Neuroscience 2005 Abstract
| Presentation Number: | 867.18 |
|---|---|
| Abstract Title: | BOLD MRI responses to repetitive TMS over human dorsal premotor cortex. |
| Authors: |
Bestmann, S.*1,2
; Baudewig, J.1
; Siebner, H. R.3
; Rothwell, J. C.2
; Frahm, J.1
1Sobell Dept., Inst. of Neurology, London, United Kingdom 2Germany, 12 Queen Square, Wc1N3BG, 3Biomedizinische NMR, 12 Queen Square, Wc1N3BG, |
| Primary Theme and Topics |
Sensory and Motor Systems - Kinematics and EMG -- Fingers and grasping |
| Secondary Theme and Topics | Techniques in Neuroscience<br />- Physiological Methods |
| Session: |
867. Kinematics and EMG: Fingers and Grasping Poster |
| Presentation Time: | Wednesday, November 16, 2005 9:00 AM-10:00 AM |
| Location: | Washington Convention Center - Hall A-C, Board # AA30 |
| Keywords: | Motor Cortex, SMA, EMG, Echo-planar Imaging |
Functional magnetic resonance imaging (fMRI) studies in humans have hitherto failed to demonstrate activity changes in the direct vicinity of transcranial magnetic stimulation (TMS) that cannot be attributed to re-afferent somatosensory feedback or a spread of excitation. In order to investigate the underlying activity changes at the site of stimulation as well as in remote connected regions we applied short trains of high-intensity (110% of resting motor threshold) and low-intensity (90% of active motor threshold) repetitive TMS (rTMS; 3 Hz, 10 s duration) over the presumed location of the left dorsal premotor cortex (PMd) during fMRI. Signal increases in the direct vicinity of the stimulated PMd were observed during rTMS at 110% RMT. However, positive BOLD MRI responses were observed with rTMS at both 90% and 110% RMT in connected brain regions such as right PMd, bilateral PMv, supplementary motor area, somatosensory cortex, cingulate motor area, left posterior temporal lobe, cerebellum, and caudate nucleus. Responses were generally smaller during low-intensity rTMS. The results indicate that short trains of TMS can modify local hemodynamics in the absence of overt motor responses. In addition, premotor rTMS can not only effectively stimulate cortico-cortical but also cortico-subcortical connections even at low stimulation intensities.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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