Source localisation of 62-electrode human laser pain evoked potential datausing a realistic head model

Laser evoked potentials (LEPs), elicited by painful laser stimulation of th e right forearm, were recorded from 62 electrodes in a single healthy subje ct. The positions of the electrodes on the scalp were co-registered with th e subject's structural magnetic resonance image (MRI) of the brain. Spatio- temporal dipole modelling, using a head model derived from the MRI, estimat ed sources in left posterior cingulate, posterior parietal and anterior ins ular cortices. The parietal source peaked in activity at 260 ms, which expl ained the N1/N2 peaks of the LEPs. The cingulate source was the most strong ly activated, at 400 ms, and accounted for the P2 LEP component. The insula r source showed late, prolonged activation, peaking in magnitude at 850 ms. This is the first study to report scalp-recorded LEP generators in posteri or parietal and insular cortices, Although these sources require replicatio n, they are consistent with other functional imaging studies. (C) 2001 Else vier Science B,V. All rights reserved.