scMRI Reveals Large-Scale Brain Network Abnormalities in Autism

Autism is a complex neurological condition characterized by childhood onset of dysfunction in multiple cognitive domains including socio-emotional function, speech and language, and processing of internally versus externally directed stimuli. Although gross brain anatomic differences in autism are well established, recent studies investigating regional differences in brain structure and function have yielded divergent and seemingly contradictory results. How regional abnormalities relate to the autistic phenotype remains unclear. We hypothesized that autism exhibits distinct perturbations in network-level brain architecture, and that cognitive dysfunction may be reflected by abnormal network structure. Network-level anatomic abnormalities in autism have not been previously described. We used structural covariance MRI to investigate network-level differences in gray matter structure within two large-scale networks strongly implicated in autism, the salience network and the default mode network, in autistic subjects and age-, gender-, and IQ-matched controls. We report specific perturbations in brain network architecture in the salience and default-mode networks consistent with clinical manifestations of autism. Extent and distribution of the salience network, involved in social-emotional regulation of environmental stimuli, is restricted in autism. In contrast, posterior elements of the default mode network have increased spatial distribution, suggesting a ‘posteriorization’ of this network. These findings are consistent with a network-based model of autism, and suggest a unifying interpretation of previous work. Moreover, we provide evidence of specific abnormalities in brain network architecture underlying autism that are quantifiable using standard clinical MRI

Atypical development of white matter microstructure of the corpus callosum in males with autism: a longitudinal investigation

Background: The corpus callosum is the largest white matter structure in the brain, and it is the most consistently reported to be atypical in diffusion tensor imaging studies of autism spectrum disorder. In individuals with typical development, the corpus callosum is known to undergo a protracted development from childhood through young adulthood. However, no study has longitudinally examined the developmental trajectory of corpus callosum in autism past early childhood. Methods: The present study used a cohort sequential design over 9 years to examine age-related changes of the corpus callosum in 100 males with autism and 56 age-matched males with typical development from early childhood (when autism can first be reliably diagnosed) to mid-adulthood (after development of the corpus callosum has been completed) (3 to 41 years of age). Results: The group with autism demonstrated a different developmental trajectory of white matter microstructure in the anterior corpus callosum’s (genu and body) fractional anisotropy, which suggests atypical brain maturation in these regions in autism. When analyses were broken down by age group, atypical developmental trajectories were present only in the youngest participants (10 years of age and younger). Significant main effects for group were found in terms of decreased fractional anisotropy across all three subregions of the corpus callosum (genu, body, and splenium) and increased mean diffusivity, radial diffusivity, and axial diffusivity in the posterior corpus callosum. Conclusions: These longitudinal results suggest atypical early childhood development of the corpus callosum microstructure in autism that transitions into sustained group differences in adolescence and adulthood. This pattern of results provides longitudinal evidence consistent with a growing number of published studies and hypotheses regarding abnormal brain connectivity across the life span in autism. Electronic supplementary material The online version of this article (doi:10.1186/s13229-015-0001-8) contains supplementary material, which is available to authorized users

Brainstem White Matter Predicts Individual Differences in Manual Motor Difficulties and Symptom Severity in Autism

127 p. // 15 - 29 : 0013Para la creación de una empresa de mantenimiento industrial en Colombia, deben integrarse varios elementos, desde el objetivo o tipos de servicios que se van a prestar, el modo de operación y las normas legales que los rigen, la seguridad industrial, las estrategias dirigidas a clientes potenciales, la planeación en inversión en equipos, en identificación de oportunidades, competencia y riesgos, metas de ventas, responsabilidad y gestión del talento humano como del conocimiento. La planeación es el factor fundamental en cada una de las fases de la creación del proyecto empresarial, teniendo en cuenta la distribución de los recursos de inversión y costos en los aspectos realmente necesarios y tendientes a ofrecer un servicio que esté al mejor nivel de calidad e idoneidad de la competencia que permita a los clientes, identificar la mejor oportunidad, aplicando modelos y métodos en la organización, los procesos y el liderazgo para obtener buenos resultados, aún cuando en Colombia resulta un tanto difícil por los altos costos de insumos, impuestos y transportes, entre otros, pero aún así tiene justificación el proyecto, porque la industria en Colombia se proyecta como un renglón importante, teniendo en cuenta que la tecnología y los mercados cada día son mas globalizado

MNI coordinates and characteristics of peak voxels and associated clusters of groupwise scMRI maps.

