Neuroimaging in autism spectrum disorder: brain structure and function across the lifespan

Abstract

Over the past decade, in-vivo MRI studies have provided many invaluable insights into the neural substrates underlying autism spectrum disorder (ASD), which is now known to be associated with neurodevelopmental variations in brain anatomy, functioning, and connectivity. These systems-level features of ASD pathology seem to develop diff erentially across the human lifespan so that the cortical abnormalities that occur in children with ASD diff er from those noted at other stages of life. Thus, investigation of the brain in ASD poses particular methodological challenges, which must be addressed to enable the comparison of results across studies. Novel analytical approaches are also being developed to facilitate the translation of fi ndings from the research to the clinical setting. In the future, the insights provided by human neuroimaging studies could contribute to biomarker development for ASD and other neurodevelopmental disorders, and to new approaches to diagnosis and treatment.

On the brain structure heterogeneity of autism: Parsing out acquisition site effects with significance‐weighted principal component analysis

“…Regarding intensity correction, in the MRC AIMS database used in this study [Ecker et al, 2012, 2013, 2015], a standardization procedure based on quantitative imaging [Deoni et al, 2008] was used to minimize inter‐site variance and improve the signal‐to‐noise contrast. However, as the between‐site analysis in “Experiment 1: Effect of Acquisition Site” section suggests, this strategy still results in variance that makes it easier to distinguish scanning sites than diagnostic groups.…”

“…Structural MRI were analysed from 136 adult, right‐handed males (68 with ASD and 68 matched controls) with no significant mean differences in age and full‐scale IQ, acquired from the centres contributing to the UK Medical Research Council Autism Imaging Multi‐centre Study (MRC AIMS) [Ecker et al, 2012, 2013, 2015] and recruited by advertisement. In this work, only participants recruited at the Institute of Psychiatry, King's College London (LON) and the Autism Research Centre, University of Cambridge (CAM) were included where an equivalent set of images were acquired from each participant.…”

“…The delimitation of both functionally and structurally affected areas in the brain in such an etiologically and neurobiologically heterogeneous condition has long been a major concern [Ecker and Murphy, 2014; Lai et al, 2013; Lenroot and Yeung, 2013]. With this context, the use of large samples is of fundamental importance, and has been addressed by establishing multi‐centre collaborations such as the UK Medical Research Council Autism Imaging Multi‐centre Study (MRC AIMS) [Ecker et al, 2012, 2013, 2015] and the Autism Brain Imaging Data Exchange (ABIDE) [Di Martino et al, 2014]…”

Recent Research Progress in Autism Spectrum Disorder

“…Early findings from several structural magnetic resonance imaging studies have shown that toddlers with ASD, aged on average 2-4 years, have a larger brain volume than typically-developing children, an effect that levels off by 6-8 years [35,36]. These findings contribute to the notion that the trajectory of brain maturation in ASD is atypical and involves an early period of overgrowth, with each brain region having its distinct trajectory [35,36].…”

“…Early findings from several structural magnetic resonance imaging studies have shown that toddlers with ASD, aged on average 2-4 years, have a larger brain volume than typically-developing children, an effect that levels off by 6-8 years [35,36]. These findings contribute to the notion that the trajectory of brain maturation in ASD is atypical and involves an early period of overgrowth, with each brain region having its distinct trajectory [35,36]. Further structural neuroimaging studies have revealed ASD to be a disorder with general and regional alterations in brain size, while functional neuroimaging studies have highlighted changes in connectivity between brain regions in ASD patients [35,[37][38][39].…”