Electrocorticogram–electromyogram coherence during isometric contraction of hand muscle in human

Ohara, Shuichi; Nakagawa, Takashi; Ikeda, Akio; Kunieda, Takeharu; Matsumoto, Riki; Taki, Waro; Hashimoto, Nobuo; Baba, Koichi; Mihara, Tadahiro; Salenius, Stephan; Shibasaki, Hiroshi

doi:10.1016/s1388-2457(00)00448-x

Cited by 72 publications

(57 citation statements)

References 24 publications

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“…Oscillations synchronized with those in EMG appear in peripheral afferents , spinal cord interneurons (Takei and Seki, 2008), and sensory and motor cortices (Porcaro et al, 2008), and coherence between oscillations in the primary motor and sensory cortices has been confirmed in man using magnetoencephalography (Porcaro et al, 2008) and epicortical recordings using subdural grid electrodes (Ohara et al, 2000). Furthermore, evidence for bidirectional information flow in CMC (Meng et al, 2008) supports the proposal that coherent oscillatory networks form connected loops from cortex to the periphery and back and would be suited to proprioceptive processing during movement (Baker, 2007).…”

Section: Cmc Probably Reflects Bidirectional Sensorimotor Processingmentioning

confidence: 58%

Developmental Tuning and Decay in Senescence of Oscillations Linking the Corticospinal System

Graziadio¹,

Basu²,

Tomasevic³

et al. 2010

J. Neurosci.

101

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There is increasing evidence of the importance of synchronous activity within the corticospinal system for motor control. We compared oscillatory activity in the primary sensorimotor cortex [EEG of sensorimotor cortex (SMC-EEG)] and a motor neuronal pool [surface electromyogram of opponens pollicis (OP-EMG)], and their coherence in children (4 -12 years of age), young adults (20 -35 years of age), and elderly adults (Ͼ55 years of age). The ratio between lower (2-13 Hz) and higher (14 -32 Hz) frequencies in both SMC-EEG and OP-EMG decreased with age, correlating inversely with motor performance. There was evidence for larger, more distributed cortical networks in the children and elderly compared with young adults. Corticomuscular coherence (CMC) was present in all age groups and shifted between frontal and parietal cortical areas. In children, CMC was smaller and less stationary in amplitude and frequency than in adults. Young adults had single peaks of CMC clustered near the modal frequency (23 Hz); multiple peaks with a broad spread of frequencies occurred in children and the elderly; the further the frequency of the maximum peak CMC was from 23 Hz, the poorer the performance. CMC amplitude was inversely related to performance in young adults but was not modulated in relation to performance in children and the elderly. We propose that progressive fine-tuning of the frequency coding and stabilization of the dynamic properties within and between corticospinal networks occurs during adolescence, refining the capacity for efficient dynamic communication in adulthood. In old age, blurring of the tuning between networks and breakdown in their integration occurs and is likely to contribute to a decrement in motor control.

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Section: Cmc Probably Reflects Bidirectional Sensorimotor Processingmentioning

confidence: 58%

Developmental Tuning and Decay in Senescence of Oscillations Linking the Corticospinal System

Graziadio¹,

Basu²,

Tomasevic³

et al. 2010

J. Neurosci.

101

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“…With rectified sEMG, CMC typically peaks between ϳ15 and 30 Hz during weak isometric contractions (Brown et al 1998;Conway et al 1995;Gross et al 2000;Halliday et al 1998;Salenius et al 1997), but peaks at ϳ6 -15 Hz have been detected in some individuals with MEG (Salenius et al 1997) or epicortical recordings over M1 (Raethjen et al 2002) as well as in epicortical recordings over the primary somatosensory cortex and the supplementary motor area (Ohara et al 2000). It is apparent that the presence of the 12-Hz CMC only with rectified, and not with unrectified, EMG will require more rigid examination in the future, using for example variable contraction levels that result in different levels of motor unit recruitment and firing frequencies, and consequently to different levels of cancellation between the motor unit action potentials in the sEMG.…”

Section: Prominent Cortex-muscle Coherence At ϳ12 Hz With Rectified Smentioning

confidence: 99%

Spatial variability in cortex-muscle coherence investigated with magnetoencephalography and high-density surface electromyography

