Figure 2. Scalp distribution of somatosensory-evoked potentials (SEPs) elicited by nonpainful tactile stimulation at the second digit of the left (deviant stimuli) or the right hand (frequent stimuli) when patients were viewing either unpleasant or pleasant slides. Waveforms correspond to the SEPs at electrodes C4 and C3 for deviant and frequent stimuli, respectively. Maps represent the scalp distribution at each peak (P50, N80, P200). Time is in milliseconds. MSK indicates musculoskeletal pain; FM = fibromyalgia.