Neural reuse in the organization and development of the brain.

Neural reuse is the process by which neural elements originally developed for one purpose are put to many different subsequent uses. In this brief review I will outline the role of neural reuse in the development of the brain. Special attention will be paid to elucidating and differentiating between two different mechanisms of neurocognitive development: Hebbian plasticity, the importance of which is already well known, and a neural search mechanism that supports the establishment of new functional partnerships in the brain. I describe how these two mechanisms work in concert throughout development to produce the functional architecture we observe in the adult brain; outline the evidence for the importance of neural reuse; offer suggestions for some clinical implications of neural reuse; and point to future research directions.