Single-trial ERPs elicited by visual stimuli at two contrast levels: Analysis of ongoing EEG and latency/amplitude jitters

To analyze the trial-to-trial variability in brain dynamics in response to visual stimuli at high- and low-contrast levels, three factors (i.e. ongoing EEG, latency jitter and amplitude jitter of ERP components) were analyzed in this preliminary study. Eight subjects were recruited to perform a visual discriminate task when electrical activity was recorded. Results derived from PO4 showed that: 1) P1 and N1 latency deviated from normal distribution under either stimulus condition; 2) the peak latency of P1 and N1 was shortened distinctly in response to high-contrast stimulus; 3) high-contrast stimulus consistently elicited larger P1-N1 amplitude, which implied the relative amplitude was likely a more reliable measurement of visual stimulus intensity.