The functions of the supplementary motor area. Summary of a workshop.
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Animals↗
Biomedical subjects
H Shibasaki
Publications and source records attributed to H Shibasaki.
[Clinical application of functional mapping: the present state of the art and its future prospects: (series 7) magneto-encephalographic study of higher brain function].
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Brain↗
Pharmacokinetics of stable isotopically labeled L-histidine in humans and the assessment of in vivo histidine ammonia lyase activities.
The pharmacokinetics of L-histidine in humans has been investigated to evaluate the in vivo histidine ammonia lyase system for the conversion of L-histidine to urocanic acid. Two healthy volunteers (subjects A and B) received a single 100-mg oral dose of L-[3,3-2H2,1',3'-15N2]histidine. Blood and urine samples were obtained over 24 hr after the administration and analyzed by stable isotope dilution ms. Labeled L-histidine was rapidly absorbed, and a maximum plasma concentration of L-histidine was observed at 30 min (1057.6 ng/ml) in subject A and at 60 min (1635.6 ng/ml) in subject B after oral administration. Pharmacokinetic parameters were calculated based on a two-compartment model. Labeled L-histidine in subject A (t1/2 = 1.0 hr) was eliminated approximately twice faster than that in subject B (t1/2 = 1.9 hr). Total body clearances were 70.0 liters/hr in subject A and 30.0 liters/hr in subject B. The low ratios of the renal clearance to the total body clearance (1.04% for subject A and 0.43% for subject B) indicated that most of L-histidine was eliminated via the nonrenal processes. L-Histidine was rapidly metabolized to urocanic acid. Maximum plasma concentrations of urocanic acid were 59.61 ng/ml at 30 min for subject A and 46.10 ng/ml at 60 min for subject B. The slope of the plot of urinary excretion rate of urocanic acid vs. the plasma concentration of unchanged L-histidine was demonstrated to reflect the metabolic clearance of L-histidine to urocanic acid. The method of evaluating the in vivo human histidine ammonia lyase activities discussed in this study offers a significant value with regard to the biochemical and clinical elucidations of the heterogeneity of histidinemia.
Adult↗
P300 abnormalities in patients with selective impairment of recent memory.
We recorded auditory event-related potential (ERP) by using the standard oddball paradigm in seven amnestic patients. Patients were divided into three groups according to brain CT or MRI findings. (1) Three patients with no detectable lesion, including two patients studied during the episode of transient global amnesia, showed a well-defined P300. (2) Three patients with detectable lesions in the mesial temporal lobes did not show any wave form corresponding to P300. In two of these three patients, the ERP wave form showed a significant change in accordance with the improvement of MRI findings. (3) One patient who had a hypothalamic lesion due to total resection of craniopharyngioma showed a low-amplitude P300. Although neuropsychological examinations showed selective and severe impairment of recent memory function in all of these patients, no significant relationship was found between the degree of memory disturbance and P300 abnormality. These results suggest that P300 is more affected by existence and extension of brain lesions, especially in the mesial temporal lobes, rather than degree of memory disturbance. However, these results do not necessarily suggest that the potential generated in the mesial temporal lobes is directly recorded as a component of the scalp-recorded P300.
Adult↗
Event-related potentials during paired associate memory paradigm.
We have studied event-related potentials (ERPs) during a visual paired association task with delayed discrimination in 10 normal right-handed subjects. After subjects completely memorized 4 pairs of figures during a learning period, they were presented with each cue (S1) and asked to judge whether the following figure (S2) formed one of the memorized pairs or not. A choice reaction task with delay was used for control in an attempt to identify brain activity specifically related to memory function. ERPs were recorded from 21 scalp electrodes and those occurring between the S1 and S2 presentation were analyzed. Two ERP components associated with memory function were identified in the difference waveform between the responses in the paired association task and those in the choice reaction task. One was a posterior positive component which appeared between 390 ms and 1100 ms after the S1 presentation and the other was a sustained frontal negative component which began at about 1100 ms after S1 and ended just before the S2 presentation. Both potentials were distributed predominantly on the scalp overlying the left hemisphere. It is postulated that the early posterior positive component may reflect retrieval of information from association memory, whereas the late frontal negativity may reflect retention of information in working memory.
Adult↗
[A case of familial juvenile dystonia-parkinsonism: 18F-6-fluorodopa and 18F-fluoro-2-deoxyglucose PET study].
