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Neuronal activity in the supplementary motor area was recorded from a monkey performing a trained motor task that required readiness for proper usage of sensory inputs. Thirty-two neurons exhibited activity changes, which supports the hypothesis that the SMA is part of the system involved in modulating responsiveness of the motor cortex to sensory inputs in association with learned movements.
1. Recordings were made of the natural discharges of neurons in the supplementary motor area (SMA) of conscious monkeys trained to perform stereotyped motor task, pulling a horizontal lever, with either hand. 2. Of the total population of cells, 80% showed modulation of their activity during particular movements of either limb. Many cells had a similar pattern of modulation regardless of whether the contralateral or ipsilateral hand was used. Of the remaining 20%, some cells were related to leg or body movements or to visual experience. 3. Cells whose activity was related to movements of distal joints were found in approximately equal numbers to those whose discharges occurred with proximal movements. 4. Only 5% of cells tested sent their axons into the pyramidal tract, and only 14% of units investigated showed responses to passive manipulation of the limbs. The effective afferent input usually was of a rather complex kind. 5. The findings suggest that the discharges of a large number of neurons in SMA are changing during particular movements of either arm, and that only a small number of cells receive peripheral afferent sensory input. These results contrast with those obtained in the primary motor area and suggest a different role for SMA in the control of movement.
1. Recordings were made of the natural dischages of neurones in the supplementary motor area (SMA) of conscious monkeys trained to perform a stereotyped motor task with either hand. 2. Eighty % of the total population of cells showed modulation of their activity during particular movements of either limb. Two thirds of this group had a similar pattern of modulation regardless of whether the contralateral or ipsilateral hand was used. 3. The number of cells whose activity was related to movements of distal joints was approximately equal to that whose discharges occurred with proximal movements. 4. Only 5% of cells tested sent their axons into the pyramidal tract, and only 15% of units investigated showed responses to passive manipulation of the limbs. The effective afferent input usually was of a rather complex kind. 5. The findings suggest that the discharges of a large number of neurones in SMA are changing during particular movements of either arm, and that only a small number of cells receive afferent sensory input. These results contrast with those obtained in the primary motor area and suggest a different role for SMA the control of movement.
OBJECTIVE: To observe the clinical efficacy and safety of electroacupuncture (EA) at the motor area for Parkinson's disease (PD) with musculoskeletal pain. METHODS: Fifty-eight patients with PD accompanied by musculoskeletal pain were randomly assigned to an EA group (29 cases, 1 case dropped out) and a sham EA group (29 cases, 1 case dropped out). The EA group was treated with EA at the motor area contralateral to the painful side (for bilateral pain, the left motor area was selected), using disperse-dense wave (2 Hz/20 Hz), with a current intensity of 1-2 mA, and needles were retained for 30 min. The sham EA group was treated with sham EA at non-acupoint area located 5-20 mm posterior to the motor area contralateral to the painful side. The connection mode was the same as that in the EA group, but no electrical current was delivered, and the needles were retained for 30 min. Both groups were treated once daily for 5 consecutive days. Visual analogue scale (VAS) for pain, unified Parkinson's disease rating scale part Ⅲ (UPDRS-Ⅲ), 24-item Hamilton depression rating scale (HAMD-24), Hamilton anxiety rating scale (HAMA), and 39-item Parkinson's disease questionnaire (PDQ-39) scores were evaluated before treatment, immediately after treatment, and at 2 and 4 weeks after treatment completion in the two groups. Safety was also assessed in the two groups. RESULTS: In both groups, VAS scores for pain after treatment and at 2 and 4 weeks after treatment completion were lower than those before treatment (P<0.01, P<0.05). VAS scores for pain in the EA group were lower than those in the sham EA group after treatment and at 2 and 4 weeks after treatment completion (P<0.05). In the EA group, UPDRS-Ⅲ, HAMD-24, HAMA, and PDQ-39 scores after treatment and at 2 and 4 weeks after treatment completion were lower than those before treatment (P<0.05, P<0.01). In the sham EA group, there were no statistically significant differences in UPDRS-Ⅲ, HAMD-24, HAMA, and PDQ-39 scores at any post-treatment time point compared with those before treatment (P>0.05). There were no statistically significant differences in UPDRS-Ⅲ, HAMD-24, HAMA, and PDQ-39 scores between the two groups at any post-treatment time point (P>0.05). No serious adverse events occurred during the trial. CONCLUSION: EA at the motor area could reduce pain intensity in patients with PD accompanied by musculoskeletal pain, and improve pain-related motor symptoms, emotional status, and quality of life, with a favorable safety profile.
