higher visual cortices

Question 1

blob regions in V1 project to

Answer 1

thin stripe region in V2

Question 2

inter blob region in V1 projects to

Answer 2

inter-stripe region in V2

Question 3

4B of V1 projects to

Answer 3

thick stipe region in V2

Question 4

V4 receives input from which areas in V2?

Answer 4

thin stripe and inter-stripe

Question 5

V5 receives input from which regions in V2?

Answer 5

thick stripe

Question 6

where does V5 (MT) project to?

Answer 6

V4 and V1

Question 7

where does V2 project to?

Answer 7

V1, V4, V5

Question 8

where does V4 project to?

Answer 8

V1, V2, V5

Question 9

input to V2 from earlier processing stages

Answer 9

V1 projects to layer 4
layer 4 projects to layer 2/3

Question 10

V2 output to subsequent processing stages

Answer 10

from layer 2/3

Question 11

V2 feedback to earlier processing stages

Answer 11

layer 2/3 to layer 5 to V1
layer 2/3 to layer 6 to V1

Question 12

what pathway is the motion pathway part of?

Answer 12

the dorsal (parietal) pathway

Question 13

what main two areas does the motion pathway include?

Answer 13

MT: middle temporal (v5)
MST: medial superior temporal

Question 14

what makes the signal in the MT fast?

Answer 14

strong myelination

Question 15

what cells give the main input for the motion pathway?

Answer 15

magnocellular

Question 16

temporal preferred frequency and spatial acuity of motion pathway

Answer 16

low spatial acuity
high preferred temporal frequency

Question 17

what does the motion pathway receive indirect input from?

Answer 17

layer 2/3 in V1 via thick stripes in V2

Question 18

receptive fields in magnocellular pathway

Answer 18

much larger than V1
can also detect colour (some parvo input)
direction selective

Question 19

what is perceived motion in drifting grids and plaids

Answer 19

composite of the two gratings

Question 20

what do drifting grating and plaids allow?

Answer 20

allows us to provide direction information that is distinct from the orientation and direction of either component

Question 21

what percentage of V5 cells are selective for composite stimulus

Answer 21

~20%
generate perceived motion

Question 22

using dot clouds to study motion

Answer 22

Here no motion but can convey information, particularly in motion
* Population of cells in V5 that like&raquo_space; or &laquo_space;motion alternately active
corresponds to our perception of composite stimulus motion

Question 23

where does the middle temporal project to?

Answer 23

the medial superior temporal (the adjacent region)

Question 24

what does the MT feed into

Answer 24

the main parietal ‘where’ stream

Question 25

MST cells receptive fields and what this causes

Answer 25

much larger than V5, sums up information from V5

Question 26

what is responded to beyond V5

Answer 26

* Respond to direction of stimulus motion but can be complex – expansion, contraction, circular or spiral processes ‘optic flow’ controls ‘smooth pursuit’ eye movements

Question 27

what is optic flow used for

Answer 27

to calculate direction of heading and distinguish self from motion object

Question 28

what does the where pathway do?

Answer 28

determine the location of objects in space, relative to ourselves

Question 29

scientific name for where pathway

Answer 29

dorsal (parietal) pathway

Question 30

where pathway projections

Answer 30

V1 projects to V2 projects to V4 projects to inferior parietal lobule: areas DP, 7a/b, VIP, LIP

Question 31

areas of inferior parietal lobule involves in the where pathway

Answer 31

DP, 7a/b, VIP, LIP

Question 32

why is there strong myelination in the LIP

Answer 32

the signal needs to be conveyed fast

Question 33

LIP (full name)

Answer 33

Lateral intraparietal cortex

Question 34

receptive field properties in LIP

Answer 34

Receptive fields are large and retinotopically organised across opposite hemifield Retinotopic receptive field has a ‘motor field’

Question 35

what are LIP responses enhanced by?

Answer 35

saccade to target cells are much more responsive to a stimulus in the receptive field if these are the target of a saccade

Question 36

saccade

Answer 36

rapid movement of eye between fixation points

Question 37

what to LIP cells not care about

Answer 37

colour and orientation

Question 38

relationship between strength of response and starting eye (or head) position

Answer 38

Strength (gain) of response changes linearly with respect to starting eye (or had) position

Question 39

what is each retinal location represented by in LIP

Answer 39

a population of cells with different field gains for every region of visual space, there are many cells which represent that location

Question 40

what does a population of LIP cells code?

Answer 40

positions of objects in space with respect to the body

Question 41

what connections do LIP cells make

Answer 41

strong callosal connections with the LIP in the other hemisphere as we need a single representation of visual space

Question 42

feature of LIP cells

Answer 42

have large axonal and dendritic arbours because they need to pool information across large areas

Question 43

what do LIP cells combine information from?

Answer 43

the retina, eye position, head position and body position

Question 44

unique feature of LIP cells

Answer 44

LIP cells have memory

Question 45

what does memory in LIP cells allow

Answer 45

allows LIP cells to decide wat we will look at next assists in forwards planning, for example in planning saccades

Question 46

what does the LIP make reciprocal connections with?

Answer 46

the frontal eye fields in the frontal cortex (FEF)

Question 47

what has memory other than LIP cells?

Answer 47

FEF

Question 48

what do the FEF and LIP have strong links to? nature of links? importance of links?

Answer 48

strong descending links to the superior colliculus important for decision to make saccades

Question 49

purpose of the what pathway

Answer 49

to discriminate between objects

Question 50

scientific name for the what pathway

Answer 50

the ventral (temporal) pathway

Question 51

what pathway projections

Answer 51

v1 projects to v2 projects to v4 projects to inferior temporal lobule

Question 52

areas of the inferior temporal lobule involved in the what pathway

Answer 52

anterior, central and anterior parts -each with dorsal and ventral parts

Question 53

features of the inferior temporal cortex cells

Answer 53

have very large receptive fields -may include fovea and both hemifields

Question 54

what so inferior temporal cortex cell do?

Answer 54

respond to complex stimuli e.g. hands and faces

Question 55

how does the inferior temporal cortex respond to faces

Answer 55

cells may be responsive to certain components of faces, expressions etc. information may be combined to make cells responsive to faces

Question 56

inferior temporal cortex receptive fields

Answer 56

* Do not normally care about the position or size of the object * Generally, don’t care about the angle of view * Responses to specific ‘objects’ will vary according to familiarity

Question 57

the what and where pathways together

Answer 57

* Higher cortical pathways need to share information * There are connections between dorsal and ventral pathways: so that ‘where’ can know where ‘what’ is, and visa versa