Chronic Stress Induces Retinal Ganglion Cell Degeneration Featuring Reduced Density, Altered Intrinsic Electrophysiology, and Light Responses

Depression is often associated with functional disturbances in the visual system. However, the fundamental features underlying these visual system aberrations in depression remain to be fully elucidated. In particular, in the first stage of visual processing, how different retinal output neuron types change their intrinsic properties and output features in response to specific light stimulation remains unclear. Here, by adopting a mouse model of depression induced by chronic unpredictable stress (CUS), we found that depression is associated with reduced blood perfusion in the retinal inner plexiform layer (IPL). The hypoperfusion in the IPL is paralleled by a remarkable reduction of retinal ganglion cell (RGC) density, with more cell loss in ipRGCs than in the general RGCs. The surviving RGCs—particularly, ipRGCs—changed their intrinsic electrical properties, exhibiting decreased membrane input resistance, more depolarized resting membrane potential, and altered spiking properties. Additionally, these cells showed stimulus-size-dependent increases in light-evoked responses. Together, our findings demonstrate that depression is associated with the retinal IPL hypoperfusion and RGC impairments (particularly ipRGCs) and suggest retinal layer- and RGC-type-specific susceptibilities, furthering our understanding of retinal pathophysiology in depression.