Development of Prosocial Behaviors and Related Brain Network in Infants of High and Low Risk of ASD

Inclusion Criteria:

• Subjects were enrolled as high-risk if they had an older sibling with a clinicaldiagnosis of ASD confirmed on the Autism Diagnostic Observation Schedule, secondedition (ADOS-2) or Autism Diagnostic Interview (ADI-R).

• Subjects were enrolled in the low-risk group if they had an older sibling withoutevidence of ASD and no family history of a first or second-degree relative with ASD.

Exclusion Criteria:

1. diagnosis or physical signs strongly suggestive of a genetic condition or syndrome (e.g., fragile X syndrome) reported to be associated with ASDs;

2. a significant medical or neurological condition affecting growth, development orcognition (e.g., CNS infection, seizure disorder, congenital heart disease);

3. sensory impairment such as vision or hearing loss;

4. low birth weight (<2000 grams) or prematurity (<37 weeks gestation);

5. possible perinatal brain injury from exposure to in-utero exogenous compoundsreported to likely affect the brain adversely in at least some individuals (e.g.,alcohol, selected prescription medications);

6. contraindication for MRI (e.g., metal implants);

7. a family history of intellectual disability, psychosis, schizophrenia or bipolardisorder in a first-degree relative.