Autism spectrum disorder (ASD) afflicts one in 50-150 children. Despite this striking statistic, we still do not understand the chemical changes present in ASD brains nor do we have effective treatments for the core symptoms of this disorder. Several studies have shown increased inflammatory markers in blood and in postmortem brain of ASD patients, providing a strong rationale for increased inflammatory processes in ASD. However, a single study investigated brain inflammation (neuroinflammation) in living ASD subjects, but unfortunately used an old -generation dye (radioligand) known for its low specificity. Using positron emission tomography (PET) scans, this project will examine the role of brain inflammation in ASD in comparison with healthy individuals using a second generation radioligand in a high resolution PET camera. By examining neuroinflammation in persons living with ASD, this project will help in understanding the chemical changes that manifest in ASD brains. This evidence of neuroinflamation in persons with ASD may help in developing new classes of anti-inflammatory therapies for ASD. Therefore, our study findings have the potential to provide novel and specific targets for ASD treatment.