Longitudinal sleep EEG trajectories indicate complex patterns of adolescent brain maturation

摘要

long-standing evidence indicates that, during adolescence, the human brain undergoes a pervasive reorganization, which appears to be driven by synaptic elimination (13). A prominent electro-physiological manifestation of adolescent brain reorganization is a well-documented decline in the 1-4 Hz (delta) EEG of non-rapid eye movement (NREM) sleep (11, 17, 32, 37). In addition to its potential value as a marker of brain development, the NREM delta decline is a focus of basic sleep research because delta reflects recuperative processes of sleep (2, 11). Although less intensively studied than delta, NREM theta EEG, another major slow-wave component of NREM sleep, is similar to delta in its within-sleep dynamics, response to sleep loss (3, 21) and steep decline across adolescence (7, 22, 27, 30). Previous reports (8, 16), presented longitudinal data from our 9- and 12-yr-old cohorts (C9 and C12), which together span ages 9-18 yr. These data modified our early finding that NREM delta EEG declines linearly across childhood and adolescence, (19). Instead, we found a curvilinear decline that accelerates between ages 12-16.5 yr. In this 4.5-yr period, NREM delta power falls by a remarkable -60% (7), indicating, according to our hypothesis, an extremely high rate of synaptic elimination.