Ultraslow brain dynamics as neurophysiological markers of information sampling during learning.

To learn, we must actively sample information from our environment: selecting, prioritizing, and extracting relevant cues. Here, we investigated whether ultraslow event-related potentials (ERPs) could track information sampling as participants learned new words from sentence contexts that provided varying amounts of information about their meaning, requiring them to actively extract learning-relevant cues. Ultraslow negative ERPs emerged while participants engaged in learning. Although ultraslow brain activity was not modulated by the level of informativeness of the contexts, individual differences in learning success were associated with steeper ultraslow voltage slopes. Specifically, participants with better learning outcomes exhibited a steeper ultraslow slope while learning from informative contexts, suggesting greater engagement and exploitation of relevant information. Together, these findings identify ultraslow brain activity as candidate neurophysiological markers of information sampling and provide evidence that individual differences in these dynamics relate to successful learning.