Visual Pathways

Question 1

Optic chiasm

Answer 1

crossing over of fibres from the hemi-retini

Question 2

LGN

Answer 2

lateral geniculate nucleus. layered structure, keeps info from eyes seperate, has receptive fields, relay of info to cortex, retinotopically arranged

Question 3

LGN layers

Answer 3

See I? I see, I see. (1,2 Magnocellular 3-6 parvocellular) Left brain processes visual info from right side and visa versa

Question 4

Magnocellular

Answer 4

originate in p-alpha channel. respond fast to changes in contrast and movement. large spread out pathway. first to respond Schmolesky et al., 1998. No colour. Give transient response if excited

Question 5

Parvocellular

Answer 5

colour opponency. small receptive fields, slightly slower than m channel, process detail, respond in sustained manner

Question 6

Optic radiations

Answer 6

a collection of axons from relay neurons in the lateral geniculate nucleus of the thalamus carrying visual information to the visual cortex

Question 7

Area devoted to vision

Answer 7

25% of cortex. area 17 is primary visual cortex

Question 8

Area 17

Answer 8

retinotopically organised. lesions give specific and predictable regions of blindness - hemianopsia. six cortical layers receiving input from m and p channels

Question 9

3 types of cell discovered by hubel and wiesel

Answer 9

simple, complex and hypercomplex

Question 10

Receptive field types

Answer 10

LGN, retinal and input cells of V1 (layer IVc also have this property)

Question 11

Simple

Answer 11

Orientation specific

Question 12

Complex

Answer 12

orientation and direction specific

Question 13

Hypercomplex

Answer 13

end stopped cells