Implications of Axonal Disease for Repair and Regeneration in the Nervous System

Axonal regeneration in the PNS was a primary subject of the classical phase of neurobiology, culminating in the prescient insights of Santiago Ramon y Cajal? The capacity lOr effective axonal outgrowth historically was thought to be restricted to the PNS, and to distinguish it from the central nervous system. The present wave of new investigation and excitement in this field is fueled by advances in cellular and molecular neurobiology, by the use of tissue culture systems to dissect cellular interactions, and by the demonstration that PNS grafts can support axonal regeneration by CNS neurons. The sobering counterweight to this enthusiasm is the recognition that in man even PNS regeneration usually remains liustratingly incomplete.