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Biomedical subjects

J Tanji

Publications and source records attributed to J Tanji.

At least 73 records · Page 4Linked to original sources
PubMed1988

Neuronal activity in cortical motor areas related to ipsilateral, contralateral, and bilateral digit movements of the monkey.

1. Single cell activity was studied in the precentral (PCM), premotor (PM), and supplementary (SMA) motor cortex of the monkey to compare magnitudes of activity changes in relation to ipsilateral, contralateral, and bilateral digit movements. 2. Three Japanese monkeys were trained to press a small key with the right or left hand, or with both hands, in accordance with visual instruction signals given 2.6-5.4 s before a visual movement-trigger signal. Great care was taken to train the animal to use only the required part of the limb. As a result of extensive training, electromyographic (EMG) studies revealed that muscle activities before the key press were limited to the digit and hand muscles of the limb instructed to move. No overt increase or decrease in activity was detectable in the proximal limb or body muscles in relation to the key-press movements or instructions. 3. Even though the movement was thus limited to distal forelimb, distinct ipsilateral relationships were observed in 8.2% of the task-related PCM neurons. They changed their activity before ipsilateral and bilateral (but not before contralateral) key press. 4. A majority of the neurons recorded from the digit area of PCM (mostly limited to the anterior bank of the central sulcus) exhibited a contralateral relationship; namely the activity increased or decreased before the onset of the contralateral and bilateral key-press movements. In most of them, the magnitudes of the activity changes before the contralateral and bilateral movements were similar. 5. In proximal limb and trunk areas of PCM and also in the somatosensory cortex, no neurons were found to exhibit distinct relations to any of the key-press movements. 6. In both SMA and PM, a number of neurons exhibited relationships of the type never or only rarely observed in the primary motor cortex. Thirty-seven percent of SMA and 62% of PM neurons exhibited premovement activity changes before all of the key-press movements. The movement-specific type of activity was observed in 28% of SMA and 16% of PM neurons. In these neurons, the activity changes were observed in relation to only one of the right or left key-press movements or exclusively in relation to the bilateral key press. Neuronal activity resembling the majority of the PCM neurons (contralateral type) was observed in 31% of SMA and 13% of PM neurons. 7. Instruction-induced changes in activity were more often found in the secondary than in the primary motor area.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Neuronal activity in the primate non-primary cortex is different from that in the primary motor cortex.

This paper describes differences in the properties of single-cell activity in the primary and non-primary motor cortex of behaving monkeys (Macaca fuscata). New findings were obtained in relation to two different behavioural paradigms. First, we found that a large number of non-primary motor cortex neurons exhibit selective or preferential relationships to either signal-triggered or self-paced movement. In the second series of experiments, monkeys were trained to press a small key with the right or left hand, or with both hands. Most primary motor cortex neurons behaved like muscles in the contralateral hand. In contrast, a number of non-primary motor cortex neurons exhibited a selective relationship to the movement (right or left key press, or bilateral key press). The differences suggest the different roles of these two areas in motor control. Studies of this sort seem to start providing answers to the old question of why the non-primary motor cortex exists.

Animals↗
PubMed1987

Neuronal activities in the primate motor fields of the agranular frontal cortex preceding visually triggered and self-paced movement.

Single cell activity was examined in the three motor fields of the monkey frontal cortex with the aim of comparing the neuronal activity preceding movements triggered by a visual signal to that preceding nontriggered (self-paced) movements. The following findings emerged from this study. 1. Neuronal activity changes were observed at two different phases in relation to the movement onset; the short-lead type observed within 480 ms prior to the movement onset and the long-lead type, beginning earlier (typically 1 to 2 s). 2. Neurons in both the supplementary motor area (SMA) and premotor area (PM) exhibited the short-lead activity changes prior to the triggered and self-paced movement. Their magnitudes were similar in 63% of SMA and in 36% of PM neurons, whether the movement was triggered or self-paced. 3. SMA neurons, as a whole, were not less active before the triggered than self-paced movement. 4. On the other hand, as many as 92 PM neurons (61%) were related exclusively or peferentially to the triggered movement. 5. The majority of precentral motor cortex (MC) neurons exhibited similar activity changes before the two modes of movement initiation. 6. The long lead type of activity changes were observed mainly prior to the self-paced and much less frequently before the triggered movement. They were particularly abundant among SMA neurons. These results do not support the simple dichotomy hypothesis that SMA primarily takes part in self-paced movement and PM is only involved in visually triggered movement. However, PM neurons show relatively more prominent responses to the visual trigger signal and SMA neurons are intimately related to a long-lasting process leading to initiation of the self-paced movement.

