Brain Differences and Autism: The Limbic System
The Autism Research Institute published the findings of Dr. Stephen Eldeson PH.D, Dr. Margaret Bauman, (Dept. of Neurology, Harvard Medical School), and Dr. Thomas Kemper, (Depts. of Neurology, Anatomy, and Pathology, Boston University School of Medicine) regarding the structural differences of an autistic person's limbic system.
The amygdala which is generally associated with the regulation of emotions, aggression and is linked to responding to sensory stimuli is smaller in an autistic person. When this is removed from an animal they will avoid eye contact and their fight or flight response is more triggered. A removed amygdala in an animal forces them to be aggressive and the inference drawn from this is that a smaller amygdala could be why some autistic people have aggressive episodes.
The hippocampus, which is also smaller in an autistic brain, controls much of a person’s ability to respond to stimuli. When it is removed from an animal self-stimulatory behavior is more prevalent, and therefore being smaller in an autistic brain could be the reason why we see similar behavior in people with autism.