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ABSTRACT: Skillful motor control by humans is achieved by the appropriate motor commands generating from the central nervous system.
An internal model in the cerebellum may contribute to the realization of accurate motor control. In this work, a model of
human motor control of manual tracking to move a visible target was constructed based on experimental data from a visual tracking
test with normal healthy adults and with patients with cerebellar ataxia. A compensation method to improve the motor function
of patients was also developed by using the model.
Artificial Life and Robotics 04/2012; 7(3):112-117.
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ABSTRACT: Deep brain stimulation (DBS) is a effective treatment method for patients with Parkinson's disease (PD). In this study, a quantitative evaluation for the availability of DBS operation to PD patients were done by use of a visual tracking test. Visual target with random trajectory was adopted and the hand movement of three PD patients were recorded in the state before and after surgery. Parameters related to the tremor, rigidity, akinesia and so on were calculated and the effect of DBS operation was quantitatively evaluated. Remarkable improvement was validated through the parameters. In addition to the above analysis, comparison of the motor function between PD patients and normal healthy person was also investigated.
Complex Medical Engineering, 2007. CME 2007. IEEE/ICME International Conference on; 06/2007
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ABSTRACT: Writer's cramp, or focal hand dystonia, is characterized by involuntary coactivation of antagonist or unnecessary muscles while writing or performing other tasks. Recent studies of changes in cerebral blood flow during writing have demonstrated a reduction in the activation of the primary motor cortex (MC) and hyperactivity of the parts of frontal nonprimary motor areas. Therefore, any measures that decrease the activities of nonprimary motor areas like the premotor cortex (PMC) or supplementary motor area (SMA) might improve dystonic symptoms. We explore this possibility of acute effect, Nine patients with writer's cramp and seven age-matched control subjects were recruited. After the preliminary experiments, we used subthreshold low-frequency (0.2 Hz) repetitive transcranial magnetic stimulation (rTMS), which exerts an inhibitory action on the cortex. We compared the silent periods and computer-assisted ratings of handwriting before and after rTMS applied to the MC, SMA, or PMC. Stimulation of the PMC but not the MC significantly improved the rating of handwriting (mean tracking error from the target, P=0.004; pen pressure, P=0.01) and prolonged the silent period (P=0.02) in the patient group. This increased susceptibility of the PMC in dystonia suggests that lack of inhibition in the MC is secondary to the hyperactivity of PMC neurons. Further physiological studies disclosed that the amplitude of frontal N30 component was significantly increased after rTMS over the PMC in control subjects (p=0.014) but not in dystonic patients, and 99mTc-ECD SPECT showed the different activation pattern in between control subjects (Brodmann area 9 and 6 including PMC and prefrontal cortex) and patients (parietal and cerebellar cortices). These findings support the idea that cortical network pattern induced by rTMS is quite different in the two groups. It is not clear whether the activated areas seen in dystonia is due to primary or compensatory mechanism, but our findings sugge-
st the PMC plays an important role in the pathophysiology of dystonia. Additionally we showed 0.2 Hz rTMS over the premotor cortex was rather effective than ordinary 1 Hz stimulation over the MC, demonstrating that different frequency and stimulation site is to be explored in each disease depending on its own pathophysiology.
Complex Medical Engineering, 2007. CME 2007. IEEE/ICME International Conference on; 06/2007
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ABSTRACT: Myasthenia gravis (MG) is a disease that is known to be accompanied by various complications. But the relationship between these complications and MG and the treatment for these complications still partly remain unknown. We report two cases of MG with unusual complications. The first one is a case of a 72-year-old woman with lingual dyskinesia, and the second is a 28-year-old man with dysgeusia. Both symptoms improved in parallel after the treatment of MG. Here we report these cases and review similar cases in the literature.
Neurological Sciences 05/2007; 28(2):114-5. · 1.32 Impact Factor
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ABSTRACT: To investigate whether cognitive slowing in Parkinson disease (PD) reflects disruption of the basal ganglia or dysfunction of the frontal lobe by excluding an influence of abnormal brain activity due to motor deficits.
