Hideki Shimazu

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Area F5, in the ventral premotor cortex of the macaque monkey, plays a critical role in determining the hand shape appropriate for grasp of a visible object. F5 neurones show increased firing for particular types of grasp, and inactivation of F5 produces deficits in visually guided grasp. But how is F5 activity transformed into the appropriate pattern of(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)
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)
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)
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)
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)
Tardive dystonia is a disabling movement disorder as a consequence of exposure to neuroleptic drugs. We followed 6 patients with medically refractory tardive dystonia treated by bilateral globus pallidus internus (GPi) deep brain stimulation (DBS) for 21 +/- 18 months. At last follow-up, the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) motor score(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)
The endometrial cavity may demonstrate various imaging manifestations such as normal, reactive, inflammatory, and benign and malignant neoplasms. We evaluated usual and unusual magnetic resonance imaging (MRI) findings of the uterine endometrial cavity, and described the diagnostic clues to differential diagnoses. Surgically proven pathologies of the(More)
Basal ganglia encompass four to five distinct loops to allow parallel processing of information. Among them, the most intensively studied is the motor loop, which includes two distinct direct and indirect pathways. The direct pathway exerts facilitatory influence upon the motor cortex, whereas the indirect pathway exerts an inhibitory effect. Overall, this(More)