Supernumerary neurons within the cerebral cortical subplate in autism spectrum disorders.

Autism spectrum disorders (ASDs) involve alterations to cortical connectivity that manifest as reduced coordinated activity between cortical regions. The neurons of the cortical subplate are a major contributor to establishing thalamocortical, corticothalamic and corticocortical long-range connections and only a subset of this cell population survives into adulthood. Previous reports of an indistinct gray-white matter boundary in subjects with ASD suggest that the adjacent subplate may also show organizational abnormalities.

Neuron numbers increase in the human amygdala from birth to adulthood, but not in autism.

Remarkably little is known about the postnatal cellular development of the human amygdala. It plays a central role in mediating emotional behavior and has an unusually protracted development well into adulthood, increasing in size by 40% from youth to adulthood. Variation from this typical neurodevelopmental trajectory could have profound implications on normal emotional development.

In Vivo Evidence of Reduced Integrity of the Gray-White Matter Boundary in Autism Spectrum Disorder.

Atypical cortical organization and reduced integrity of the gray-white matter boundary have been reported by postmortem studies in individuals with autism spectrum disorder (ASD). However, there are no in vivo studies that examine these particular features of cortical organization in ASD. Hence, we used structural magnetic resonance imaging to examine differences in tissue contrast between gray and white matter in 98 adults with ASD and 98 typically developing controls, to test the hypothesis that individuals with ASD have significantly reduced tissue contrast.

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

Quantitative evaluation of neuropathology within the cortex often requires a significant investigator time commitment. Here we elaborate on a method of quantifying the distinctiveness of the gray-white matter boundary using function fitting methods (Avino and Hutsler, 2010) and demonstrate that it can also be adapted to reliably identify the location of the gray matter/white matter (GM-WM) boundary in microscopic images, even when that boundary is indistinct. Multiple images of the gray-white matter boundary were acquired from sixteen subjects.

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

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.