Towards closing the gap between visual neuroprostheses and sighted restoration: Insights from studying vision, cross-modal plasticity and sensory substitution

Abstract

Restoration of sight imposes clinical and scientific challenges. Despite intensive efforts, restoration of functional vision using neuroprostheses has not been achieved. A major reason for this failure might be that the brain in the blind undergoes profound plasticity and we do not know enough about vision and about how to communicate with this altered cortex to generate meaningful visual perception. New findings regarding the nature of representation of visual functions (such as perception versus imagery of object¹) or tactile functions² in sighted and weeklong blindfold subjects will be presented. These studies show that interactions between sensory modalities are critical to our understanding of sensory representations in the brain. Next, I will review recent studies showing robust plasticity in the visual cortex of blind using fMRI and TMS as a virtual lesion tool to assess the functional relevance of these plastic changes in the tactile and language domains³. Finally, sensory substitution devices (SSD) and will be discussed. In SSD, visual information captured by an artificial receptor is delivered to the brain using non-visual sensory information via a human-machine interface. Specifically, blind and sighted using an auditory-to-visual SSD called “The vOICe” are showing both successful performance behaviorally and specialized recruitment of visual structures (such as the ‘visual’ object related area LOC)⁴. This suggests “The vOICe” can be used for daily activities such as object recognition and might have the potential to play a role in ‘guiding’ the visual cortex to interpret visual information arriving from a retinal prosthesis in a blind subject^4,5,6.

Footnotes

 Supported by grants from the National Institutes of Health (K24 RR018875 and RO1-EY12091; PI, Alvaro Pascual Leone).  Amir Amedi is supported by The International Human Frontier Science Program Organization.