Blankenburg, F.; Ruff, C.C.; Bestmann, S.; Bjoertomt, O.; Eshel, N.; Josephs, O.; ... Driver, J.; + view all Blankenburg, F.; Ruff, C.C.; Bestmann, S.; Bjoertomt, O.; Eshel, N.; Josephs, O.; Weiskopf, N.; Driver, J.; - view fewer (2008) Interhemispheric effect of parietal TMS on somatosensory response confirmed directly with concurrent TMS-fMRI. Journal of Neuroscience , 28 (49) pp. 13202-13208. 10.1523/JNEUROSCI.3043-08.2008.
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Transcranial magnetic stimulation (TMS) has been used to document some apparent interhemispheric influences behaviorally, with TMS over right parietal cortex reported to enhance processing of touch for the ipsilateral right hand (Seyal, Ro & Rafal, 1995). However, the neural bases of such apparent interhemispheric influences from TMS remain unknown. Here, we studied this directly by combining TMS with concurrent functional magnetic resonance imaging (fMRI). We applied bursts of 10-Hz TMS over right parietal cortex, at high or low intensity, during two sensory contexts: either without any other stimulation, or while participants received median-nerve stimulation to the right wrist, which projects to left primary somatosensory cortex (SI). TMS to right parietal cortex affected BOLD signal in left SI, with high-versus-low intensity TMS increasing the left SI signal during right-wrist somatosensory input, but decreasing this in the absence of somatosensory input. This state-dependent modulation of SI by parietal TMS over the other hemisphere was accompanied by a related pattern of TMS-induced influences in thalamus, as revealed by region-of-interest analyses there. A behavioral experiment confirmed that the same right-parietal TMS protocol of 10Hz bursts led to enhanced detection of peri-threshold electrical stimulation of the right median nerve, which is initially processed in left S1. Our results confirm directly that TMS over right parietal cortex can affect processing in left SI of the other hemisphere, with rivalrous effects (possibly transcallosal) arising in the absence of somatosensory input, but facilitatory effects (possibly involving thalamic circuitry) in the presence of driving somatosensory input.
|Title:||Interhemispheric effect of parietal TMS on somatosensory response confirmed directly with concurrent TMS-fMRI|
|Open access status:||An open access version is available from UCL Discovery|
|Additional information:||This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. The license allows you to copy, distribute, and transmit the work, as well as adapting it. However, you must attribute the work to the author (but not in any way that suggests that they endorse you or your use of the work), and cannot use the work for commercial purposes without prior permission of the author. If you alter or build upon this work, you can distribute the resulting work only under the same or similar license to this one. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/3.0/ or send a letter to Creative Commons, 444 Castro Street, Suite 900, Mountain View, California, 94041, USA.|
|Keywords:||TMS, fMRI, interhemispheric, rivalry, somatosensory, SI|
|UCL classification:||UCL > School of Life and Medical Sciences > Faculty of Brain Sciences > Institute of Neurology > Imaging Neuroscience|
UCL > School of Life and Medical Sciences > Faculty of Brain Sciences > Psychology and Language Sciences (Division of) > Institute of Cognitive Neuroscience
UCL > School of Life and Medical Sciences > Faculty of Brain Sciences > Institute of Neurology > Motor Neuroscience and Movement Disorders
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