Visually evoked potentials (VEPs) across the visual field in hearing and deaf cats

IntroductionCongenitally deaf cats perform better on visual localization tasks than hearing cats, and this advantage has been attributed to the posterior auditory field. Successful visual localization requires both visual processing of the target and timely generation of an action to approach the target. Activation of auditory cortex in deaf subjects during visual localization in the peripheral visual field can occur either via bottom-up stimulus-driven and/or top-down goal-directed pathways. MethodsIn this study, we recorded visually evoked potentials (VEPs) in response to a reversing checkerboard stimulus presented in the hemifield contralateral to the recorded hemisphere in both hearing and deaf cats under light anesthesia. ResultsAlthough VEP amplitudes and latencies were systematically modulated by stimulus eccentricity, we found little evidence of changes in VEP in deaf cats that can explain their behavioral advantage. A statistical trend was observed, showing larger peak amplitudes and shorter peak latencies in deaf subjects for stimuli in the near- and mid-peripheral field. Additionally, latency of the P1 wave component had a larger inter-sweep variation in deaf subjects. DiscussionOur results suggested that cross-modal plasticity following deafness does not play a major part in cortical processing of the peripheral visual field when the vision for action system is not recruited.

Automated summary

Congenitally deaf cats perform better than hearing cats on visual localization tasks, but the reasons behind this advantage remain unclear. In this study, visually evoked potentials (VEPs) were recorded in both hearing and deaf cats during a reversing checkerboard stimulus. The results showed that while VEPs were influenced by stimulus eccentricity, there was little evidence of changes in VEPs that could explain the behavioral advantage of deaf cats. These findings suggest that cross-modal plasticity may not play a significant role in the cortical processing of the peripheral visual field in deaf subjects.