MODULE 6- ARPIN STUDY GUIDE

Question 1

different parts of the retina

Answer 1

-macula (fovea)
-optic disc (blind spot)

Question 2

different types of neurons in the retina (5)

Answer 2

-photoreceptors (rods + cones)
-bipolar cells
-ganglion cells
-horizontal cells
-amacrine cells

Question 3

direct path of light

Answer 3

photoreceptors (rods/cones) ->
bipolar cells->
ganglion cells

Question 4

what makes the optic nerve

Answer 4

axons of ganglion cells

Question 5

horizontal connections

Answer 5

-horizontal cells
-amacrine cells

^make horizontal connections between photoreceptors/ganglion cells

Question 6

photoreceptors depolarize/hyperpolarize to light

Answer 6

hyperpolarize

Question 7

do photoreceptors have APs

Answer 7

no

Question 8

membrane potential response to light intensities is ____

Answer 8

graded

Question 9

electrical activity of photoreceptors is depends on what 2 types of channels

Answer 9

-K+ channels
-cGMP-gated Na+/Ca2+ channels

Question 10

K+ channels are always open/closed

Answer 10

open

Question 11

steps in phototransduction

Answer 11

light stimulus ->
absorption of photos leads to decrease in cGMP levels ->
closing of Na/Ca channels (gated by cGMP) ->
reduction of Na+/Ca+ influx ->
receptor hyperpolarization

Question 12

dark- photoreceptors membrane potential

Answer 12

~40mV

-due to Na+ and Ca2+ influx which acts to depolarize and K+ efflux which acts to hyperpolarize

Question 13

light- what happens to photoreceptors

Answer 13

hyperpolarize
-due to reduced Ca+/Ca2+ influx and continued K+ efflux

Question 14

rods/cones have greater sensitivity to low light intensity

Answer 14

rods

Question 15

response in rods do what in bright conditions

Answer 15

saturate

Question 16

cones

Answer 16

response to 3 different wavelengths of light -> color vision

Question 17

are there rods/cones on fovea

Answer 17

lots of cones
-no rods

Question 18

greater convergence from rods -> bipolar -> ganglion cells

Question 19

scotopic

Answer 19

night vision
-rods

Question 20

photopic

Answer 20

daylight/color vision
-cones

Question 21

ON + OFF-center bipolar cells have different ____

Answer 21

glutamate receptors

Question 22

the connection between photoreceptor + bipolar cell is sign inverting/conserving for ON-center cell

Answer 22

inverting

Question 23

the connection between photoreceptor + bipolar cell is sign inverting/conserving for OFF-center cell

Answer 23

conserving

Question 24

ON-center receptor

Answer 24

mGluR6 receptor

Question 25

OFF-center receptor

Answer 25

AMPA receptor

Question 26

light- ON-center bipolar cell

Answer 26

hyperpolarize photoreceptor -> reduce glutamate from photoreceptor -> depolarize ON-center bipolar cell (sign inverting)

Question 27

light- OFF-center bipolar cell

Answer 27

hyperpolarize photoreceptor -> reduce glutamate from photoreceptor -> hyperpolarize OFF-center bipolar cell (sign conserving)

Question 28

dark- ON-center bipolar cell

Answer 28

depolarize photoreceptor -> glutamate release from photoreceptor -> hyperpolarize ON-center bipolar cell (sign inverting)

Question 29

dark- OFF-center bipolar cell

Answer 29

depolarize photoreceptor -> glutamate release from photoreceptor -> depolarize OFF-center bipolar cell (sign conserving)

Question 30

where do retinal ganglion cells project (4)

Answer 30

-hypothalamus -pretectum -superior colliculus -lateral geniculate nucleus

Question 31

hypothalamus is responsible for

Answer 31

circadian rhythm

Question 32

pretectum is responsible for

Answer 32

pupil reflex

Question 33

superior colliculus is responsible for

Answer 33

eye movements

Question 34

lateral geniculate nucleus is responsible for

Answer 34

part of main pathway for visual perception

Question 35

striate cortex + primary visual cortex are/aren't directly connected to retinal ganglion cells

Answer 35

ARENT

Question 36

LGN projects to what

Answer 36

layer 4 of primary visual cortex to ocular dominance columns

Question 37

neurons in same cortical columns have what

Answer 37

same receptive field/response preferences

Question 38

visual cortex neurons have

Answer 38

preferred orientation

Question 39

extrastriate visual areas

Answer 39

-ventral stream -dorsal stream

Question 40

ventral stream

Answer 40

what

Question 41

dorsal stream

Answer 41

where

Question 42

ventral stream- what temporal area

Answer 42

inferior temporal cortex -area V4

Question 43

dorsal stream- what temporal area

Answer 43

medial temporal area -MT