Researchers from the University of North Carolina at Chapel Hill are the first to demonstrate overgrowth of the amygdala in the first year of an infant's life. They showed that this is commonly found in babies who later develop autism even before infants display most behavioral symptoms that later prove the diagnosis.
The team said that this overgrowth of the amygdala may be only seen in those with autism spectrum disorder since babies with Fragile X syndrome have different brain growth patterns.
Autism Spectrum Disorder: What Does Overgrowth of Amygdala During the First Year of Infant's Life Mean?
Increased Growth of Amygdala in Infants An Early Sign of Autism
The amygdala is a complex structure of cells in the limbic system that plays an important part in how animals or humans assess and respond to threats in their environment, according to Simply Psychology. Its main job is to regulate emotions, such as fear and aggression, and is also associated with putting meaning to memories and reward processing and decision making.
Previous experiments in which the amygdala is stimulated electrically showed animals displaying aggressive behavior. Also, it is thought to play a crucial role in the difficulties of social behavior that is commonly seen in autism.
Children with autism have an enlarged amygdala but scientists do not precisely know when the enlargement occurs. For the first time, using magnetic resonance imaging (MRI), scientists at the Infant Barin Imaging Study (IBIS) Network demonstrated that the amygdala grows rapidly during infancy.
PR Newswise reported that the accelerated growth begins between 6 and 12 months of age. Out of the 408 infants they tested, 270 were at higher risk of developing ASD, while 29 infants have the inherited developmental and intellectual disability called Fragile X syndrome, and 109 are typically developing infants.
They found that 58 infants went on to develop ASD. These were the babies who had normal-sized amygdala at 6 months but slowly enlarged at 12 and 24 months when behavioral symptoms of autism may be observable. On the other hand, infants with Fragile X syndrome had no differences in amygdala growth but had an enlarged caudate linked to increased repetitive behaviors.
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Pre-Symptomatic Intervention is Advised on Babies With Large Amygdala
Scientists are starting to fit the puzzles of when and how the overgrowth of the amygdala could affect the development of autism. According to the news release of UNC-Chapel Hill, earlier studies of the IBIS tea showed that infants who develop autism have problems with visual and sensory information.
So, the team hypothesizes that these problems may place significant stress on the amygdala that might cause its overgrowth linked to chronic stress, depression, and anxiety. They believe that this provides a clue to understanding this observation in infants who later n develop autism.
Dr. Joseph Piven, a Professor of Psychiatry and Pediatrics at UNC-Chapel Hill and the senior author of the study, said that the findings suggest the best time to start interventions and give children who are likely to develop autism the support needed may be the first year of life. He emphasized the importance of focusing on pre-symptomatic intervention to improve visual and sensory processing before other symptoms start to appear.
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