Brain Activation During Thermal Stimulation in Neuropathic Pain

Patients with peripheral neuropathy frequently exhibit treatment-refractory neuropathic pain. Although both peripheral and central determinants are recognized for the pathophysiological basis of neuropathic pain following peripheral injury, the modulating effect on pain processing in brain by peripheral mechanisms remains elusive. Here, we will systematically compare the sensory symptoms and brain activation to painful heat stimulation applied to the foot dorsum between patients with peripheral neuropathy and healthy controls. Functional magnetic resonance imaging will be used to define brain activation to thermal stimulation with noxious heat and innocuous warm thermal stimuli applied by contact heat stimulator. Brain activation during thermal stimulation in patients with neuropathic pain will be clarified, and we will also analyze the potential relationships between the topography, quality and intensity of the different painful symptoms and the magnitude and pattern of brain activation during thermal stimulation. This will add in our understanding in the pathophysiology of brain modulation in pain and provide clinically useful message toward the potential therapeutics in the management of neuropathic pain.