FIG 1. Ratio of rCBF values to those in adults distributed by age. rCBF values increased with development in all areas. The last increase was observed in the frontal association area. Compared with rCBF values in adults, low values were observed in the frontal and visual association areas and the sensorimotor area in the <1-year-old group, and in the frontal association area in the 1- to <3-year-old group, whereas rCBF values were significantly increased in all areas in the 3- to <8-year-old group, except for the frontal association area. rCBF values were always lower in the association areas than in the primary areas, except for those in the visual association area and the visual area in the 8-year-old group. Asterisk indicates Mann-Whitney U-test, P < .05; a, paired t-test, P < .05