Cortical sources of the respiratory-related evoked potential.

The respiratory-related evoked potential (RREP) is increasingly used to study the neural processing of respiratory signals. However, little is known about the cortical origins of early (Nf, P1, N1) and later RREP components (P2, P3). By using high-density EEG, we studied cortical sources of RREP components elicited by short inspiratory occlusions in 18 healthy volunteers (6 female, mean age 20.0+/-1.8 years). Topographical maps for Nf and P1 showed bilateral maximum EEG voltages over the frontal and centro-parietal cortex, respectively. Cortical source analyses (minimum-norm estimates) in addition to topographical maps demonstrated bilateral sensorimotor cortex origins for N1 and P2 which were paralleled by an additional frontal cortex source (p's<0.05). The source of the P3 was located at the parietal cortex (p<0.05). The results support previous findings on the cortical sources of early RREP components Nf, P1 and N1 and demonstrate the cortical sources of later RREP components P2 and P3.