title: Cortico-muscular coherence parallels coherence of postural tremor and MEG during static muscle contraction.
abstract: Corticokinematic coherence (CKC), i.e., coherence calculated between MEG and an accelerometer signal, recording movement kinematics, can be used for functional mapping of the sensorimotor cortex. Cortical sources of CKC, induced by both voluntary and passive movements, localize at the proximity of sensorimotor cortex. We tested the CKC during a static muscle contraction to compare it with simultaneously measured cortico-muscular coherence (CMC) estimated between MEG and surface EMG to study the role of postural tremor in CMC in ten healthy volunteers. CKC was detectable also during this static task. CKC and CMC spectra had similar power distributions, and sources of CMC and CKC colocalized at the cortex in close proximity of the central sulcus. During the static hold task, the accelerometer signal originates from the postural tremor. The similarities between CMC and CKC indicate that postural tremor is related to CMC in healthy subjects.
authors.affiliation: BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Finland; Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital, Finland. Electronic address: katja.airaksinen@helsinki.fi.
authors.forename: Katja
authors.initials: K
authors.lastname: Airaksinen
authors.affiliation: BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Finland.
authors.forename: Tuuli
authors.initials: T
authors.lastname: Lehti
authors.affiliation: BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Finland.
authors.forename: Jussi
authors.initials: J
authors.lastname: Nurminen
authors.affiliation: BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Finland.
authors.forename: Jarkko
authors.initials: J
authors.lastname: Luoma
authors.affiliation: Elekta Oy, Helsinki, Finland.
authors.forename: Liisa
authors.initials: L
authors.lastname: Helle
authors.affiliation: Elekta Oy, Helsinki, Finland; Institute for Learning and Brain Sciences, University of Washington, Seattle, USA; Department of Physics, University of Washington, Seattle, USA.
authors.forename: Samu
authors.initials: S
authors.lastname: Taulu
authors.affiliation: Department of Neurology, University of Helsinki and Helsinki University Hospital, Finland.
authors.forename: Eero
authors.initials: E
authors.lastname: Pekkonen
authors.affiliation: BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Finland.
authors.forename: Jyrki P
authors.initials: JP
authors.lastname: Mäkelä
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D004576:Electromyography; D005260:Female; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D009068:Movement; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000503:physiopathology*; D011187:Posture; D014202:Tremor / Q000503:physiopathology*; D014953:Wrist / Q000503:physiopathology; D055815:Young Adult
keywords: Cortico-muscular coherence; Corticokinematic coherence; Magnetoencephalography; Postural tremor