MEMBRANE BIOLOGYContinuous theta-burst stimulation over the primary somatosensory cortex modulates interhemispheric inhibitionZapallow, Christopher M.a; Jacobs, Mark F.a; Lee, Kevin G.H.a; Asmussen, Michael J.a; Tsang, Philemonb; Nelson, Aimee J.a,bAuthor Information aDepartment of Kinesiology, University of Waterloo, Waterloo bDepartment of Kinesiology, McMaster University, Hamilton, Canada Correspondence to Aimee J. Nelson, Department of Kinesiology, McMaster University, 1280 Main Street, West Hamilton, Ontario, Canada L8S 4L8 Tel: +1 905 525 9140 x28053; fax: +1 905 523 6011; e-mail: [email protected] Received February 19, 2013 Accepted March 11, 2013 NeuroReport: May 8, 2013 - Volume 24 - Issue 7 - p 394-398 doi: 10.1097/WNR.0b013e32836131ca Buy Metrics Abstract One mechanism thought to mediate hand and upper limb control across motor cortices is called interhemispheric inhibition (IHI). Somatosensory cortices are important in the motor control of the hand, although the neural mechanisms by which somatic loci act are not fully understood. In the present study, we study the possibility that the primary somatosensory cortex (SI) influences IHI as one mechanism to modulate hand control. IHI from the motor cortices was measured before and after continuous theta-burst stimulation (cTBS) was delivered over the left-hemisphere SI. IHI was evoked using paired-pulse transcranial magnetic stimulation and measured using electromyography electrodes over the first dorsal interosseous muscles of both hands at short (10 ms) and long (40 ms) intervals to evoke short interval IHI and long interval IHI, respectively. Measures were taken before and for up to 1 h after 600 pulse cTBS was delivered over SI. Results indicate that cTBS over SI increases short interval IHI in the left hand (i.e. ipsilateral to cTBS) for 45–60 min after stimulation. These results indicate that SI is indeed able to modify IHI, and this is therefore one neural mechanism by which SI may influence hand control. © 2013 Lippincott Williams & Wilkins, Inc.