Modulatory Effects of Somatosensory Tasks on Pain Thresholds and Cortical Excitability (P01.172)

Abstract

Objective: The study aimed to test the effects of three different somatosensory tasks including somatosensory learning with and without visual feedback and simple somatosensory input on pressure pain threshold and motor cortex activation using transcranial magnetic stimulation (TMS). Background Chronic pain is linked to brain dysfunctions, whose precise neural correlates still remain not completely understood. Recent investigations on novel therapies for pain are targeting these malfunctioning processes inside the brain. The activation of the motor cortex via non-invasive brain stimulation has been proven to be effective in the treatment of pain conditions. Thus, this cortical area has been proposed to play a role in central pain processing. Since it is known that the motor and somatosensory cortices are functionally connected, somatosensory input may be used in order to activate motor cortex mediated analgesic effects. Design/Methods: This single-blinded, randomized, untreated-controlled, and parallel designed trial included forty healthy right-handed male subjects. Statistical analyses involved t-tests and a mixed ANOVA model for TMS and pain threshold levels, respectively. Results: Results showed a significant reduction of pain perception of the ipsilateral hand induced by somatosensory learning and a pain sensitization of the contralateral hand due to simple somatosensory input. Comparing pain and TMS measurements revealed a significant effect of hand and task. Conclusions: In conclusion, this study shows that somatosensory learning is effective to alleviate pain perception and that somatosensory input can change motor cortex excitability in a task-dependent manner. These findings may help lead to the development of novel approaches for the treatment of pain syndromes based on an adjunct and multimodal method. Disclosure: Dr. Volz has nothing to disclose. Dr. Suarez-Contreras has nothing to disclose. Dr. Mendonca has nothing to disclose. Dr. Santos Pinheiro has nothing to disclose. Dr. Merabet has nothing to disclose. Dr. Fregni has received research support from Highland Instruments and First One.