Author(s): ROOSE, M., ROELANDS, B., RAEYMAEKERS, R., VAN SCHUERBEEK, P., Institution: VRIJE UNIVERSITEIT BRUSSEL, Country: BELGIUM, Abstract-ID: 2112

Introduction: Mental fatigue (MF) is a psychophysiological state arising from prolonged cognitive effort that impairs sport performance, decision-making, and self-regulation, likely via altered executive functions such as inhibitory control [1, 2]. MF has been associated with changes in cortical and subcortical activity, particularly in the anterior cingulate cortex, and within networks such as the executive control network [3]. Given that inhibitory control underpins pacing, tactical decisions, and error monitoring in sport, understanding its neural modulation under MF can be important. This study examined the effects of MF, induced by sustained cognitive effort, on executive task-related brain activity using BOLD fMRI.

Methods: Twenty-one healthy participants (M11, 10F; [21-30y]) underwent a 45-min Stroop task (MF) or watched a documentary (control). Pre- and post-task, they completed a 5-min Go/NoGo task assessing response inhibition. fMRI data was acquired throughout the entire protocol and processed in SPM25, focusing on Go/NoGo BOLD signals. Individual contrast maps were analyzed via repeated-measures ANOVA (Time×Condition), the found clusters were saved as regions-of-interest (ROI) to perform post-hoc t-tests. Subjective measures (MF, mood, sleepiness) were assessed with M-VAS, KSS, and BRUMS, analyzed with 2×2repeated-measures ANOVAs (p<0.05).

Results: At baseline, all ROIs (SMC, SOG, MFG, FuG) exhibited the expected NoGo>Go pattern. Following the Stroop task, this reversed to Go>NoGo across all ROIs (p<0.001), indicating reduced inhibitory control. No changes occurred in the control condition. Time×Condition interactions confirmed a stronger shift under MF. Subjective measures confirmed MF induction: M-VAS increased significantly post-Stroop (F(1,20)=37.75, p<0.001). Sleepiness increased over time (F(1,20)=7.52, p=0.013), with higher post-task scores in both conditions, while mood remained unchanged.

Discussion/Conclusion: Acute MF induced by prolonged cognitive effort led to a clear reduction in inhibitory-control network engagement, reflected by a reversal of the typical NoGo>Go activation pattern. This suggests that MF diminishes neural efficiency within executive-control regions, likely reflecting increased effort or reduced inhibitory resources. The BOLD results provide neurophysiological evidence of MF-effects and may help inform strategies to mitigate fatigue-related performance decline in athletes.

References:
1. Goodman, S. P. J., et al. (2025). Approaches to inducing mental fatigue: A systematic review and meta-analysis. Behavior Research Methods, 57(4).
2. Pageaux, B., & Lepers, R. (2018). The effects of mental fatigue on sport-related performance. In Progress in Brain Research (Vol. 240, pp. 291-315).
3. Möckel, T., Beste, C., & Wascher, E. (2015). The effects of time on task in response inhibition: An ERP study of mental fatigue. Brain and Cognition, 97, 1-9.