retinal layers neurophysiology

Question 1

synaptic networks

Answer 1

convert graded sensory photoreceptor potentials into patterns of action potential

Question 2

layers of the retina (outermost to innermost)

Answer 2

(1) pigment epithelium (2) photoreceptor layer (3)outer limiting membrane (4) outer nuclear layer (5) outer plexiform layer (6) inner nuclear layer (7) inner plexiform layer (8) ganglion layer (9) optic nerve fiber layer (10) inner limiting membrane

Question 3

cells of retinal pigment epithelium

Answer 3

hexagonal cells and melanin pigment

Question 4

functions of the RPE

Answer 4

light absorption, epithelial transport, glia(?), visual cycle, phagocytosis, and secretion

Question 5

“type” of photoreceptor signal

Answer 5

graded hyperpolarizations

Question 6

membrane potential of rods/cones

Answer 6

-40 mV

Question 7

inner limiting membrane

Answer 7

separate retina from vitreous

Question 8

nerve fiber layer

Answer 8

relay impulses to lateral geniculate nucleus via optic nerve

Question 9

cells in nerve fiber layer

Answer 9

ganglion cell axons

Question 10

nerve fiber layer pathology

Answer 10

soft exudates and flame shaped hemorrhage

Question 11

muller cells

Answer 11

glial cells that extend throughout all retinal layers - multiple functions especially as structural and metabolic role

Question 12

interplexiform cell signalling

Answer 12

provide a feedback pathway from IPL to OPL via input from amacrine cells in IPL

Question 13

ipRGCs

Answer 13

“intrinsic photosensitive retinal ganglion cells” - involved in circadian rhythm and pupillary light reflex

Question 14

terminal for ipRGCs in pupillary light reflex

Answer 14

pretectal nucleus

Question 15

terminal for ipRGCs in circadian rhythym

Answer 15

superchiasmatic nucleus

Question 16

spatial filters

Answer 16

photoreceptor mosaic sampled at multiple scales

Question 17

temporal filters

Answer 17

sustained (something is present) vs transient (something changed) responses - based on motion perception

Question 18

cells involved in chromatic signals

Answer 18

midget cells (red/green opponent receptive fields), small bistratified (blue/yellow oppenency)

Question 19

midget cells

Answer 19

fine detail and sustained response

Question 20

parasol cells

Answer 20

coarse detail and transient responses

Question 21

x type ganglion cells

Answer 21

beta or parvocellular pathway (midget cells)

Question 22

y type ganglion cells

Answer 22

alpha or magnocellular pathway (parasol cells)

Question 23

w type ganglion cells

Answer 23

gamma cells