154 Cortical thickness and sleep slow wave activity mediates age-related improvements in cognition during late adolescence. (3rd May 2021)

• Record Type: Journal Article
• Authors: Ong, Ju Lynn; Jamaluddin, Azrin; Leong, Ruth; Lo, June; Chee, Michael
• Is Part Of: Sleep. Volume 44(2021)Supplement 2
• Page Start: A63
• Page End: A63
• Publication Date: 2021-05-03
• Subjects: Sleep -- Physiological aspects -- Periodicals; Sleep disorders -- Periodicals; Sommeil -- Aspect physiologique -- Périodiques; Sommeil, Troubles du -- Périodiques; Sleep disorders; Sleep -- Physiological aspects; Sleep -- physiological aspects; Sleep Wake Disorders; Psychophysiology; Electronic journals; Periodicals; 616.8498
• DOI: 10.1093/sleep/zsab072.153
• Languages: English
• ISSNs: 0161-8105

Abstract

Abstract: Introduction: Adolescence is a period of rapid brain maturation, and studies have independently documented reductions in cortical thickness, reduced sleep slow wave activity (0.5-4Hz), and improved cognition as a child transitions into adulthood. In the present work, we investigate whether these factors interact in late adolescence. Methods: 114 adolescents aged 15-19y (52 males) underwent a structural MRI scan, polysomnography (PSG) and a series of cognitive tests assessing fluid intelligence, sustained attention, speed of processing and working memory. As sleep history has been known to affect EEG measures of slow wave activity, actigraphic recordings ensured that participants received 9h of night the week prior to the PSG session. Cognitive scores were combined to obtain a single measure of global cognition. For assessment of cortical thickness, the Freesurfer (v5.3) pipeline was used to obtain measures for all regions of interest from the Desikan-Killiany cortical atlas. Pearson correlations were conducted to independently confirm associations between aging and reductions in cortical thickness, slow wave activity and improved global cognition, controlling for sex. Finally, a serial mediation model (SPSS PROCESS Model 6) was performed to test the mediating role of cortical thickness and slow wave activity between aging and global cognition. Results: Reductions in EEG sleep slow wave activity, cortical thickness and improved global cognition was observed with increasing age, likely representing synaptic pruning and a decrease in waking metabolic activity that contributes to increased overall neural efficiency. Regions in the temporal and parietal areas showed the steepest age-related reductions. In addition, the age-related improvement in cognition was found to be mediated by both cortical thinning as well as reduced SWA activity, particularly in the middle temporal cortex. Conclusion: The adolescent brain undergoes rapid growth in preparation for adulthood. Cortical restructuring through pruning of neural circuits during this period is associated with reduced slow wave activity, mediating the age-related improvement in cognition. Future work should investigate whether insults to the brain during this critical period alters this trajectory. Support (if any): This work was supported by grants awarded to Michael Chee (NMRC/STaR/015/2013, NRF2016-SOL002-001 and the Far East Organization).