Sigmoid fits to locate and characterize cortical boundaries in human cerebral cortex

Hutsler, Jeffrey J.; Avino, Thomas A.

doi:10.1016/j.jneumeth.2012.10.007

Cited by 7 publications

(7 citation statements)

References 17 publications

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“…We found that the GWC was significantly reduced in ASD, particularly at the grey-white matter boundary, and in many brain regions that have previously been linked to autistic symptoms and traits [ 16 ]. Our in vivo finding of a reduced GWC is also consistent with prior postmortem reports of a less well-defined grey-white matter boundary in ASD [ 11 , 12 ]. However, based on tissue contrast alone, it is not possible to disentangle whether the observed between-group effects are driven by (1) differences in grey matter cytoarchitecture, as suggested by the above histological studies, or by (2) local variations in myelin content.…”

Section: Introductionsupporting

confidence: 91%

“…Moreover, our study agrees with previous post-mortem reports suggesting that the boundary between cortical layer VI and the underlying white matter may be more ‘indistinct’ in ASD. This indistinct boundary may be due to increased ‘dispersion’ of neuronal cells across the grey-white matter interface [ 11 , 12 ]. In turn, supernumerary neurons beneath the cortical plate may then arise as a consequence of disrupted migratory processes during prenatal brain development and/or atypical development and resolution of the cortical subplate (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…More recently, however, the attention of structural neuroimaging studies is shifting towards examining the grey-white matter boundary, as histological evidence suggests that the grey-white matter tissue contrast may be regionally less well defined (i.e. less distinct) in ASD [ 11 ]. Such ‘blurring’ of the grey-white matter transition zone seems to be caused by the presence of supernumerary neurons beneath the cortical plate, which—in turn—may result from migration deficits or failed apoptosis in the subplate region [ 12 ].…”

Section: Introductionmentioning

confidence: 99%

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The effect of age on vertex-based measures of the grey-white matter tissue contrast in autism spectrum disorder

et al. 2018

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BackgroundHistological evidence suggests that autism spectrum disorder (ASD) is accompanied by a reduced integrity of the grey-white matter boundary. This has also recently been confirmed by a structural neuroimaging study in vivo reporting significantly reduced grey-white matter tissue contrast (GWC) in adult individuals (18–42 years of age) with ASD relative to typically developing (TD) controls. However, it remains unknown whether the neuroanatomical differences in ASD at the grey-white matter boundary are stable across development or are age-dependent.MethodsHere, we examined differences in the neurodevelopmental trajectories of GWC in a cross-sectional sample of 77 male ASD individuals and 76 typically developing (TD) controls across childhood and early adulthood (from 7 to 25 years).ResultsUsing nested model comparisons, we first established that the developmental trajectory of GWC is complex in many regions across the cortex and includes linear and non-linear effects of age. Second, while ASD individuals have significantly reduced GWC overall, these differences are age-dependent and are most prominent during childhood (< 15 years).ConclusionsTaken together, our findings suggest that differences in GWC in ASD are unlikely to reflect atypical grey matter cytoarchitecture alone, but may also represent other aspects of the cortical architecture such as age-dependent variability in myelin integrity.Electronic supplementary materialThe online version of this article (10.1186/s13229-018-0232-6) contains supplementary material, which is available to authorized users.

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Section: Introductionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The effect of age on vertex-based measures of the grey-white matter tissue contrast in autism spectrum disorder

et al. 2018

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“…Furthermore, FreeSurfer has been shown to provide a sub-voxel precision (i.e., scan-rescan reproducibility) of 120 µm in its cortical thickness measurements derived from standard 1×1×1 mm 3 voxels {Han et al , 2006}. Given that the exact anatomical boundary between gray matter and white matter is partially indistinct {Hutsler & Avino, 2012} and that it has been shown to become blurry and ambiguous in some cortical regions during healthy aging {Salat et al , 2009}, the exact definition for the gray-white boundary is somewhat subjective. However, because cortical thickness is typically used as a tool to track or detect changes in gray matter either longitudinally (in studies of brain atrophy or plasticity) or cross-sectionally across groups (in studies of neurodegeneration or development for example), the exact definition of the cortical boundaries may not be as relevant as the precision with which the thickness is measured.…”

