Bimanual recoupling by visual cueing in callosal disconnection.
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.
Seitz
Rüdiger J
RJ
Department of Neurology, University Hospital Düsseldorf, Düsseldorf, Germany. seitz@neurologie.uni-duesseldorf.de
Kleiser
Raimund
R
Bütefisch
Cathrin M
CM
Jörgens
Silke
S
Neuhaus
Oliver
O
Hartung
Hans-Peter
HP
Wittsack
Hans-Jörg
HJ
Sturm
Volker
V
Hermann
Manuel M
MM
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*