Visual deprivation leads to the involvement of occipital (visual) regions in the processing of non-visual inputs. These mechanisms of crossmodal plasticity, classically considered compensatory, inevitably raise crucial challenges for sight-restoration. In the current study, we had the unique opportunity to track the behavioral and neurophysiological changes taking place in the occipital cortex of an early visually deprived patient before and after partial sight restoration with Boston Keratoprosthesis. The patient was tested 3 weeks before, as well as 1.5 and 7 months after the surgery with identical behavioral and fMRI tasks. Behavioral tasks consisted of computerized tests evaluating visual acuity, contrast sensitivity, global motion perception, and face categorization and individuation. Each fMRI session comprised 2 visual runs testing the integrity of face-selective and motion-selective networks, and 2 auditory runs investigating the presence of general and specific crossmodal reorganizations. The success of the intervention was witnessed by massive improvements in visual functions. fMRI analyses revealed (1) massive auditory responses in occipital regions, which were still existing 7 months post-surgery, but significantly reduced when compared to pre-surgery; (2) a regain of specific responses to visual motion 7 months post-surgery relative to pre-surgery in early visual regions (3) no between sessions differences in higher level regions involved in face- (FFA, OFA) and motion- (hMT+/V5) processing suggesting that even rudimentary vision may set the functional tuning of these regions. Finally, we observe massive structural changes in primary occipital cortex as soon as 1.5 months after surgery. Present results are the first to unravel the important neuro- functional and structural changes ensuing sight restoration and are clinically important given the therapeutic advances in sensory-restoration.

fMRI - Blindness - Sight restoration - Boston Keratoprosthesis - Crossmodal plasticity - Face processing - Motion processing