A 27-year-old Japanese woman was admitted to Kyoto University Hospital because of gait disturbance since age 25. Her elder sister had been suffering from childhood-onset dystonia-parkinsonism with diurnal fluctuation which initially responded well to levodopa therapy, but later larger dose of levodopa was needed because of severe treatment-related fluctuation of the clinical symptoms. Physical examination revealed left foot dystonia, mild parkinsonism with kinesie paradoxale and dyskinesia of lower limbs. Symptoms were relieved by sleep and worsened by walking. Laboratory data including serum ceruloplasmin, serum and urinary amino acid analysis, and hexosaminidase and beta-glucosidase activity in leukocytes were all normal. Homovanillic acid (HVA) in cerebrospinal fluid was normal (68 ng/ml) at 8 pm but markedly decreased (7 ng/ml) at 4 pm. Cranial MRI was normal. 18F-6-fluorodopa PET demonstrated decreased dopa uptake in the bilateral striatum, especially in the putamen. 18F-fluoro-2-deoxyglucose PET showed decreased regional glucose metabolism in the bilateral putamen. Levodopa therapy rendered equivocal effects while trihexyphenydil was effective. This case indicated that some cases of dopa-unresponsive dystonia with parkinsonism might be a clinical variant of juvenile parkinsonism. 18F-6-fluorodopa PET is useful in evaluating juvenile dystonia-parkinsonism, though it may not predict levodopa effectiveness. 18F-fluoro-2-deoxyglucose PET study will be helpful in predicting the effect of levodopa therapy, because decreased regional glucose metabolism in the putamen probably indicates poor response to levodopa. Further study including dopaminergic receptor imaging study is needed to clarify the physiological mechanism of co-existing dystonia and parkinsonism in patients with juvenile parkinsonism and related disorders.
Adult↗
Effect of photic conditioning on blink reflex recovery function in blepharospasm.
Patients with blepharospasm may have selective sensitivity to photic stimuli, for their symptoms are often aggravated after exposure to brightness. To investigate the pathophysiology underlying this phenomenon, we compared the effects of electric and photic conditioning on electrically-evoked blink reflex in 21 patients with blepharospasm and 11 age-matched control subjects. With electric conditioning, R1 was facilitated at inter-stimulus intervals (ISIs) of up to 100 ms in both groups. R2 was inhibited at all ISIs longer than 20 ms in the normals, but to a much lesser extent in the patients, suggesting increased excitability of the multi-synaptic reflex pathway. Compared to electric conditioning, photic conditioning was less potent in inhibiting R2 in the normals. In contrast, photic conditioning in the patients produced R2 inhibition as powerful as electric conditioning. These findings indicate that, in patients with blepharospasm, photic input has a relatively more profound inhibitory effect on the test blink reflex than electric conditioning as compared with normal subjects. The greater susceptibility of the brainstem interneurons to photic conditioning in blepharospasm may be related to the clinically-observed light sensitivity.
Adult↗
[A case of intractable temporal lobe epilepsy: discrepancy between epileptogenic area and structural lesion demonstrated by subdural recording].
We reported a 25-year-old man with intractable right temporal lobe epilepsy in whom subdural recording successfully delineated the epileptogenic area in the right anterior mesial to basal temporal region in spite of the presence of a postoperative lesion in the right posterior temporal region. The patient underwent right posterior temporal resection due to ependymoma at the age of 8 years. Since age 19, he had suffered from medically intractable psychomotor seizures. Ictal scalp-recorded EEG suggested an epileptogenic area at the right temporal area, but it could not specifically demarcate the site because of bone deficits from the previous surgery. Ictal SPECT showed a hyperactive area in the right anterior temporal area, which was inconsistent with the MRI finding. In case of partial epilepsy associated with structural lesion like in the present case, if results of various non-invasive studies are discrepant as to the epileptogenic area, invasive studies using, for example, subdural EEG monitoring is necessary to determine the responsible area.
Adult↗
Regional cerebral blood flow changes in motor cortical areas after transient anesthesia of the forearm.
To study the effect of deafferentation on cortical areas activated by movement of the proximal muscles, we measured regional cerebral blood flow with positron emission tomography and 15O-labeled water. Flexion-extension movements of the right elbow before deafferentation were associated with an increase of regional cerebral blood flow in the primary sensorimotor area bilaterally, posterior supplementary motor area bilaterally, ipsilateral cerebellum, contralateral putamen, premotor area, anterior cingulate area, and posterior parietal region. Transient anesthesia of the right forearm induced by ischemic block caused an increase of regional cerebral blood flow in the primary sensorimotor area bilaterally at rest, but there was no change of regional cerebral blood flow with movement, indicating that the movement-related change in cerebral blood flow was reduced. These findings are consistent with increased excitability of neurons as a result of deafferentation. In the supplementary motor area, anesthesia did not induce any change in regional cerebral blood flow at rest, but there was a decline with movement, again indicating a reduction of the change in cerebral blood flow related to movement. This might be due to a reduction in sensory feedback because of the anesthesia.
