This research investigated the effects of different doses of lithium on rats' behavior in an attempt to understand lithium's therapeutic mechanism of action in major affective disorders. / Although high doses (1.50 mEq/kg LiCl) decreased rats' open field activity, low doses (0.15 mEq/kg LiCl) increased activity, which is a new finding. A study of the effects of these two doses on reaction to environmental complexity and novelty suggested that, irrespective of dose, lithium increases readiness to engage in inspective exploration of a novel environment and promotes longer inspective exploration of a known complex environment. This was interpreted as increased selective attention to stimuli providing relevant information about the environment. The prediction derived from these findings, that both doses would decrease distractability, was supported in an experiment on tone-induced suppression of licking. / A two factor (activity, selective attention) model of lithium's action was proposed and its relevance to lithium's clinical efficacy in major affective disorders was discussed.

No description available.