Neuroscience Lecture 11

Front 1

sclera

Back 1

outside layer of eye composed of white fibrous tissue

Front 2

Iris

Back 2

colored portion of the eye. Contains muscles that adjust the pupil size under neural control. Open duiring dim light, closed during bright light.

Front 3

Ciliary body

Back 3

ring of tissue that encircles the lens and includes both a muscle component and a vascular component

Front 4

Choroid

Back 4

composed of a rich capillary bed that serves as main blood supply for the photoreceptors

Front 5

Retina

Back 5

neural part of the eye, detects light, processes info, sends it to brain

Front 6

aqueous humor

Back 6

anterior chamber, supplies nutrients to anterior eye

Front 7

vitreous humor

Back 7

gelatinous substancec in posterior chamber, provides shape, contains macrophages that removes debris.

Front 8

5 types of neurons in the retina

Back 8

photoreceptors, bipolar cells, ganglion cells, horizontal cells, and amacrine cells

Front 9

basic unit of transmission through retina

Back 9

photoreceptor to bipolar cell to ganglion cell

Front 10

Light absorption leads to _______ of the neuron

Back 10

hyperpolarization. LESS neurotransmitter release to post-synaptic cell.

Front 11

what is the main channel affected by light?

Back 11

calcium channels, and also sodium channels. Open in the dark, light causes them to close

Front 12

Retinal

Back 12

photopigment that absorbs a photon of light. An aldehyde of Vitamin A. Coupled to Opsin

Front 13

transducin

Back 13

alpha subunit of G-protein activated by the conformational change in retinal and opsin. Activate cGMP to GMP, causes less opening of channels. (hyperpolarization)

Front 14

phosphodiesterase

Back 14

cleaves cGMP, results int he closing of ion channels.

Front 15

Rhodopsin kinase

Back 15

phosphorylates rhodopsin, allowing the binding of arrestin which prevents the activation of transducin.

Front 16

Rod

Back 16

low spatial resolution, extremely sensitive to light. dim light. respond to one photon of light.

Front 17

cone

Back 17

high spatial resolution, relatively insensitive to light. takes many photons of light

Front 18

scotopic vision

Back 18

when only rods are used. not very good vision.

Front 19

photopic

Back 19

when only cones are used.

Front 20

Mesopic

Back 20

when both cones and rods are used.

Front 21

Rod Circuitry

Back 21

rods synapse onto bipolar cells that synapse onto amacrine cells which contact cone bipolars and ganglion cells.

Front 22

Cone circuitry

Back 22

synapse on bipolar to RGC directly

Front 23

are there more rods or cones in the fovea?

Back 23

cones

Front 24

Fovea

Back 24

central retina

Front 25

bipolar cells

Back 25

cell bodies in the inner nuclear layer. transmits info from photoreceptors to ganglion cells

Front 26

ganglion cells

Back 26

output neurons of the retina

Front 27

horizontal cells

Back 27

in inner nuclear layer, makes multiple contacts with photoreceptors and bipolar cells. luminance contrast

Front 28

amacrine cells

Back 28

inner nuclear layer, makes contact with bipolar and ganglion cells. coordinates ganglion cell activity

Front 29

Retinal ganglion cells

Back 29

have circular receptive fields. on center and off center.

Front 30

Off centere bipolar cells

Back 30

usee AMPA receptors that depolarize cell in response to glutamate

Front 31

on center bipolar cells

Back 31

use metabotropic glutamate receptors that hyperpolarize cell

Front 32

Magmo retinal ganglion cells

Back 32

large receptive fields, detection of movement

Front 33

parvo retinal ganglion cells

Back 33

center surround cells for color