Abstract
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.
Original language | English |
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Pages (from-to) | 433-439 |
Number of pages | 7 |
Journal | Brain Topography |
Volume | 3 |
Issue number | 4 |
DOIs | |
Publication status | Published - Jun 1991 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Evoked responses
- Magnetoencephalography
- Man
- Movement-related brain activity
- Voluntary movement