Sex differences in the development of neuroanatomical functional connectivity underlying intelligence found using Bayesian connectivity analysis

Abstract

A Bayesian method for functional connectivity analysis was adapted to investigate between-group differences. This method was applied in a large cohort of almost 300 children to investigate differences in boys and girls in the relationship between intelligence and functional connectivity for the task of narrative comprehension. For boys, a greater association was shown between intelligence and the functional connectivity linking Broca's area to auditory processing areas, including Wernicke's areas and the right posterior superior temporal gyrus. For girls, a greater association was shown between intelligence and the functional connectivity linking the left posterior superior temporal gyrus to Wernicke's areas bilaterally. A developmental effect was also seen, with girls displaying a positive correlation with age in the association between intelligence and the functional connectivity linking the right posterior superior temporal gyrus to Wernicke's areas bilaterally. Our results demonstrate a sexual dimorphism in the relationship of functional connectivity to intelligence in children and an increasing reliance on inter-hemispheric connectivity in girls with age.

Figure 1

Regions activated during the fMRI paradigm of narrative comprehension for a cohort of 303 normal children ages 5–18. Regions significant with p < 1e-6 (corrected). Slice location: Z = −15 mm to Z = +40 mm. All images in neurologic orientation.

Figure 2

Regions with a significant positive correlation of Wechsler Full-Scale IQ with BOLD activation for the fMRI paradigm of narrative comprehension performed by a cohort of 303 normal children ages 5–18. Regions significant with p < 0.01 (corrected). Slice location: Z = −15 mm to Z = +40 mm. All images in neurologic orientation. The color legend is shown in Table 2.

Figure 3

Sagittal view of regions in Figure 2 (slice locations: top, X = −45 mm; bottom, X = +45 mm) showing delineation of Wernicke’s area from posterior superior temporal gyrus. Color legend shown in Table 2.

Figure 4

Regions with a significant IQ-X-sex interaction (girls > boys) on BOLD activation for the fMRI paradigm of narrative comprehension performed by a cohort of 303 normal children ages 5–18. Regions significant with p < 0.01 (corrected). Slice location: Z = −15 mm to Z = +40 mm. All images in neurologic orientation.

Figure 5

Regions with a significant IQ-X-sex-X-age interaction (boys > girls) on BOLD activation for the fMRI paradigm of narrative comprehension performed by a cohort of 303 normal children ages 5–18. Regions significant with p < 0.01 (corrected). Slice location: Z = −15 mm to Z = +40 mm. All images in neurologic orientation.

Figure 6

Regions exhibiting a positive main effect of connectivity with IQ. (Abbreviations: LWERN = Left Wernicke’s Area; RWERN = Right Wernicke’s Area; SMFG = Superior Medial Frontal Gyrus; LPSTG = Left Posterior Superior Temporal Gyrus; BROCA = Broca’s Area.)

Figure 7

Regions exhibiting a significant IQ-X-sex (girls > boys) interaction on functional connectivity. (Pink line indicates connectivity has positive main effect for girls. Abbreviations: LWERN = Left Wernicke’s Area; RWERN = Right Wernicke’s Area; LPSTG = Left Posterior Superior Temporal Gyrus.)

Figure 8

Regions exhibiting a significant IQ-X-sex (boys > girls) interaction on functional connectivity. (Blue line indicates connectivity has positive main effect for boys; pink line indicate connectivity has negative main effect for girls. (Abbreviations: LWERN = Left Wernicke’s Area; RWERN = Right Wernicke’s Area; SMFG = Superior Medial Frontal Gyrus; LPSTG = Left Posterior Superior Temporal Gyrus; RPSTG = Right Posterior Superior Temporal Gyrus; BROCA = Broca’s Area.)

Figure 9

Regions exhibiting a significant IQ-X-age-X-sex (girls > boys) interaction on functional connectivity. (Dashed blue line indicates connectivity has positive effect for youngest (5 years) boys; dashed pink line indicates connectivity has negative effect for youngest (5 years) girls; solid pink line indicates connectivity has positive effect for oldest (18 years) girls. Abbreviations: LWERN = Left Wernicke’s Area; RWERN = Right Wernicke’s Area; RPSTG = Right Posterior Superior Temporal Gyrus.)