Animals↗
PubMed1986

Efficacy of tolciclate solution in patients with tinea pedis.

Forty patients with tinea pedis were treated for six weeks in a double-blind study with a tolciclate or placebo solution. The tolciclate solution demonstrated moderate efficacy compared with placebo. The finding of positive KOH preparations in a significant number of tolciclate-treated patients with persistently negative cultures suggests that the vehicle used (polyethylene glycol-400) may not provide adequate penetration of this effective antifungal agent. No adverse effects were noted.

Administration, Cutaneous↗
PubMed1986

Premotor cortex neurons in macaques: activity before distal and proximal forelimb movements.

Single unit activity was examined in the premotor cortex of three awake, behaving macaque monkeys. Premotor cortex (PM) neurons were found to be active in association with a movement involving specifically the distal forelimb. Other PM neurons were active in relation to more proximal forelimb movements. The spatial distribution of neurons related to distal movements differed from that of neurons related to proximal forelimb movements, the former being focused at a postarcuate region near the genu of the arcuate sulcus and the latter being shifted more posteromedially. The distal movement was triggered by one of the three sensory signals: visual, auditory, and vibrotactile. Of 190 PM neurons related to the distal forelimb movements, 123 (65%) showed similar premovement activity changes irrespective of the modality of the triggering signal. However, a number of neurons (35%) responded preferentially to one or two of the three signals. The modality-specific activity before movements distinguishes PM from the caudally adjacent primary motor cortex.

Animals↗
PubMed1985

The effect of cooling of the supplementary motor cortex and adjacent cortical areas.

The medial surface of the rostral part of frontal agranular cortex, largely corresponding to the supplementary motor area, was rapidly and reversibly cooled while a monkey was performing a trained motor task requiring a premovement selection process of determining sensory signals as movement triggering or non-triggering. During cooling, the motor task was poorly performed with grossly altered reaction times and variable amount of force, along with erroneous responses. Neuronal activity in the precentral motor cortex in response to sensory signals was also found to be altered.

Animals↗
PubMed1985

Distribution of neurons related to a hindlimb as opposed to forelimb movement in the monkey premotor cortex.

Single cell recordings were made from the premotor cortex (lateral part of area 6) of a monkey trained to perform either a distal hindlimb or forelimb movement separately. Out of 175 movement-related neurons, 59 neurons showed modulation of activity only prior to the hindlimb movement, and the majority of them was distributed in a focal region around the superior precentral sulcus, several mm posteromedial to the genu of the arcuate sulcus. The hindlimb focus was separate from a focal region for forelimb movement-related neurons, which lay immediately posterior to the genu of the arcuate sulcus.

Animals↗
PubMed1985

Contrasting neuronal activity in supplementary and precentral motor cortex of monkeys. I. Responses to instructions determining motor responses to forthcoming signals of different modalities.

