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Corticospinal tract development and its plasticity after perinatal injury

Lookup NU author(s): Professor Janet Eyre

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Abstract

The final pattern of the origin and termination of the corticospinal tract is shaped during development by the balance between projection and withdrawal of axons. In animals, unilateral inhibition of the sensorimotor cortex during development results in a sparse contralateral projection from this cortex and retention of a greater number of ipsilateral projections from the more active cortex. Similarly in subjects with hemiplegic cerebral palsy if transcranial magnetic stimulation (TMS) of the damaged motor cortex fails to evoke responses in the paretic upper limb, TMS of the undamaged ipsilateral motor cortex evokes abnormally large and short-onset responses. Rather than representing a "reparative plasticity in response to injury", this review presents evidence that increased ipsilateral projections from the non-infarcted motor cortex arise from perturbation of ongoing developmental processes, whereby reduced activity in the damaged hemipshere, leads to increased withdrawal of its surviving contralateral corticospinal projections because their terminals have been displaced by the more active ipsilateral projections of the undamaged hemisphere and thereby adding to the degree of long-term motor impairment. © 2007 Elsevier Ltd. All rights reserved.

Publication metadata

Author(s): Eyre JA

Publication type: Review

Publication status: Published

Journal: Neuroscience and Biobehavioral Reviews

Year: 2007

Volume: 31

Issue: 8

Pages: 1136-1149

Print publication date: 01/01/2007

ISSN (print): 0149-7634

ISSN (electronic): 1873-7528

URL: http://dx.doi.org/10.1016/j.neubiorev.2007.05.011

DOI: 10.1016/j.neubiorev.2007.05.011

PubMed id: 18053875

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