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Query: UMLS:C0004352 (autism)
 32,579 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The objective of this study was to examine the relationship between thalamic volume and brain size in individuals with Asperger's disorder (ASP). Volumetric measurements of the thalamus were performed on MRI scans obtained from 12 individuals with ASP (age range: 10-35 years) and 12 healthy controls (age range: 9-33 years). A positive correlation was found between total brain volume and thalamic size in controls, but not in ASP subjects. This occurred in the absence of differences in mean thalamic volumes between the study groups. Findings from this investigation point to an abnormal relationship between the thalamus and its projection areas in ASP and are consistent with similar studies in autism, supporting that these disorders are qualitatively similar and possibly quantitatively different.
J Autism Dev Disord 2008 Feb
PMID:Brief report: abnormal association between the thalamus and brain size in Asperger's disorder. 1764 63

Human attentional control is unrivaled. We recently proposed that adults depend on distinct frontoparietal and cinguloopercular networks for adaptive online task control versus more stable set control, respectively. During development, both experience-dependent evoked activity and spontaneous waves of synchronized cortical activity are thought to support the formation and maintenance of neural networks. Such mechanisms may encourage tighter "integration" of some regions into networks over time while "segregating" other sets of regions into separate networks. Here we use resting state functional connectivity MRI, which measures correlations in spontaneous blood oxygenation level-dependent signal fluctuations between brain regions to compare previously identified control networks between children and adults. We find that development of the proposed adult control networks involves both segregation (i.e., decreased short-range connections) and integration (i.e., increased long-range connections) of the brain regions that comprise them. Delay/disruption in the developmental processes of segregation and integration may play a role in disorders of control, such as autism, attention deficit hyperactivity disorder, and Tourette's syndrome.
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PMID:Development of distinct control networks through segregation and integration. 1767 91

The cerebellum coordinates movement, thought and emotion through its feedback projections from the deep cerebellar nuclei. Despite recent advancement in our understanding of the functions of the cerebellar cortex, little is known about the functional correlates of the deep cerebellar nuclei in humans. This is mainly due to the inability of current MRI techniques to visualize the cerebellar nuclei and therefore perform in vivo clinico-anatomical correlation studies in patient populations. Here we visualize in vivo the detailed anatomy of the dentate nucleus and other cerebellar nuclei using quantitative T1 and proton density (rho) imaging. Compared to conventional qualitative T1, T2 or T2*-weighted imaging, quantitative T1 and proton density (rho) imaging facilitates direct visualization of the dentate and interposed nuclei, allowing us to perform segmentation and volumetric measurements of the dentate nucleus. Also the fine architecture of the microgyric and macrogyric dentate nucleus was visible on the high-resolution images. The high concentration of paramagnetic iron within the cerebellar nuclei and the resulting local field inhomogeneities surrounding the iron-containing nuclei is believed to be responsible for the observed effect on T1 and proton density signal. The application of this technique to disorders with cerebellar dysfunction could provide new insight into pathologies like autism and movement disorders.
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PMID:Visualization of the deep cerebellar nuclei using quantitative T1 and rho magnetic resonance imaging at 3 Tesla. 1770 7

Recent MRI studies have indicated that regions of the temporal lobe including the superior temporal gyrus (STG) and the temporal stem (TS) appear to be abnormal in autism. In this study, diffusion tensor imaging (DTI) measurements of white matter in the STG and the TS were compared in 43 autism and 34 control subjects. DTI measures of mean diffusivity, fractional anisotropy, axial diffusivity, and radial diffusivity were compared between groups. In all regions, fractional anisotropy was significantly decreased and both mean diffusivity and radial diffusivity were significantly increased in the autism group. These results suggest that white matter microstructure in autism is abnormal in these temporal lobe regions, which is consistent with theories of aberrant brain connectivity in autism.
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PMID:Diffusion tensor imaging of white matter in the superior temporal gyrus and temporal stem in autism. 1771 69

This report addresses behavioral abnormalities in children with cerebellar anomalies demonstrated on MRI scans. Published data are presented showing an interaction between cerebellar pathology and early childhood autism. The cerebellum is involved not only in movement coordination, but also in social adaptation and verbal communication. The genes expressed in the cerebellum during childhood are identical to those expressed in the hippocampus. We have observed 20 children with MRI-identified agenesis of the cerebellar vermis and behavioral abnormalities; children were aged 3-15 (mean 7.05) years and there were 12 males and eight females. A variety of autistic characteristics were identified in these children.
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PMID:Clinical-psychological characteristics of children with dysgenesis of the cerebellar vermis. 1792 38