We measured neuronal activity during a verbal mental-operation task with H(2)(15)O PET. This task enabled us to evaluate brain activity change associated with an increase in the cognitive speed without an influence on motor deficits.
As the speed of the verbal mental-operation task increased, healthy controls exhibited proportional increase in activities in the anterior striatum and medial premotor cortex, suggesting the involvement of the corticobasal ganglia circuit in normal performance of the task. By contrast, patients with PD lacked an increase in the striatal activity, whereas the medial premotor cortex showed a proportional increase.
Although the present study chose a liberal threshold and needs subsequent confirmation, the findings suggest that striatal disruption resulting in abnormal processing in the corticobasal ganglia circuit may contribute to cognitive slowing in Parkinson disease, as is the case in motor slowing.
Neurology 04/2007; 68(13):1062-8. · 8.31 Impact Factor
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ABSTRACT: Reported are three patients with ictal monoparesis of an arm. In the hemisphere contralateral to the monoparesis, ictal and interictal epileptiform discharges were observed in the centroparietal area, and a well-circumscribed lesion was commonly present in the primary arm somatosensory area (SI). In the presence of an SI lesion, the epileptic activity at the sensorimotor area could lead to selective or predominant activation of the inhibitory motor system.
Neurology 12/2005; 65(9):1476-8. · 8.31 Impact Factor
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ABSTRACT: We report a long-term outcome of motor function in a patient with adult-onset adrenoleukodystrophy after bone marrow transplantation (BMT). Clinically motor function gradually improved and became almost normal in 2 years after BMT. Serial transcranial magnetic stimulation showed gradual improvement of central motor conduction until 1 year after BMT, and then it became stable. Central motor conduction time and motor threshold were useful for monitoring the central motor function in this patient.
European Journal of Neurology 11/2005; 12(10):807-10. · 3.69 Impact Factor
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ABSTRACT: The present study employed functional magnetic resonance imaging (fMRI) to investigate the neural mechanisms underlying orthographic, phonological and semantic processing of single character Chinese words. Twelve right-handed native Chinese speakers participated in the study. Three fundamental linguistic tasks including orthographic judgment, phonological matching and semantic association task were used. Our results demonstrated robust activation in the left posterior inferior temporal cortex (BA 37) for all three tasks. While the phonological matching task produced left-lateralized activation in the inferior frontal and parietal regions, semantic association task showed considerable bilateral activation in the inferior frontal and occipito-parietal regions. Direct comparison between phonological matching and semantic association task yielded semantic related activation in the anterior portion of the left inferior frontal gyrus (BA 47) and the right inferior frontal region (Broca's homology; BA 45). Behaviorally, there was no difference in response time between phonological matching and semantic association task. Our findings suggested that differential neural pathways were involved in the processing of meaning and sound of single-character Chinese words. The present study provided systemic information of the neural substrates underlying the processing of different components of Chinese language.
Neuroscience Research 07/2005; 52(2):139-45. · 2.25 Impact Factor
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ABSTRACT: To clarify the mechanism of congenital mirror movements.
The triple stimulation technique (TST) and the silent period were used to investigate a patient with congenital mirror movements. The TST was used to calculate the ratio of ipsilateral to contralateral corticospinal tracts from the two hemispheres to the spinal motor neurones.
Transcranial magnetic stimulation over unilateral M1 induced larger ipsilateral than contralateral motor evoked potentials on both sides. Only 9% of spinal motor neurones innervating the abductor digitorum minimi were excited by contralateral primary motor cortex (M1) stimulation, while 94% were excited by the ipsilateral M1 stimulation. The silent period was examined during mirror movements and with voluntary contraction of the right first dorsal interosseus mimicking mirror movements. Left M1 stimulation (through the crossed corticospinal tract) did not show any difference in silent period between the two conditions, while right M1 stimulation (through the uncrossed tract) caused a longer silent period during mirror movements than during voluntary contractions.