<p>FWE, family-wise error.</p

Structural covariance maps of the default mode network in autism and controls.

<p>Statistical parametric maps depict brain regions in which gray matter intensity covaried with that of the seed ROI (right PCC) in each group. (A) Structural covariance patterns appear robust in posterior brain regions, but restricted in frontal areas in autism (hot colors; see also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0049172#pone-0049172-t002" target="_blank">Table 2</a>). Covariance outside of canonical DMN boundaries is also evidenced. (B) Corresponding scMRI map in normal controls corresponds to a robust canonical default mode network (cool colors). (C) scMRI maps from both groups overlaid on a single anatomic volume. scMRI data are T-statistic maps (p<0.01, FWE-corrected) displayed on the average anatomical template of all subjects. The left side of the image corresponds to the right side of the brain. DMN, default mode network; FWE, family-wise error; PCC, posterior cingulate cortex; ROI, region of interest; scMRI, structural covariance MRI.</p

Whole brain structural covariance with ADOS-SI scores as a result of direct between-group contrasts.

<p>Statistical parametric maps depict brain regions in which gray matter intensity covaried with ADOS Social Impairment (ADOS-SI) score differently between groups. In controls, ADOS-SI scores covaried with frontal regions overlapping with SN including medial frontal wall, anterior cingulate, and frontoinsular cortex. In contrast, in autistic subjects ADOS-SI covaried with posterior brain regions including cuneus, precuneus, parieto-occipital regions, and temporoparietal cortex. scMRI data are T-statistic maps (p<0.05, inclusively masked to the network global map for both groups at p<0.01 FWE) displayed on the average anatomical template of all subjects. scMRI maps from both groups overlaid on a single anatomic volume reveal distinct between-group differences. The left side of the image corresponds to the right side of the brain. SN, salience network.</p

Structural covariance maps of salience and default mode networks as a result of direct between-group contrasts.

<p>Statistical parametric maps depict brain regions in which gray matter intensity covaried with that of the seed ROI (right FI or PCC) differently between groups. (A) Structural covariance with right FI is greater in bilateral SMA in autistic subjects (hot colors; see also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0049172#pone-0049172-t003" target="_blank">Table 3</a>), whereas control subjects (cool colors) demonstrate more robust covariance in extensive frontal and temporal brain regions, in addition to insular cortex. Covariance outside of canonical SN boundaries is evidenced only in the autistic group. (B) Structural covariance with right PCC includes posterior cingulate, parieto-occipital, and temporal brain regions in autism (hot colors), whereas frontal covariance is absent. In contrast, control subjects demonstrate more robust covariance in frontal, lateral inferior parietal, and paracentral regions (cool colors; see also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0049172#pone-0049172-t003" target="_blank">Table 3</a>). Covariance outside of canonical DMN boundaries is evidenced only in the autistic group. scMRI data are T-statistic maps (p<0.05, inclusively masked to the network global map for both groups at p<0.01 FWE) displayed on the average anatomical template of all subjects. The left side of the image corresponds to the right side of the brain. DMN, default mode network; FI, frontoinsula; FWE, family-wise error; PCC, posterior cingulate cortex; ROI, region of interest; SN, salience network.</p

Group demographics and neuropsychiatric test characteristics.

<p>ADOS-SI, ADOS Social Impairment score; ADOS-C, ADOS Communication score; VIQ, Verbal IQ; PIQ, Performance IQ.</p

Structural covariance maps of the salience network in autism and controls.

<p>Statistical parametric maps depict brain regions in which gray matter intensity covaried with that of the seed ROI (right FI) in each group. (A) Structural covariance patterns appear substantially spatially restricted in autism (hot colors; see also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0049172#pone-0049172-t002" target="_blank">Table 2</a>). (B) Corresponding scMRI map in normal controls corresponds to a robust canonical SN (cool colors). (C) scMRI maps from both groups overlaid on a single anatomic volume. scMRI data are T-statistic maps (p<0.01, FWE-corrected) displayed on the average anatomical template of all subjects. The left side of the image corresponds to the right side of the brain. FI, frontoinsula; FWE, family-wise error; ROI, region of interest; scMRI, structural covariance MRI; SN, salience network.</p