Pain Beliefs and Intracortical Excitability During Experimental Pain

Pain can influence the way the motor system functions. However, responses to pain vary widely between individuals, and this variability may be partly related to pain-related beliefs such as kinesiophobia.

This study examines whether temporary experimental pain changes intracortical excitability in the motor cortex, and whether this response differs according to baseline kinesiophobia. Healthy adults will complete one experimental session. Motor cortex excitability will first be assessed at baseline using transcranial magnetic stimulation, a non-invasive brain stimulation technique. A topical capsaicin cream will then be applied to the forearm to induce temporary, moderate experimental pain. Once pain is established, the same neurophysiological assessments will be repeated.

The main objective is to measure changes in short-interval intracortical inhibition before and during capsaicin-induced pain, with particular attention to whether these changes are associated with baseline kinesiophobia.

Secondary objectives are to characterize other markers of motor cortex excitability, including long-interval intracortical inhibition, short-interval intracortical facilitation, intracortical facilitation, and corticospinal excitability assessed using input-output recruitment curves. Pain intensity will be monitored using a visual analog scale to characterize the experimental pain response. Baseline kinesiophobia will be assessed using the Tampa Scale of Kinesiophobia and examined as a factor associated with interindividual variability in neurophysiological responses to experimental pain.

The researchers expect that changes in motor cortex excitability during experimental pain will vary between individuals, and that individuals with higher kinesiophobia may show smaller changes in motor cortex excitability during capsaicin-induced pain.