Elucidating the functional specialization of motion sensitive cortical regions in congenitally blind and sighted adults.

摘要

The human motion-sensitive middle temporal cortex, known as the hMT+ complex, is responsible for processing different types of visual motion cues in sighted individuals. It has been suggested that hMT+ may be a supramodal area, with evidence from fMRI studies showing BOLD responses to both tactile and auditory motion within this region (Hagen et al., 2002; Poirier et al., 2005). Furthermore, research has shown that hMT+ responds to auditory and tactile motion in early blind individuals (Jiang, Stecker, & Fine, 2014; Matteau, Kupers, Ricciardi, Pietrini, & Ptito, 2010). This study aims to elucidate the functional specialization of hMT+ in response to auditory and tactile motion in early blind and sighted individuals. Specifically, the supramodal nature of hMT+ is assessed using fMRI. Tactile and auditory motion tasks are administered to early blind and sighted adults to ascertain whether 1) auditory and tactile motion cues result in BOLD responses in hMT+, 2) BOLD responses to tactile and auditory motion cues overlap within hMT+, or 3) whether these motion cues are processed in functionally distinct cortical regions in both groups, as has previously been found for tactile and visual motion in sighted individuals (Jiang, Beauchamp, & Fine, 2015). This study comprises four early blind and four sighted controls presented with tactile motion (brush stimulating the volar forearm) and auditory motion (looming and receding sounds). An additional visual motion task (looming and receding ball) and visual field localizers are employed to map hMT+ within the sighted group. Individual subject analyses reveal the functional specialization of hMT+ in both early blind and sighted controls. The results of the current study go towards understanding the role of hMT+ in processing motion cues in early blind adults and have far-reaching implications for the design of sensory substitution devices for this cohort.