Electrical imaging of light-induced signals within and across retinal layers

Abstract

The mammalian retina processes sensory signals through two major pathways: a vertical excitatory pathway, which involves photoreceptors, bipolar cells and ganglion cells, and a horizontal inhibitory pathway, which involves horizontal cells and amacrine cells. This concept explains the generation of excitatory center – inhibitory surround sensory receptive fields but fails to explain modulation of the retinal output by stimuli outside the receptive field. Electrical imaging of the light-induced signal propagation at high spatial and temporal resolution across and within different retinal layers might reveal mechanisms and circuits involved in the remote modulation of the retinal output. Here I took advantage of a high-density complementary metal-oxide semiconductor -based microelectrode array and investigated light-induced propagation of local field potentials in vertical mouse retina slices. I found that the local field potentials propagation within the different retinal layers depends on stimulus duration and stimulus background. Application of the same spatially restricted light stimuli to flat-mount retina induced ganglion cell activity at remote distances from stimulus center. This effect disappeared if a global background was provided or if gap junctions were blocked. I hereby presented a neurotechnological approach and demonstrated its application, in which electrical imaging evaluates stimulus-dependent signal processing across different neural layers.