The Effects of Foreknowledge and Task-Set Shifting as Mirrored in Cue- and Target-Locked Event-Related Potentials

Abstract

The present study examined the use of foreknowledge in a task-cueing protocol while manipulating sensory updating and executive control in both, informatively and non-informatively pre-cued trials. Foreknowledge, sensory updating (cue switch effects) and task-switching were orthogonally manipulated in order to address the question of whether, and to which extent, the sensory processing of cue changes can partly or totally explain the final task switch costs. Participants responded faster when they could prepare for the upcoming task and if no task-set updating was necessary. Sensory cue switches influenced cue-locked ERPs only when they contained conceptual information about the upcoming task: frontal P2 amplitudes were modulated by task-relevant cue changes, mid-parietal P3 amplitudes by the anticipatory updating of stimulus-response mappings, and P3 peak latencies were modulated by task switching. Task preparation was advantageous for efficient stimulus-response re-mapping at target-onset as mirrored in target N2 amplitudes. However, N2 peak latencies indicate that this process is faster for all repeat trials. The results provide evidence to support a very fast detection of task-relevance in sensory (cue) changes and argue against the view of task repetition benefits as secondary to purely perceptual repetition priming. Advanced preparation may have a stronger influence on behavioral performance and target-locked brain activity than the local effect of repeating or switching the task-set in the current trial.

Task-switching preparation across semantic and spatial domains: An event-related potential study

“…The first difference between switch and repeat trials as a function of domain was already observed in the time range of the frontal P2, which tended to be larger for repeat trials than for switch trials in the spatial domain only. Therefore, the modulation of the P2 in the spatial domain differed from previous results of enhanced P2 amplitude following a switch cue as compared to a repeat cue (e.g., Finke, Escera, & Barceló, 2012;Periáñez & Barceló, 2009;West, Langley, & Bailey, 2011). One might interpret this pattern of data as reflecting an encoding benefit due to repetition of the same cue.…”

“…In addition to these sustained positive-and negative-going potentials, another reliable ERP signature often reported in the task-switching literature is an early cue-locked fronto-central positivity (P2), emerging approximately at 200 ms after cue onset, which is usually larger following a switch cue relative to a repeat cue (e.g., Finke, Escera, & Barceló, 2012;Periáñez & Barceló, 2009;West, Langley, & Bailey, 2011). The enhanced P2 amplitude for switch trials has been generally attributed to the functioning of an early task-set updating process that would rapidly "detect" a relevant change in the task to be performed (see also De Baene & Brass, 2014).…”

“…The ERP analysis focused on the following cue-locked potentials: frontal P2, frontal negativity and switch positivity that were chosen on the basis of visual inspection of the grand average Task-switching and ERPs 15 waveforms and according to prior literature. The P2 amplitude was analyzed over fronto-central electrodes (left: F1, F3, FC1, FC3; midline: Fz, FCz; right: F2, F4, FC2, FC4) in a time window ranging from 200 to 240 ms after cue onset (see Finke, Escera, &Barceló, 2012 andBailey, 2011, for very similar analysis windows and electrodes). A repeated-measures ANOVA tested for amplitude differences in the P2 with Domain (semantic, spatial), Switching from the previous task (repeat, switch) and Electrode side (left, midline, right) as within-participant factors.…”

The neural dynamic mechanisms of asymmetric switch costs in a combined Stroop-task-switching paradigm

“…After removing trials with EEG artifact and data trimming, the mean number of trials used to compute average ERP waveforms ranged across task transition from 65.6 (SD = 8.2) to 65.8 (SD = 8.8) for the color task, and from 61.8 (SD = 8.4) to 63.1 (SD = 7.9) for the word task. Based on the previous task switching and Stroop studies 34 43 44 and visual inspection of the scalp distribution maps of the present data, the following ERP components, time windows and scalp region-of-interests (ROIs) were selected for statistical analyses. Mean amplitudes were measured within a time window of 180-220 ms after S2 onset for P2 and 250-350 ms for N2 at fronto-central sites (Fz, F1, F2, FC1, FCz, and FC2).…”

Task‐switching costs have distinct phase‐locked and nonphase‐locked EEG power effects

“…The excellent time resolution of event‐related potential (ERP) and time–frequency analyses of electroencephalogram (EEG) data has provided insight into neural processes activated by switch and mixed‐repeat trials. During the CTI, switch cues elicit a larger centroparietal positivity than mixed‐repeat cues (Barcelo, Escera, Corral, & Perianez, ; Finke, Escera, & Barcelo, ; Jost, Mayr, & Rosler, ; Karayanidis, Coltheart, Michie, & Murphy, ; Karayanidis et al, ; Nicholson, Karayanidis, Poboka, Heathcote, & Michie, ), which in turn elicit a larger positivity than all‐repeat cues (Jost et al, ; Karayanidis, Whitson, Heathcote, & Michie, ; Manzi, Nessler, Czernochowski, & Friedman, ; Whitson et al, ). These effects are commonly referred to as the switch and the mixing positivities and have been mapped to processes involved in task set reconfiguration and active maintenance of the repeated task set, respectively (Karayanidis et al, ).…”