Abstract
INTRODUCTION: It is well known that face perception is mediated in the ventral visual pathway. Although face activation in this part of cortex has been reported in late blind (LB), contradictory results have been found in congenital blind (CB) subjects. Here we directly compared CB and LB subjects and asked whether training on tactile face perception would produce the same or different effects in the ventral pathway of the two groups. METHODS: We used a non-visual drawing-based training paradigm (Likova 2010) to train and study groups of CB and LB subjects. Each subject was required to explore a set of raised-line tactile face profiles with left hand. These profiles were different from each other in appearance and expression. A five-day one-hour training was applied to learn to recognize and reproduce the fine facial characteristics. FMRI (Siemens 3T scanner) was run before and after the training. The group activation maps for the two groups were generated and shown on a single brain. Bilateral regions of interest (ROI) - LOC, FFA, and OFA, were defined. RESULTS AND CONCLUSIONS: Differential activation was found across the two hemispheres. In the left hemisphere, before training the CB-group showed minimal activation in all three ROIs in contrast to strong activation after training, while the LB-group showed the opposite effect of strong activation before training in contrast to reduced activation after training. In the right hemisphere, the training effect was minimal, although generally in the same direction, with the exception of LOC, which hardly showed any significant change in both groups. These results are of importance for better understanding of brain plasticity and rehabilitation strategies in two types of blindness.
Meeting abstract presented at VSS 2012