Blindness

blindness-pic

Studying the blind brain enables studying how the visual cortex becomes organized to process information through other senses. It is traditionally considered that the visual cortex requires visual experience during early development (in critical or sensitive periods), to develop its proper structure and abilities. My neuroimaging (fMRI) research, along with that of other groups, shows that some of its roles can actually be acquired without any visual experience, so long as they are carried out with other senses.

For example, the visual “word-form area” can still process letters and the visual “extrastriate body area” can still respond to body-shapes, when those are conveyed with a sensory substitution device (see here). Even large-scale organization principles of the visual cortex, such as the division-of-labor between the ventral “what” processing stream and dorsal “where and how” stream can be found in the blind, as well as the connectivity basis for spatial, retinotopic, mapping of the visual cortex.

visual cortex activations in the blind

These findings suggest that these brain regions develop to conduct specific tasks or computations, regardless of the sense in which information is provided, and without relying on visual experience. This type of organization can form on the basis of the brain’s connectivity patterns which develop prior to birth, and can direct “visual cortex” regions to organize to their roles.

In order to test how general the idea of cortex organization which is invariant to specific senses is, I also test brain organization in people born deaf (testing organization of the auditory cortex) or dysmelic (testing interactions between vision and motor actions, as well as touch and motor acts on their own).