This image illustrates individual differences in the left arcuate and superior longitudinal fasciculi of 40 children aged 4 to 6 years. Three-dimensional tract renderings from high-resolution diffusion-tensor imaging scans were superimposed on a 2D sagittal slice of a template brain. Warmer colors indicate regions with higher fractional anisotropy (FA), while cooler colors indicate lower FA. The amount of real-world language exposure children experienced predicted FA in these tracts, which in turn predicted developmental language skills. For more information, see the article by Romeo et al. (pages 7870–7877).