The results suggest that mirror movements may be caused by a strong connection between ipsilateral M1 and the mirror movements conveyed through a dominant ipsilateral corticospinal pathway.
Journal of Neurology Neurosurgery & Psychiatry 03/2005; 76(2):276-9. · 4.76 Impact Factor
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K Mizutani,
N Oka,
R Kaji,
M Matsui,
K Asanuma,
T Kubori,
Y Kojima,
M Kanda,
T Kawanishi,
H Tomimoto,
I Akiguchi, H Shibasaki
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ABSTRACT: We analyzed the CD16+CD57- lymphocyte subset, which is considered to have strong natural killer (NK) cell activity, in peripheral blood from patients with chronic immune-mediated neuropathies and patients with other neurological diseases. We found that the ratio of CD16+CD57- NK cells to total lymphocytes was increased in 4 of 6 patients with multifocal motor neuropathy (MMN) with persistent conduction block. Since the CD16 molecule is an Fc receptor for immunoglobulin G (IgG), high-dose intravenous immunoglobulin (IVIg) may interfere with CD16+CD57- NK cells via Fc receptor blockade. In addition, cyclophosphamide (Cy) is often used to suppress NK cells. Therefore, our findings may partly account for the effectiveness of IVIg or Cy, which is the current treatment of choice for MMN.
European Neurology 02/2005; 53(2):64-7. · 1.81 Impact Factor
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T Satow,
A Ikeda,
N Hayashi,
J Yamamoto,
M Takayama,
M Matsuhashi,
N Mikuni,
J Takahashi, H Shibasaki,
S Miyamoto,
N Hashimoto
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ABSTRACT: OBJECTIVES AND IMPORTANCE: It is important to evaluate the seizure manifestation of epilepsy before surgical planning. A patient with partial epilepsy manifesting hypersalivation who underwent resection of the epileptogenic foci with satisfactory postoperative seizure control is reported. CLINICAL PRESENTATION AND INTERVENTION: A 26-year-old man, with a history of perinatal asphyxia, started having medically intractable partial epilepsy at the age of 10 years. His seizure was characterized by throat discomfort followed by hypersalivation. Brain MRI showed an atrophic lesion around the peri-Sylvian area. Scalp recorded EEG did not demonstrate robust epileptiform activity localized enough to define the epileptogenic zone. The patient underwent invasive recording by multiple subdural electrode grids, which showed that the seizure arose from the left anterior frontal operculum. After resection of epileptogenic opercular cortex, the seizures disappeared with no additional neurological deficits. CONCLUSION: Although the responsible sites for ictal drooling are distributed in multiple areas including insula, medial temporal area and operculum, the seizure can be successfully controlled by focus resection of the frontal opercular area in a selected patient with careful presurgical evaluation.
Acta Neurochirurgica 10/2004; 146(9):1021-5; discussion 1026. · 1.52 Impact Factor
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R Matsumoto,
A Ikeda,
T Nagamine,
M Matsuhashi,
S Ohara,
J Yamamoto,
K Toma,
N Mikuni,
J Takahashi,
S Miyamoto,
H Fukuyama, H Shibasaki
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ABSTRACT: To locate the visual motion complex (MT+) and study its response properties in an epilepsy surgery patient.
A 17-year-old epilepsy patient underwent invasive monitoring with subdural electrodes in the right temporo-parieto-occipital area. MT+ was investigated by cortical electric stimulation and by epicortical visual evoked potentials time-locked to motion onset of sinusoidal gratings (motion VEP). Motion-related visual evoked magnetic field (motion VEF) was also recorded before the electrode implantation to complement the invasive recording.
Motion VEPs revealed two subregions within MT+, generating early and late potentials respectively. The early activity with a peak around 130 ms was localized at a single electrode situated immediately caudal to the initial portion of the ascending limb of the superior temporal sulcus (AL-STS). The late activity, peaking at 242-274 ms, was located ventro-rostrally over three electrodes. Among the four electrodes with motion VEPs, cortical stimulation at the most caudal pair elicited motion-in-depth perception involving the whole visual field. In addition to two subregions revealed on the gyral crown, magnetoencephalography (MEG) demonstrated another subregion with a late motion VEF in AL-STS immediately rostral to the electrode with the early motion VEP.
