title: EEG alpha phase at stimulus onset significantly affects the amplitude of the P3 ERP component.
abstract: Analysis of the relationship between prestimulus EEG alpha phase and the subsequent ERP has proved difficult because of the non-Euclidean nature of phase measurements. In this study, we employed a conventional P3 templating method of single-trial analysis to identify the P3 component in target auditory oddball data from 25 normals. As in previous studies, the absence or near absence of P3 from a subset of single-trials was clearly demonstrated. We investigated this phenomenon to determine whether those single-trials with a large P3 had a different prestimulus alpha phase from those with a small or no P3. Statistical analysis of phase required the use of circular statistical analysis and the development of a new form of topographic mapping, circular topography. The alpha phase at stimulus onset in single-trials with a large P3 was significantly different from that in single-trials with a small or no P3 (p = .02).
authors.affiliation: University of Sydney, Australia. ahaig@tip.csiro.au
authors.forename: A R
authors.initials: AR
authors.lastname: Haig
authors.forename: E
authors.initials: E
authors.lastname: Gordon
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D000513:Alpha Rhythm; D001931:Brain Mapping; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male