Pain perception and its genesis in the human brain.

In the past two decades, pain perception in the human brain has been studied with EEG/MEG brain topography and PET/fMRI neuroimaging techniques. A host of cortical and subcortical loci can be activated by various nociceptive conditions. The activation in pain perception can be induced by physical (electrical, thermal, mechanical), chemical (capsacin, ascoric acid), psychological (anxiety, stress, nocebo) means, and pathological (e.