Amygdala dysfunction

• Amygdala


  • 13 nuclei, 1 on each side
  • Highly networked
  • Connection to hypothalamus, prefrontal cortex and other
• Amygdala


  Powerful influence on behaviour, motivation, emotion and social interaction
• In ASD, the amygdala is 6-9% bigger and increases with age, but no difference by adulthood
• The unusual patterns of development in the amygdala may result in abnormalities in neural organisation and damage its function
• Because of the connections of the amygdala

  Abnormalities in its development are a major cause of the main social and behavioural deficits found in ASD
• Deficits in social perception, behaviour and processing social information in ASD

  Linked to abnormalities in the amygdala
• People with ASD have difficulty understanding emotional expression in others
• Study on emotional expression in ASD

  • ASD matched with control, eye test, fMRI used colour to indicate activity
  • ASD performed worse, left amygdala not activated, it was in the control
• Inferring emotional states is impaired in ASD
• Women with lost function in both amygdala due to rare genetic disorder

  • Preference for personal space with 1/2 the control, 'perfectly comfortable' distance for her, rated 'uncomfortable' by control
• Some studies show increase volume of the amygdala in ASD and others decreased, the precise role is unclear
• Oversimplifying the role of the amygdala alone cannot account for the social behaviours in ASD
• There is no reliable evidence that the amygdala is more dysfunctional than other brain structures in ASD, it is likely a more complex issue involving several structures