title: Cortical neuromagnetic fields evoked by voluntary and passive hand movements in healthy adults.
abstract: Neuromagnetic fields were recorded from the left cerebral hemisphere of six healthy right-handed subjects under three different conditions: (1) externally triggered rapid voluntary extension and flexion of the right hand, (2) passive extension and flexion of the right hand, and (3) stimulation of the skin of the right index finger by means of air pressure. Location analysis using the current density analysis did not reveal any differences between motor evoked field I (MEF I) in active and passive movements, and met the maximum of cerebral activation in the contralateral precentral region. In contrast, the sensory evoked field was located clearly in the contralateral postcentral region. Additionally, a significantly shorter latency of MEF I (with respect to movement onset) was observed in flexion compared with extension in both passive and active movements. These results support the assumption that MEF I is generated by cortical activation resulting from proprioceptive, probably muscle spindle, input. The current density analysis has proved to be an appropriate method for investigating movement-related fields. Furthermore, the described method seems to be appropriate for evaluating the processes of cortical reorganization and the influence of neurorehabilitation within longitudinal studies in patients with lesions in motor centers of the brain.
authors.affiliation: Neurologisches Rehabilitationszentrum Leipzig, Leipzig University, Germany. woldag@sachsenklinik.de
authors.forename: Hartwig
authors.initials: H
authors.lastname: Woldag
authors.forename: Guido
authors.initials: G
authors.lastname: Waldmann
authors.forename: Margot
authors.initials: M
authors.lastname: Schubert
authors.forename: Ulrich
authors.initials: U
authors.lastname: Oertel
authors.forename: Burkhard
authors.initials: B
authors.lastname: Maess
authors.forename: Angela
authors.initials: A
authors.lastname: Friederici
authors.forename: Horst
authors.initials: H
authors.lastname: Hummelsheim
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods; D002540:Cerebral Cortex / Q000502:physiology*; D004574:Electromagnetic Fields; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D005385:Fingers / Q000502:physiology; D006225:Hand / Q000502:physiology*; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D009038:Motion; D009044:Motor Cortex / Q000502:physiology; D009068:Movement / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D010812:Physical Stimulation; D011312:Pressure; D012879:Skin Physiological Phenomena; D013003:Somatosensory Cortex / Q000502:physiology; D014110:Touch / Q000502:physiology; D014836:Volition / Q000502:physiology