November 16, 2022The brains of autistic individuals experience widespread molecular changes across the cerebral cortex. The most differential changes occur in the primary visual cortex, according to a recent study published in Nature that analyzed 11 cortical areas of the brain.1 Most molecular profiling studies highlight changes limited to the frontal and temporal cortex.To further understand the brain pathology of autism spectrum disorder (ASD), researchers performed RNA-sequencing analysis on 112 post-mortem samples.
Consistent transcriptomic signatures of ASD were found across all cortical regions analyzed in the study. The greatest signal of expression came from the primary visual cortex (BA17).When compared to control samples, ASD brains demonstrated significantly reduced gene expression between regions of the cerebral cortex.
The primary visual cortex and parietal cortex (BA39/40), which function as primary sensory regions, exhibited significant patterns of attenuation. These results suggest cortical regions are more molecularly homogeneous in autistic individuals and pronounced in the posterior region of the brain.“It is interesting to speculate that the substantial changes observed in primary sensory regions may relate to the widespread sensory processing differences in ASD, which are so pervasive that they have been included in the DSM-5 diagnostic criteria,” the researchers wrote.An attenuation of transcriptomic regional identity (ARI) translates to a “reduction in the magnitude of gene expression” and was often used as a marker in the current study.
