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Biomedical subjects

K Matsunami

Publications and source records attributed to K Matsunami.

At least 109 records · Page 6Linked to original sources
PubMed1983

Activities of single precentral neurons of the monkey during different tasks of forelimb movements.

The neuronal activity in the motor cortex of the rhesus monkey was investigated in three different tasks performed with finger, wrist, and arm movements. A total of 125 neuronal activities were analysed. They were classified into five groups in terms of muscular contractions provoked by intracortical stimulation; neurons related to contractions of finger, wrist, elbow, shoulder, or trunk muscles. The neuronal activities in three tasks performed with finger, wrist, or arm movements were investigated for each group. Most of the neurons related to the contractions of elbow, shoulder, or trunk muscles were associated solely with arm movement. Smaller numbers of neuronal activities changed their firing frequencies in association with two or three tasks. Neurons related to the contractions of finger and wrist muscles showed various firing patterns in the three tasks; some responded to a single task with wrist or arm movement, while others changed their activities in association with more than one task. The presence of multi-task related neurons is discussed with respect to the multisegmental termination of corticospinal axons in the spinal cord.

Animals↗
PubMed1982

Radioactive deoxyglucose uptake into forelimb muscles in task performing monkeys.

Incorporation of [14C]2-deoxy-d-glucose (2-DG) into forelimb muscles of task-performing monkeys was studied. Extensor muscles of used forelimbs showed a significant increase in 2-DG uptake; they were ext.dig.2nd and 3rd, ext.dig.com., ext.carp.rad. and ext.carp.uln. On the other hand, flexor muscles in the used forelimb did not show such a significant increase in 2-DG uptake. Muscles of non-used limbs, flexors or extensors, did not show a significant 2-DG uptake.

Animals↗
PubMed1981

Characteristics of the ipsilateral movement-related neuron in the motor cortex of the monkey.

The characteristics of the precentral neuron activity related to ipsilateral movements were studied while the monkey was performing finger, wrist and arm movements on either side. Out of 197 task-related neurons, 134 discharged in association with contralateral movements, but not with any one of 3 ipsilateral movements. Fifty neurons discharged with bilateral movements. Thirteen neurons discharged in association with ipsilateral movements (ipsi-neurons). Ten were recorded from the trunk or shoulder area of the motor cortex and were accompanied by contraction of those muscles by intracortical stimulation (ICS). The remaining 3 were related to elbow or wrist, but no ipsi-neurons were related to finger muscle contractions. In ipsilateral task performance, 7 ipsi-neurons discharged in association with finger and/or wrist movements in addition to arm movement. Five others were associated with arm movement. The last one discharged with wrist movement. Most of the units showed similar response to contralateral movement. Ipsi-neurons were classified into two groups. One group was recorded around the sulcus precentralis superior, had the lower threshold current and was mostly associated with finger, wrist and arm movements. The other was recorded in the rostral motor cortex, and had the higher threshold current and was related to arm movement. Among 185 neurons to which pyramidal tract stimulation was delivered, 2 out of the 80 PTNs and 11 out of the 105 non-PTNs were ipsi-neurons. EMGs were recorded from various muscles involved in the forelimb movements. Arm and finger muscles showed no activity when the monkey used the ipsilateral hand, while most of the shoulder and trunk muscles showed tonic or moderate transient changes in the activity during the ipsilateral tasks. The ipsi-neuron activity was discussed in consideration with EMGs.

Animals↗
PubMed1981

Radioactive 2-deoxy-D-glucose incorporation into the prefrontal and premotor cortex of the monkey performing a forelimb movement.

Radioactive 2-deoxy-D-glucose (2-DG) incorporation into the monkey prefrontal and premotor cortex was studied in relation to extention-flexion movement at the wrist joint in two experimental and two control monkeys. With 2-DG injection and 45 min' intensive task performance thereafter, the following areas showed increased accumulations of radioactive glucose: the dorsomedial and dorsolateral prefrontal areas, including the lateral and medial banks of the principle sulcus; the ventral prefrontal and orbitofrontal areas; the cingulate gyrus, and the premotor cortex. In these areas, patch- or strip-like patterns were observed in the accumulation of 2-DG.

Animals↗
PubMed1980

Antidromic latency of the monkey pyramidal tract neuron related to ipsilateral hand movements.

