Beat Detection Recruits the Visual Cortex in Early Blind Subjects

Thick visual cortex in the early blind.

We investigated the key neurodevelopmental factors that determine cortical thickness, namely synaptogenesis and regression, by analyzing the thickness of the visual cortex in humans with early- and late-onset blindness. The bilateral visual cortices of the early blind were significantly thicker than those of the late blind and the sighted controls, but the latter two groups did not differ signi...

Improved beat asynchrony detection in early blind individuals.

Although early blind (EB) individuals are thought to have a better musical sense than sighted subjects, no study has investigated the musical rhythm and beat processing abilities in EB individuals. Using an adaptive 'up and down' procedure, we measured the beat asynchrony detection threshold and the duration discrimination threshold, in the auditory and vibrotactile modalities in both EB and si...

Visual cortex activity in early and late blind people.

Different activation patterns in the visual cortex of late and congenitally blind subjects.

A key issue in developmental neuroscience is the role of activity-dependent mechanisms in the epigenetic induction of functional organization in visual cortex. Ocular blindness and ensuing visual deprivation is one of the rare models available for the investigation of experience-dependent cortical reorganization in man. In a PET study we demonstrate that congenitally blind subjects show task-sp...

Changes in visual cortex excitability in blind subjects as demonstrated by transcranial magnetic stimulation.

Any attempt to restore visual functions in blind subjects with pregeniculate lesions provokes the question of the extent to which deafferented visual cortex is still able to generate conscious visual experience. As a simple approach to assessing activation of the visual cortex, subjects can be asked to report conscious subjective light sensations (phosphenes) elicited by focal transcranial magn...