Perinatal inflammation of the brain can lead to neurodegenerative changes especially in the amygdala and hippocampus that are essential for emotions and memory. In addition, amygdala sense fear and regulate responsive behaviors. Focal inflammation in the amygdala and hippocampus could disrupt neuronal connectivity and lock the brain into a perpetual fight or flight mode. S
uch inflammation could develop as a result of activation of mast cells, typically associated with allergic reactions, but also present in the brain where they can be triggered by neuropeptides, stress and toxins leading to breach of the blood-brain-barrier (BBB) and activation of microglia. Microglia “prune” nerve connections (synapses) during development.
When activated, however, microglia disrupt neuronal connectivity, lower the fear threshold and derail emotions as seen in autism spectrum disorder (ASD). In fact, many large epidemiological studies have reported a strong association between ASD and asthma or atopic dermatitis (eczema), both of which involve activated mast cells.