More oder less pain – central gain control in the nociceptive system

It is increasingly recognized that pain-induced plasticity may not only provoke sensory gain (hyperalgesia), but also sensory decline, i.e. hypoesthesia and hypoalgesia. In the present talk I will present psychophysical and functional imaging studies investigating perceptual changes induced by conditioning electrical stimulation of C-nociceptors differing in stimulation frequencies and duty cycles provoking either sensory gain (i.e. mechanical hyperalgesia; Stim1) or sensory decline (i.e. hypoesthesia and hypalgesia; Stim2). Before conditioning stimuli, tactile stimulation and pin-prick stimuli lead to different…