Lecture 12 Flashcards
Receptive field
Small area of retina where light changes a neuron’s firing rate
Photoreceptor ___polarizes to light
hyperpolarizes
Receptive field has ___ and ___ bipolar cells
On and off
Off bipolar cells
Light shined onto a photoreceptor will hyperpolarize (light effectively turns them off)
ON bipolar cells
Light depolarizes (cells are turned on by light)
How do OFF bipolar cells react to light? (what kind of receptor, etc)
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
How do ON bipolar cells react to light?
(what kind of receptor, etc)
G-protein coupled receptors which respond to glutamate by hyperpolarizing.
What are the 2 parts of the receptive field of a bipolar cell?
Receptive field center
Receptive field surround
Receptive field center
Circular area of retina providing direct photoreceptor input
Receptive field surround
Surrounding area of retina providing input via horizontal cells
Antagonistic center-surround receptive fields
Response of a bipolar cell’s membrane potential to light in the receptive field is OPPOSITE to that of light in the surround
ON-center (____-surround) bipolar cell
Depolarized by light in receptive field center
Hyperpolarized by light in receptive field surround
Bipolar cells are also connected via ______ cells to _______ that surround the _______ _______
Horizontal cells
Photoreceptors
Central cluster
When a photoreceptor hyperpolarizes in response to light, output is sent to ________ cells that also _______
Horizontal
Hyperpolarize
The effect of light on the surround photoreceptors is always _______ to the effect of light on the center photoreceptors.
Opposite
Ganglion cell receptive fields have the same ______-_______ receptive field organization as _______ cells
center-surround
Bipolar
The ON-center and OFF-center ganglion cells receive input from the _________ type of _______ cell
Corresponding
Bipolar
How will an ON-center ganglion cell respond to a small spot of light on the center of the receptive field?
Depolarize and send a barrage of action potentials
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?
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)
Ganglion cells are mainly responsive to _______ in illumination, not ______ in illumination that include the entire receptive field (center and surround)
Differences; changes
Study ganglion cell receptive field graphics
Got it
