Mapping brain abnormalities in boys with autism

Abstract

Children with autism spectrum disorder (ASD) exhibit characteristic cognitive and behavioral differences, but no systematic pattern of neuroanatomical differences has been consistently found. Recent neurodevelopmental models posit an abnormal early surge in subcortical white matter growth in at least some autistic children, perhaps normalizing by adulthood, but other studies report subcortical white matter deficits. To investigate the profile of these alterations in 3D, we mapped brain volumetric differences using a relatively new method, tensor-based morphometry (TBM). 3D T1-weighted brain MRIs of 24 male children with ASD (age: 9.5 years ± 3.2 SD) and 26 age-matched healthy controls (age: 10.3 ± 2.4 SD) were fluidly registered to match a common anatomical template. Autistic children had significantly enlarged frontal lobes (by 3.6% on the left and 5.1% on the right), and all other lobes of the brain were enlarged significantly, or at trend level. By analyzing the applied deformations statistically point-by-point, we detected significant gray matter volume deficits in bilateral parietal, left temporal and left occipital lobes (p=0.038, corrected), trend-level cerebral white matter volume excesses, and volume deficits in the cerebellar vermis, adjacent to volume excesses in other cerebellar regions. This profile of excesses and deficits in adjacent regions may (1) indicate impaired neuronal connectivity, resulting from aberrant myelination and/or an inflammatory process, and (2) help to understand inconsistent findings of regional brain tissue excesses and deficits in autism.

Autism Spectrum Disorder: Does Neuroimaging Support the DSM-5 Proposal for a Symptom Dyad? A Systematic Review of Functional Magnetic Resonance Imaging and Diffusion Tensor Imaging Studies

“…Similarly, DTI supports these MRI findings by showing a reduced integrity of WM tracts that are part of these 'social' fronto-temporal cortical and subcortical networks Barnea-Goraly et al 2004;BarneaGoraly et al 2010;Ben Bashat et al 2007;Bloemen et al 2010;Brito et al 2009;Brun et al 2009;Catani et al 2008;Conturo et al 2008;Cheng et al 2010;Cheung et al 2009;Groen et al 2011;Jou et al 2011;Ke et al 2009;Keller et al 2007;Knaus et al 2010;Lange et al 2010;Lee et al 2007a;Noriuchi et al 2010;Pardini et al 2009;Pugliese et al 2009;Sahyoun et al 2010;Shukla et al 2010aShukla et al , 2011Sivaswamy et al 2010;Sundaram et al 2008;Thakkar et al 2008;Weinstein et al 2011). See Fig.…”

Neuroimages in Autism

“…On the other hand, Brun et al (2009) found significantly decreased cortical volumes in the parietal, left temporal, and left occipital lobes, bilaterally, using TBM. Alterations of the basal ganglia, especially the caudate nuclei, have been repeatedly described in ASD patients and were often found to correlate with impaired motor performance or repetitive and stereotyped behavior (for review see (Nickl-Jockschat et al 2012)).…”

MRI Surface-Based Brain Morphometry in Egyptian Autistic and Typically Developing Children

“…Brun et al [46] suggested that delayed or aberrant myelination is a cause of abnormal white matter in autism. The development of myelin sheaths allows a smooth flow of neural impulses through the brain [47].…”