TY - JOUR
T1 - MEG insight into the spectral dynamics underlying steady isometric muscle contraction
AU - Bourguignon, Mathieu
AU - Piitulainen, Harri
AU - Smeds, Eero
AU - Zhou, Guangyu
AU - Jousmäki, Veikko
AU - Hari, Riitta
N1 - Funding Information:
This work was supported by the Academy of Finland Grants 131483 and 263800 to R.H. and Grants 13266133 266133, 296240, 307250, and 304294 to H.P., Tekes (the Finnish Funding Agency for Technology and Innovation) Grant 1104/10, the program Attract of Innoviris Grant 2015-BB2B-10 to M.B., by the Spanish Ministry of Economy and Competitiveness Grant PSI2016-77175-P to M.B., the Karolinska Institutet Strategic Neuroscience Program,
Publisher Copyright:
© 2017 Bourguignon et al.
PY - 2017/10/25
Y1 - 2017/10/25
N2 - To gain fundamental knowledge on how the brain controls motor actions, we studied in detail the interplay between MEG signals from the primary sensorimotor (SM1) cortex and the contraction force of 17 healthy adult humans (7 females, 10 males). SM1 activity was coherent at ~20 Hz with surface electromyogram (as already extensively reported) but also with contraction force. In both cases, the effective coupling was dominant in the efferent direction. Across subjects, the level of ~20 Hz coherence between cortex and periphery positively correlated with the “burstiness” of ~20 Hz SM1 (Pearson r ≈ 0.65) and peripheral fluctuations (r ≈ 0.9). Thus, ~20 Hz coherence between cortex and periphery is tightly linked to the presence of ~20 Hz bursts in SM1 and peripheral activity. However, the very high correlation with peripheral fluctuations suggests that the periphery is the limiting factor. At frequencies <3 Hz, both SM1 signals and ~20 Hz SM1 envelope were coherent with both force and its absolute change rate. The effective coupling dominated in the efferent direction between (1) force and the ~20 Hz SM1 envelope and (2) the absolute change rate of the force and SM1 signals. Together, our data favor the view that ~20 Hz coherence between cortex and periphery during isometric contraction builds on the presence of ~20 Hz SM1 oscillations and needs not rely on feedback from the periphery. They also suggest that effective cortical proprioceptive processing operates at <3 Hz frequencies, even during steady isometric contractions.
AB - To gain fundamental knowledge on how the brain controls motor actions, we studied in detail the interplay between MEG signals from the primary sensorimotor (SM1) cortex and the contraction force of 17 healthy adult humans (7 females, 10 males). SM1 activity was coherent at ~20 Hz with surface electromyogram (as already extensively reported) but also with contraction force. In both cases, the effective coupling was dominant in the efferent direction. Across subjects, the level of ~20 Hz coherence between cortex and periphery positively correlated with the “burstiness” of ~20 Hz SM1 (Pearson r ≈ 0.65) and peripheral fluctuations (r ≈ 0.9). Thus, ~20 Hz coherence between cortex and periphery is tightly linked to the presence of ~20 Hz bursts in SM1 and peripheral activity. However, the very high correlation with peripheral fluctuations suggests that the periphery is the limiting factor. At frequencies <3 Hz, both SM1 signals and ~20 Hz SM1 envelope were coherent with both force and its absolute change rate. The effective coupling dominated in the efferent direction between (1) force and the ~20 Hz SM1 envelope and (2) the absolute change rate of the force and SM1 signals. Together, our data favor the view that ~20 Hz coherence between cortex and periphery during isometric contraction builds on the presence of ~20 Hz SM1 oscillations and needs not rely on feedback from the periphery. They also suggest that effective cortical proprioceptive processing operates at <3 Hz frequencies, even during steady isometric contractions.
KW - Cortex-muscle coherence
KW - Corticokinematic coherence
KW - Isometric contraction
KW - Magnetoencephalography
KW - Motor control
KW - Primary sensorimotor cortex
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U2 - 10.1523/JNEUROSCI.0447-17.2017
DO - 10.1523/JNEUROSCI.0447-17.2017
M3 - Article
C2 - 28951449
AN - SCOPUS:85032357042
VL - 37
SP - 10421
EP - 10437
JO - Journal of Neuroscience
JF - Journal of Neuroscience
SN - 0270-6474
IS - 43
ER -