Temporally stable beta sensorimotor oscillations and corticomuscular coupling underlie force steadiness

• Published in: NeuroImage (Orlando, Fla.) Vol. 261; p. 119491
• Main Authors: Mongold, Scott J., Piitulainen, Harri, Legrand, Thomas, Vander Ghinst, Marc, Naeije, Gilles, Jousmäki, Veikko, Bourguignon, Mathieu
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.11.2022; Elsevier Limited; Elsevier
• Subjects: Beta sensorimotor oscillations; Cerebral cortex; Corticomuscular coherence; Isometric contraction; Magnetoencephalography; Medical imaging; Motor controling; Motor task performance; Mu rhythm; Muscle contraction; Muscle electromechanical coupling; Neuroimaging; Oscillations; Primary sensorimotor cortex; Somatosensory cortex; Temporal cortex; United States > US; Finland; Motor controling; Isometric contraction; Magnetoencephalography; Corticomuscular coherence; Beta sensorimotor oscillations; Primary sensorimotor cortex; Muscle electromechanical coupling; Mu rhythm
• ISSN: 1053-8119; 1095-9572; 1095-9572
• DOI: 10.1016/j.neuroimage.2022.119491

As humans, we seamlessly hold objects in our hands, and may even lose consciousness of these objects. This phenomenon raises the unsettled question of the involvement of the cerebral cortex, the core area for voluntary motor control, in dynamically maintaining steady muscle force. To address this issue, we measured magnetoencephalographic brain activity from healthy adults who maintained a steady pinch grip. Using a novel analysis approach, we uncovered fine-grained temporal modulations in the beta sensorimotor brain rhythm and its coupling with muscle activity, with respect to several aspects of muscle force (rate of increase/decrease or plateauing high/low). These modulations preceded changes in force features by ∼40 ms and possessed behavioral relevance, as less salient or absent modulation predicted a more stable force output. These findings have consequences for the existing theories regarding the functional role of cortico-muscular coupling, and suggest that steady muscle contractions are characterized by a stable rather than fluttering involvement of the sensorimotor cortex.