Original Research Articles
Modulatory Effects of Transcranial Direct Current Stimulation on Laser-Evoked Potentials
Article first published online: 24 SEP 2008
© American Academy of Pain Medicine
Volume 10, Issue 1, pages 122–132, January/February 2009
How to Cite
Csifcsak, G., Antal, A., Hillers, F., Levold, M., Bachmann, C. G., Happe, S., Nitsche, M. A., Ellrich, J. and Paulus, W. (2009), Modulatory Effects of Transcranial Direct Current Stimulation on Laser-Evoked Potentials. Pain Medicine, 10: 122–132. doi: 10.1111/j.1526-4637.2008.00508.x
- Issue published online: 31 JAN 2009
- Article first published online: 24 SEP 2008
- Primary Motor Cortex;
Objective. Invasive stimulation of the motor cortex has been used for years to alleviate chronic intractable pain in humans. In our study, we have investigated the effect of transcranial direct current stimulation (tDCS), a noninvasive stimulation method, for manipulating the excitability of cortical motor areas on laser evoked potentials (LEP) and acute pain perception.
Designs and Settings. The amplitude of the N1, N2, and P2 LEP components of 10 healthy volunteers were evaluated prior to and following anodal, cathodal, and sham stimulation of the primary motor cortex. In a separate experiment subjective, pain rating scores of 16 healthy subjects in two perceptual categories (warm sensation, mild pain) were also analyzed.
Results. Cathodal tDCS significantly reduced the amplitude of N2 and P2 components compared with anodal or sham stimulation. However, neither of the tDCS types modified significantly the laser energy values necessary to induce moderate pain. In a separate experiment, cathodal stimulation significantly diminished mild pain sensation only when laser-stimulating the hand contralateral to the side of tDCS, while anodal stimulation modified warm sensation.
Conclusions. The possible underlying mechanisms of our findings in view of recent neuroimaging studies are discussed. To our knowledge this study is the first to demonstrate the mild antinociceptive effect of tDCS over the primary motor cortex in healthy volunteers.