"Animal experiments": In experiments with rats, early, short-term low-dose exposure to chlorpyrifos resulted in lasting neurological changes, with larger effects on emotional processing and cognition than on motor skills. Such rats exhibited behaviors consistent with depression and reduced anxiety. In rats, low-level exposure during development has its greatest neurotoxic effects during the period in which sex differences in the brain develop. Exposure leads to reductions or reversals of normal gender differences. Exposure to low levels of chlorpyrifos early in rat life or as adults also affects metabolism and body weight. These rats show increased body weight as well as changes in liver function and chemical indicators similar to prediabetes, likely associated with changes to the cyclic AMP system. Moreover, experiments with zebra fish showed significant detriments to survivability, reproductive processes, and motor function. Varying doses created a 30%–100% mortality rate of embryos after 90 days. Embryos were shown to have decreased mitosis, resulting in mortality or developmental dysfunctions. In the experiments where embryos did survive, spinal lordosis and lower motor functions were observed. The same study showed that chlorpyrifos had more severe morphological deformities and mortality in embryos than diazinon, another commonly used organophosphate insecticide.