Adult↗
Tonic vibration reflex and muscle afferent block in writer's cramp.
Patients with focal dystonia take advantage of certain cutaneous or proprioceptive sensory inputs to alleviate their symptoms ("sensory trick"). We examined the effects of increasing muscle spindle activity by the tonic vibration reflex maneuver and decreasing it by intramuscular injection of lidocaine. The vibration was applied to the palm or the tendon of forearm muscles in 15 patients with writer's cramp and 15 age-matched normal subjects. In 11 patients, the vibration induced dystonic postures or movements typical of those seen during writing. Normal subjects showed either no response to the vibration or a gradually developing tonic vibration reflex only in the wrist and finger flexors, which produced visible movements with a significantly longer latency (12.5 +/- 6.7 seconds [mean +/- standard deviation]) than what was observed in the patients (2.7 +/- 2.5 seconds, p < 0.0001). Local injection of lidocaine (0.5%, 5-40 ml/muscle) attenuated the tendon reflex with relatively little effect on the M response. Injection into muscles with increased activity produced marked reduction of dystonic movements and significant clinical improvement in 13 patients, whereas injection into the other muscles had no effect. The clinical benefit lasted for 1 to 24 hours after injection. In 13 patients who had additional injections of 10% ethanol, which blocks sodium channels for a longer period than does lidocaine, the duration of action was prolonged to 5 to 21 days. These findings suggest that muscles causing dystonic movements have abnormal sensitivities to vibration at rest and that muscle afferents may play a pivotal role in producing dystonic movements.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Writer's cramp: a disorder of motor subroutine?
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Dystonia↗
Muscle afferent block by intramuscular injection of lidocaine for the treatment of writer's cramp.
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Adult↗
Movement-related potentials associated with bilateral simultaneous and unilateral movements recorded from human supplementary motor area.
To clarify the differences of movement-related potentials (MRPs) among ipsilateral, contralateral and simultaneous bilateral movements, MRPs with finger, thumb or foot movements were recorded from subdural electrodes chronically implanted on the supplementary motor area (SMA) in 3 patients, and also from the primary sensorimotor area in two of them being evaluated for epilepsy surgery. As a result: (1) SMA generated clear pre-movement potentials regardless of the type of movement. Its amplitude was almost identical between contralateral and bilateral movements except for the motor potential (MP). The pre-movement potentials associated with ipsilateral movements were relatively smaller than those with contralateral or bilateral movements. (2) The primary sensorimotor area generated clear pre-movement potentials in contralateral and bilateral movements with similar amplitude. With ipsilateral hand movements, however, only a small Bereitschaftspotential (BP) and no negative slope (NS') or MP was seen, and ipsilateral foot movements were not preceded by any BP. It is, therefore, most likely that, as far as the preparation for simple voluntary self-paced movement is concerned, the SMA plays an equally important role in unilateral and bilateral movements, whereas the primary sensorimotor area is involved predominantly in the preparation of contralateral movements.
Adult↗
Movement-related cortical potentials associated with voluntary muscle relaxation.
We recorded movement-related cortical potentials (MRCPs) associated with voluntary muscle relaxation, which was not accompanied by contraction of the antagonist or any other muscles, in 10 normal subjects. Voluntary, self-paced relaxation of the wrist extensors from the extended position was employed as the relaxation task, and wrist flexion by muscle contraction was employed as the contraction task. The accelerogram was used to obtain the trigger signals for both tasks. The electromyograms of the ipsilateral agonist and antagonist, the proximal muscles and the contralateral corresponding muscles were monitored to confirm the absence of muscle contraction for the relaxation task. All MRCP components were identified in both tasks; Bereitschaftspotential (BP), negative slope (NS'), parietal peak of motor potential (ppMP) and frontal peak of motor potential (fpMP). BP started earlier and was larger at the contralateral parietotemporal electrodes for the relaxation than for the contraction task, and the slow positive shift at the bilateral frontopolar electrodes was seen more often in the relaxation task. It is concluded that the voluntary muscle relaxation needs a cortical preparatory process similar to voluntary muscle contraction, and needs a more extensive and longer preparation process in the primary motor area and possibly in other motor areas as compared with the contraction.
