An experiment conducted on over 200 individuals with autism and published in the American Journal of Psychiatry did not reveal any abnormal functional connectivity in the amygdala, an area of the brain that is essential for detecting emotions, fear, and danger.
Autism, also known as a neurological condition, is a type of neurodevelopmental disorder that results in difficulties with social interaction, communication, and repetitive behaviors. The severity and incidence of autism varies greatly, leading to problems interpreting social and relationship cues. Additionally, individuals with autism often struggle to understand changes in routine, particularly changes in their social habits.
However, much remains to be discovered about the causes and neural basis of autism: one of the mainstays of research is that brain regions of individuals with autism display marked changes with functional connectivity (although one theory suggests that this phenomenon may not be universal) and that autistic people also have abnormal features such as amygdala structure; recently there have also been some theories that indicate that structural brain abnormalities may be partly or entirely dependent on either of these hypotheses, although these are often conflicting in numbers.
Dorit Kleiman and her colleagues aimed to investigate the functional correlation of different brain regions using functional magnetic resonance imaging (fMRI). They used fMRI to investigate the association of different brain regions during various cognitive and behavioral tasks.
Using data from the Autism Brain Imaging Data Exchange (ABIDE), a publicly available dataset of neuroimaging data that includes data for both autistic people and people in the non-autistic category, this study included data from 488 people aged 16 to 50, of whom 212 were autistic.
The results were consistent, but did not reveal any signs of decreased functional connectivity in individuals with autism. Analytical techniques identified some regions with slightly decreased functional connectivity, but these results varied from person to person and did not match any specific analytical method.
In addition, there was no sign of abnormal connectivity in Amy Woolfoul (often an autistic person) among the people studied for each type of neurodegeneration (i.e., autism spectrum disorder): Differences in functional connectivity in autistic people were found to be no greater than those seen in neurotypical participants, as reported in two studies of autism and neurodegeneration.
The study found no significant differences in amygdala functional connectivity between neurotypical and autistic participants.
The authors concluded that the findings regarding amygdala FC in ASD do not support the first hypothesis, as they were pre-registered analyses. To improve the chances of finding reliable evidence for amygdala FC in autism, the study authors suggested that future studies should investigate hypotheses from multiple processing pathways, collect more data per individual, and consider more diverse data sources.
The study strengthens scientific understanding of the neural basis of autism. Nevertheless, the analysis was based on resting-state functional connectivity data, meaning it only analyzed brain activity during the resting state, not participation in specific tasks.
This implies that the brains of both autistic and non-autistic individuals may behave differently when engaged in specific activities, which highlights the differences. Dorit Kleinman, Paola Galdi, Avery L.
Van de Water, Brandon Egger, Dorota Jarecka, Ralph Adolphs, and Satrajit S. Ghosh wrote the paper, “Resting-state functional connectivity of the amygdala in autism: a pre-registered large-scale study.” The paper was accompanied by Ghosh’s observations of the test subjects and summarized the findings.