Curiouser and curiouser: genetic disorders of cortical specialization.

The processes by which cortical areas become specialized for high-level cognitive functions may be revealed by the study of familial developmental disorders such as dyslexia, dyscalculia, prosopagnosia, color agnosia and amusia. These disorders are characterised by the inability to integrate information across multiple areas and the consequent failure to develop representations of the knowledge of some category based on its associated attributes. In contrast, synesthesia may be seen as a hyper-associative condition, possibly due to a failure to properly segregate areas into distinct networks. Here, I consider recent advances in our understanding of the genetic and neurobiological bases of these conditions and the developmental mechanisms underlying the specialization of cortical areas and networks.