Lecture 12

Question 1

Receptive field

Answer 1

Small area of retina where light changes a neuron’s firing rate

Question 2

Photoreceptor ___polarizes to light

Answer 2

hyperpolarizes

Question 3

Receptive field has ___ and ___ bipolar cells

Answer 3

On and off

Question 4

Off bipolar cells

Answer 4

Light shined onto a photoreceptor will hyperpolarize (light effectively turns them off)

Question 5

ON bipolar cells

Answer 5

Light depolarizes (cells are turned on by light)

Question 6

How do OFF bipolar cells react to light? (what kind of receptor, etc)

Answer 6

Ionotropic glutamate receptors
Mediate depolarizing postsynaptic potential from the influx of Na+
Hyperpolarization of photoreceptor after light causes less neurotransmitter release and results in hyperpolarization

Question 7

How do ON bipolar cells react to light?
(what kind of receptor, etc)

Answer 7

G-protein coupled receptors which respond to glutamate by hyperpolarizing.

Question 8

What are the 2 parts of the receptive field of a bipolar cell?

Answer 8

Receptive field center
Receptive field surround

Question 9

Receptive field center

Answer 9

Circular area of retina providing direct photoreceptor input

Question 10

Receptive field surround

Answer 10

Surrounding area of retina providing input via horizontal cells

Question 11

Antagonistic center-surround receptive fields

Answer 11

Response of a bipolar cell’s membrane potential to light in the receptive field is OPPOSITE to that of light in the surround

Question 12

ON-center (____-surround) bipolar cell

Answer 12

Depolarized by light in receptive field center
Hyperpolarized by light in receptive field surround

Question 13

Bipolar cells are also connected via ______ cells to _______ that surround the _______ _______

Answer 13

Horizontal cells
Photoreceptors
Central cluster

Question 14

When a photoreceptor hyperpolarizes in response to light, output is sent to ________ cells that also _______

Answer 14

Horizontal
Hyperpolarize

Question 15

The effect of light on the surround photoreceptors is always _______ to the effect of light on the center photoreceptors.

Answer 15

Opposite

Question 16

Ganglion cell receptive fields have the same ______-_______ receptive field organization as _______ cells

Answer 16

center-surround
Bipolar

Question 17

The ON-center and OFF-center ganglion cells receive input from the _________ type of _______ cell

Answer 17

Corresponding
Bipolar

Question 18

How will an ON-center ganglion cell respond to a small spot of light on the center of the receptive field?

Answer 18

Depolarize and send a barrage of action potentials

Question 19

How will an OFF-center ganglion cell respond when a small spot of light is projected to the center of its receptive field? What if it is a small dark spot?

Answer 19

Fire fewer action potentials
Fire more action potentials if there is a small dark spot (slightly less will be fired if large dark spot, but still more than light)

Question 20

Ganglion cells are mainly responsive to _______ in illumination, not ______ in illumination that include the entire receptive field (center and surround)

Answer 20

Differences; changes

Question 21

Study ganglion cell receptive field graphics

Answer 21

Got it