title: Intraindividual reaction time variability affects P300 amplitude rather than latency.
abstract: The neural correlates of intraindividual response variability were investigated in a serial choice reaction time (CRT) task. Reaction times (RTs) from the faster and slower portions of the RT distribution for the task were separately aggregated and associated P300 event-related potentials computed. Independent behavioral measures of executive function and IQ were also recorded. Across frontal, fronto-central, central, centro-parietal and parietal scalp regions, P300 amplitudes were significantly greater for faster relative to slower behavioral responses. However, P300 peak amplitude latencies did not differ according to the speed of the behavioral RT. Importantly, controlling for select independent measures of executive function attenuated shared variance in P300 amplitude for faster and slower trials. The findings suggest that P300 amplitude rather than latency is associated with the speed of behavioral RTs, and the possibility that fluctuations in executive control underlie variability in speeded responding.
authors.affiliation: Department of Psychology, Goldsmiths, University of London London, Greater London, UK.
authors.forename: Anusha
authors.initials: A
authors.lastname: Ramchurn
authors.affiliation: Department of Psychology, Goldsmiths, University of London London, Greater London, UK.
authors.forename: Jan W
authors.initials: JW
authors.lastname: de Fockert
authors.affiliation: Department of Psychology, Goldsmiths, University of London London, Greater London, UK.
authors.forename: Luke
authors.initials: L
authors.lastname: Mason
authors.affiliation: Division of Psychology and Sociology, Queen Margaret University Edinburgh, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Darling
authors.affiliation: Faculty of Medicine and Health, Institute of Psychological Sciences, University of Leeds Leeds, UK.
authors.forename: David
authors.initials: D
authors.lastname: Bunce
keywords: ERP; P300; executive function; intraindividual variability; reaction time