During three different motor tasks of finger, wrist and arm movements on either side, 80 pyramidal tract neuron (PTN) activities were recorded in the monkey motor cortex. They were divided into three groups; PTNs related to contralateral movement (contra-PTNs), those related to ipsilateral and contralateral movement (bilateral-PTNs) and those related to ipsilateral movement (ipsi-PTNs). The latency histogram of the antidromic activation was similar for contra-PTNs as well as ipsi- and bilateral-PTNs in the fast PTN group, but most of slow PTNs appeared among contra-PTNs. Intracortical microstimulation (ICMS) was delivered to correlate muscular contraction with PTN activity. Most of slow PTNs were related to proximal muscular contraction and PTNs related to proximal muscles appeared more in ipsi- and bilateral-PTNs than in contra-PTNs.

Animals↗
PubMed1978

Precentral neuron activity associated with ipsilateral forelimb movements in monkeys.

Unit activity was recorded in motor cortex on one side, while monkeys were moving left or right fingers, wrists, or arms. On hundred and eighty five movement-related neurons were obtained from two monkeys. Of these, 122 were related to contralateral movements, 50 were to movements of both sides, and the remaining 13 to ipsilateral movements. It was found that ipsilateral-movement-related neurons tended to appear in groups of neurons that were related more to arm movements than to finger and/or wrist movements.

Action Potentials↗
PubMed1975

Precentral unit activity following torque pulse injections into elbow movements.

(1) Precentral neural activity was studied in relation to transient load changes on self-paced elbow movements. Four Cebus monkeys were trained to turn a freely moving handle back and forth between two targets by alternating self-paced elbow flexions and extensions. Torque pulses (of 10 or 100 msec) injected randomly to load or unload the movements stretched or slackened the appropiate prime movers: biceps or triceps. Perturbed movements oscillated at about 5.5 Hz but were completed successfully in about the same time as unperturbed movements. (2) Torque pulses evoked distinct "early" responses with latencies of 20-40 msec in 134 out of 153 precenteral neurons. Oppositely directed torque pulses evoked reciprocal (i.e. increased or decreased) early responses in 61 neurons, and uniform responses in 27 neurons. (3) Early responses were followed by "late" responses with peaks succeeding one another at about 5.5 Hz in 111 neurons, but another 16 exhibited late responses only. (4) Timing of both early and late cortical responses was tightly coupled to peripheral changes. Early responses were timed by the initial torque-induced passive elbow jerk. Timing of late responses was best related to subsequent peak decelerations of accelerations. Intensity of the early but not of all late precentral responses was tightly coupled to peripheral events. (5) Torque pulses that impeded flexions or extensions evoked spinal stretch reflexes in biceps or triceps with EMG latencies of about 15 msec, leading to an acceleration peak about 25 msec later. A second EMG burst followed the first in about 30 msec. The second burst occurred about 20 msec after onset of the early precentral response, which is thought to have caused it, as well as a second acceleration peak that was seen about 60 msec after precentral response (for flexion load pulses). Peaks of late precentral responses were followed by acceleration peaks within about 70 msec. (6) An interaction akin to the spinal stretch reflex is thus revealed between elbow perturbations, early responses of precentral neurons and subsequent elbow movements: discharges of neurons that usually fire in relation to an intended movement can be altered by sudden load changes so that the neurons tend to reduce mismatch between intended and actual movements (cortical load compensation), created by the perturbation. An analagous interaction may also occur with late cortical responses.

Adaptation, Physiological↗
PubMed1975

Effects of dentate cooling on precentral unit activity following torque pulse injections into elbow movements.

(1) The effects were studied of brief, reversible cooling of the dentate nucleus of two Cebus monkeys on the activity of 69 precentral neurons that were related to self-paced elbow flexions or extensions. Sixty-two neurons were studied when movements were randomly perturbed by transient load changes. (2) During unperturbed movements dentate cooling altered precentral activity and movement parameters in the same direction. Extension movements and extension-related precentral neurons developed oscillations and rhythmical activity at about 4 Hz with increased peak values of acceleration and discharge intensity. Flexion peak accelerations and dynamic properties of flexion-related precentral neurons decreased. (3) Dentate cooling had no major effects on the "early" precentral responses to torque pulses and on the initial rapid movement adjustment. (4) Dentate cooling decreased intensity of "late" precentral responses and slowed their frequency together with associated movement oscillations from 5-6 Hz to 3-4 Hz. EMG bursts of biceps and triceps were prolonged accordingly. (5) It is concluded that the tightly coupled interaction between precentral motor cortex and the evolving movement was independent of dentate function in the early stage of the cortical load compensation. The dentate nucleus was involved, however, in adjusting intensity and frequency of subsequent late precentral responses and of movement oscillations.

Adaptation, Physiological↗