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The ventral premotor area (F5) is part of the cortical circuit controlling visuomotor grasp. F5 could influence hand motor function through at least two pathways: corticospinal projections and corticocortical projections to primary motor cortex (M1). We found that stimulation of macaque F5, which by itself evoked little or no detectable corticospinal(More)
OBJECTIVE To investigate cortical control of the electromyogram (EMG). METHODS We examined the directed transfer function (DTF) between the EMG and local field potential oscillations in the monkey sensorimotor area during both an isotonic muscle contraction task and the rest condition with EMG silence. DTF computation based on a multivariate model is(More)
Somatosensory-evoked potentials (SEPs) are attenuated by movement. This phenomenon of 'gating' reflects sensorimotor integration for motor control. The frontal N30 component after median nerve stimulation was shown to be reduced in amplitude prior to hand movement. To investigate the mechanism of this sensory gating, we recorded median SEPs immediately(More)
OBJECTIVE To optimize the clinical uses of repetitive transcranial magnetic stimulation (rTMS), we compared the effects of rTMS on somatosensory-evoked potentials (SEPs) and regional cerebral blood flow (rCBF) using different phases (monophasic vs. biphasic) or frequencies (0.2Hz vs. 0.8Hz) of stimulation. METHODS In the first experiment, different phases(More)
Previously, we introduced a monkey model for human frontal midline theta oscillations as a possible neural correlate of attention. It was based on homologous theta oscillations found in the monkey's prefrontal and anterior cingulate cortices (areas 9 and 32) in a self-initiated hand-movement task. However, it has not been confirmed whether theta activity in(More)
One characteristic of focal dystonia is the sensory trick, by which sensory input to a certain area of the body can reduce abnormal contractions in muscles nearby. This suggests that adjusting the link between sensory input and movement allows motor commands to be issued more effectively from the brain. To explore this sensorimotor link, we studied the(More)
Dystonia is a neurological syndrome characterized by sustained muscle contractions that produce repetitive twisting movements or abnormal postures. X-linked recessive dystonia parkinsonism (XDP; DYT3; Lubag) is an adult-onset disorder that manifests severe and progressive dystonia with a high frequency of generalization. In search for the anatomical basis(More)
Camptocormia, known also as "bent spine syndrome", is characterized by involuntary truncal flexion of the thoraco-lumbar spine that appears in the sitting or standing position. Although Parkinson's disease (PD) is the most frequent etiologic factor, this postural disorder responds poorly to levodopa or other medications. We report a PD patient in whom(More)
Camptocormia becomes increasingly recognized as a disabling symptom associated with Parkinson's disease (PD). We here report six patients with advanced PD in whom continuous bilateral stimulation of the subthalamic nucleus produced substantial (mean 78% +/- 9.1% of the thoracolumbar angle) improvement of camptocormia along with other motor symptoms.
Recent evidence has suggested that theta-frequency (4-7 Hz) oscillations around the human anterior cingulate cortex (ACC) and frontal cortex--that is, frontal midline theta (Fm theta) oscillations--may be involved in attentional processes in the brain. However, little is known about the physiological basis of Fm theta oscillations because invasive study in(More)