AROUSAL-DEPENDENT TUNING OF FRONTAL OSCILLATORY DYNAMICS DURING COGNITIVE CONTROL AND REINFORCEMENT LEARNING

Adaptive behavior depends on the ability to dynamically balance stable goal maintenance with flexible updating, yet we still lack a mechanistic understanding of how neural dynamics support this balance. Frontal theta and beta oscillations are consistently associated with cognitive control processes, but recent work suggests that, beyond amplitude, finer-grained temporal and spectral features such as oscillatory burst structure and peak frequency shifts are key to understanding their function. One key candidate tuning knob is neuromodulatory systems. Yet, the mechanistic relationship between these oscillatory properties and neuromodulators remains largely unknown.
Here, we examine arousal-dependent modulation of oscillatory dynamics across three independent EEG–pupillometry datasets (total N ≈ 150) spanning instructed task implementation and reinforcement learning paradigms. Pupil diameter provided a continuous index of arousal, while burst- and frequency-resolved EEG analyses captured variability in oscillatory dynamics. Across tasks, we observed systematic covariation between arousal fluctuations and oscillatory properties, including shifts in dominant frequency, changes in burst duration, and state-dependent differences of timing and alternation of theta and beta oscillations. These modulations were associated with variability in reaction times, accuracy, and learning dynamics.
To assess mechanistic plausibility, we implemented a computational model in which arousal tunes oscillatory dynamics by reshaping the contribution of inhibitory processes operating at distinct temporal scales. The model reproduced key qualitative relationships between arousal and oscillatory properties observed in the data.​
Together, these findings highlight a critical and currently under-specified mechanism in models of cognitive control, underscoring the need to understand how neuromodulators shape neural rhythms to support adaptive behavior.