Measurements of cerebral blood flow in man revealed that complex voluntary movements are associated with a blood flow increase in the supplementary motor area of the brain. This increase is additional to and similar in magnitude to the Rolandic sensorimotor area activation that occurs during all kinds of movement. When subjects counted silently there was no activation of any focal cortical area in the brain; when they counted aloud there was a marked increase in activity in the supplementary motor area. These results are consistent with the hypothesis that the supplementary motor area plays a major role in the initiation and control of at least some kinds of voluntary movement in man and is, therefore, a motor center of a higher order than the primary Rolandic areas.
This paper reports and illustrates in figurine style results obtained by electrical stimulation of the cortex in 20 patients and by recording of cortical evoked potentials (EPs) in 13 of these patients, whose surgery required wide exposure of the Rolandic or paracentral regions of the cortex. This study is unique in that cutaneous receptive fields related to specific cortical sites were defined by mechanical stimulation, as is done in animals, in contrast to electrical stimulation of peripheral nerves at fixed sites, as in scalp EP recordings. Observations were made on pre- and postcentral gyri, on the second somatic sensory-motor area, on the supplementary motor area, and on the supplementary sensory area. In two patients with phantom limb pain, the pain was elicited in one on stimulation of the postcentral arm area, and in the other on stimulation of the supplementary sensory leg area. Surgical removal of these areas had the immediate effect of abolishing the phantoms and the pain. Long-term follow-up review was not possible. In one patient with severe Parkinson's disease, stimulating currents subthreshold for the elicitation of movement resulted in disappearance of tremor and rigidity for short periods after stimulation of the precentral gyrus. The possible patterns of organization of the human pre- and postcentral areas are considered and compared with those of the chimpanzee and other primates. In patients in whom data from pre- and postcentral gyri were adequate, it appeared that the precentral face-arm boundary is situated 1 to 2 cm higher than the corresponding postcentral boundary.
Motor disorders reported in the present paper do not result from cortical ablations stricto sensu since some white matter was excised in every patient. However they appear to suggest that, as suggested by Walshe (1935), the central region and premotor area are a functional entity, i.e. they work as a whole. The extensive lesions of the premotor area, leaving untouched the motor region, have the same motor and tonic consequences as lesions limited to the central region. This point which appears specific for man does not imply that the premotor region subserves activities similar to those subserved by the central region. Rather it may suggest a deafferentiation of the central region, the consequences of which would be more important than is generally assumed. Extensive central or premotor lesions determine various tonic disorders: a well known spasticity, with exaggeration of the stretch reflex, associated with an increase in passive swinging of segments of limbs and in extensibility of joints. These two latter phenomena are usually defined as hypotonia. With premotor and precentral lesions the hypotonia disappears and a hemiplegic posture is observed. This hemiplegic posture is a dystonia which apparently does not result directly from the exaggeration of the stretch reflex. Anatomically it appears to result from lesions of both central and premotor regions. This is in agreement with Denny-Brown's (1966) contention that an extrapyramidal region lies rostral to the prerolandic sulcus. As suggested by Evarts (1973) motor regions appear to control automatic as well as voluntary movements. They probably play a role in the trophic function of muscle, since, despite rehabilitation, amyotrophy was present in every case reported in the present paper.
The topographical organization of the contralateral cortical projections of the motor hand area was studied with autoradiographic methods in 11 macaque monkeys. Two general observations were noted in the material studied. (1) The commissural cortico-cortical connections of the motor hand area were directed to the contralateral precentral gyrus. The projections were preferentially directed to both homotopic and non-homotopic areas. (2) Focally labeled areas of motor cortex (diameter 900 micrometers) gave rise to individual terminal columns of label (diameter 600-900 micrometers). Larger areas of labeled motor cortex, (3,000 micrometers in diameter) gave rise to contralateral terminal bands of label. These bands (600-1,000 micrometers in width) were oriented in an antero-posterior direction and appeared to be formed by a sequence of adjacent labeled columns.
The connections of auditory fields AI, AII and Ep with the motor area were studied in 14 cats by anterograde degeneration method by means of impregnation techniques of Nauta-Gigax and Fink-Heimer in Victorov's modification. Direct connections were established between the three auditory fields and the motor projection field of the forepaw. The connections coming from the auditory field Ep spread wider, to the motor projection field of the head. The greatest number of these interzonal connections originates in zone Ep, and the smallest in AII zone.
Monkeys were trained to perform two different motor acts, one involving muscle activity in distal forelimb muscles and the other in proximal forelimb and shoulder girdle muscles. After confirming spatial and temporal dissociation of muscle activity in the two motor acts, single unit activity in the supplementary motor area (SMA) was recorded. SMA neurons related with the distal and proximal forelimb movements were found to be arranged rostrocaudally with a considerable overlap. In the overlapping region, neurons related with the distal movement were located more deeply.
Correlation between activity of cortical neurons in the biceps motor area and a conditioning movement of the contralateral forelimb was studied in chronic experiments of two male cats. In the group of neurons related to the movement sensory inputs were not found in 68.1% of neurons, in the group not related to the movement in 97.9% of neurons. 24.2% of neurons from the first group had cutaneous receptive fields on the dorsal surface of the distal part of the moving forelimb, in this group 5 neurons had inputs from the forelimb joints.
