Short-term monocular deprivation boosts neural responsiveness to audio-visual events for the undeprived eye

Abstract

A brief period of monocular deprivation (MD) in adults is known to induce short-term plasticity of the visual system. However, to what extent MD impacts beyond visual processing is unclear. Here, we investigated alterations of visual and audio-visual processing induced by MD measuring neural oscillations. Results revealed that MD modified neural activities associated with unimodal and multisensory processes in an eye-specific manner. Selectively for the Deprived eye, alpha activity was reduced within the first 150 ms of visual processing. Conversely, the response to audio-visual events was enhanced in the gamma range only for the Undeprived eye within 100-300 ms after stimulus onset. The analysis of gamma responses to unimodal auditory events clarified that MD elicited a crossmodal upweighting for the Undeprived eye. Source modeling suggested that the right parietal cortex played a major role in both visual and audio-visual MD effects. Notably, visual and audio-visual processing alterations emerged selectively for the induced (but not the evoked) component of the neural oscillations, indicating primary alterations in feedback connectivity. These findings support a model in which MD increases excitability for the Deprived eye and neural responsiveness to audio-visual and auditory events for the Undeprived eye. On the one hand, these results reveal the causal impact of MD on both unisensory and multisensory processes but with distinct frequency-specific profiles and, on the other hand, highlight the feedback nature of short-term neural plasticity. Overall this study shed light on the high flexibility and interdependence of the unimodal and multisensory functions.