Relationship between resistive loads and P1 peak of respiratory-related evoked potential.

This study investigated the relationship between resistive-load (DeltaR) magnitude, the first positive peak (P1) amplitude of the respiratory-related evoked potential (RREP), and load-magnitude estimation (ME). The first experiments determined the subject's (n = 9) ME of five DeltaR magnitudes randomly presented at the onset of an inspiration or by interrupting an inspiration. No significant differences were found in the slopes of the two different presentations, but the subjects estimated the interrupted inspiratory loads to be of lesser magnitude than loads presented at the onset of the breath. In the second series of experiments, the subject's (n = 6) RREPs were recorded in response to three DeltaR magnitudes. The amplitude of the short-latency P1 peak of the RREP significantly increased with increases in the DeltaR magnitude. A log-log plot of the group-averaged P1 amplitudes showed a linear relationship with DeltaR. These results were consistent with the hypothesis that the perceptual magnitude of the respiratory load was related to the P1 amplitude of the RREP, suggesting the physical magnitude of the load-related stimulus was correlated with the amplitude of the cortical neural activation.