Retrograde changes in the giant pyramids of the layer V in the motor area of the cortex isolated neuronally at different dates after operation were followed by Nissl method. The cortex isolation was surgically performed by sectioning projection fibres which connect the cortex with subcortical structures after M. M. Hananashvily method (1961). Characteristic retrograde changes appeared in the giant pyramids on the third postoperative day: moderate swelling of cellular bodies, chromatolysis and nuclear displacement towards the periphery. In the following days the retrograde changes progressed rapidly and by the 10th day resulted in a partial destruction of the giant pyramids. One month later in the layer V, only separate cellular shadows were visible; from one month to one year period the giant pyramids in the layer V disappeared completely. Neurons of other layers in this area, as well as small and middle size neurons of the layer V are preserved and show no signs of pathological changes.
The speech disturbance of a patient with a single embolic infarct of the left supplementary motor area was characterized by initial mutism, rapid recovery to fluent speech marked by short sentences with normal grammar, persistent severe impairment of writing, and frustration and anxiety related to language tasks.
In four macaque monkeys horseradish peroxidase (HRP) was injected into physiologically defined hand-arm motor area. Ipsilaterally, HRP labeled neurons were found in both upper and lower limbs of the posterior bank of the arcuate sulcus and in an area surrounding the arcuate spur. Contralaterally, labeled neurons were found in the same areas, though less dense in concentration. Labeled neurons were found mostly in layer III of the cortex.
As a result of 6 cases of frontal tumour presenting central facial paralysis with inverse dissociation this symptom was investigated in patients subjected to cortical excisions for intractable epielpsy. A study of 8 cases of frontal cortical excision, 6 of them affecting the internal and posterior portion, and two the prefrontal region, has provided evidence of a link between inverse automatic-voluntary dissociation facial paralysis and lesions affecting the Penfield supplementary motor area. In such cases, facial palsy is usually associated with motor disorders in the limbs, the most characteristic of which is unilateral motor under-utilisation. The possibility of inverse dissociated facial paralysis occurring as a result of a rostral premotor lesion cannot be ruled out in our present state of knowledge.
Three patients with well-mapped, circumscribed ablations of the medial part of the frontal lobe are reported. A specific clinical evolution in 3 stages was observed: (1) post-operatively there was global akinesia, more prominent contralaterally, with an arrest of speech; (2) recovery occurred suddenly but even then there was severe reduction of spontaneous motor activity contralaterally, an emotional type facial palsy and a reduction of spontaneous speech; (3) long after the operation the only sequela was disturbance of the alternating movements of the hands. The anatomical basis of these disorders appears to be a lesion of the supplementary motor area (SMA). Three main points have been discussed, namely: (1) the nature of the motor disorder which may be a disturbance of the function of the SMA in initiating and sustaining spontaneous and automatic motor activity; (2) the nature of the arrest of speech which appears not to be aphasic; the studies reported in the present paper do not support a left cerebral dominance for the SMA as suggested by previous studies; (3) the method of clinical examination appears to be important in distinguishing between spontaneous and voluntary motor and speech performance. Differences in method may account for differences between our findings and those reported in previous studies.
Focal activation in the cerebral cortex during different motility and language tests in 52 patients examined by arteriography was studied by measuring focal cerebral blood flow (fCBF) by means of an apparatus of high resolution. A sterotactic or functional approach demonstrated that the upper premotor activation previously noted in certain types of movement, corresponds to supplementary motor area (SMA). A retrospective study of 157 maps of fCBF recorded during motor or verbal behaviour, compared to 90 recordings in subjects at rest, showed that SMA is involved in most voluntary movements, either verbal or non-verbal. An analysis of the results suggests that SMA acts during the establishment of new motor programs, and in the control of pre-established automatic activities, in response to internal and external stimuli.
Two monkeys were trained to exert a precision grip of the thumb and forefinger and to maintain constant near-isometric force for a one-second duration. Both animals were trained to perform the task with about equal proficiency with either hand. A total of 134 neurons were recorded from the supplementary motor area (SMA) of the hemisphere contralateral to the performing hand. SMA neurons were identified by either the presence of peripheral fields on the contralateral arm or by consistent changes in discharge frequency during contralateral arm movement. Sixty-one cells demonstrated reliable changes in firing frequency during performance of the maintained precision grip. SMA neurons showed little tendency to discharge at higher frequency during force change rather than during maintained force. Only two neurons significantly increased firing frequency with increased finger force and no modulation of discharge related to rate of force change could be shown. The changes in spike frequency among SMA cells related to the arm were, on the average, about 100 msec after the onset of contraction in the forearm flexors and extensors of the wrist and fingers, although a contingent of cells discharging consistently before the onset of muscular activity was found.