Motor cortex brain activity induced by 1-Hz transcranial magnetic stimulation is similar in location and level to that for volitional movement.
OBJECTIVE
The relatively high temporal and spatial resolution of functional MR imaging was used to compare the blood oxygenation level dependent (BOLD) response associated with movement induced by transcranial magnetic stimulation (TMS) with that for a similar movement executed volitionally (VOL).


METHODS
Seven healthy adults were studied in a 1.5-T MR scanner. One hertz TMS at 110% of motor threshold was applied over the motor cortex for the thumb in 21-pulse trains in alternation with VOL every 63 seconds and interleaved with functional MR imaging.


RESULTS
BOLD increases in motor cortex associated with TMS and VOL movement were similar (2%-3%). Mean separation of their centers of activity was 3.7 + 1.9 mm (mean displacement: left/right = 0.3 +/- 4.1 mm; superior/inferior = 0.7 +/- 1.9 mm). There was no indication of supraphysiological brain activity.


CONCLUSIONS
Motor cortex BOLD response associated with thumb movement induced by 1-Hz TMS at 110% motor threshold is similar in both location and level to that caused by a similar movement executed volitionally.
Bohning
D E
DE
Department of Radiology, Medical University of South Carolina, Charleston 29425, USA. bohninde@musc.edu
Shastri
A
A
McGavin
L
L
McConnell
K A
KA
Nahas
Z
Z
Lorberbaum
J P
JP
Roberts
D R
DR
George
M S
MS
D000328:Adult; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009044:Motor Cortex / Q000502:physiology*; D009068:Movement / Q000502:physiology; D010100:Oxygen / Q000097:blood; D013933:Thumb / Q000502:physiology; D050781:Transcranial Magnetic Stimulation
D010100:Oxygen