Activity-dependent plasticity in spinal cord injury

Abstract

Abstract-The adult mammalian central nervous system (CNS) is capable of considerable plasticity, both in health and disease. After spinal neurotrauma, the degrees and extent of neuroplasticity and recovery depend on multiple factors, including the level and extent of injury, postinjury medical and surgical care, and rehabilitative interventions. Rehabilitation strategies focus less on repairing lost connections and more on influencing CNS plasticity for regaining function. Current evidence indicates that strategies for rehabilitation, including passive exercise, active exercise with some voluntary control, and use of neuroprostheses, can enhance sensorimotor recovery after spinal cord injury (SCI) by promoting adaptive structural and functional plasticity while mitigating maladaptive changes at multiple levels of the neuraxis. In this review, we will discuss CNS plasticity that occurs both spontaneously after SCI and in response to rehabilitative therapies.

Effect of Locomotor Training in Completely Spinalized Cats Previously Submitted to a Spinal Hemisection

“…The fact that left/right asymmetries that occurred after hemisection were shown to reverse after a 3 week period of training indicates that new left/right equilibrium was achieved in the spinal cord through locomotor activity and suggests that the spinal networks below the first lesion were more sensitive to the repetitive sensory inputs provided by treadmill training. Accordingly, improvement of locomotor capacities of the limb affected by a partial SCI by training has already been reported in rodents (Goldshmit et al, 2008;Martinez et al, 2009) and humans (Visintin et al, 1991;Dietz and Harkema, 2004) and can be attributable to several neural mechanisms (for review, see Lynskey et al, 2008). The fast reversion of left/right asymmetries observed in trained cats suggests that changes have occurred in the functional connectivity of the central pattern generators (CPG) controlling left and right HLs.…”

Recovery of hindlimb locomotion after incomplete spinal cord injury in the cat involves spontaneous compensatory changes within the spinal locomotor circuitry

“…Since the expression of numerous plastic mechanisms can depend on a high level of maintained activity within the neural networks (Fouad and Pearson 2004;Lynskey et al 2008;Martinez et al 2009; Thomas and Gorassini 2005), we first asked whether locomotor training was specifically needed to induce this spinal reorganization and, second, whether such changes occur when the delay between the two lesions is short.…”

Effectiveness of intense, activity-based physical therapy for individuals with spinal cord injury in promoting motor and sensory recovery: Is olfactory mucosa autograft a factor?

“…In rodent and feline models, exercise and locomotor training led to partial recovery of locomotion and spinal cord neurological recovery. [3][4][5][6] Human studies have focused on the effects of body weight-supported treadmill training (BWSTT) [7][8][9] and functional electric stimulation cycling. [10][11][12] Considerable evidence demonstrates that individuals with incomplete SCI have the potential to transition from BWSTT and regain over-ground ambulation; 7,8,13,14 however, even when the SCI is complete, the neural networks below the level of the lesion generate locomotor activity.…”

“…17,23 Many have advocated for multifaceted approaches to therapy for individuals with SCI. 5,[24][25][26] Individuals with SCI who participated in a multi-modal, intense exercise program improved their American Spinal Injury Association (ASIA) total motor scores (TMS) and lower extremity motor scores (LEMS). 27 TMS gains correlated with total hours per week spent in intense exercise.…”