Antinociceptive Effect of Transauricular Electrical Vagal Nerve Stimulation

This investigation is going to study whether electrical tVNS applied at the cymba of auricular conchae reduces central sensitization of experimentally induced pain in comparison with electrical sham stimulation applied at the earlobes and whether the hypoalgesic effects of tVNS disappear after pharmacological block of muscarinic receptors. Also, this investigation will examine whether tVNS is associated with activation in brain areas, involved in processing of thermal pain stimuli and emotional and vegetative modulation of thermal pain in subjects who will respond with antinociceptive reaction to tVNS.