Application of PET and SPECT to the study of autism spectrum disorders

Abstract

Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental disorders involving defi cits in social communication and stereotyped behaviors. It has been estimated that over 100 genes may be involved in the risk for autism, many of them involving brain synaptic transmission or brain development and growth. Neuroimaging studies with PET and SPECT have been used to assess metabolic and blood fl ow changes, as well as proteinc synthesis in the brain associated with ASD. In addition, PET and SPECT have been used to target a number of neurotransmitter systems, including serotonin, dopamine, GABA, and acetylcholine. These studies have employed tracers that are neurotransmitter precursors and ligands for receptors and transporters. These studies have provided clues about how differences in development of these systems play a role in altered brain function in ASD and provide information leading to new intervention approaches.