title: Simultaneous recording of slow brain potentials and transcranial magnetic stimulation of hand area in human motor cortex.
abstract: Recording of slow brain potentials (SPs) and transcranial magnetic stimulation (TCMS) of the human motor cortex were combined to probe the relationship between SP level and excitability of cortical neurons. In experiment 1, TCMS was applied during and shortly after the warning interval in a forewarned reaction time task. Electromyographic (EMG) responses to TCMS increased only slightly during the warning interval and were significantly elevated 150 ms after the imperative stimulus. In experiment 2, TCMS was applied during biofeedback-induced cortical positivity and negativity. In this non-motor task a dependence of TCMS response on SP amplitude was not significant. Results indicate higher local excitability of motor cortex during cortical negativity when a preparatory motor task is required. TCMS may better be suited to probe processes involved in motor tasks rather than non-motor and cognitive conditions.
authors.affiliation: Institut für Medizinische Psychologie und Verhaltensneurobiologie Universität Tübingen, Germany.
authors.forename: U H
authors.initials: UH
authors.lastname: Häusler
authors.forename: W
authors.initials: W
authors.lastname: Lutzenberger
authors.forename: N
authors.initials: N
authors.lastname: Birbaumer
mesh_terms: D000328:Adult; D001676:Biofeedback, Psychology; D003265:Contingent Negative Variation; D004569:Electroencephalography; D004585:Electrooculography; D005071:Evoked Potentials / Q000502:physiology; D006225:Hand / Q000294:innervation* / Q000502:physiology; D006801:Humans; D015225:Magnetoencephalography; D009044:Motor Cortex / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology