Autism

Question 1

Genetics/Heritability

Answer 1

• Highly heritable but also multifactorial
• Pleitropy: mutation w/ different phenotypes
  
  • overlapping/shared genetic underpinnings b/t many neurodevelopmental disorders
• ASD-associated genetic syndromes (most have low penetrance – not always associated w/ ASD

Question 2

Environmental factors

Answer 2

• epigeneticmodification
• toxic/chemical exposure
• Prenatal exposures:
  
  • thalidomide, valproic acid, maternal rubella infection

Question 3

Social Communication Difficulties

Answer 3

• Defects in social-emotional reciprocity
  
  • lack of social sharing, abnormal social appraoch, failure of normal back and forth conversation, reduced sharing of interests, failure to initiate or respond to social intx
• Defects in non-verbal communication
  
  • gestures, expressions, eye-contact
  • poor integration b/t verbal & non-verbal cues
• defects in developing, understanding and maintaining relationships

Question 4

Social motivation model

Answer 4

• diminished social interest
  
  • early onset impairments deprive child of adequate social learning experiences (i.e. development of autism)
  • would rather look at geometric shapes (not faces)
• interaction between social motivation, social perception, and social cognition –> intervene between social cognition/motivation
• Focus on reward centers/mechanisms
• this model doesn’t apply to everyone on the spectrum

Question 5

Neurobiological findings

Answer 5

• ** underconnectivity in the brain
• less activity in
  
  • reward systems
  • fusiform gyrus – the area responsible for recognizing faces (seen clinically too)
  • amygdala – social arousal
  • superior temporal sulcus – facial expression perception
  • superior frontal gyrus – “theory of mind”
• larger brain
  
  • temporal and frontal regions enlarged
  • deficits in neural pruning
    
    • overactive mTOR pathway –> blocks autophagy