Correlations of surface measures with full-scale IQ in high- vs. low-CPF exposure groups. Surface distances (in mm from the corresponding point on the surface of the template brain), adjusted for age and sex, are plotted on the y axis. Surface measures in the superior temporal, inferior frontal, inferior precentral, and inferior postcentral gyri bilaterally, and the precuneus of the left hemisphere, correlated positively with full-scale IQ in the low- but not the high-CPF group, producing a significant IQ × exposure interaction. Scatterplots (pink denotes high and green denotes low exposure) suggest that high CPF exposure was associated with enlargement of these regions, consistent with findings for the main effects of CPF on surface measures (Fig. 1), also indicating that those regional enlargements were associated with lower IQ scores in the high-CPF group. Distances in the right fusiform gyrus correlated inversely with IQ in the low-CPF group, but positively in the high group, also producing a significant IQ × exposure interaction. FG, fusiform gyrus; FSIQ, full-scale IQ; IFG, inferior frontal gyrus; PoCG, postcentral gyrus; PreCG, precentral gyrus; PreCu, precuneus.

(Upper) Maps of exposure group differences in morphological measures of the cerebral surface. At each point on the cerebral surface of the template brain, we compared (i) average distance of the surface of each brain in the high-CPF group from the corresponding point on the surface of the template, with (ii) average distance of the surface of each brain in the low-CPF group from the same point on the surface of the template, adjusted for age and sex. Warm colors (yellow, orange, and red) indicate significantly larger distances (local enlargements, outward deformations) in high- vs. low-CPF group; cool colors (blue and purple) indicate reduced distances (indentations, inward deformations) in high- vs. low-CPF group. The color bar indicates P values, corrected for multiple comparisons using a false discovery rate P < 0.05. High-CPF group brains were significantly enlarged bilaterally in the superior temporal, posterior middle temporal, and inferior postcentral gyri, and superior frontal gyrus, gyrus rectus, cuneus, and precuneus in the mesial views of the right hemisphere. CU, cuneus; GR, gyrus rectus; MTG, middle temporal gyrus; PoCG, postcentral gyrus; PreCU, precuneus; SFG, superior frontal gyrus; STG, superior temporal gyrus. (Lower) Correlations of local surface measures with prenatal CPF exposure levels in the high-exposure group. Surface distances (in mm from the corresponding point on the surface of the template brain), adjusted for age and sex, are plotted on the y axis. Log-transformed CPF cord-blood levels (pg/g) are plotted on the x axis. Warm colors (red and yellow) indicate positive correlations, and cool colors (blue and purple) indicate inverse correlations between surface measures and CPF exposure. The scatterplot of individuals shows enlarged surfaces along the superior frontal gyrus with increasing exposure to CPF.

Maps of differences in local cortical surface measures by sex and prenatal CPF exposure level in sexually dimorphic brain regions. (Upper Left) Sex × exposure interaction, indicating a loss in the high-CPF group of normal female-larger-than-male sex effects in the right inferior parietal lobule and supramarginal gyrus, and reversal of normal male-larger-than-female effects in the right mesial superior frontal gyrus. (Upper Center) shows normal female-larger-than-male effects (purple) in the inferior parietal lobule, supramarginal gyrus, and middle and superior temporal gyri in the low-CPF group, and normal male-larger-than-female effects in the right mesial superior frontal gyrus in the low CPF group. (Upper Right) shows less extensive but similar effects in the high-CPF group. In the corresponding graphs (Lower), surface distances (in mm from the corresponding point on the surface of the template brain) are plotted on the y axis. Male data are coded yellow and female red. Error bars represent SEs. IPL, inferior parietal lobule; MTG, middle temporal gyrus; SFG, superior frontal gyrus; SMG, supramarginal gyrus; STG, superior temporal gyrus. High-CPF group: n = 19; low-CPF group: n = 18.