PhD Scientific Days 2025

Mental Health Sciences I.

Procedural Training Enhances Sleep Spindle Clustering

Name of the presenter

Bocskai Gábor

Institute/workplace of the presenter

Semmelweis Doctoral College Mental Health Sciences Division.

Authors

Gábor Bocskai¹, Patrícia Gerván², Ferenc Gombos³, Andrea Berencsi⁴, Ilona Kovács⁵

1: Semmelweis Doctoral College Mental Health Sciences Division.
2: Laboratory for Psychological Research, Pázmány Péter Catholic University HUN-REN-ELTE-PPKE Adolescent Development Research Group
3: Laboratory for Psychological Research, Pázmány Péter Catholic University, Hungary, HUN-REN-ELTE-PPKE Adolescent Development Research Group
4: HUN-REN-ELTE-PPKE Adolescent Development Research Group, Institute for the Methodology of Special Needs Education and Rehabilitation, Bárczi Gusztáv Faculty of Special Needs Education, Eötvös Loránd University
5: HUN-REN-ELTE-PPKE Adolescent Development Research Group Institute of Psychology, Faculty of Education and Psychology, Eötvös Loránd University

Text of the abstract

Introduction
This study investigates the temporal and spatial dynamics of cortical plasticity during adolescence, focusing on sleep spindle activity. Prior research suggests that the rhythmic occurrence and clustering of sleep spindles support memory consolidation and engage modality-specific, interconnected cortical areas (Schönauer, 2018; Boutin & Doyon, 2020; Boutin et al., 2018; Lutz et al., 2021).
Aims
We aimed to examine how extensive visual procedural training modulates the temporal and spatial organization of sleep spindles (Gerván et al., 2025). Specifically, we investigated changes in spindle parameters, rhythmicity, and clustering in brain regions associated with a visual procedural task (Kovács & Julesz 1994).
Methods
Data were drawn from an existing database (Gombos et al., 2022), including polysomnographic and behavioral recordings of 39 participants aged 16–20 years. Sleep spindles were detected from 122-channel high-density EEG across two consecutive nights. Between recordings, participants engaged in three sessions of procedural learning, followed by a morning retest. Our analyses focused on the contour integration task. We assessed four basic spindle features, four clustering, and four rhythmicity measures during NREM sleep.
Results
No significant changes were observed in slow spindle parameters. For fast spindles, peak spindle density topography remained stable post-training. However, spindle clustering significantly increased from Night 1 to Night 2, particularly over temporal and occipital electrodes. Linear mixed-effects models revealed a significant effect of night on three clustering measures in the occipital region and on four clustering and two rhythmicity parameters in the temporal region.
Conclusion
Visual procedural learning induces task-specific reorganization of fast sleep spindle activity, particularly in the temporal and occipital regions. These findings suggest that spindle clustering plays a pivotal role in the offline consolidation of visual procedural memory.
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.