The present report contrasts neuronal activity in two motor cortical fields after instructions that determine which of two sensory signals will trigger a movement and which will not. The goal of the study was to determine possible differential roles of the two cortical fields in the process of preparing to move in response to one external cue and to ignore another. Single-cell recordings were made from the supplementary motor area (SMA) and the precentral motor area (PCM) of monkeys trained to perform key-press movements in two different modes. In the auditory mode, an instruction signal warned the animal to prepare to start the movement promptly in response to a forthcoming 1,000-Hz tone burst (trigger signal), but to remain motionless if the signal was vibrotactile (nontrigger signal). In the tactile mode, the trigger and nontrigger signals were reversed: a different instruction signal warned the animal to prepare to perform the key-press movement in response to the vibrotactile cue, but to withhold it in response to the 1,000-Hz tone. The instruction signals were auditory tones of 300 Hz for the auditory mode and 100 Hz for the tactile mode. Out of 259 task-related SMA neurons, 128 (49%) responded to instructions. Three types of instruction responses were observed: 1) 95 neurons showed continuous instruction-induced activity changes lasting until the occurrence of the movement-triggering signal, regardless of whether an intervening nontrigger signal occurred. 2) 24 neurons showed increased activity until the occurrence of the nontriggering signal, after which the activity subsided. When there was no nontrigger signal, the activity increased during a period when the nontrigger signal might have been given. 3) Nine neurons responded with a transient, short-latency discharge after the instruction. The responses of SMA neurons to two instructions were often different. Forty-four SMA neurons exhibited a selective response to only one of the two instructions. In 43 neurons the response was differential, with the magnitude of activity increase or decrease being at least three times greater after one instruction than the other. In the remaining 41 neurons the response was nondifferential. Out of 112 task-related PCM neurons, 25 (22%) responded to the instructions. In the majority of them (21 neurons), the instruction response was nondifferential.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Contrasting neuronal activity in supplementary and precentral motor cortex of monkeys. II. Responses to movement triggering vs. nontriggering sensory signals.

This report compares neuronal activity in the supplementary motor area (SMA) and the precentral motor cortex (PCM) in response to auditory and vibrotactile signals that required a monkey either to start a key-press movement or to refrain from initiating such a movement. Confirming previous reports (3, 9), a vibrotactile stimulus that triggered movement gave rise to two phases of neuronal activity in PCM neurons: a short-latency response time-locked to the occurrence of the vibrotactile stimulus, and a response related to the time of onset of the movement. When the animal was required to refrain from moving in response to the vibrotactile signal, the short-latency response was often attenuated and there was rarely any later activity. There was no attenuation of the short-latency response to the nontriggering vibrotactile stimulus in the anterior part of the postcentral somatosensory cortex. As reported previously (23), short-latency stimulus-locked responses of SMA neurons to a vibrotactile signals were less frequent and the magnitude of the responses was smaller than in the PCM. However, the properties of the later-occurring responses of SMA neurons were often different from those of PCM neurons. Many SMA neurons responded to both the triggering and nontriggering vibrotactile signals. Twenty-nine SMA neurons responded to the nontriggering signal only and not to the movement-triggering signal. Most of the PCM neurons were active after the auditory signal only when the signal was a trigger to start the key-press movement; three neurons exhibited a slight activity increase after the nontriggering auditory signal. In contrast, a number of SMA neurons responded to the nontriggering auditory signal as well as the movement-triggering auditory signal. Twenty-three neurons responded exclusively to the nontriggering auditory signal. These results indicate the extent to which SMA neuronal activity, in contrast to that of the PCM, is related to factors other than the execution of movement.

Animals↗
PubMed1983

Responses of pyramidal tract neurons in the postcentral cortex to tactile inputs.

Pyramidal tract neurons were recorded from postcentral cortex of awake monkeys and their responses to step indentation and vibratory stimulus were studied. The majority of them exhibited slowly adapting response to the indentation stimulus but failed to show phase-locked response to 50-200 Hz vibrations. The response properties appeared to be in contrast to those of non-pyramidal tract neurons whose responses were largely quickly adapting.

Adaptation, Physiological↗
PubMed1981

Contrasting neuronal activity in the ipsilateral and contralateral supplementary motor areas in relation to a movement of monkey's distal hindlimb.

Recordings were made from the supplementary motor areas in both cortical hemispheres of a monkey trained to press a foot pedal. As a result of appropriate limb fixation, the movement was performed with activity predominantly in distal muscles of the right hindlimb. Forty-three percent of contralateral neurons showed movement-related activity. In contrast, only 9% of ipsilateral neurons were active and magnitudes of their activity were smaller.

Animals↗