What type of potentials do horizontal cells produce?

Horizontal cells in the retina are responsible for providing lateral connections between photoreceptors and bipolar cells, playing a key role in visual processing through mechanisms such as lateral inhibition. The type of signals they generate is primarily graded potentials.

Graded potentials are changes in membrane potential that vary in size, as opposed to action potentials which are all-or-nothing responses. Horizontal cells respond to light and neurotransmitter release from photoreceptors, resulting in hyperpolarization or depolarization. This modulation is vital for adjusting the sensitivity of the retinal response to various light levels and helps in processing visual information.

Through their graded potential generation, horizontal cells can influence the activity of bipolar cells and, subsequently, ganglion cells, facilitating various visual functions including contrast enhancement and spatial resolution. The absence of action potentials in horizontal cells underlines their role in local, graded changes rather than long-range signal propagation typical in neuron firing patterns.