title: Enhanced motor cortical excitability in the unaffected hemisphere after hemispherectomy.
abstract: We evaluated motor cortical excitability of the unaffected hemisphere in three patients with intractable epilepsy who underwent hemispherectomy, using transcranial magnetic stimulation (TMS) and PET. TMS of the unaffected hemisphere evoked motor responses not only in the contralateral muscles but also in the ipsilateral ones in all the patients. A PET study in one patient showed activation of the unaffected motor cortex by movement of either arm. All of these responses were enhanced after the hemispherectomy, probably due to motor cortical disinhibition by transection of the corpus callosum. The PET study also showed postoperative activation of the premotor area of the unaffected hemisphere. These phenomena indicate posthemispherectomy neuroplastic reorganization leading to preservation of the motor function after the operation.
authors.affiliation: Department of Neurology, Tokyo Metropolitan Neurological Hospital, Fuchu, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Shimizu
authors.forename: T
authors.initials: T
authors.lastname: Nariai
authors.forename: T
authors.initials: T
authors.lastname: Maehara
authors.forename: T
authors.initials: T
authors.lastname: Hino
authors.forename: T
authors.initials: T
authors.lastname: Komori
authors.forename: H
authors.initials: H
authors.lastname: Shimizu
authors.forename: S
authors.initials: S
authors.lastname: Hirai
authors.forename: M
authors.initials: M
authors.lastname: Senda
mesh_terms: D000328:Adult; D002541:Cerebral Decortication; D002560:Cerebrovascular Circulation / Q000502:physiology; D002648:Child; D003337:Corpus Callosum / Q000502:physiology; D004558:Electric Stimulation; D004827:Epilepsy / Q000000981:diagnostic imaging / Q000601:surgery*; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008280:Magnetics; D008297:Male; D009044:Motor Cortex / Q000503:physiopathology* / Q000601:surgery; D009416:Nerve Regeneration / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D020127:Recovery of Function / Q000502:physiology*; D014055:Tomography, Emission-Computed