In combination with MEG recording, the present invasive exploration demonstrated human MT+ in a focal area of the temporo-parieto-occipital junction and delineated possible three subregions as indicated by the different latencies and distributions of the motion VEP/VEFs.
Comparative MEG and direct electrocorticographic recordings delineated possible subregions within the human MT complex.
Clinical Neurophysiology 10/2004; 115(9):2056-65. · 3.41 Impact Factor
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M Takayama,
S Miyamoto,
A Ikeda,
N Mikuni,
J B Takahashi,
K Usui,
T Satow,
J Yamamoto,
M Matsuhashi,
R Matsumoto,
T Nagamine, H Shibasaki,
N Hashimoto
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ABSTRACT: To evaluate the usefulness of propofol as an alternative drug to amobarbital for the Wada test.
The authors analyzed 67 right-handed patients out of 123 patients who were candidates for neurosurgical therapy and thus underwent the Wada test as a preoperative evaluation. Twelve were tested with propofol and 55 were tested with amobarbital. Test conditions of the Wada test, recovery time of muscle power to manual muscle testing (MMT) Grade 3 (T3/5) and Grade 5 (T5/5), onset time of the first verbal response (Tverb) after injection and that of the first nonverbal response (Tnon-verb), were compared between the two groups. Power spectrum analysis of EEG background activity during the Wada test was performed and the time and spatial distribution of polymorphic slow activities were also compared in three cases.
With propofol injection, lateralities of language and memory function were identified in 12 and 9 of 12 patients in comparison to amobarbital (52 and 41 of 55 patients detection in language and memory function). No complications with direct intracarotid injection of propofol were observed. T3/5 and T5/5 with propofol injection were shorter while Tverb and Tnon-verb were longer compared to amobarbital. Absolute power of polymorphic slow EEG waves gradually increased and then rapidly decreased with propofol, which was in contrast to amobarbital injection.
With direct intracarotid propofol injection, the Wada test was satisfactorily performed in all 12 patients and 2 more patients with left-handedness or with different injection dose for each side without any complications. Clinical usefulness of propofol as an alternative drug to amobarbital for the Wada test was indicated.
Neurology 09/2004; 63(3):510-5. · 8.31 Impact Factor
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ABSTRACT: The authors describe a patient who showed paroxysmal dysarthria and right-limb ataxia after midbrain infarction. SPECT imaging showed marked hypoperfusion in the left parietal lobe while the patient was having frequent paroxysmal attacks. After treatment with phenytoin, the symptoms and hypoperfusion in SPECT imaging improved. The authors conclude that dysfunction of the cerebellothalamocortical pathway after midbrain infarction may cause paroxysmal dysarthria and ataxia.
Neurology 08/2004; 63(2):345-7. · 8.31 Impact Factor
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M Ihara,
H Tomimoto,
K Ishizu,
T Mukai,
H Yoshida,
N Sawamoto,
M Inoue,
T Doi,
K Hashikawa,
J Konishi, H Shibasaki,
H Fukuyama
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ABSTRACT: [11C]flumazenil (FMZ), a ligand that selectively binds to the central benzodiazepine receptor in the neuronal membrane, is useful for evaluating neuronal viability in a positron emission tomography (PET) scan. Using this ligand, we investigated whether there was a correlation between neuronal integrity in various brain structures and dementia in patients with leukoaraiosis.
Twelve patients with extensive leukoaraiosis on magnetic resonance imaging were divided into groups of patients with or without dementia. Based on a 2-compartment, 2-parameter model that included metabolite-corrected arterial input and PET-measured cerebral radioactivity, the distribution volume of FMZ (FMZ-V(d)) was calculated in various regions of interest by nonlinear curve fitting. Additionally, tracer kinetic analysis was applied for voxel-by-voxel quantification of FMZ-V(d), and data analysis was performed by statistical parametric mapping.
