title: Bimanual recoupling by visual cueing in callosal disconnection.
abstract: The cerebral control of bimanual movements is not completely understood. We investigated a 59-year-old, right-handed man who presented with an acute bimanual coordination deficit. Magnetic resonance imaging showed a lesion involving the entire corpus callosum, which was found on stereotactic biopsy to be an ischemic infarct. Paired-pulse transcranial magnetic stimulation indicated that the patient had a lack of interhemispheric inhibition, while intracortical inhibition in motor cortex of either side was normal. Functional magnetic resonance imaging showed activation of the left SMA, the bilateral motor cortex and anterior cerebellum during spontaneous bimanual thumb-index oppositions, which were uncoupled as evident from simultaneous electromyographic recordings. In contrast, when the bimanual thumb-index oppositions were cued by a visual stimulus, the movements of both hands were tightly correlated. This synchronized activity was accompanied by additional activations bilateral in lateral occipital cortex, dorsal premotor cortex and cerebellum. The data suggest that the visually cued movements of both hands were recoupled by action of a bihemispheric motor network.
authors.affiliation: Department of Neurology, University Hospital Düsseldorf, Düsseldorf, Germany. seitz@neurologie.uni-duesseldorf.de
authors.forename: Rüdiger J
authors.initials: RJ
authors.lastname: Seitz
authors.forename: Raimund
authors.initials: R
authors.lastname: Kleiser
authors.forename: Cathrin M
authors.initials: CM
authors.lastname: Bütefisch
authors.forename: Silke
authors.initials: S
authors.lastname: Jörgens
authors.forename: Oliver
authors.initials: O
authors.lastname: Neuhaus
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Hartung
authors.forename: Hans-Jörg
authors.initials: HJ
authors.lastname: Wittsack
authors.forename: Volker
authors.initials: V
authors.lastname: Sturm
authors.forename: Manuel M
authors.initials: MM
authors.lastname: Hermann
mesh_terms: D000368:Aged; D001706:Biopsy; D002544:Cerebral Infarction / Q000150:complications / Q000503:physiopathology / Q000523:psychology; D003337:Corpus Callosum / Q000473:pathology / Q000503:physiopathology*; D003463:Cues; D004574:Electromagnetic Fields; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*