The amygdala is a brain structure involved in the processing of emotions, such as interpreting facial expressions or feeling afraid when exposed to a threat.
The study included 408 infants, 270 of whom were at a higher likelihood of ASD because they had an older sibling with ASD, 109 typically developing infants, and 29 infants with Fragile X syndrome, an inherited form of developmental and intellectual disability.
Researchers conducted MRI scans of the children at 6, 12, and 24 months of age. They found that the 58 infants who went on to develop ASD had a normal-sized amygdala at 6 months, but an enlarged amygdala at 12 months and 24 months.
The infants with Fragile X syndrome had a distinct pattern of brain growth. They had no differences in amygdala growth but enlargement of another brain structure, the caudate, which was linked to increased repetitive behaviors.
The study findings are published in the American Journal of Psychiatry.
Researchers suggest that the difficulty in processing sensory information during infancy may stress the amygdala, leading to its overgrowth.
Source: Medindia
