A new study conducted by monitoring the brain waves of sleeping adolescents has found that changes occur in the brain as it prunes away neuronal connections and makes the major transition from childhood to adulthood.

“We’ve provided the first long-term, longitudinal description of developmental changes that take place in the brains of youngsters as they sleep,” said Irwin Feinberg, professor emeritus of psychiatry and behavioral sciences and director of the UC Davis Sleep Laboratory. “Our outcome confirms that the brain goes through a remarkable amount of reorganization during puberty that is necessary for complex thinking.”

The research, published in the February 15 issue of the American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, also confirms that electroencephalography, or EEG, is a powerful tool for tracking brain changes during different phases of life, and that it could potentially be used to help diagnose age-related mental illnesses.

For the current study, Feinberg and his research team monitored 28 healthy, sleeping children between the ages of 6 and 10 for two nights every six months. The new findings show that synaptic density in the cerebral cortex reaches its peak at age 8 and then begins a slow decline. The recent findings also confirm that the period of greatest and most accelerated decline occurs between the ages of 12 and 16-1/2 years, at which point the drop markedly slows.

“Discovering that such extensive neuronal remodeling occurs within this 4-1/2 year timeframe during late [childhood] and the early teen years confirms our view that the sleep EEG indexes a crucial aspect of the timing of brain development,” said Feinberg.