Summary: A new study identifies specific brain network hotspots associated with autism, aggression and other social behavioral problems. The results revealed that those with ASD who scored lower on face processing tests were more likely to have more severe symptoms of autism, particularly social behavioral problems. Researchers report that treatments like TRMS may offer some hope for those on the autism spectrum.
Source: Children’s Hospital Boston
What if doctors could break down conditions like autism into their core symptoms, map these symptoms to “hotspots” in the brain, and then treat those areas directly with brain stimulation? If it turns out, such an approach could turn the care of neurological and developmental disorders on its head, focusing on symptoms shared across multiple conditions.
It is Dr. View by Alexander Lee Cohen, a child neurologist and researcher who leads the Translational Neuroimaging Laboratory and is part of the Autism Spectrum Center at Boston Children’s. “What we’ve seen is that different parts of human behavior map to different brain networks,” he says.
Face blindness: A window into understanding autism
Dr. Cohen began by studying a common problem in autism: face blindness, or the inability to recognize faces—even the faces of loved ones. Studying people with autism spectrum disorder, he found that those who scored poorly on tests of face processing had more severe symptoms, particularly social impairment. Can understanding face blindness provide clues to understanding autism?
To answer this question, he first studied people who developed face blindness after a stroke. By analyzing MRIs of their brains, he found that many had damage to an area known as the fusiform face area. Others had no direct damage there, but damage to the part of the brain that connects to that area, as shown by a technique called lesion network mapping.
“It may take an entire brain network to cause a symptom,” explains Dr. Cohen.
Tuberous sclerosis, fusiform face area and autism
To begin connecting the dots with autism, he next studied patients with tuberous sclerosis. In this rare genetic condition, abnormal growths called tubers occur in the brain and other organs. Forty percent of affected children develop autism.
“I was interested in understanding whether the pattern of tubers in the brain affected the likelihood of developing autism,” said Dr. Cohen.
Indeed it did. In an analysis of 115 young children with tuberous sclerosis, he found that those with fusiform facial tubercles were 3.7 times more likely to develop autism. The research is published in the journal History of Neurology.
Dr. Cohen now wants to see if children with autism who do not have tuberous sclerosis have abnormalities in the brain network associated with this area. To that end, he and his colleagues began recruiting 15- to 18-year-old teenagers to compare their brain MRIs with and without autism. The team is assessing each participant for face processing ability, social impairment and severity of autism symptoms to see how these correlate with brain imaging results.
Brain stimulation for autism?
Can differences in face processing cause autism, or result from autism? That’s another question Dr. Cohen hopes to answer. He suspects that people with autism may rely too heavily on a specific brain network to process faces, perhaps focusing on smaller details than the face as a whole.
“It’s something that kids with autism can have a lot of difficulty with,” he says.
If face blindness can be treated in children with autism, will their social functioning also improve? “Now that we’re starting to look directly at autism, we’ll see what we can figure out.”
Dr. Cohen envisions noninvasive treatments such as transcranial magnetic stimulation (TMS), in which a small electromagnet induces currents on the surface of the brain, in targeted areas. TMS has been found to be safe and approved for the treatment of depression and obsessive compulsive disorder in adults. Boston Children’s researchers are currently testing it in some children with epilepsy that cannot be effectively treated with drugs or surgery.
Addressing agitation and aggression in autism and beyond
Ultimately, Dr. Cohen wants to identify brain hotspots and networks that drive different autism symptoms and behaviors, not just face processing. At the top of her list are aggression and agitation, which can create difficult situations for children with autism and their families. Currently, they are often treated with drugs for psychosis, which have significant side effects and do not always work.
Dr. Cohen hopes a new study will help change that. He and his colleagues are tapping brain mapping data from various groups at risk for aggressive behavior, including people with autism, people who have had strokes and people with other types of brain injuries, looking for aggression “hotspots.” ” So far, they have collected data from more than 1,200 children and adults.
“You can sort people by the most versus the least aggressive and ask, ‘What’s different in the brain?'” explains Dr. Cohen.
“We can try to find out what people who are aggressive have in common and see if there’s something we can turn into a treatment target. If we can nip some of these symptoms in the bud early, we may be able to help the brain go down a different path.”
About this autism research news
Author: Nancy Fleisler
Source: Children’s Hospital Boston
Contact: Nancy Fleisler – Children’s Hospital Boston
Image: Images are credited History of Neurology/ Researchers
Original Research: Access to all.
“Tuberculosis affecting the fusiform face area is associated with a diagnosis of autismBy Alexander Lee Cohen et al. History of Neurology
abstract
Tuberculosis affecting the fusiform face area is associated with a diagnosis of autism
purpose
Tuberous sclerosis complex (TSC) is associated with focal brain “tubercles” and a high incidence of autism spectrum disorder (ASD). Brain stem location associated with autism may provide insight into the neuroanatomical substrate of ASD symptoms.
method
We described tuber locations for 115 TSC participants with ASD (n = 31) and without ASD (n = 84) from the Tuberous Sclerosis Complex Autism Center of Excellence Research Network. We tested for associations between ASD diagnosis and cortical burden in the whole brain, specific lobes, and 8 regions of interest derived from the ASD neuroimaging literature, including anterior cingulate, orbitofrontal and posterior parietal cortices, inferior frontal and fusiform gyri, superior temporal. sulcus, amygdala and supplementary motor area. Next, we performed an unbiased data-driven voxelwise lesion symptom mapping (VLSM) analysis. Finally, we calculated the risk of ASD associated with a positive outcome from the above analyses.
result
There were no significant ASD-related differences in mean tubers across the whole brain, within specific lobes, or within a priority region derived from the ASD literature. However, using VLSM analysis, we found that tubers involving the right fusiform face area (FFA) were associated with a 3.7-fold increased risk of developing ASD.
explanation
Although TSC is a rare cause of ASD, there is a strong correlation between tuberous involvement in correct FFA and ASD diagnosis. This highlights a potential causal mechanism for the development of autism in TSC that may guide research on ASD symptoms more generally. ANN NEUROL 2023; 93:577–590
