Visual cortex responds to transient sound changes without encoding complex auditory dynamics [post]

David Brang, John Plass, Aleksandra Sherman, William C. Stacey, Vibhangini S. Wasade, Marcia Grabowecky, EunSeon Ahn, Vernon L. Towle, James X Tao, Shasha Wu, Naoum P Issa, Satoru Suzuki
2019 unpublished
Signals encoded in one sensory modality can enhance cortical sensitivity for co-occurring signals in another modality. Previous research has demonstrated that this facilitation occurs through crossmodal modulations of cortical oscillatory activity. However, the source and content of the information conveyed by this mechanism remain poorly understood. Using human electrocorticography (ECoG), we examined the temporal dynamics of crossmodal modulations to identify the level of hierarchical coding
more » ... t which auditory information is transmitted to visual cortex. Multiple visual areas displayed transient onset and offset responses to amplitude-modulated sounds, but no entrainment to amplitude modulation frequencies. These results suggest that auditory information conveyed to visual cortex does not include temporally fine-grained stimulus dynamics encoded by the auditory midbrain and thalamus but, rather, a temporally segmented representation of auditory events that emerges only in auditory cortex. Crossmodal responses were maximal in low-level visual cortex (putative V1/V2) and lateral occipital cortex (putative V5/hMT+), potentially implicating a direct pathway for rapid interactions between low-to-mid-level auditory and visual cortices. This mechanism may facilitate perception by time-locking visual computations to environmental events marked by discontinuities in auditory input.
doi:10.31234/osf.io/kgn5h fatcat:xgrmf4apwvdp3nzrt4qn3iu2ia