Abstract
The contributions of innate predispositions versus experience to face-selectivity in vOTC is hotly debated. Recent studies with people born blind suggest face specialization emerges regardless of experience. In blindness the FFA is said to process face shape, accessed through touch or sound, or maintain its behavioral role in person recognition by specializing for human voices. We hypothesized instead that in blind people the anatomical location of the FFA responds to language.
While undergoing fMRI, congenitally blind English speakers (N=12) listened to spoken language (English), foreign speech (Russian, Korean, Mandarin), non-verbal vocalizations (e.g., laughter) and control non-human scene sounds (e.g., forest sounds) during a 1-back repetition task. Participants also performed a ‘face localizer’ task by touching 3D printed models of faces and control scenes and a language localizer (spoken words > backwards speech, Braille > tactile shapes). We identified individual-subject ROIs inside a FFA mask generated from sighted data.
In people born blind, the anatomical location of the FFA showed a clear preference for language over all other sounds, whether human or not. Responses to spoken language were higher than to foreign speech or non-verbal vocalizations, which were not different from scene sounds. This pattern was observed even in parts of vOTC that responded more to touching faces.
Specialization for faces in vOTC is influenced by experience. In the absence of vision, lateral vOTC becomes implicated in language. We speculate that shared circuits that evolved for communication specialize for either face recognition or language depending on experience.