Equiprobable Go/NoGo auditory ERP components: Adults vs. children

Abstract presented at the 23rd Australasian Society for Psychophysiology Conference, 20-22 Nov 2013, Wollongong, Australi

ERP source localisation using eLORETA: Adults vs. children

Abstract presented at the 23rd Australasian Society for Psychophysiology Conference, 20-22 Nov 2013, Wollongong, Australi

Sequential processing in the equiprobable auditory Go/NoGo task: children vs. adults

Objective To compare sequential processing in the unwarned auditory equiprobable Go/NoGo task in children and adults, in the context of a recently developed adult schema. Methods Adult and child samples completed an equiprobable auditory Go/NoGo task while EEG was recorded from 19 channels. Go and NoGo ERPs were decomposed using unrestricted Varimax-rotated PCAs for the groups separately, and in combination. The separate adult and child components were compared using the Congruence Coefficient. Brain sources of each assessed component were examined using eLORETA. Results Corresponding adult/child components were tentatively identified: two N1 subcomponents (N1-1, PN) and P2, followed by N2, P3 (separate P3a/P3b in children), the classic Slow Wave (SW), and a diffuse Late Positivity (LP). While early and late components showed similarities, the intermediate P2 and N2 differed substantially in their stimulus effects. Conclusions Aspects of Go vs. NoGo categorisation differ between adults and children, but subsequent processing reflected in the different Go/NoGo P3 components, and their sequellae, are similar. Significance This is the first detailed examination of child responses in this paradigm. The tested schema appears relatively robust in adults, and the child results may aid our understanding of developmental aspects of cognitive processing in normal and atypical individuals

Sequential processing in an auditory equiprobable Go/NoGo task with variable interstimulus interval

A recent series of studies of the auditory equiprobable Go/NoGo task, using fixed interstimulus intervals (ISIs), proposed a processing schema relating observed event-related potential (ERP) components to sequential processing stages. However, it has been demonstrated that attention and ERP components can be affected by the predictable rhythmic timing of fixed ISIs. Hence the aim of the current study was to test the robustness of that processing schema with an unpredictable arrhythmic variable ISI. EEG was recorded from 30 university students at 30 scalp sites in an unwarned auditory equiprobable Go/NoGo task using a variable ISI. Following our previous studies, Go and NoGo ERP components were derived using temporal principal components analysis (PCA). Of the unrestricted Varimax-rotated factors, seven were identifiable as components based on their topography, polarity, and latency: two subcomponents of the N1 (N1-1, and processing negativity, PN), P2/N2b, N2c/P3a, P3b, and two subcomponents of the slow wave (SW-1 and SW-2). These components showed Go/NoGo effects comparable to those previously noted with fixed ISI, supporting the proposed processing schema. The Late Positivity (LP) component, previously speculated to mark cortical deactivation after processing the NoGo stimulus, was not present in the sequence of components. In its absence, activity underlying the observed sustained P300/late positive complex may be involved in processing temporally-uncertain stimuli