Task load modulates network interactions between bilateral fronto-parietal and cerebellar areas during verbal working...

Verbal working memory (VWM) relies on frontal and parietal regions, yet their functional interactions, particularly with the cerebellum, remain underexplored. Prior studies link higher VWM load to increased parieto-prefrontal coupling and associate stronger interactions with better performance. This suggests that connectivity may underlie individual differences in efficiency. However, fronto-parieto-cerebellar dynamics have not been systematically examined to date. We investigated activation and directed functional coupling between six pre-selected regions of interest during a VWM task. Higher task load increased activity in fronto-parietal regions and the cerebellum. Connectivity analyses revealed bidirectional facilitatory interactions between fronto-parietal regions, but reduced cerebello-cortical coupling as demands increased. Positive left parieto-frontal coupling with increasing load showed links to performance, indicating that less interaction was required for good performance. These effects were consistent across two sessions. Our study highlights that fronto-parietal coupling adapts to support increasing task demands, whereas reduced cerebello-cortical interactions suggest a distinct role for the cerebellum.