High arousal disrupts the neural signatures of conflict processing but not behavioural performance

Abstract

ABSTRACTFluctuations in physical arousal occur constantly along the day and become particularly pronounced at extreme states such as deep sleep or intense physical exertion. While changes in arousal are thought to affect cognitive control, it has been suggested that cognitive control is resilient during the drowsy state as a result of neural compensatory mechanisms. Here, we investigate the higher end of the arousal spectrum by looking at the modulatory effect of high arousal on behavioural and neural markers of cognitive control. We predicted that preserved behavioural measures of cognitive control under high arousal would be accompanied by changes in its typical neural correlates. We conducted an electroencephalography study in which 39 expert cyclists (37 males, 2 females) were presented with an auditory stimulus-response conflict task while cycling on a stationary bike. Participants performed two experimental sessions on different days: one at low intensity and one at high intensity pedalling. Consistent with our predictions, we found no behavioural difference in cognitive conflict measures between the two exercise conditions. However, the typical midfrontal-theta power signature of cognitive control was no longer reliable at high-intensity exercise. Similarly, time-frequency multivariate decoding failed to decode stimulus conflict. On the other hand, we found no difference between intensity levels in whole-brain connectivity measures. Therefore, we suggest that the human cognitive control system is resilient even at high arousal states and propose that the dissociation between behavioural and neural measures could indicate the activation of neural compensatory mechanisms as a response to physiological pressure.SIGNIFICANCE STATEMENTEffects of spontaneous physiological changes on brain and cognition have traditionally been studied in states of decreased arousal. However, virtually no research has been conducted on the higher end of the arousal spectrum. In this study, participants performed an auditory conflict task while cycling at low and high intensity. Behavioural performance was robust in both conditions. However, changes in the typical univariate and multivariate signatures of cognitive control induced by arousal suggest a reconfiguration of the neural processes supervising cognitive control during heightened states of strain.