P163 Slow wave transcranial electrical stimulation during wake to investigate the consolidation of new learning

INTRODUCTION: Slow, oscillatory, transcranial electrical stimulation (so-tES) applies a current over the scalp that oscillates in intensity at a frequency associated with slow wave sleep (SWS; 0.75Hz). When applied during SWS, so-tES can enhance SWS EEG power compared to sham stimulation, as well as overnight declarative memory consolidation. When applied during wake, so-tES can enhance local EEG power in the slow wave frequency range (0.5–4.5Hz) compared to sham. Therefore, this study will investigate whether so-tES can enhance the early consolidation of new learning compared to sham, when applied during wake. A preliminary analysis of data will be presented. METHODS: Healthy, young, right-handed adults (18–35 years) practiced a motor sequence learning task for 30 minutes, before receiving 15 minutes of active or sham so-tES (0.75Hz) during quiet wakefulness. Task performance was assessed by recording the total number of correct sequences performed in 30 seconds before practice, after practice, and after stimulation. Performance improvements will be compared between stimulation conditions. Non-invasive, electrophysiological corticospinal excitability measurements (i.e., motor-evoked potentials) were also recorded at six timepoints throughout each session, to investigate whether active so-tES can modulate corticospinal excitability differently to sham. Progress to date Data collection is ongoing, and completion is expected by late 2021. Intended outcome and impact We expect so-tES to enhance early skill consolidation during wake, and that enhanced consolidation will be associated with less variable measurements of corticospinal excitability, when compared with sham stimulation.