The idea that neural activation may lead to anatomical
and chemical changes in the CNS was first postulated in
the 19th and early 20th centuries by influential figures
such as Darwin, Ramón y Cajal, and Hebb. Further corroboration
of this idea has occurred through numerous
studies conducted over the last 50 or more years [8,43]
and has led to strategies to elicit activity-dependent plasticity
to promote recovery after spinal neurotrauma [1].
As summarized in the Figure, rehabilitative therapies can
promote plasticity both rostral and caudal to injury in the
spinal cord by activating the nervous system and influencing
multiple substrates. One approach to activating the