bioRxiv2017
Cortical sensory systems often activate in parallel, even when stimulation is experienced through a single sensory modality1-3. Critically, the functional relationship between coactivated cortical systems is unclear: Co-activations may reflect the interactive coupling between information-linked cortical systems or merely parallel but independent sensory processing. Here, we report causal evidence that human somatosensory cortex (S1), which co-activates with auditory cortex during the processing of vibrations and textures4-9, interactively couples to cortical systems that support auditory perception. Acute manipulation of S1 activity using transcranial magnetic stimulation (TMS) impairs auditory frequency perception when subjects simultaneously attend to auditory and tactile frequency, but not when attention is directed to audition alone. Auditory frequency perception is unaffected by TMS over visual cortex thus confirming the privileged coupling between the somatosensory and auditory cortical systems in temporal frequency processing10-13. Our results provide a key demonstration that selective attention can enhance the functional coupling between cortical systems that support different sensory modalities. The gating of crossmodal coupling by selective attention may critically support multisensory interactions and feature-specific perception.\n\nAuthor ContributionsS.C. and J.M.Y. designed the study and wrote the manuscript. S.C. and M.S.R. performed the experiments and analyzed the data. All authors contributed to the final revisions of the manuscript.