Altered corpus callosum morphology associated with autism over the first 2 years of life

Abstract

Numerous brain imaging studies indicate that the corpus callosum is smaller in older children and adults with autism spectrum disorder. However, there are no published studies examining the morphological development of this connective pathway in infants at-risk for the disorder. Magnetic resonance imaging data were collected from 270 infants at high familial risk for autism spectrum disorder and 108 low-risk controls at 6, 12 and 24 months of age, with 83% of infants contributing two or more data points. Fifty-seven children met criteria for ASD based on clinical-best estimate diagnosis at age 2 years. Corpora callosa were measured for area, length and thickness by automated segmentation. We found significantly increased corpus callosum area and thickness in children with autism spectrum disorder starting at 6 months of age. These differences were particularly robust in the anterior corpus callosum at the 6 and 12 month time points. Regression analysis indicated that radial diffusivity in this region, measured by diffusion tensor imaging, inversely predicted thickness. Measures of area and thickness in the first year of life were correlated with repetitive behaviours at age 2 years. In contrast to work from older children and adults, our findings suggest that the corpus callosum may be larger in infants who go on to develop autism spectrum disorder. This result was apparent with or without adjustment for total brain volume. Although we did not see a significant interaction between group and age, cross-sectional data indicated that area and thickness differences diminish by age 2 years. Regression data incorporating diffusion tensor imaging suggest that microstructural properties of callosal white matter, which includes myelination and axon composition, may explain group differences in morphology.

Brain Connectivity in Autism: The Significance of Null Findings

“…This heterogeneity would make it more difficult to find group differences on a single structural measure and highlights the need for more nuanced analysis of individual variations to find the most salient connections between brain and behavior. Finally, the negative findings in the present study apply only to individuals 7.5-40 years old, leaving open the possibility that structural abnormalities of the corpus callosum may be present and detectable earlier in development (8,9) …”

Subcortical Brain and Behavior Phenotypes Differentiate Infants With Autism Versus Language Delay

“…The current study had two main objectives: (1) to chart the development of language skills in high-risk infants later diagnosed with ASD and high-risk infants who showed signs of early language delay, and (2), to determine if the subcortical neurobiology of language and brain-behavior associations differed between high-risk infants with ASD and high-risk infants with language delay. Given the previous literature showing brain changes preceding behavioral changes in ASD (1, 3, 45), we focused on 12-month subcortical volumes and 24-month language skills.…”

Struktur Otak dan Keberfungsiannya pada Anak dengan Gangguan Spektrum Autis: Kajian Neuropsikologi

“…Wolff, Gerig, dan Lewis (2015), mengemukakan bahwa corpus callosum (bagian jembatan penghubung antara kedua belahan otak/hemisphere kanan dan kiri) menunjukkan peningkatan dan ketebalan pada bayi dengan hasil scan pada anak autis usia 6 bulan, berbeda dengan bayi normal (Steinmetz, Staiger, & Schlaug, 1996, dalam Ecker, 2016 …”

“…Berfungsi sebagai penghubung kedua belahan otak berbagi informasi, meskipun awalnya hanya satu belahan yang menerima informasi, memungkinkan pertukaran informasi antara hemisphere kiri dan kanan (Springer et al dalam Zillmer et al, 2008)  Penelitian yang dilakukan oleh Wolff, et al, (2015) menjelaskan bahwa terdapat peningkatan dan ketebalan corpus callosum pada bayi yang mengalami autis berusia 6 bulan  Frazier & Hardan, 2009;Lainhart et al, (dalam Casanova, et al, 2011) (Schumann, et al, 2010)  Penelitian yang dilakukan Wolff, et al, (2012) dengan menggunakan diffusion tensor imaging (DIT), menemukan gangguan dalam perkembangan white matter sudah ada pada bayi berusia 6 bulan (kemungkinan akan semakin besar jika mempunyai saudara kandung yang terdiagnosa autis). Penelitian-penelitian yang dilakukan oleh Carper, Moses, Tigue, Courchesne, 2002;Hazlett, et al, 2005;Schumann, et al, (dalam Ecker, 2016); menjelaskan bahwa pelebaran otak dipengaruhi oleh peningkatan volume white matter pada anak autis  Perkembangan yang tidak normal dari white matter cortex dan/atau berbeda dalam jumlah CSF (cerebrospinal fluid) berkontribusi terhadap peningkatan volume otak (Carper, et al, 2002;Hazlett, et al, 2005;Schumann, et al, dalam Ecker, 2016).…”