Understanding Receptive Fields and Bipolar Cells

These flashcards focus on the definition of receptive fields, the roles of photoreceptors, bipolar cells, and ganglion cells in visual transduction and encoding.

What defines a receptive field in the context of photoreceptors and bipolar cells?

A receptive field is a group of photoreceptors that send inputs to a particular bipolar cell or retinal ganglion cell.

What are the primary photoreceptors in the retina that respond to light?

Cones and rods.

How do on-center and off-center bipolar cells respond differently to glutamate?

On-center bipolar cells have metabotropic glutamate receptors and hyperpolarize in response to glutamate, while off-center bipolar cells have ionotropic glutamate receptors and depolarize in response to glutamate.

What happens to the release of glutamate from photoreceptors in response to light?

Photoreceptors hyperpolarize in response to light, releasing less glutamate.

What neurotransmitter do horizontal cells release in response to glutamate, and what is its function?

Horizontal cells release glycine, which inhibits the central photoreceptor.

Under what condition does an off-center bipolar cell show the highest firing response?

An off-center bipolar cell shows the highest firing response when the center is dark and the surround is light.

What is the effect of a dark center and light surround on off-center ganglion cells?

It causes the most action potentials in the off-center ganglion cells.

What is the key difference between on-center and off-center bipolar cells?

The difference lies in their receptors: on-center cells have metabotropic receptors and off-center cells have ionotropic receptors.

How does the amount of glutamate released affect the action potentials fired by ganglion cells?

More glutamate released from bipolar cells onto ganglion cells leads to more action potentials fired.

In terms of receptor activation, what occurs when the surround is dark for a bipolar cell?

The photoreceptors in the surround depolarize, releasing more glutamate and causing a greater response in the on-center ganglion cell.