Early blindness shifts the feedforward laminar profile of hMT+/V5 from visual to auditory motion

The occipital cortex of people born blind massively enhances its response to sounds, but the brain circuitry supporting such crossmodal plasticity remains elusive. Here we capitalized on ultra-high-field fMRI (7T) coupled with sub-millimetre BOLD and VASO acquisitions to infer whether motion-related information is processed via feedforward or feedback pathways, probing responses to visual motion in sighted participants and auditory motion in both sighted and early blind individuals. By identifying circuitry from layer-dependent activity of the middle temporal cortex (hMT+/V5), we observed that moving, but not static, sounds selectively elicited a feedforward response in the middle layers of hMT+/V5 of blind people, analogous to visual motion processing in sighted individuals. Furthermore, we observed that hMT+/V5 shows enhanced auditory motion-selective connectivity with the Planum Temporale in the sighted and with the cuneus in blind people. These findings reveal that hMT+/V5 implements a feedforward motion selective response profile in sighted and blind individuals, with its sensory input shifting from vision to audition in the absence of visual experience.