Lesions of Premotor Cortex in Man

Freund, Hans‐Joachim; Hummelsheim, Horst

doi:10.1093/brain/108.3.697

Cited by 235 publications

(84 citation statements)

References 68 publications

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“…Theoretical formulations have ascribed to the PMA a central role in the maintenance of ''motor set.'' Lesions in this area impair motor control (29). The effect seen in the medial wall, comprising the posterior (behind the anterior commissure) SMA and a locus in the cingulate gyrus bilaterally, again is in accordance with results of previous nonparametric neuroimaging studies (24,30,31).…”

Section: Discussionsupporting

confidence: 89%

Transitions between dynamical states of differing stability in the human brain

Meyer‐Lindenberg

Ziemann

Hajak

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

171

130

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What mechanisms underlie the flexible formation, adaptation, synchronization, and dissolution of large-scale neural assemblies from the 10 10 densely interconnected, continuously active neurons of the human brain? Nonlinear dynamics provides a unifying perspective on self-organization. It shows that the emergence of patterns in open, nonequilibrium systems is governed by their stability in response to small disturbances and predicts macroscopic transitions between patterns of differing stability. Here, we directly demonstrate that such transitions can be elicited in the human brain by interference at the neural level. As a probe, we used a classic motor coordination paradigm exhibiting well described movement states of differing stability. Functional neuroimaging identified premotor (PMA) and supplementary motor (SMA) cortices as having neural activity linked to the degree of behavioral instability. These regions then were transiently disturbed with graded transcranial magnetic stimulation, which caused sustained and macroscopic behavioral transitions from the less stable out-of-phase to the stable in-phase movement, whereas the stable pattern could not be affected. Moreover, the strength of the disturbance needed (a measure of neural stability) was linked to the degree of behavioral stability, demonstrating the applicability of nonlinear system theory as a powerful predictor of the dynamical repertoire of the human brain.I maging of the living human brain routinely reveals patterns corresponding to the synchronized action of billions of neurons (1). The brain's formation of these large-scale distributed neural assemblies and the rapid transition between them is a striking example of self-organization. In complex systems far from equilibrium, nonlinear systems theory has proposed that the decisive parameter governing such collective emergent behavior is stability to small-scale disturbances; which dynamic patterns get selected from the vast array of possible combinations depends on their relative stability (2). Nonlinear systems exhibit pronounced susceptibility to small disturbances due to a hallmark property called ''sensitive dependence on initial conditions,'' meaning that minute changes to the system's state result in large-scale alterations.A further fundamental prediction of this approach is that self-organization depends on the occurrence of sudden macroscopic transitions between states of differing stability (usually called phase transitions; ref. 3). Therefore, if the presence of transitions between differentially stable patterns could be established, this would uncover a fundamental determinant of the dynamic repertoire of the central nervous system (4). Consequently, transition, synchronization and stability phenomena in neuronal membranes, cells, and small assemblies have been studied intensively (5-7). In humans, correlative evidence comes from the observation of electrophysiological changes as a consequence of alterations of stability in motor behavior, an area to which this theory has been applie...

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Section: Discussionsupporting

confidence: 89%

Transitions between dynamical states of differing stability in the human brain

Meyer‐Lindenberg

Ziemann

Hajak

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

171

130

View full text Add to dashboard Cite

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“…The chronological coordination of motor cortical activity in performing voluntary movements is controlled by areas of the secondary motor cortex. Changes in the activation sequence of arm muscles in damage to the premotor cortex have already been observed (Freund and Hummelsheim, 1985). arm was rotated to ventral in flexion movement, it was parallel to the axis of the body in abduction.…”

Section: Methodsmentioning

confidence: 89%

Sequential muscle activation in the hemiparetic arm

Mucha¹

2004

South African Journal of Physiotherapy

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This study investigated the chronological activation sequence of multiple joint movements of the hemiparetic arm in patients with central hemiparesis compared to healthy test subjects.Twelve patients with central hemiparesis and eight healthy control subjects were studied. First, in rapid abduction movement of the upper limb, the electromyographic activities of the middle part of the deltoid muscle, the brachial biceps muscle and the extensor muscles of the fingers, were registered. Second, in rapid flexion of the arm, the electromyographic activities of the ventral part of the deltoid muscle, the brachial biceps muscle and the superficial flexor muscles of the fingers, were measured. From the EMG data registered, activation duration, activation latency and the innervation sequence were determined and compared between the patient group and the control group. In the patient group, a significant prolongation of the activation duration was shown only in abduction. However, the activation latency was significantly prolonged in both movements compared to healthy test subjects. In the innervation sequences, a simultaneous activation was most frequently shown in healthy subjects. In healthy subjects, the deltoid muscle also usually functioned as leading muscle, whereas there was sometimes a shift distally to the brachial biceps muscle in the hemiparetic patients. The speed of rapid multiple joint movements in hemiparetic extremities seems to be unaffected in certain movements (anteversion), in others (abduction) it seems to be significantly reduced. This, as well as the fact that the activation latency is significantly longer in the hemiparetic limbs should be taken into consideration when choosing rehabilitation exercises.

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“…Bütefisch et al [39] reported that repetition of a specific movement is a critical component of motor recovery in stroke patients. Repetitive training influences the functional recovery of synaptic plasticity, which includes alternative descending pathway, secondary motor area, and ipsilateral motor area [40][41][42][43][44]. Page et al [45] recently reported that sufficient task-related training with electrical stimulation can elicit the largest and most consistent upper limb motor changes in stroke patients, compared to a lowfrequency exercise group or a sham group.…”

Section: Discussionmentioning

confidence: 99%

Effect of repetitive wrist extension with electromyography-triggered stimulation after stroke: a preliminary randomized controlled study

Lee

Cha

Kim

et al. 2017

PTRS

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Objective: The purpose of this study was to explore the effect of repetitive wrist extension task training with electromyography (EMG)-triggered neuromuscular electrical stimulation (NMES) for wrist extensor muscle recovery in patients with stroke. Design: Randomized controlled trial. Methods: Fifteen subjects who had suffered a stroke were randomly assigned to an EMG-triggered NMES group (n=8) or control group (n=7); subjects in both groups received conventional therapy as usual. Subjects in the experimental group received application of EMG-triggered NMES to the wrist extensor muscles for 20 minutes, twice per day, five days per week, for a period of four weeks, and were given a task to make a touch alarm go off by activity involving extension of their wrist. In the control group, subjects performed wrist self-exercises for the same duration and frequency as those in the experimental group. Outcome measures included muscle reaction time and spectrum analysis. Assessments were performed during the pre-and post-treatment periods. Results: In the EMG-triggered NMES group, faster muscle reaction time was observed, and median frequency also showed improvement, from 68.2 to 75.3 Hz, after training (p<0.05). Muscle reaction time was significantly faster, and median frequency was significantly higher in the experimental group than in the experimental group after training. Conclusions: EMG-triggered NMES is beneficial for patients with hemiparetic stroke in recovery of upper extremity function.

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Lesions of Premotor Cortex in Man

Cited by 235 publications

References 68 publications

Transitions between dynamical states of differing stability in the human brain

Transitions between dynamical states of differing stability in the human brain

Sequential muscle activation in the hemiparetic arm

Effect of repetitive wrist extension with electromyography-triggered stimulation after stroke: a preliminary randomized controlled study

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