Adult↗
REM sleep without atonia at early stage of sporadic olivopontocerebellar atrophy.
In order to investigate whether REM sleep without atonia (RWA) is detected even at early stage of sporadic olivopontocerebellar atrophy (OPCA), all-night polysomnography with video monitoring was performed on 5 patients presenting with no nocturnal behavioral complaints. RWA associated with sleep talk and/or minor movements in the head, neck, face and extremities was documented in all cases. Preserved proper NREM/REM cycle and relatively normal sleep architecture suggest the abnormality is confined to REM sleep. Dysfunction of the mechanisms underlying muscle atonia in REM sleep, especially functional or anatomical interruption of ponto-medullary pathways mediating REM sleep atonia, seems to cause RWA in these patients. RWA may be a clinically important finding as a sign of brainstem dysfunction at early stage of neurodegenerative diseases.
Aged↗
Generator locations of movement-related potentials with tongue protrusions and vocalizations: subdural recording in human.
Movement-related potentials (MRPs) associated with tongue protrusions and vocalizations were recorded from chronically implanted subdural electrodes over the lower perirolandic area in 7 patients being evaluated for epilepsy surgery. In 3 patients, tongue protrusions elicited a clearly defined, well localized slow negative Bereitschaftspotential (BP) at the motor tongue area, and a positive BP at the sensory tongue area. At the motor tongue area the negative BP was followed by a negative slope (NS') and a motor potential (MP), and at the sensory tongue area the positive BP and a positive reafferent potential (RAP) were seen but no NS' and MP could be identified. In the other 4 patients, tongue protrusions elicited positive BP, NS' and MP at the motor and sensory tongue area, and positive RAP at the sensory area. It was concluded that BPs, NS' and MPs are mainly generated in the motor cortex involving the crown as well as the anterior bank of the central fissure. The sensory cortex (areas 3a and 3b) also participated in the generation of BPs but to a lesser degree. Different degree of involvement of these multiple generators most likely explains the interindividual variability of polarity and distribution of the MRPs. RAPs most likely arise from primary sensory areas 1 and 2. Brain potentials were also recorded at the motor (2 patients) and sensory (2 patients) language areas, but no specific language-related potentials could be identified. Evoked potentials to lip stimulation were investigated in 4 patients. In 3 patients, the responses at the sensory tongue area (P16, N21 and P30) had the same latency but opposite polarity to those at the motor tongue area. In the other patient, the responses (P16, N21 and P30) at the motor and sensory tongue areas were of the same polarity. The MRPs to tongue protrusions in those 4 patients revealed the same polarity relationship between the pre- and postcentral potentials. However, the maximal amplitude of evoked potentials and MRPs was seen at almost the same electrodes, suggesting that the main generators for these MRPs and evoked potentials must be located at contiguous areas in the anterior and posterior bank, respectively, of the central fissure.
Adolescent↗
Peri-rolandic and fronto-parietal components of scalp-recorded giant SEPs in cortical myoclonus.
Scalp topography of giant SEPs to median nerve stimulation was studied in 4 patients with cortical myoclonus of various etiology. The positive peak (P30) at the contralateral parietal area was simultaneously accompanied by a negative peak at the frontal area (N30), and at least one of these two peaks was enhanced in 2 patients. Another positive peak (P25) and a negative peak (N35) were also identified at the peri-rolandic area with different latency from P30 and N30, respectively, in all patients. N35 was enhanced in 3 patients, and P25 in 2 patients. It is concluded that, as seen in normal subjects, tangential (P30-N30) and radial (P25 and N35) components of SEPs are most likely distinguishable in giant SEPs, and that either one or both of those components is enhanced in different ways depending on the patients.
Adolescent↗
Construction of a morphological filter for detecting an event-related potential P300 in single sweep EEG record in children.
A morphological filter for single sweep records of event-related potential (ERP) obtained in an auditory oddball paradigm, especially P300 waveform, was constructed. By combining four basic operations; erosion, dilation, opening and closing, we could derive a desired filter whose properties fit the current objectives. The morphological filter for the single sweep records of ERP was constructed by taking into account the features of the signal and noise components. The morphological filter had superior properties for distinguishing the signal from the noise even when both were within the same frequency band, as in case of children. The constructed morphological filter was evaluated by using the simulation data of ERP and then applied to the actual ERP data obtained from nine normal children. The constructed morphological filter was proved to be an appropriate tool for single sweep analysis of ERP.
Adolescent↗