ELECTROPHYSIOLOGICAL ASSESSMENT OF VISUAL CORTICAL ACTIVITY IN MOUSE MODELS OF RETINAL DEGENERATION

Retinal degeneration (RD) results in progressive loss of photoreceptors (rods and cones), which leads to profound changes in the downstream visual pathway. Extensive research has characterized retinal remodeling during RD; however, the subsequent effects on cortical function remain poorly understood. The present study examines baseline and visual evoked electrophysiological activity in the primary visual cortex (V1), using two mouse models of RD—the genetic rd1 and N-methyl-N-nitrosourea (MNU) induced degeneration model, along side C57BL/6 (control) mice. Retinal evaluation was carried out to confirm degeneration associated structural and cellular alterations. In-vivo electrophysiological recordings were obtained from V1 to evaluate spontaneous and stimulus driven cortical activity. Baseline cortical dynamics were analyzed using low frequency power spectral density (PSD) analysis to assess different frequency specific oscillatory patterns, while sensory evoked responses were assessed using controlled light emitting diode (LED) stimulation, and visual evoked potentials (VEPs) were analyzed. Comparative analysis across groups revealed differences in both baseline oscillatory activity and VEP responses between control and RD models, with both the RD models exhibiting different electrophysiological profiles. The results demonstrate that genetic and chemically induced RD are associated with measurable changes in visual cortical activity, establishing a foundation for future investigation into visual circuit function for restoration of vision during reduced retinal input and will be helpful for the development of strategies to restore high resolution vision.