title: Inter-individual and intra-individual variability of the N2 component: on reliability and signal-to-noise ratio.
abstract: The nogo N2 component, an anterior negative peak supposed to be generated in the anterior cingulate cortex, has been used as an indicator of conflict monitoring and response conflict in basic and clinical research. Here, we investigate the reliability and the signal-to-noise ratio (SNR) of inter-individual differences of the N2 amplitudes as well as of intra-individual standard deviations of N2 amplitudes. Effects of the number of nogo epochs, type of summary measure (peak vs. average amplitude), and filter cut-offs (1-12 Hz vs. 1-30 Hz) are investigated. A sample of N=32 participants, performed a go/nogo task. Excellent Cronbach's alpha coefficients (> or = .90) were obtained for the fronto-central average N2 amplitude at 40 nogo epochs and for the peak N2 amplitude at 60 nogo epochs. The SNR was higher for the average nogo N2 amplitude compared to the peak N2 amplitude. Split-half reliability coefficients of the intra-individual standard deviation of the nogo N2 amplitudes were at least moderate. Based on these results we provide suggestions for a reliable N2 measurement. Moreover, although intra-individual variability has often been conceived as noise the present findings support the idea that intra-individual N2 variability incorporates systematic variance.
authors.affiliation: University of Bonn, Dietkirchenstrasse 28, 53111 Bonn, Germany. anja.leue@uni-bonn.de
authors.forename: Anja
authors.initials: A
authors.lastname: Leue
authors.forename: Christoph
authors.initials: C
authors.lastname: Klein
authors.forename: Sebastian
authors.initials: S
authors.lastname: Lange
authors.forename: André
authors.initials: A
authors.lastname: Beauducel
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping / Q000379:methods; D002540:Cerebral Cortex / Q000502:physiology*; D003220:Conflict, Psychological; D004569:Electroencephalography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D055815:Young Adult
keywords: Intra-individual variability; N2 component; Reliability; Signal-to-noise ratio