Current theories of human neural development emphasize the posterior-to-anterior pattern
of brain maturation. However, this scenario leaves out significant brain areas not
directly involved with sensory input and behavioral control. Suggesting the relevance
of cortical activity unrelated to sensory stimulation, such as sleep, we investigated
adolescent transformations in the topography of sleep spindles. Sleep spindles are
known to be involved in neural plasticity and in adults have a bimodal topography:
slow spindles are frontally dominant, while fast spindles have a parietal/precuneal
origin. The late functional segregation of the precuneus from the frontoparietal network
during adolescence suggests that spindle topography might approach the adult state
relatively late in development, and it may not be a result of the posterior-to-anterior
maturational pattern. We analyzed the topographical distribution of spindle parameters
in HD-EEG polysomnographic sleep recordings of adolescents and found that slow spindle
duration maxima traveled from central to anterior brain regions, while fast spindle
density, amplitude and frequency peaks traveled from central to more posterior brain
regions. These results provide evidence for the gradual posteriorization of the anatomical
localization of fast sleep spindles during adolescence and indicate the existence
of an anterior-to-posterior pattern of human brain maturation.
