While young children sleep, connections between the left and the right hemispheres of their brain strengthen, which may help brain functions mature, according to a new study by the University of Colorado Boulder. The research teamâled by Salome Kurth, a postdoctoral researcher, and Monique LeBourgeois, assistant professor in integrative physiologyâused electroencephalograms, or EEGs, to measure the brain activity of eight sleeping children multiple times at the ages of 2, 3 and 5 years.