Cross-modal plasticity after monocular enucleation of the adult rabbit.

The mature brain undergoes compensatory reorganization of the primary visual cortex (V1) in response to retinal lesions. This study demonstrates that V1 also supports cross-modal reorganization by observing an increase in tactile responses in V1 after monocular enucleation of the adult rabbit. The proportion of tactile-responsive V1 neurons increased from 0% to 31%, in an area of cortex equivalent to 40 degrees of visual space. Retrograde fiber-tracing analysis suggests that intracortical connections from association areas may underlie these novel responses. Cortical plasticity of this kind may be involved in recovery from sensory system damage and could provide an enhanced sense of touch to the blind.