The presence of dementia was associated with a reduced FMZ-V(d) in widespread areas of the cerebral cortex, including the bilateral frontopolar and frontal/insular areas, the left temporo-occipital border areas, and the left marginal cortical areas.
Differences in neuronal integrity in the cerebral cortex might determine whether patients with leukoaraiosis become symptomatic or not.
Stroke 05/2004; 35(4):942-7. · 5.73 Impact Factor
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ABSTRACT: Cerebrovascular white matter lesions represent an age-related neurodegenerative condition that appears as a hyperintense signal on magnetic resonance images. These lesions are frequently observed in aging, hypertension and cerebrovascular disease, and are responsible for cognitive decline and gait disorders in the elderly population. In humans, cerebrovascular white matter lesions are accompanied by apoptosis of oligodendroglia, and have been thought to be caused by chronic cerebral ischemia. In the present study, we tested whether chronic cerebral hypoperfusion induces white matter lesions and apoptosis of oligodendroglia in the rat. Doppler flow meter analysis revealed an immediate reduction of cerebral blood flow ranging from 30% to 40% of that before operation; this remained at 52-64% between 7 and 30 days after operation. Transferrin-immunoreactive oligodendroglia decreased in number and the myelin became degenerated in the medial corpus callosum at 7 days and thereafter. Using the TUNEL method, the number of cells showing DNA fragmentation increased three- to eightfold between 3 and 30 days post-surgery compared to sham-operated animals. Double labeling with TUNEL and immunohistochemistry for markers of either astroglia or oligodendroglia showed that DNA fragmentation occurred in both of these glia. Messenger RNA for caspase-3 increased approximately twofold versus the sham-operated rats between 1 and 30 days post-surgery. Immunohistochemistry revealed up-regulation of caspase-3 in the oligodendroglia of the white matter, and also in the astroglia and neurons of the gray matter. Molecules involved in apoptotic signaling such as TNF-alpha and Bax were also up-regulated in glial cells. These results indicate that chronic cerebral hypoperfusion induces white matter degeneration in association with DNA fragmentation in oligodendroglia.
Acta Neuropathologica 01/2004; 106(6):527-34. · 9.32 Impact Factor
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Journal of Neurology Neurosurgery & Psychiatry 08/2003; 74(7):1004-5. · 4.76 Impact Factor
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ABSTRACT: APOE polymorphisms were studied in 200 unrelated patients with primary dystonia as well as 300 age-matched control subjects. Although no difference was found in APOE genotype between the patients with dystonia and the controls, APOE-epsilon4 carriers developed the disease on average approximately 10 years earlier than APOE-epsilon4 noncarriers (p = 0.0012). This suggests that APOE-epsilon4 genotype affects the clinical presentation of primary dystonia.
Neurology 07/2003; 60(12):2003-5. · 8.31 Impact Factor
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ABSTRACT: The case is described of a 20-year-old man with adrenoleukodystrophy who showed right spastic hemiparesis and gait disturbance. Brain magnetic resonance imaging disclosed predominant involvement of the left corticospinal pathway. The clinical symptoms improved after bone marrow transplantation. Transcranial magnetic stimulation disclosed significant improvement in various parameters of central motor conduction.
Journal of Neurology Neurosurgery & Psychiatry 04/2003; 74(3):373-5. · 4.76 Impact Factor
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ABSTRACT: To test whether low-frequency repetitive transcranial magnetic stimulation (rTMS) of sensorimotor cortex (SM1) has prolonged effects on somatosensory function, eight subjects were given 900 TMS pulses over the left hand SM1 (0.9Hz, 90% of the resting motor threshold) or at sites 3 cm anterior or posterior to it. Tactile threshold of the right hand was increased for a short duration after rTMS over SM1, but two-point discrimination and median nerve SEPs were unaffected after rTMS at any sites.
Neurology 04/2003; 60(6):1045-7. · 8.31 Impact Factor
