The Visual System

Question 1

Different cell types in the retina

Answer 1

• ganglion cells
• amacrine cells: receive input from bipolar cells and project to other photoreceptors and bipolar cells
• bipolar cells
• horizontal cells: receive input from photoreceptors and project to other photoreceptors and bipolar cells

Question 2

Structure of photoreceptors

Answer 2

• 4 regions: outer segment, inner segment, cell body, synaptic terminal
• coverts electromagnetic radiation to neural signals (transduction)
• membranous disks contain photopigment, which converts light into signals
• membranous disks are provided to photoreceptors by supporting cells in retina

Question 3

Basis of phototransduction

Answer 3

1) vertebrate photoreceptors have depolarisaed rmp (Vm) compared to other neurons, resting Vm is more positive (~20mV)
2) with light exposure Vm hyperpolarises

Question 4

Different cell types in the LGN

Question 5

Different cell types in the cortex

Question 6

Properties of cell types in retina

Question 7

Properties of cell types in LGN

Question 8

Properties of cell types in cortex

Question 9

What is the dark current

Answer 9

a cGMP-gated Na+ channel current that is open in the dark and closed in the light

Question 10

What are the molecules involved in phototransduction

Question 11

Different types of glutamate receptors in ON pathway

Question 12

Different types of glutamate receptors in OFF pathway

Question 13

What is the duplex theory of vision

Question 14

Qualities and functions of rods

Question 15

Qualities and functions of cones

Question 16

Pathway for visual information from retina to cortex

Question 17

How is retinotopy perserved

Question 18

What are receptive fields

Question 19

What is retinotopy

Question 20

What is ocular dominance

Question 21

Effects of monocular deprivation in animal

Question 22

Effects of no monocular deprivation in animal