QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

The Journal of Neuroscience, December 3, 2008, 28(49):13202-13208; doi:10.1523/JNEUROSCI.3043-08.2008

This Article Free Access Article Free Access Article Full Text Full Text (PDF) Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Blankenburg, F. Articles by Driver, J. Search for Related Content PubMed PubMed Citation Articles by Blankenburg, F. Articles by Driver, J.

 Previous Article  |  Next Article 

Behavioral/Systems/Cognitive
Interhemispheric Effect of Parietal TMS on Somatosensory Response Confirmed Directly with Concurrent TMS–fMRI

Felix Blankenburg,^1,2,4 Christian C. Ruff,^1,2 Sven Bestmann,^2,3 Otto Bjoertomt,¹ Neir Eshel,¹ Oliver Josephs,² Nikolaus Weiskopf,² and Jon Driver^1,2

¹Institute of Cognitive Neuroscience, University College London, London WC1 3AR, United Kingdom, ²Wellcome Trust Centre for Neuroimaging and ³Sobell Department for Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom, and ⁴Department of Neurology and Bernstein Center for Computational Neuroscience, Charité, 10115 Berlin, Germany

Correspondence should be addressed to Felix Blankenburg, Department of Neurology and Bernstein Center for Computational Neuroscience, Charité, Philippstrasse 13, House 6, 10115 Berlin, Germany. Email: felix.blankenburg{at}charite.de

Transcranial magnetic stimulation (TMS) has been used to document some apparent interhemispheric influences behaviorally, with TMS over the right parietal cortex reported to enhance processing of touch for the ipsilateral right hand (Seyal et al., 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 a 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 the blood oxygenation level-dependent 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 the thalamus, as revealed by region-of-interest analyses. A behavioral experiment confirmed that the same right parietal TMS protocol of 10 Hz bursts led to enhanced detection of perithreshold electrical stimulation of the right median nerve, which is initially processed in left SI. 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.

Key words: TMS; fMRI; interhemispheric; rivalry; somatosensory; SI

---

Received July 1, 2008; accepted Aug. 14, 2008.

Correspondence should be addressed to Felix Blankenburg, Department of Neurology and Bernstein Center for Computational Neuroscience, Charité, Philippstrasse 13, House 6, 10115 Berlin, Germany. Email: felix.blankenburg{at}charite.de

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help