Researchers at the Mayo Clinic in collaboration with the National Center for Toxicological Research (NCTR) are conducting a population-based study of long-term cognitive development in a large cohort of Rochester, MN children. The study compares performance of children with no anesthetic exposure to those with single or multiple exposures prior to age three years on an extensive battery of neurocognitive tests including the operant test battery (OTB). Researchers at NCTR and Arkansas Children’s Hospital are using the OTB to evaluate cognitive performance in both children and non-human primates.