Sources and sinks of light-evoked Δ[K+]o in the vertebrate retina

Abstract

In the vertebrate retina, recordings of light-evoked changes in extracellular K⁺ concentration Δ[K⁺]_o are of particular interest because this tissue is complex and multilayered, yet can be activated routinely with its "natural" stimulus (i.e., light). This review identifies the components of the spatiotemporal profile of retinal light-evoked Δ[K⁺]_o and then presents evidence concerning the specific neural origins of these components as well as the mechanisms by which these Δ[K⁺]_o are dispersed from extracellular space. Finally, to gain improved resolution of K⁺ sources and sinks, the technique of ion source density is introduced and applied to both model and real spatiotemporal distributions of Δ[K⁺]_o.