Linked alterations in gray and white matter morphology in adults with high-functioning autism spectrum disorder: A multimodal brain imaging study

Abstract

Growing evidence suggests that a broad range of behavioral anomalies in people with autism spectrum disorder (ASD) can be linked with morphological and functional alterations in the brain. However, the neuroanatomical underpinnings of ASD have been investigated using either structural magnetic resonance imaging (MRI) or diffusion tensor imaging (DTI), and the relationships between abnormalities revealed by these two modalities remain unclear. This study applied a multimodal data-fusion method, known as linked independent component analysis (ICA), to a set of structural MRI and DTI data acquired from 46 adult males with ASD and 46 matched controls in order to elucidate associations between different aspects of atypical neuroanatomy of ASD. Linked ICA identified two composite components that showed significant between-group differences, one of which was significantly correlated with age. In the other component, participants with ASD showed decreased gray matter (GM) volumes in multiple regions, including the bilateral fusiform gyri, bilateral orbitofrontal cortices, and bilateral pre- and post-central gyri. These GM changes were linked with a pattern of decreased fractional anisotropy (FA) in several white matter tracts, such as the bilateral inferior longitudinal fasciculi, bilateral inferior fronto-occipital fasciculi, and bilateral corticospinal tracts. Furthermore, unimodal analysis for DTI data revealed significant reductions of FA along with increased mean diffusivity in those tracts for ASD, providing further evidence of disrupted anatomical connectivity. Taken together, our findings suggest that, in ASD, alterations in different aspects of brain morphology may co-occur in specific brain networks, providing a comprehensive view for understanding the neuroanatomy of this disorder.

Age‐related differences in autism: The case of white matter microstructure

“…White matter abnormalities in early adulthood in ASD appear to converge towards lower FA, and, despite being scarcely reported, also higher MD and RD in various tracts [Bloemen et al, 2010;Conturo et al, 2008;Gibbard et al, 2013;Itahashi et al, 2015;Langen et al, 2012;Mueller et al, 2013;Thakkar et al, 2008]. However, other studies reported no differences in FA and/or MD [Bakhtiari et al, 2012;Kirkovski et al, 2015;Pugliese et al, 2009;Thomas et al, 2011], or even higher FA [Roine et al, 2013] in young adults with ASD.…”

Multimodal Fusion of Brain Imaging Data: A Key to Finding the Missing Link(s) in Complex Mental Illness

“…Additionally, white matter networks adjacent to basal ganglia correlated with obsessive-compulsive symptoms. Another study(93) reported linked alterations in GM and WM morphology in adults with high-functioning autism spectrum disorder (ASD) via linked ICA, ASD patients showed decreased GM volumes in bilateral fusiform gyri, orbitofrontal cortices, and pre-/post-central gyri, which were linked with a pattern of decreased FA in tracts of inferior longitudinal fasciculi, inferior fronto-occipital fasciculi, and corticospinal tracts, all bilaterally.…”

Structural Correlates of Reading the Mind in the Eyes in Autism Spectrum Disorder

“…However, note that our results did not show a main effect of group (i.e., group differences in gray matter volume regardless of Eyes Test score) in the TPJ, which is consistent with several structural MRI studies in adults with ASD (Abell et al, 1999; McAlonan et al, 2002; Schmitz et al, 2006, 2008; Wilson et al, 2009; Dziobek et al, 2010; Toal et al, 2010; Ecker et al, 2013; Lai et al, 2013; Bernhardt et al, 2014; Riedel et al, 2014; Balardin et al, 2015; Gebauer et al, 2015; Itahashi et al, 2015; Libero et al, 2015; for a review see Yang et al, 2016). Our results suggest that individuals with ASD may have atypical brain–behavior associations that cannot be detected using structural MRI data alone.…”