New sleep research, the first long term study of developmental changes in children’s sleeping brains, found evidence of significant reorganization among neural connections in adolescent brains. The results of the study, published in the American Journal of Physiology: Regulatory, Integrative, and Comparative Physiology, ties neural reorganization to increasing maturity. The article marks the conclusion of 10 years of study and more than 3,500 EEG recordings, each lasting an entire night.
The data provide a unique look at the brain’s electrical behavior in the same kids from early childhood through puberty. The February 2013 publication is the final stage in a three-part series.
Maturity and Sleep: Research findings
The researchers found that electroencephalogram, or EEG, readings may be particularly powerful in observing change in the brain, even diagnosing mental illness that may be undetectable to other forms of neural imaging. The study confirmed some previous research findings while also offering new insights to adolescent brain function.
Early in life, the numbers of synaptic connections in the brain vastly outnumber those later in life. Those myriad connections help children adapt, learn, and recover from injuries – but they may also impair logical thinking and streamlined problem-solving abilities that emerge with maturity. This study is the first to show that the shift in thought characteristics can actually be detected by measuring electrical (EEG) activity in the brain as childrens’ brains mature over time.
Brain Development and Brain Activity During Sleep
The two earlier installments in the research series illuminated EEG fluctuations during the delta stage of sleep –the deepest sleep phase – declined in adolescents, most notably between the ages of 12 years and 16.5 years. The three studies together led authors Feinberg, Campbell, and their colleagues to suggest that neuronal pruning, or the streamlining of neural connections that presages characteristically adult thought processes, happens at approximately the same time as reproductive maturity. Synaptic density for kids in the study peaked at age 8 and then began to decline. The greatest and fastest decline also occurred between 12 and 16.5 years, the same age range when EEG fluctuations dropped.
Feinberg told Science Daily, “Discovering that such extensive neuronal remodeling occurs within this 4-1/2 year timeframe during late adolescence and the early teen years confirms our view that the sleep EEG indexes a crucial aspect of the timing of brain development.”