| dc.description.abstract | Lead has long been known as a neurotoxicant and, in recent years, has been shown to have behavioral effects at concentrations much lower than the safety levels set by the government. Behavioral toxicology is a sensitive method using behavioral measures to determine the effects of toxins and toxicants at these low level concentrations. Through these methods, one of the effects that has been observed is that neonatal exposure to lead increases resistance to extinction(Taylor et al., 1982). This could be due to changes in brain anatomy or to neurochemical disturbances. For example, lesions of the hippocampus can cause an inability to inhibit responses whereas disturbances in gamma-amino butyric acid (an inhibitory neurotransmitter) activity can cause an increase in emotionality. The objectives of this study were to determine if this effect of increased resistance to extinction occurs in adults exposed to lead and, if so, to determine the causal factors implicated in this effect. To obtain this information, rats were run in a straight alley maze after exposure to inorganic lead; the reinforcement schedules were manipulated in order to elucidate the causal factors involved. Overall, it was determined that there was a marginally significant effect of the lead exposure of resistance to extinction and the data suggest that anatomical changes are responsible. | en |
