ABNORMALITIES OF THE GYRAL WINDOW IN AUTISM: A MACROSCOPIC CORRELATE TO A PUTATIVE MINICOLUMNOPATHY

Abstract

Autism is a neurodevelopmental disorder characterized by impairments in social interaction, language, and range of interests. Recent studies suggest that the brains of autistic patients have an increased number of minicolumns. This finding helps explain the presence of macroencephaly or increased brain size in a significant proportion of autistic patients. Changes in brain size and gyrification are usually concurrent. In this study we have implemented an algorithm that measured the gyrification window in the brains of 23 postmortem autistic and 16 postmortem control brains. At the 85% confidence level the algorithm correctly classified 22/23 autistics, a 0.96 accuracy rate, and 15/16 controls, a 0.94 accuracy rate. Previous structural neuroimaging studies in autism have emphasized volumetric measures. These methodologies are very sensitive to segmentation artifacts, being compromised by image noise, lack of strong edges, and sharing of color/texture among different structures. The present study offers a new approach to the classification of autism based on structural MRI.The finding bears relevance to the clinical presentation of autism as increased gyrification reduces the gyral window and constrains connectivity in favor of short corticocortical fibers.

Keywords

• Autism
• magnetic resonance imaging (MRI)
• neocortex
• minicolumns