L-2-Hydroxyglutaric aciduria (L-2-HGA) is an autosomal recessive neurometabolic disorder characterized by psychomotor delay, ataxia, macrocephaly and typical neuroradiological findings of subcortical leucoencephalopathy. Recently, the disease causing gene has been discovered (L2HGDH) encoding L-2-hydroxyglutarate dehydrogenase. We present a 3-year-old boy with L-2-HGA, who demonstrated macrocephaly, noted already in utero with ultrasound. Cranial MRI demonstrated diffuse subcortical encephalopathy with increased signal of the subcortical white matter. Subsequent metabolic screening revealed increased levels of L-2-HGA, and genomic DNA analysis demonstrated two missense mutations in L-2-HGDG. Patient's further motor development was mildly impaired, whilst his speech development was profoundly impaired (first words at the age of 2 years). Since the age of 2 years he started demonstrating autistic repetitive behaviors and movements, increasing aloofness to his environment and limitations in the variety of spontaneous activity (CARS score: 44/60-severe autism). Autism has not so far been described in L-2-HGA and may be considered as an additional feature of the phenotypic spectrum.
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PMID:L-2-Hydroxyglutaric aciduria presenting with severe autistic features. 1798 16

The importance of accurate early diagnostics of autism that severely affects personal behavior and communication skills cannot be overstated. Neuropathological studies have revealed an abnormal anatomy of the cerebral white matter (CWM) in autistic brains. We explore a possibility of distinguishing between autistic and normal brains by a quantitative shape analysis of CWM gyrifications on 3D proton density MRI (PD-MRI) images. Our approach consists of (i) segmentation of the CWM on a 3D brain image using a deformable 3D boundary; (ii) extraction of gyrifications from the segmented CWM, and (iii) shape analysis to quantify thickness of the extracted gyrifications and classify autistic and normal subjects. The boundary evolution is controlled by two probabilistic models of visual appearance of 3D CWM: the learned prior and the current appearance model. Initial experimental results suggest that the proposed 3D texture analysis is a promising supplement to the current techniques for diagnosing autism.
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PMID:Autism diagnostics by 3D texture analysis of cerebral white matter gyrifications. 1804 52

In higher functioning individuals with autism, a striking disparity exists between impaired social and emotional abilities and relatively preserved sustained attention and goal-directed cognitive abilities. As these two functional domains appear to map onto two distinct large-scale brain networks, the Task-Negative Network and the Task-Positive Network, respectively, we examined their intrinsically defined functional organization in individuals with autism. Using resting functional connectivity MRI (fcMRI), we found that, in autism, there was altered functional organization of the network involved in social and emotional processing, but no group difference in the functional organization of the network involved in sustained attention and goal-directed cognition. We suggest that these findings might serve to relate the seemingly disparate strengths and weaknesses of the autistic behavioral, perceptual, and cognitive phenotype into a tractable neurofunctional framework. These results also highlight the usefulness of resting fcMRI for studying the brain in neuropsychiatric and neurodevelopmental disorders.
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PMID:The intrinsic functional organization of the brain is altered in autism. 1808 65

We describe a protocol with which we achieved a 93% success rate in acquiring high quality MRI scans without the use of sedation in 2.5-4.5 year old children with autism, developmental delays, and typical development. Our main strategy was to conduct MRIs during natural nocturnal sleep in the evenings after the child's normal bedtime. Alternatively, with some older and higher functioning children, the MRI was conducted while the child was awake and watching a video. Both strategies relied heavily on the creation of a child and family friendly MRI environment and the involvement of parents as collaborators in the project. Scanning very young children with autism, typical development, and developmental delays without the use of sedation or anesthesia was possible in the majority of cases.
J Autism Dev Disord 2008 Sep
PMID:Brief report: methods for acquiring structural MRI data in very young children with autism without the use of sedation. 1815 24

Prenatal viral infection has been associated with development of schizophrenia and autism. Our laboratory has previously shown that viral infection causes deleterious effects on brain structure and function in mouse offspring following late first trimester (E9) administration of influenza virus. We hypothesized that late second trimester infection (E18) in mice may lead to a different pattern of brain gene expression and structural defects in the developing offspring. C57BL6J mice were infected on E18 with a sublethal dose of human influenza virus or sham-infected using vehicle solution. Male offsping of the infected mice were collected at P0, P14, P35 and P56, their brains removed and prefrontal cortex, hippocampus and cerebellum dissected and flash frozen. Microarray, qRT-PCR, DTI and MRI scanning, western blotting and neurochemical analysis were performed to detect differences in gene expression and brain atrophy. Expression of several genes associated with schizophrenia or autism including Sema3a, Trfr2 and Vldlr were found to be altered as were protein levels of Foxp2. E18 infection of C57BL6J mice with a sublethal dose of human influenza virus led to significant gene alterations in frontal, hippocampal and cerebellar cortices of developing mouse progeny. Brain imaging revealed significant atrophy in several brain areas and white matter thinning in corpus callosum. Finally, neurochemical analysis revealed significantly altered levels of serotonin (P14, P35), 5-Hydroxyindoleacetic acid (P14) and taurine (P35). We propose that maternal infection in mouse provides an heuristic animal model for studying the environmental contributions to genesis of schizophrenia and autism, two important examples of neurodevelopmental disorders.
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PMID:Maternal infection leads to abnormal gene regulation and brain atrophy in mouse offspring: implications for genesis of neurodevelopmental disorders. 1824 90


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