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Neural Plasticity
Volume 2016, Article ID 3670951, 9 pages
Research Article

Developmental Changes in Sleep Spindle Characteristics and Sigma Power across Early Childhood

1Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA
2Child Development Center, University Children’s Hospital Zurich, 8032 Zurich, Switzerland
3Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
4Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland

Received 1 January 2016; Accepted 1 March 2016

Academic Editor: Julie Carrier

Copyright © 2016 Ian J. McClain et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Sleep spindles, a prominent feature of the non-rapid eye movement (NREM) sleep electroencephalogram (EEG), are linked to cognitive abilities. Early childhood is a time of rapid cognitive and neurophysiological maturation; however, little is known about developmental changes in sleep spindles. In this study, we longitudinally examined trajectories of multiple sleep spindle characteristics (i.e., spindle duration, frequency, integrated spindle amplitude, and density) and power in the sigma frequency range (10–16 Hz) across ages 2, 3, and 5 years (; 3 males). At each time point, nocturnal sleep EEG was recorded in-home after 13-h of prior wakefulness. Spindle duration, integrated spindle amplitude, and sigma power increased with age across all EEG derivations (C3A2, C4A1, O2A1, and O1A2; all s < 0.05). We also found a developmental decrease in mean spindle frequency () but no change in spindle density with increasing age. Thus, sleep spindles increased in duration and amplitude but decreased in frequency across early childhood. Our data characterize early developmental changes in sleep spindles, which may advance understanding of thalamocortical brain connectivity and associated lifelong disease processes. These findings also provide unique insights into spindle ontogenesis in early childhood and may help identify electrophysiological features related to healthy and aberrant brain maturation.