Piitulainen

Botter

Bourguignon

et al. 2015

Journal of Neurophysiology

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muscle coherence (CMC) reflects coupling between magnetoencephalography (MEG) and surface electromyography (sEMG), being strongest during isometric contraction but absent, for unknown reasons, in some individuals. We used a novel nonmagnetic high-density sEMG (HD-sEMG) electrode grid (36 mm ϫ 12 mm; 60 electrodes separated by 3 mm) to study effects of sEMG recording site, electrode derivation, and rectification on the strength of CMC. Monopolar sEMG from right thenar and 306-channel whole-scalp MEG were recorded from 14 subjects during 4-min isometric thumb abduction. CMC was computed for 60 monopolar, 55 bipolar, and 32 Laplacian HD-sEMG derivations, and two derivations were computed to mimic "macroscopic" monopolar and bipolar sEMG (electrode diameter 9 mm; interelectrode distance 21 mm). With unrectified sEMG, 12 subjects showed statistically significant CMC in 91-95% of the HD-sEMG channels, with maximum coherence at ϳ25 Hz. CMC was about a fifth stronger for monopolar than bipolar and Laplacian derivations. Monopolar derivations resulted in most uniform CMC distributions across the thenar and in tightest cortical source clusters in the left rolandic hand area. CMC was 19 -27% stronger for HD-sEMG than for "macroscopic" monopolar or bipolar derivations. EMG rectification reduced the CMC peak by a quarter, resulted in a more uniformly distributed CMC across the thenar, and provided more tightly clustered cortical sources than unrectifed sEMGs. Moreover, it revealed CMC at ϳ12 Hz. We conclude that HD-sEMG, especially with monopolar derivation, can facilitate detection of CMC and that individual muscle anatomy cannot explain the high interindividual CMC variability.

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“…8); if present, it is usually weak compared with that around 20 Hz (Conway et al 1995;Kilner et al 2000;Salenius et al 1997). Exceptionally, some recent reports have demonstrated such low-frequency coherence between EMGs and electrocorticograms recorded from subdural grids implanted in patients undergoing surgery for intractable epilepsy (Ohara et al 2000;Raethjen et al 2002) and also between MEG and EMG (Gross et al 2002;Marsden et al 2001). It is possible that the findings with epileptic patients have been influenced by the underlying pathology of the sub-jects or its pharmacological treatment.…”

Section: Implications For Corticomuscular Coherencementioning

confidence: 99%

Synchronization in Monkey Motor Cortex During a Precision Grip Task. II. Effect of Oscillatory Activity on Corticospinal Output

Baker

Pinches

Lemon

2003

Journal of Neurophysiology

201

185

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Baker, Stuart N., Elizabeth M. Pinches, and Roger N. Lemon. Synchronization in monkey motor cortex during a precision grip task. II. Effect of oscillatory activity on corticospinal output. J Neurophysiol 89: 1941Neurophysiol 89: -1953Neurophysiol 89: , 2003 10.1152/jn.00832.2002. Recordings from primary motor cortex (M1) during periods of steady contraction show oscillatory activity; these oscillations are coherent with the activity of contralateral muscles. We investigated synchronization of corticospinal output neurons with the oscillations, which could provide the pathway for their transmission to the spinal motoneurons. One hundred seventy-six antidromically identified pyramidal tract neurons (PTNs) were recorded from M1 in three macaque monkeys trained to perform a precision grip task. Local field potentials (LFP) were simultaneously recorded. All analysis was confined to the hold period of the task, where our previous work has shown that there is the strongest oscillatory activity. Coherence was calculated between LFP and PTN discharge. Significant coherence was seen in three bands, with frequencies of 10 -14, 17-31, and 34 -44 Hz. Coherence values were low, with the majority of PTN-LFP coherences having a peak lower than 0.05. The phase of coherence was approximately Ϫ/2 radians for each band (with LFP polarity defined as negative upward), although there was some dispersion of phase across the population of PTNs. Coherence was also calculated between pairs of PTNs that had been simultaneously recorded. Where there was significant coherence, it was also generally smaller than 0.05. The phase of PTN-PTN coherence clustered around zero radians. A computer model was constructed to assist the interpretation of the experimental results. It simulated an integrate-and-fire neuron responding to synaptic inputs. A fraction of the synaptic inputs was synchronized with a simulated LFP; the remainder were uncorrelated with it. The model showed that coherence between the LFP and the output spike train considerably underestimated the fraction of synchronized inputs. Additionally, for a given fraction of synchronized inputs, coherence was smaller for high-compared with low-frequency bins. Cell discharge rate also influenced the spike-LFP coherence: coherence was higher for simulations in which the cell discharged at a faster rate. Thus although levels of PTN-LFP coherence seen experimentally were low, a considerable proportion of the input to the PTN must be synchronized with the global oscillatory activity recorded by the LFP. The low LFP-PTN coherences do however indicate that cortical oscillations are transmitted with only low fidelity in the discharge of a single PTN. Using further computer simulations, it was demonstrated that a small population of PTNs could encode the cortical oscillatory signal effectively, since the action of averaging across the population improves the signal:noise ratio. The oscillations will therefore be effectively transmitted to spinal motoneurons, and this has important consequences for ...

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Electrocorticogram–electromyogram coherence during isometric contraction of hand muscle in human

Cited by 72 publications

References 24 publications

Developmental Tuning and Decay in Senescence of Oscillations Linking the Corticospinal System

Developmental Tuning and Decay in Senescence of Oscillations Linking the Corticospinal System

Spatial variability in cortex-muscle coherence investigated with magnetoencephalography and high-density surface electromyography

Synchronization in Monkey Motor Cortex During a Precision Grip Task. II. Effect of Oscillatory Activity on Corticospinal Output

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