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Top Hat: Lecture 15 (exam 3)

Terms in this set (13)

Photoreceptor bleaching releases retinol which activates transducin which activates the enzymatic degradation of cGMP and results in the closing of Na+ channels and the hyperpolarization of the photoreceptor.
true
Glutamate released in the retina can be excitatory or inhibitory.
true
The first retinal cell that responds with an action potential to light is the

a)photoreceptor

b)bipolar cell

c)ganglion cell
c)ganglion cell
What is correct regarding the receptive field? (Multiple correct answers possible.)


a)It is a portion of the visual field in which visual stimuli will alter the activity of the neuron of interest.

b)It is of unifor size across all bipolar cells.

c)Its size varies across retinal ganglion cells
a)It is a portion of the visual field in which visual stimuli will alter the activity of the neuron of interest.

c)Its size varies across retinal ganglion cells
The same photon (particle of light) can stimulate more than one photoreceptor simultaneously.
false
cGMP is ...

a)an ion channel

b)a G protein

c)a second messenger

d)an enzyme
c)a second messenger
What is PDE

a)It is an enzyme inhibitor

b)It is a degradative enzyme

c)It is a G protein
b)It is a degradative enzyme
How many different photoreceptors are based on the type of photopigment they contain?
4
Which cells inhibit bipolar cells


a)Rods/cones

b)Horizontal cells

c)Amacrine cells
a)Rods/cones

b)Horizontal cells
What happens if light is shone in the periphery of the receptive field of a center on bipolar cell.


a)It will stop firing.

b)Nothing

c)It will start firing.

d)It will increase its firing rate.
a)It will stop firing.
What happened if you shine light on the periphery of the receptive field of a center on RGC?

a)It will increases its firing rate

b)It will start firing.

c)Its activity will not change.

d)It will decrease its firing rate.
d)It will decrease its firing rate.
You are staring at a black box on a white background. The firing of your RGCs that have receptive fields on either sides of the edge of the box suddenly decreases. What factors contribute to this?


a)These RGCs are not stimulated differently in the center and surround.

b)These RGCs are connected to RGCs whose receptive fields fall right on the edge.

c)These RGCs are laterally inhibited by the horizontal cells/amacrine cells that connect them with the edge detecting RGCs..
a)These RGCs are not stimulated differently in the center and surround.

b)These RGCs are connected to RGCs whose receptive fields fall right on the edge.

c)These RGCs are laterally inhibited by the horizontal cells/amacrine cells that connect them with the edge detecting RGCs..
__________ is a visual illusion that arises from lateral inhibition altering the perception of brightness.
mach bands
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