Section: Discussionmentioning

confidence: 99%

Quantitative comparison of cortical surface reconstructions from MP2RAGE and multi-echo MPRAGE data at 3 and 7T

et al. 2014

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The Magnetization-Prepared 2 Rapid Acquisition Gradient Echo (MP2RAGE) method achieves spatially uniform contrast across the entire brain between gray matter and surrounding white matter tissue and cerebrospinal fluid by rapidly acquiring data at two points during an inversion recovery, and then combining the two volumes so as to cancel out sources of intensity and contrast bias, making it useful for neuroimaging studies at ultrahigh field strengths (≥ 7 T). To quantify the effectiveness of the MP2RAGE method for quantitative morphometric neuroimaging, we performed tissue segmentation and cerebral cortical surface reconstruction of the MP2RAGE data and compared the results with those generated from conventional Multi-Echo MPRAGE (MEMPRAGE) data across a group of healthy subjects. To do so, we developed a preprocessing scheme for the MP2RAGE image data to allow for automatic cortical segmentation and surface reconstruction using FreeSurfer and analysis methods to compare positioning of the surface meshes. Using image volumes with 1 mm isotropic voxels we found a scan-rescan reproducibility of cortical thickness estimates to be 0.15 mm (or 6%) for the MEMPRAGE data and a slightly lower reproducibility of 0.19 mm (or 8%) for the MP2RAGE data. We also found that the thickness estimates were systematically smaller in the MP2RAGE data, and that both the interior and exterior cortical boundaries estimated from the MP2RAGE data were consistently positioned within the corresponding boundaries estimated from the MEMPRAGE data. Therefore several measureable differences exist in the appearance of cortical gray matter and its effect on automatic segmentation methods that must be considered when choosing an acquisition or segmentation method for studies requiring cortical surface reconstructions. We propose potential extensions to the MP2RAGE method that may help to reduce or eliminate these discrepancies.

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“…We decided on pursuing a postmortem study, rather than neuroimaging, in order to optimize the resolution of the gray-white matter transition zone. Previous studies suggest that using neuroimaging to measure cortical thickness may provide for inaccurate results due to blurring of the transition zone by an increased number of neurons within the subcortical white matter [10,11,14]. Embedding in celloidin was selected so as to minimize tissue shrinkage.…”

Section: Introductionmentioning

confidence: 99%

Focal cortical dysplasias in autism spectrum disorders

Casanova

El-Baz

Kamat

et al. 2013

acta neuropathol commun

127

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BackgroundPrevious reports indicate the presence of histological abnormalities in the brains of individuals with autism spectrum disorders (ASD) suggestive of a dysplastic process. In this study we identified areas of abnormal cortical thinning within the cerebral cortex of ASD individuals and examined the same for neuronal morphometric abnormalities by using computerized image analysis.ResultsThe study analyzed celloidin-embedded and Nissl-stained serial full coronal brain sections of 7 autistic (ADI-R diagnosed) and 7 age/sex-matched neurotypicals. Sections were scanned and manually segmented before implementing an algorithm using Laplace’s equation to measure cortical width. Identified areas were then subjected to analysis for neuronal morphometry. Results of our study indicate the presence within our ASD population of circumscribed foci of diminished cortical width that varied among affected individuals both in terms of location and overall size with the frontal lobes being particularly involved. Spatial statistic indicated a reduction in size of neurons within affected areas. Granulometry confirmed the presence of smaller pyramidal cells and suggested a concomitant reduction in the total number of interneurons.ConclusionsThe neuropathology is consistent with a diagnosis of focal cortical dysplasia (FCD). Results from the medical literature (e.g., heterotopias) and our own study suggest that the genesis of this cortical malformation seemingly resides in the heterochronic divisions of periventricular germinal cells. The end result is that during corticogenesis radially migrating neuroblasts (future pyramidal cells) are desynchronized in their development from those that follow a tangential route (interneurons). The possible presence of a pathological mechanism in common among different conditions expressing an autism-like phenotype argue in favor of considering ASD a “sequence” rather than a syndrome. Focal cortical dysplasias in ASD may serve to explain the high prevalence of seizures and sensory abnormalities in this patient population.

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Sigmoid fits to locate and characterize cortical boundaries in human cerebral cortex

Cited by 7 publications

References 17 publications

The effect of age on vertex-based measures of the grey-white matter tissue contrast in autism spectrum disorder

The effect of age on vertex-based measures of the grey-white matter tissue contrast in autism spectrum disorder

Quantitative comparison of cortical surface reconstructions from MP2RAGE and multi-echo MPRAGE data at 3 and 7T

Focal cortical dysplasias in autism spectrum disorders

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