The mystery of autism is one step closer to being solved, thanks to a meticulous study conducted by researchers in Washington and California. The research team discovered that autism begins in the womb. It is still unclear if the disorder is caused solely by fetal neurological development or if environmental and / or genetic factors trigger the development of symptoms.

Eric Courchesne, Director of the Autism Center of Excellence at the University of California, San Diego, worked with researchers at the Allen Institute for Brain Science in Seattle to examine the brain tissue of autistic children. Only a few studies of autism involve brain tissue; most others rely on imaging technology such as magnetic resonance imaging (MRI).

The joint research team analyzed more than 12,000 slides of brain tissue taken from 22 children between 2 and 15 years of age. Eleven of the children had been diagnosed with autism spectrum disorder (ASD) before they died while the remaining 11, the control group, were never diagnosed with ASD.

Rich Stoner, lead author of the study, created a three-dimensional model of the brain that pinpointed the locations where cellular evidence of autism was found.

The evidence revealed a disruption of cellular development in most of the brains of the autistic children. These undeveloped neurological cells were randomly scattered throughout regions of the brain that govern communication, learning and social skills, all of which are affected by autism.

Courchesne says the wide range of undeveloped neurological cells may explain why symptoms and severity of autism vary so much. He says the cellular disruptions happen during the second and third trimesters, when fetal brain development is in full swing.

During the second trimester, fetal brain development escalates and becomes complex. The cortex splits into six layers formed by brain cells unique to each layer. Assembly patterns, cell connections, and networks required for information processing begin to take shape.

The undeveloped cells of the autistic children occurred in disorganized patches in the brain cortex. These randomly dispersed patches were present in the brain tissue of 10 of the 11 autistic children but only in one of the control groups.

Dan Smith hails the news, saying, "It helps make the case that we need to start earlier to understand causative factors." Smith, Senior Director of Discovery Neuroscience at the New York-based advocacy group, Autism Speaks, expects the study to lead to expanded understanding of biological markers that can detect the disorder before behavioral changes begin.

Courchesne says that even though his study involves more slides than any previous study, future exploration is needed to discover the factors that cause the brain cell disruptions.

Source: Courchesne, Eric, PhD, et al. "Patches of Disorganization in the Neocortex of Children with Autism." The New England Journal of Medicine. Massachusetts Medical Society. Mar 27, 2014. Web. Apr 3, 2014.