Abstract:

PURPOSE: Previous studies demonstrated that fusiform face area (FFA) is the core region of face processing, which is largely innate and tuned by visual experience. However, the degree to which the face-selectivity of FFA was genetic determined remains unclear. Moreover, evidence is still lacking on elucidating the neural plasticity of the FFA in other sensory modalities (e.g. tactile).
METHODS: To investigate these questions, we studied 38 eyesight obstacle disabled subjects, who consist of four sub-groups: congenital blind, early blind, late blind and low vision. All subjects were trained ~3 hrs on perceiving man-made tactile faces and other complex object categories. Functional magnetic resonance imaging (fMRI) was performed both before and after training.
RESULTS: We found robust face-selective activation in the FFA in both the early blind and low vision subjects after training. In contrast, this was not seen in the congenital blind or late blind subjects.
CONCLUSIONS: Our results suggest that even after more than 14 years of absence of visual face exposure, the FFA can still quickly become engaged in processing face information, and even from a different sensory modality. However, despite of strong genetic determined, the specialization of face processing requires an initial visual driven start.

Key words: fusiform face area, visual experience, cross-modal plasticity, the blind, tactile training