1. Sequential analysis of the ERP 300 in young adults

Abstract

Introduction: The discrimination from a random stimulus in one sequence of rhythmic auditory stimuli generates a potential in which the fundamental wave is P300 (or ERP300). These cognitive potentials have a high inter-subject variability, but less is known on intra-subject variability over time. Objective: The aim of this study is to determine whether the amplitude and the latency of scalp ERP300 maintain their general characteristics over time in young adults. Methodology: Oddball paradigm was used to generate ERP300 elicited after a set of 50 stimuli. Potentials were recorded on Fz, Cz, C3 and C4 in 30 healthy subjects. During each session subjects were submitted to two consecutive trials. The same protocol was repeated on the same day at an interval of 6 h (from early morning to afternoon) and again one week later. Results: No statistically significant differences were found in terms of week period (p > 0.05) or morning and afternoon analysis (p > 0.05). Topographically, the scalp distribution of P300 varied significantly in terms of amplitude and latency; Cz amplitude was significantly higher (p < 0.05) and latency was significantly lower (p < 0.05) when compared to the remaining scalp locations. Significant differences in amplitude were found between the first and the second trial in each one of the recording sessions (lower in the second trial, p < 0.05). Comments: The results suggested an individual stability on ERP 300 latency when studied at different times of the same day, which remained stable a week later. However, lower amplitude in the second trial is difficult to explain.