In response to light, ON-center ganglion cells do what?

In the context of visual processing, ON-center ganglion cells play a critical role in signaling changes in light intensity. When light is directed toward the center of the receptive field of an ON-center ganglion cell, these cells undergo depolarization.

This depolarization occurs because ON-center ganglion cells receive excitatory input from bipolar cells that are activated by photoreceptors in the presence of light. Specifically, when the photoreceptors, such as rods and cones, are stimulated by light, they hyperpolarize, which reduces the release of the inhibitory neurotransmitter glutamate. This leads to a decrease in inhibition on the bipolar cells connected to the ganglion cells, allowing these bipolar cells to become activated and release their excitatory neurotransmitter, ultimately facilitating the depolarization of the ganglion cells.

As a result of this process, ON-center ganglion cells increase their firing rate in response to light stimulation, allowing for the perception of brightness. This mechanism is integral to the functioning of the visual system, particularly in differentiating light from dark areas in the visual field. Understanding this response is crucial for grasping how the retina processes visual information and how it contributes to overall vision.