Frontal theta synchronization facilitates the updating of statistical regularities, evidenced by predictive eye...

Frontal midline theta oscillations are key neural markers for learning, set-shifting, and adaptive behavior, signaling cognitive control and the reorganization of neural representations. The present study explored how these oscillations mediate the extraction and updating of statistical regularities. We delivered 6-Hz in-phase or sham transcranial alternating current stimulation, synchronizing frontal midline theta during an eye-tracking probabilistic sequence learning task designed to test cognitive flexibility and assess changes in pre-stimulus gaze direction. A novel probabilistic sequence with a partially overlapping structure was introduced that allowed us to distinguish between the retention of old sequences and the acquisition of new ones. Following comparable statistical learning in both groups during the stimulation session, our results showed that frontal midline theta synchronization enhances the adaptation of predictive processes shown by the reduction of erroneous anticipations of previously learned regularities and more flexible anticipation of novel regularities. These results suggest a role of frontal midline theta in the flexible rewiring of the mental representations of prior probabilistic structures and in making predictions more accurate.