Circuits & Receptive Fields of the Retina Flashcards
What are the two types of bipolar cells?
Inverting(On) and NonInverting(Off)
Does light hyperpolarize or depolarize in photoreceptors?
Hyperpolarize
What receptors do inverting(on) bipolar cells use?
Metabotropic Glutamate Receptors
What is the difference in the setup of cells between the central and peripheral retina?
The central retina has its own ganglion and cell making it better for seeing stuff in detail. It has a 1:1 ratio for cone to ganglion cell. The Peripheral retina has many more rods and cone coverage per ganglion cell
How do inverting(on) bipolar cells work?
On bipolar cells use a metabotropic receptor and invert the signal given from the receptive field to either depolarize or hyperpolarize depending on the amount of light
How do non-inverting(off) bipolar cells work?
(Off) bipolar cells use a iontropic receptor and have a direct correlation to the receptive field depending if it’s hyperpolarized or depolarized
What is the receptive field of a bipolar cell?
The area of the retina from which that cell gets information; any photoreceptor that when stimulated with light changes the membrane potential of said bipolar field
What is the center receptive cell?
Photoreceptors that synapse directly on a bipolar cell from a central part of the receptive field
What is the receptive field surround?
Photreceptors that synapse indirectly on a bipolar cell via horizontal cells and form a peripheral ring of the receptive field surrounding the center
Where would light be best directed for the ganglion cell to increase firing of NTs with an off-bipolar cell? Why?
The light would be best directed at the surround receptive field with no light hitting the center receptive field. This is because having the light hit the surround receptive field minimizes the release of glutamate allowing less inhibition of NTs passing through the center photoreceptor.
What are horizontal cells?
Horizontal cells inhibit the release of glutamate to the center/direct photreceptor
Where would light be best directed for the ganglion cell to increase firing of NTs with an on-bipolar cell?
The light would be best directed at the center receptive field and the surrounding receptive field having no light. This is because when we have an on-bipolar cell that cell inverts the signal meaning that in normal circumstances no light would mean depolarization and shooting of NTs but since we have an on-bipolar cell we want there to be less light to invert the signal
What does the retina see mostly?
Edge detection
Where is shading, brightness, and color processed?
Visual Cortex
What are the two types of ganglion cells and what are their differences?
Paravocellular ganglions cells get input from the cones and are used for color and detail. Magnocellular ganglion cells moslty get input from rods and are used for movement and pattern
