Recent studies have suggested that an alteration in neurons that secrete serotonin in the brainstem could be linked to Sudden Infant Death Syndrome (SIDS), a common cause of death in infants between the ages of a few months to a year.  It is believed that infants that die of SIDS succumb to environmental stressors such as hyperthermia and/or low oxygen (hypoxic) stress. To determine the role of brainstem serotonin in the thermoregulatory response to stress I followed an ongoing project this summer that involved microinjection of drugs that alter normal neurotransmission into brainstem areas that are rich in serotonin while measuring thermoregulatory responses to hypoxic stress. The eventual goal of this project is to help determine which brainstem areas and neurotransmitters are responsible for protective responses to hypoxic stress and thereby help determine the etiology of SIDS.