Neurotransmitters and Motor Activity: Effects on Functional Recovery after Brain Injury

Department of Medicine (Neurology), Duke Center for Cerebrovascular Disease, Duke University, Durham, NC 27710, USA.
NeuroRx 11/2006; 3(4):451-7. DOI: 10.1016/j.nurx.2006.07.010
Source: PubMed


There are complex relationships among behavioral experience, brain morphology, and functional recovery of an animal before and after brain injury. A large series of experimental studies have shown that exogenous manipulation of central neurotransmitter levels can directly affect plastic changes in the brain and can modulate the effects of experience and training. These complex relationships provide a formidable challenge for studies aimed at understanding neurotransmitter effects on the recovery process. Experiments delineating norepinephrine-modulated locomotor recovery after injury to the cerebral cortex illustrate the close relationships among neurotransmitter levels, brain plasticity, and behavioral recovery. Understanding the neurobiological processes underlying recovery, and how they might be manipulated, may lead to novel strategies for improving recovery from stroke-related gait impairment in humans.

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    • "The effects of cerebral monoaminergic excesses in the cytotoxic cascade are not understood fully, although in experimental injury models traumatically induced elevations of cerebral serotonin seem to decrease cerebral glucose use,28,29 and serotonin agonists are not particularly helpful in improving post-traumatic neurobehavioral status or TBI outcome.30,31 Administration of catecholamine antagonists impedes recovery from brain injury32-34 and delay emergence from post-traumatic amnesia in humans,35 suggesting that blocking catecholamine excesses is not an effective means by which to mitigate the cytotoxic cascade after TBI. "
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    • "A great deal of investigation has focused on pharmacological means of improving long-term motor outcome. To this end, drugs that enhance central noradrenergic activity have shown some promise for promoting motor recovery following brain injury (Berends et al., 2009;Boyeson and Feeney, 1990;Feeney et al., 2004;Goldstein, 2006). "
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    • "Research on the physiological underpinnings of movement dynamics has traditionally focused most extensively on the primary motor cortex (M1) pointing out that neurons in M1 are modulated by external dynamic perturbations. Some investigators [10] indicate that several premotor areas feed M1 which then projects to the spinal cord. These areas are intensely interconnected with each other, with a parallel contribution to the control of movement [11]. "
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