Brain activity associated with skilled finger movements: multichannel magnetic recordings.
We recorded with a 24-channel SQUID magnetometer cerebral activity preceding and following self-paced voluntary 'skilled' movements in four healthy adults. The subject pressed buttons successively with the right index and middle fingers aiming at a time difference of 40-60 ms; on-line feedback on performance was given after each movement. Slow magnetic readiness fields (RFs) preceded the movements by 0.5 s and culminated about 20 ms after the electromyogram (EMG) onset. Movement-evoked fields, MEFs, opposite in polarity to RFs, were observed 90-120 ms after the EMG onset. They were followed by an additional 'skilled-performance field', SPF, 400-500 ms after the EMG onset. The source locations of RF, MEF, and SPF were within 2 cm from sources of the somatosensory evoked responses, which were situated in the posterior wall of the Rolandic fissure; the sources of MEF were closest to the midline. Neural generators of these deflections and of the corresponding electric potentials are discussed.
Chiarenza
G A
GA
Low Temperature Laboratory, Helsinki University of Technology, Espoo, Finland.
Hari
R K
RK
Karhu
J J
JJ
Tessore
S
S
D000328:Adult; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D004558:Electric Stimulation; D004569:Electroencephalography; D004576:Electromyography; D004585:Electrooculography; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005246:Feedback; D005260:Female; D005385:Fingers / Q000502:physiology*; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008959:Models, Neurological; D009068:Movement / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology