title: Electrophysiological correlates of the cognitive control processes underpinning mixing and switching costs.
abstract: Typically, in task-switching contexts individuals are slower and less accurate when repeating a task in mixed blocks compared to single-task blocks (mixing cost) and when switching to a new task compared to repeating a previous one (switch cost). Previous research has shown that distinct electrophysiological correlates underlie these two phenomena. However, this evidence is not a consistent result. The goal of this study was to better characterize differences between the control processes involved in mixing and switch costs. To this aim, we examined event-related potentials (ERPs) evoked during a cued task-switching experiment. In order to minimize the confounding effects of cognitive demands unrelated to task-switching, we asked participants to shift between two simple tasks (a letter identity task and a letter position task). The mixing cost was defined, in terms of ERPs, by contrasting repeat and single-task trials, whereas the ERP switch cost was obtained from the comparison of switch and repeat trials. Cue-locked ERPs showed that the mixing cost was mediated by two sustained components, an early posterior positivity and a late anterior negativity. On the other hand, the switch cost was associated with two early phasic positive components, one principally distributed over centro-parietal sites and the other located over left posterior sites. In target-locked ERPs the mixing cost was expressed by a frontal positivity, whereas the switch cost was expressed by a reduced parietal P3b. Overall, the results extend previous findings by providing elucidating ERP evidence on distinct proactive and reactive control processes involved in mixing and switch costs.
authors.affiliation: Department of Neuroscience, University of Padua, via Giustiniani 5, 35128 Padua, Italy. Electronic address: vincenza.tarantino@unipd.it.
authors.forename: Vincenza
authors.initials: V
authors.lastname: Tarantino
authors.affiliation: Department of Neuroscience, University of Padua, via Giustiniani 5, 35128 Padua, Italy; Department of Information Engineering, University of Padua, Via Gradenigo 6/b, 35131 Padua, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Mazzonetto
authors.affiliation: Department of Neuroscience, University of Padua, via Giustiniani 5, 35128 Padua, Italy; Cognitive Neuroscience Center, University of Padua, via Venezia 8, 35131 Padua, Italy.
authors.forename: Antonino
authors.initials: A
authors.lastname: Vallesi
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D003463:Cues; D004569:Electroencephalography; D005071:Evoked Potentials; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011597:Psychomotor Performance; D011930:Reaction Time; D055815:Young Adult
keywords: Cognitive control; ERP; Executive functions; Switch positivity; Task switching; Task-set