PhD Scientific Days 2024

Mental Health Sciences II.

Sleep Spindle Clustering Revealing Age-Related Differences in Cortical Plasticity in Adolescents: An EEG Study Complemented by Procedural Training

Text of the abstract

Introduction
The study integrates insights from recent research (Schönauer, 2018; Boutin & Doyon, 2020, Antony, 2018), suggesting that sleep spindles' clustering and rhythmicity create a disturbance-free window, facilitating memory reactivation, and subsequently induce cortical plasticity.
Aims
Building on previous work that outlined the developmental trajectories of sleep spindle parameters (Bocskai et al., 2022) and their spatial redistribution throughout adolescence (Gombos et al., 2022), this study aims to investigate the temporal and spatial dynamics of cortical plasticity in adolescents.
Methods
60 adolescents aged 12, 16, and 20 years underwent PSG recordings over two experimental nights. Between these nights, they completed three sessions of contour integration and sequential finger-tapping tasks, with a follow-up retest the next morning. We analyzed data from 122 EEG channels and specific tasks to examine differences in spindle clustering between the two nights. Metrics such as Spindle Trains and Spindle Local Density assessed the rhythmic occurrence and low-frequency clustering of spindles during NREM sleep.
Results
Our findings indicate that the 12-year-olds initially had increased plasticity as compared to the 16–20-year-olds. This was signaled by an enhanced clustering of fast sleep spindles across several functional cortical regions. We observed a significant increase in spindle clustering on the temporal and occipital electrodes in the 16-20 years group against the 12-year-olds following practice. Notably, there was no alteration in the topographical peak positioning of spindle density following the training.
Conclusion
The findings suggest that there is an initially elevated plasticity in 12-year-olds. We may also conclude that intensive practice does not further enhance plasticity of younger adolescents, whereas older participants may experience a restoration of plasticity revealed by increased clustering of fast sleep spindles.
Funding
The project was funded by the National Research, Development, and Innovation Office of Hungary (Grants NRLN NK-104481 and K-134370 to I.K.), by the Hungarian Research Network (HUN-REN-ELTE-PPKE Adolescent Development Research Group), and the PPKE-BTK-KUT-23-1 project funding by the Faculty of Humanities and Social Sciences, Pázmány Péter Catholic University.