Mapping normal brain development: Age, gender, asymmetry and IQ effects

Our goal was to map normal in vivo brain development using high-resolution magnetic resonance imaging (MRI) data. More specifically, it was our aim to examine age, gender, and asymmetry on the morphological and volumetric patterns that occur during normal development in cortical sulci, prefrontal cortex, the cerebral lobes, and the cerebellum. We further aimed to investigate the relationship between cognition, using IQ measurements, and cerebral morphology. Lastly, we used the patterns of normal development to help elucidate changes in abnormal developmental populations such as autism and childhood-onset schizophrenia.;Normal, autistic, and schizophrenic male and female children and adolescents, ranging in age from 6 to 18 years, were included as subjects. Cortical sulcal patterns were mapped in normal and autistic subjects using high-resolution magnetic resonance imaging (MRI) data to assess age, gender, asymmetry, and diagnosis effects.;Significant age-associated changes were found in the left inferior frontal sulcus, superior and inferior frontal cortical complexity, the left inferior frontal gyrus, and the left and right parietal lobes.;A significant positive linear relationship between global IQ and total right cerebellum and also total right neocerebellum was found. Additionally, a significant effect was found with performance (PIQ) but not verbal IQ.;Significant anatomical differences were also found between normal and abnormal developmental populations. Autistic subjects showed a significant anterior and superior shifting of the left and right superior frontal sulci and anterior shifting of the right sylvian fissure relative to the normal group.;Childhood-onset schizophrenia (COS) patients showed significantly less asymmetry in the cingulated relative to normal subjects.;In summary these results suggest continued sulcal and volumetric neurodevelopment occurring into late adolescence. Furthermore these studies suggest that neurodevelopment is a heterogeneous and gender dependent process with regions such as the left inferior prefrontal cortex increasing in white matter with age in and volumes of the left and right parietal lobe gray matter decreasing in girls. Additionally, our finding, of a sulcal pattern modification with age in the left inferior frontal sulcus, is further represented and corroborated by underlying volumetric changes in inferior frontal anatomy as well. (Abstract shortened by UMI.)...