Systems Lecture 5

Question 1

who worked out the receptive fields of the striate cortex

Answer 1

david hubel and torsten weisel

Question 2

what is responsible for conscious perception of visual input

Answer 2

LGN –> Striate cortex

Question 3

striate cortex:

Answer 3

• area 17 - brodmann’s area
• ## conscious perception of vision

Question 4

retinotopy

Answer 4

• map of visual field onto a target structure (representation)
• central visual field (fovea) overly represented
• ON and OFF regions can detect edges- high amount of conservation between retina, LGN, and striate cortex

Question 5

retinotopy distorted

Answer 5

looking at visual field, info from chiasm being represented in bakc

• flipped at back of striate cortex
• can put pieces back together again at back of brain to process info in receptive field

Question 6

layers of the striate cortex

Answer 6

6 layers - but layer 4 has 4 sub sectsion so really 9 slayers

layer 4 has A, A, C (alpha and beta)

Question 7

neurons in the striate cortex layers

Answer 7

spinu stellate cells (short, small)
- layer IVc (4c)

pyramidal cells
- layers III, IVb, V, VI

inhibitory neurons (lack spines; regulate release of NT from stelate and pyramidal cells; excrete GABA)
- IVa

Question 8

inputs from LGN in stiate

Answer 8

layer IVc magno and parvo

Question 9

Ocular Dominance Columns in Striate

Answer 9

hubel and wife found them
- overlapping of visual info from R and L eye –> depth perception

• usually predators have ocular dominance

Question 10

outputs of striate cortex

Answer 10

• pyramidal cells - project down
• layer II, III, IVb (faciliiatated by pyramidal cells; send info to other cortical areas)
• layer V (superior colliculus and pons- regulates eye movement)
• layer VI (back to the LGN - feedback to non-cortical visual areas as well

Question 11

retinal ganglion cells and LGN have receptive fields that are

Answer 11

monocular (receive info from one eye)

- centre/surround

Question 12

receptive field of striate cortex layer IVc

Answer 12

monocular (centre/surround (mostly))

Question 13

receptive field of other striate layers

Answer 13

binocular - no more doughnut shape –> bar shape (results form overlapping doughnut shapes)

Question 14

orientation selectivity

Answer 14

certain neurons are more receptive based on orientation they are facing (not mushc different for cells within same columns)
- orientation of light within receptive field is encoded in back of brain by particular neurons

Question 15

orientation selectivity map

Answer 15

• ## evidence for plasticity ( for individuals missing parts of or having damage to the LGN)

Question 16

what layer of the striate cortex has orientation selectivity

Answer 16

layer IV c (alpha and beta)

Question 17

direction sensitivity

Answer 17

within a visual field, a stimulus moving form L to R acorss a receptive field

Question 18

simple cell - receptive fields

Answer 18

binocular, orientation selective

- elongated

Question 19

complex cell receptive fields

Answer 19

binocular
orientation selective
elongated
ON or OFF responses
NO distinct regions