Our research has focused on how chemicals in the environment or workplace contribute to nervous system disorders. Metals such as mercury and lead and solvents such as toluene and styrene are examples of environmental contaminants that target the nervous system. Exposures to these chemicals may contribute to learning impairment, attention deficit hyperactivity disorder, or sleep disturbances. Millions of American children have been exposed to lead in sufficient amounts to warrant investigation. Lead-related deficits in learning have been demonstrated by computerized tests of children who were clinically normal. Using an animal model of lead-induced behavioral disorder, we investigate the cellular basis of these effects and potential therapeutic drugs. In the graph below, rats were recorded as becoming hyperactive (habituation) at low levels of Pb in blood resembling those of concern in children but without apparent signs of toxicity (weight). The behavioral disorder is accompanied by an increase in the astrocyte marker protein (GFAP) in the hippocampus, suggesting that lead aroused the brain's defense against intruding chemicals. The chelating drug DMSA reversed both the behavioral and the neurochemical aspects of the lead-induced neurotoxicity and thus offers hope for clinical therapy of such disorders.