Modern neuroimaging techniques have provided researchers with invaluable tools to explore anatomical and functional brain abnormalities in individuals with autism spectrum disorder (ASD). Converging evidence from structural MRI studies demonstrates differences in post-natal brain maturation in individuals with ASD compared to healthy controls, with early brain overgrowth followed by a subsequent plateauing of growth through adolescence and specific regional brain volume reductions in adulthood. These brain volume reductions occur in regions (e.g. amygdala, cerebellum, corpus callosum) which have been linked repeatedly to the clinical phenotype. Functional MRI, MRI spectroscopy and diffusion tensor imaging studies have further clarified the neurobiology of ASD, with increasing evidence demonstrating brain dysconnectivity and white matter abnormalities. Future longitudinal neuroimaging studies using a variety of neuroimaging techniques aligned to clinical and behavioural data should further clarify the neurobiology of ASD.
Keywords: autism spectrum disorder, neuroimaging, structural MRI, functional MRI, MRI spectroscopy