<p>In the context of relevance and social significance of the problem of attention deficit disorder among schoolchildren, we performed 3D-visualization of the brain in children (<i>n=</i>17; age 9-12 years) and adolescents (<i>n=</i>16; age 13-15 years). We found correlations between fractional anisotropy of the white matter fiber tracts (reflecting the quantity of axons and myelinization) assessed by diffusion-weighted magnetic resonance imaging (dMRI) and attention indicators (accuracy and task completion time) in children and adolescents. The improvement of attention between the ages of 9 and 12 years (the second childhood period) was accompanied by an increase in fractional anisotropy in the corpus callosum, while the decrease of attention was associated with the increase in the level of anisotropy in the third segment of superior longitudinal fasciculus (SLF_III). The opposite results were obtained for adolescents. In both groups, the improvement in attention was associated with an increase in fractional anisotropy in the SLF_I. A relationship of the obtained results with the data on different terms of maturation of the median (earlier development) and lateral (later development) cerebral structures in ontogeny is discussed.</p>