognize faces (face blindness)
type of associative agnosia

Question 22

population encoding

Answer 22

uses hierarchal feature coding up to a pt

Question 23

prbs w population encoding

Answer 23

if whole population of neurons required to identify single perception,
how do you link that percept to stored knowledge (there isn’t one cell to connect, there are many)

Question 24

form-cue invariance

Answer 24

our ability to recognize objects regardless of their dimensionality (diff shapes but same thing)

Question 25

perceptual constancy

Answer 25

perceiving objs as unchanging even as illumination and retinal images change

Question 26

lateral occipital complex (LOC)

Answer 26

may represent abstract shape representations to support recognition despite invariance

Question 27

fusiform face area (FFA)

Answer 27

area in temporal lobe that contains many neurons that respond selectively to faces possibly just due to experience (expertise)

Question 28

greeble experiment

Answer 28

concluded that there was some sort of expertise in facial recognition; visual neurons can be shaped by experience

Question 29

parahippocampal place (PP)

Answer 29

an area in the temporal lobe that contains neurons that are selectively activated by pictures of indoor and outdoor scenes

Question 30

extrastriate body area (EBA)

Answer 30

responds specifically to pictures of bodies and parts of bodies

Question 31

word form area (VWFA)

Answer 31

responsive to written words in ventral stream of left hemisphere

Question 32

feature-based encoding

Answer 32

encoding based on individual parts

Question 33

configural encoding

Answer 33

encoding based on whole unit or figure

Question 34

conjunctive enoding

Answer 34

assumes that features are explicitly conjoined, or linked together, through hierarchical processing in which lower-level regions representing features send their output to higher-level regions representing the shapes that result from the joining of those features

Question 35

damage to right hemisphere on representation

Answer 35

struggle to see a unit as a whole

Question 36

sparse encoding

Answer 36

"grandmother hypothesis" (one cell for when you see your grandma) using hierarchal feature combination (one cell or small set for one thing like apple etc)

Question 37

patients w left hem damage show struggle with

Answer 37

seeing features or smaller parts of unit

Question 38

prbs w sparse encoding

Answer 38

1. what abt hwere you learn something new 2. how does this work developmentally 3. what happens if neuron at top of hierarchy dies

Question 39

is location important in primary visual cortex or the IT (inferior temporal)

Answer 39

primary visual cortex IT relies on stimulus but not location (size and complexity, larger receptive field)

Question 40

form-cue invariance

Answer 40

the brain's categorization is constant regardless of form of cue that represents obj

Question 41

lateral occipital complex (LOC)

Answer 41

may represent abstract shape reresentation to support recognition despite invariance

Question 42

inversion effect

Answer 42

phenomenon in which recgnition (particualrly of faces) is poorer when obj is turned upside down; thought to reflect disruption to which recognition of obj relies on configural relationships

Question 43

Kanwisher et al (1997) (FFA)

Answer 43

FMRI study participatns look at car or face and BOLD signal measured in FFA activity showed increase when shown face

Question 44

greeble experiment

Answer 44

concluded that there was some sort of expertise in facial recognition. Visual neurons can be shape by experience

Question 45

James & James 2013 FFA/ Pokemon

Answer 45

experts showed inc BOLD activity in FFA when seeing pokemon characters

Question 46

MT (medial temporal)

Answer 46

detects motion and diretion of obj in visual field, part of dorsal/parietal pathway