Aligned representation of visual and tactile motion directions in hMT+/V5 and fronto-parietal regions

Abstract

Moving events on the skin can be perceived through vision and touch. How does the brain create a unified multisensory representation of motion directions initially acquired in different coordinate systems? Using functional magnetic resonance imaging, we demonstrate that individually and functionally defined hMT+/V5 shows univariate preference for both visual and tactile motion and encodes motion directions across hand postures. Unlike somatosensory regions, information about tactile directions is enhanced in right hMT+/V5 when mapped using an external rather than a somatotopic frame of reference. Crossmodal decoding reveals alignment between tactile and visual motion directions in the right hMT+/V5 (both in MT and MST) only when tactile motion is defined in external space. A whole-brain searchlight analysis extends this aligned representation to parietal and frontal regions. Our findings reveal a network involving right hMT+/V5 and fronto-parietal regions that encodes motion directions in vision and touch using a common external frame of reference.