Audio-Visual + Attention at high-resolution

Description: In our natural environment our senses are bombarded with a myriad of diverse signals, only a subset of which is relevant for our current goals. Using sub-millimeter-resolution fMRI at 7T we resolved BOLD response and activation patterns across cortical depth in early sensory cortices to auditory, visual and audiovisual stimuli under auditory and visual attention. Irrespective of attention, auditory stimulation induced widespread inhibition in visual cortices, while auditory relative to visual attention suppressed mainly central visual field representations. Conversely, visual stimulation suppressed activations in auditory cortices, but amplified the response to concurrent auditory stimuli, in a patchy topography. Critically, the competitive and cooperative multisensory interactions in auditory cortices were stronger in relatively deeper cortical laminae, while attentional influences were greatest at the cortical surface. These distinct depth-dependent activation profiles suggest that multisensory and attentional mechanisms regulate sensory processing via partly distinct neural circuitries. Our findings are crucial for understanding how the human brain flexibly regulates information flow across the senses to interact effectively with our complex multisensory world.