Cortex areas involved in the processing of normal and altered pain

Abstract

Publisher Summary This chapter focuses on source analyses from simultaneously measured electroencephalography and magnetoencephalography signals with respect to pain. The specific approach used in the chapter is the application of individual magnetic resonance imaging scans in the course of the brain source computations, presetting the space for mathematical solutions by the subject's head morphology. Phasic pain is induced by brief radiant heat pulses from an infrared thulium laser stimulator or by intracutaneously applied electrical stimuli. The laser stimulus is particularly useful for diagnostic examinations of normal and disturbed pain sensitivity in patients. It can be applied to any body area under study and norm data and norm variances are available. The intracutaneous stimulus, best applied through the horny skin of the finger tip, is usually used when quick changes in pain perception are to be demonstrated. Both pain models activate predominantly nociceptive A delta fibers in normal subjects, eliciting a well localizable pricking and burning painful sensation and inducing, in parallel, reliable changes of neuronal activity in defined cortex areas. In patients, these experimental “test pain stimuli” are processed in a different way.