Alpha and beta oscillations mediate the effect of motivation on neural coding of cognitive flexibility

Cognitive flexibility is crucial for adaptive human behaviour. Prior studies have analysed the effect of reward on cognitive flexibility; however, the neural mechanisms underlying these effects remain largely unknown. This study explores how reward influences neural oscillations and how these changes impact behavioural performance. Using time-frequency decomposition, we examined electroencephalographic data from participants engaged in rule-guided task-switching with varying reward prospects. Higher anticipated rewards lead to greater desynchronisation of alpha (8-12 Hz) and beta (20-30 Hz) oscillations, which in turn correlated with improved task performance. Both alpha power and event-related potential (ERP) coding of reward independently predicted reward-based performance improvements, suggesting distinct mechanisms supporting proactive control. These findings underscore the unique contributions of neural oscillations in mediating motivational effects on cognitive flexibility. • Participants who showed greater behavioral changes in response to reward strength exhibited larger alpha (8-12 Hz) and beta (12-30 Hz) desynchronization during task performance. • Time-frequency clusters in the alpha and beta bands were significant predictors of the behavioral benefits associated with reward, indicating their role in cognitive flexibility. • Both event-related potentials (ERPs) and oscillatory components independently contributed to behavioral performance, suggesting distinct neural mechanisms at play.