Low-frequency rTMS over lateral premotor cortex induces lasting changes in regional activation and functional coupling of cortical motor areas.
OBJECTIVE
To study the effect of 0.9 Hz repetitive transcranial magnetic stimulation (rTMS) of the lateral premotor cortex on neuronal activity in cortical motor areas during simple motor tasks.


METHODS
In 8 subjects, electroencephalogram (EEG) and electromyogram (EMG) were simultaneously recorded during voluntary contractions of the thumb before and after a 15 min train of 0.9 Hz rTMS over the left lateral premotor cortex at stimulus intensity of 90% of active motor threshold. After-effects on cortical motor activity were assessed by measuring the task-related EEG power and inter-regional coherence changes, and the EEG-EMG coherence (EMGCoh).


RESULTS
Low-frequency rTMS over the premotor cortex gave rise to (i) a reduction of the task-related power decrease in the alpha and beta bands, (ii) a selective increase in the task-related coherence change among cortical motor areas in the upper alpha band, and (iii) a decrease in the cortico-muscular coherence. These effects lasted about 15 min after the end of rTMS intervention.


CONCLUSIONS
The attenuated task-related power changes and decreased EMGCoh point to a lasting suppression of voluntary activation of cortical motor areas after rTMS. The present data provide an evidence for a transient reorganization of movement-related neuronal activity in the cortical motor areas after 0.9 Hz rTMS over the premotor cortex.


CONCLUSIONS
Low-frequency rTMS changes the regional activation and functional coupling of cortical motor areas as demonstrated by EEG analysis.
Chen
Wei-Hung
WH
Department of Neurology, Shin-Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
Mima
Tatsuya
T
Siebner
Hartwig R
HR
Oga
Tatsuhide
T
Hara
Hidemi
H
Satow
Takeshi
T
Begum
Tahamina
T
Nagamine
Takashi
T
Shibasaki
Hiroshi
H
D000328:Adult; D001931:Brain Mapping; D004558:Electric Stimulation / Q000379:methods*; D004569:Electroencephalography; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000502:physiology; D006801:Humans; D008280:Magnetics; D008297:Male; D009044:Motor Cortex / Q000033:anatomy & histology / Q000502:physiology*; D009068:Movement / Q000502:physiology; D010296:Parietal Lobe / Q000502:physiology; D013933:Thumb / Q000502:physiology; D013997:Time Factors