Abnormal cell patterning at the cortical gray-white matter boundary in autism spectrum disorders

Psychology Department, University of Nevada, Reno, NV 89557, USA.
Brain research (Impact Factor: 2.83). 11/2010; 1360:138-46. DOI: 10.1016/j.brainres.2010.08.091
Source: PubMed

ABSTRACT Previous research on neuronal spacing and columnar organization indicates the presence of cell patterning alterations within the cerebral cortex of individuals with autism spectrum disorders (ASD). These patterning abnormalities include irregularities at the gray-white matter boundary and may implicate early neurodevelopmental events such as migration in altering cortical organization in ASD. The present study utilized a novel method to quantify the gray-white matter boundary in eight ASD and eight typically developing control subjects. Digital photomicrographs of the gray-white matter boundary were acquired from multiple positions within the superior temporal gyrus (BA21), dorsolateral frontal lobe (BA9), and dorsal parietal lobe (BA7) of each case. A sigmoid curve was fitted to the transition zone between layer VI and underlying white matter (subplate), and the slope of the resulting curve was used as a measure of the spatial extent of the transition zone. For all three cortical regions examined, ASD subjects showed "shallower" sigmoid curves compared to neurotypicals, indicating the presence of an indistinct boundary between cortical layer VI and the underlying white matter. These results may reflect the presence of supernumerary neurons beneath the cortical plate that could be the result of migration deficits or failed apoptosis in the subplate region. Furthermore, these findings raise questions regarding the validity of cortical measures that rely on gray-white matter parcellation, since an indistinct transition zone could lead to a misplaced cortical boundary and errors in both thickness and volume measures.

  • Source
    • "In addition, because of the decreased airway diameter and the resulting greater airway resistance, long distance running and other athletic endeavors would likely be more difficult for ASD patients. Since the diagnosis of ASD is presently based on very subjective criteria (Anney et al. 2010; Avino and Hutsler 2010; Hu et al. 2011) it would be helpful to have more objective criteria for the diagnosis of ASD. The unusual doublet anatomy phenotype we describe here does portend to be a viable diagnostic biological marker for ASD. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Bronchoscopic evaluations revealed that some children have double branching of bronchi (designated "doublets") in the lower lungs airways, rather than normal, single branching. Retrospective analyses revealed only one commonality in them: all subjects with doublets also had autism or autism spectrum disorder (ASD). That is, 49 subjects exhibited the presence of initial normal anatomy in upper airway followed by doublets in the lower airway. In contrast, the normal branching pattern was noted in all the remaining 410 subjects who did not have a diagnosis of autism/ASD. We propose that the presence of doublets might be an objective, reliable, and valid biologic marker of autism/ASD.
    Journal of Autism and Developmental Disorders 08/2012; 43(4). DOI:10.1007/s10803-012-1635-4 · 3.06 Impact Factor
  • Source
    • "The studies appear contradictory, finding either no difference in numbers in adults (Kennedy et al., 2007) or an increased ratio of spindle neurons to pyramidal neurons in children (Santos et al., 2010), but this disagreement may reflect the developmental trajectory of the disorder. Two studies of neuronal organization revealed ill-defined cortical layers in the dorsolateral prefrontal cortex (Mukaetova-Ladinska et al., 2004) as well as a poorly defined boundary between gray matter and white matter (Avino and Hutsler, 2010), suggesting the possibility of abnormalities in neurogenesis or neuronal migration. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Autism is clearly a disorder of neural development, but when, where, and how brain pathology occurs remain elusive. Typical brain development is comprised of several stages, including proliferation and migration of neurons, creation of dendritic arbors and synaptic connections, and eventually dendritic pruning and programmed cell death. Any deviation at one or more of these stages could produce catastrophic downstream effects. MRI studies of autism have provided important clues, describing an aberrant trajectory of growth during early childhood that is both present in the whole brain and marked in specific structures such as the amygdala. However, given the coarse resolution of MRI, the field must also look towards postmortem human brain research to help elucidate the neurobiological underpinnings of MRI volumetric findings. Likewise, studies of postmortem tissue may benefit by looking to the findings from MRI studies to narrow hypotheses and target specific brain regions and subject populations. In this review, we discuss the strengths, limitations, and major contributions of each approach to autism research. We then describe how they relate and what they can learn from each other. Only by integrating these approaches will we be able to fully explain the neuropathology of autism.
    Brain research 03/2011; 1380:175-86. DOI:10.1016/j.brainres.2010.09.061 · 2.83 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We previously reported a genetic analysis of the growth-inhibitory effect caused by the overexpression of the Aspergillus oryzae rntA gene, encoding RNase T1 (Ribonuclease T1), in Saccharomyces cerevisiae. Subsequently, rns (ribonuclease T1 sensitive) mutants with mutations in the rns1 (DSL1), rns2 (UMP1), and rns3 (SEC17) genes, were identified. In the present study, rns4 (VPS32/SNF7) gene mutation was identified by complementation of tunicamycin sensitivity. While the rns4 mutant exhibited sensitivity to ambient stress conditions (200 mM CaCl(2), 1M NaCl and pH 8.0), genome-wide expression analysis revealed a similar pattern of genes up-regulated as was observed under nitrogen depletion condition by Gasch et al. [Mol. Biol. Cell 11 (2000) 4241]. Notably, the genes participating in autophagy (ATG4 and ATG8), the genes encoding a vacuolar protease (PRB1), vacuolar protease inhibitors (PAI3, PBI2 and TFS1) and YHR138c (a PBI2 homolog) were up-regulated in the rns4 mutant. Interestingly, the RNase T1*-GFP fusion protein (*inactive form) expressed in the rns4 mutant strain localized at the ER and vacuole under both stress or no-stress conditions. In contrast, the RNase T1*-GFP fusion protein expressed in the wild-type strain could not be detected under no-stress conditions, however, a stress-dependent localization of the fusion protein was observed at the vacuole. Since, the rns4 mutant exhibited a partial starvation-like response in spite of a rich ambient environment, leading to transportation of the secretory protein to the vacuole and accumulation in the endoplasmic reticulum, the present findings implicate a novel role for Rns4/Vps32 in proper response and adaptation to ambient conditions.
    FEMS Yeast Research 07/2005; 5(9):801-12. DOI:10.1016/j.femsyr.2005.03.003 · 2.44 Impact Factor
Show more