Biomaterial Database

Reorganization of corticospinal pathways following spinal cord injury. 1991

H Topka, and L G Cohen, and R A Cole, and M Hallett

Human Cortical Physiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.

To assess changes in the relationship between cortical motor representation areas and their target muscles following spinal cord lesions, we studied motor evoked potentials (MEPs) to transcranial magnetic stimulation in six patients with complete spinal cord injuries at low thoracic levels and eight healthy subjects. Magnetic stimulation at rest activated a larger fraction of the motoneuron pool and evoked MEPs with shorter latencies from a larger number of scalp positions in muscles immediately rostral to the level of a spinal cord injury than in corresponding muscles in controls. The MEPs associated with maximal voluntary activation were not significantly different in the two groups. These results suggest enhanced excitability of motor pathways targeting muscles rostral to the level of a spinal transection, reflecting reorganization of motor pathways either within cortical motor representation areas or at the level of the spinal cord. The data do not allow the determination of the contribution of spinal or cortical mechanisms. However, they support the notion of a limited flexible relationship between primary motor cortex and its target muscles following alterations of normal input-output patterns.

UI	MeSH Term	Description	Entries
D008280	Magnetics	The study of MAGNETIC PHENOMENA.	Magnetic
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D009046	Motor Neurons	Neurons which activate MUSCLE CELLS.	Neurons, Motor,Alpha Motorneurons,Motoneurons,Motor Neurons, Alpha,Neurons, Alpha Motor,Alpha Motor Neuron,Alpha Motor Neurons,Alpha Motorneuron,Motoneuron,Motor Neuron,Motor Neuron, Alpha,Motorneuron, Alpha,Motorneurons, Alpha,Neuron, Alpha Motor,Neuron, Motor
D009068	Movement	The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.	Movements
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
D009434	Neural Pathways	Neural tracts connecting one part of the nervous system with another.	Neural Interconnections,Interconnection, Neural,Interconnections, Neural,Neural Interconnection,Neural Pathway,Pathway, Neural,Pathways, Neural
D011930	Reaction Time	The time from the onset of a stimulus until a response is observed.	Response Latency,Response Speed,Response Time,Latency, Response,Reaction Times,Response Latencies,Response Times,Speed, Response,Speeds, Response
D002540	Cerebral Cortex	The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulci. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions.	Allocortex,Archipallium,Cortex Cerebri,Cortical Plate,Paleocortex,Periallocortex,Allocortices,Archipalliums,Cerebral Cortices,Cortex Cerebrus,Cortex, Cerebral,Cortical Plates,Paleocortices,Periallocortices,Plate, Cortical
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical