EEG markers of vigilance, task-induced fatigue and motivation during sustained attention: Evidence for decoupled alpha- and beta-signatures

Hanzal, Simon; Learmonth, Gemma; Thut, Gregor; Harvey, Monika · 2024 · Crossref

DOI: 10.1101/2024.10.16.618638

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Summary

This study investigates the neural mechanisms underlying vigilance, task-induced fatigue, and motivation during sustained attention. While sustained attention tasks typically induce a "vigilance decrement" (performance decline), the specific relationships between this decline, mental fatigue, and motivational states remain unclear. Previous research suggests motivation can restore performance, but the electrophysiological markers linking motivation to vigilance changes are tentative. This preregistered study aimed to dissociate the EEG signatures of fatigue, response strategy, and motivation using the Sustained Attention to Response Task (SART). The researchers recruited 34 healthy participants, divided into young (mean age 22.6) and older (mean age 66.5) adult groups. Participants performed a 45-minute SART, consisting of eight baseline blocks followed by a ninth block where motivation was manipulated for half the participants via a monetary incentive. EEG data was recorded continuously, alongside subjective measures of fatigue and mind-wandering. The SART required participants to respond to all digits except 3 and 6, allowing the measurement of commission errors as indicators of attentional lapses. Statistical analyses included mixed-effects models for behavioral data and time-frequency analysis for EEG signals, focusing on alpha and beta oscillations and P300 event-related potentials. Contrary to typical findings, the study observed no significant behavioral vigilance decline over the 45-minute period, despite significant increases in subjective fatigue and mind-wandering. However, distinct age-related differences in response strategies emerged: younger participants adopted a speed-based strategy (faster, more erroneous responses), while older participants adopted an accuracy-based strategy (slower, more accurate responses). Neurophysiologically, the study identified three dissociated EEG signatures. First, subjective fatigue and mind-wandering correlated with increased pre-stimulus alpha power. Second, post-stimulus beta activity revealed a fronto-central topography associated with response strategy. Third, a separate fronto-parietal beta distribution was modulated specifically by the motivational manipulation. These findings suggest that fatigue, response strategy, and motivation are underpinned by distinct neural mechanisms rather than a single unified process. The absence of a behavioral vigilance decrement, despite rising fatigue, implies that cognitive control mechanisms, potentially driven by motivation, can reset or offset performance declines. The study provides evidence for decoupled alpha and beta signatures, indicating that alpha oscillations track internal states like fatigue and mind-wandering, while beta oscillations reflect strategic control and motivational engagement. This dissociation clarifies the neurophysiological basis of sustained attention, highlighting that maintaining performance under fatigue may rely on specific motivational and strategic neural adjustments rather than merely resisting fatigue.

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discover success Crossref 1 2026-08-09
archive success canonical_url 1 2026-08-09
extract success cached 4 2026-08-10
clean success clean 1 2026-08-09
chunk success chunk 1 2026-08-09
embed success embed Qwen/Qwen3-Embedding-8B 1 2026-08-09
promote success 1 2026-08-09
summarize success llm qwen3.6-27b-nvidia summ-v5 2 2026-08-10
tag success vector_similarity 11 2026-08-11
verify success 2 2026-08-10

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