Acta physiologica
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Recovery of voluntary movements after partial spinal cord injury depends, in part, on a take-over of function via unlesioned pathways. Using precise forelimb movements in the cat as model, spinal pathways contributing to motor restitution have been investigated in more detail. The food-taking movement by which the cat graSPS a morsel of food with the digits and brings it to the mouth is governed by interneurones in the forelimb segments (C6-Th1) and is normally controlled via the cortico- and rubrospinal tracts. ⋯ Deficits in preshaping during the final approach to the morsel as well as lack of force were observed. A C5 DLF lesion spares corticofugal pathways to the brainstem and upper cervical segments. It is suggested that indirect corticomotoneuronal pathways may provide for recovery of dexterous finger movements and that the role of CM pathways for such movements should be broadened to include not only the monosynaptic connexion.
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Throughout normal life, activity-dependent plasticity occurs in the spinal cord as well as in brain. Like other central nervous system (CNS) plasticity, spinal cord plasticity can occur at numerous neuronal and synaptic sites and through a variety of mechanisms. Spinal cord plasticity is prominent early in life and contributes to mastery of standard behaviours like locomotion and rapid withdrawal from pain. ⋯ Explorations of spinal cord plasticity are necessary for understanding motor skills. Furthermore, the spinal cord's comparative simplicity and accessibility makes it a logical starting point for studying skill acquisition. Induction and guidance of activity-dependent spinal cord plasticity will probably play an important role in realization of effective new rehabilitation methods for spinal cord injuries, cerebral palsy and other motor disorders.