title: Expansion of sensorimotor cortical activation for unilateral hand motion during contralateral hand deafferentation.
abstract: Acute deprivation of unilateral sensory input rapidly enhances contralateral hand motor function, but the underlying mechanisms remain poorly understood. We herein used functional MRI to evaluate, in 14 healthy individuals, motor cortical activation for right finger motion before, during, and after sensory deprivation of left forearm induced by reversible, noninvasive ischemic nerve block (INB). Before INB, the motor task activated the left primary sensorimotor cortex (SM1) as expected. During INB, the volume of the left SM1 activation significantly increased, and, after INB, it returned to the pre-INB, baseline level. The effectiveness of the INB of the left forearm was ensured by confirming disappearance of the activation in right primary sensory cortex that is normally caused by tactile stimulation of the left index finger. These findings demonstrate that acute deafferentation of unilateral forearm causes rapid and reversible changes in the neural substrates for contralateral finger motion, mediated possibly by attenuation of transcallosal interhemispheric inhibition.
authors.affiliation: aDepartment of Neurosurgery bCenter for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Niigata, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kurabe
authors.forename: Kosuke
authors.initials: K
authors.lastname: Itoh
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Matsuzawa
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nakada
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Fujii
mesh_terms: D000344:Afferent Pathways / Q000502:physiology; D001931:Brain Mapping / Q000295:instrumentation / Q000379:methods*; D005260:Female; D005385:Fingers / Q000502:physiology*; D005542:Forearm / Q000294:innervation; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009068:Movement / Q000502:physiology*; D009407:Nerve Block / Q000706:statistics & numerical data; D009473:Neuronal Plasticity / Q000502:physiology*; D066191:Sensorimotor Cortex / Q000502:physiology*; D013997:Time Factors; D014110:Touch / Q000502:physiology; D055698:Touch Perception / Q000502:physiology; D055815:Young Adult