The Effect of Lithium on Motivation and Learning in the Rat

Abstract

Recent research has suggested that lithium (Li) may increase cholinergic activity with a resulting increase in cholinergically mediated behavior. Li toxicity, however, poses serious methodolgical problems for researchers in this area. In Experiment I, daily i.p. injections of 1.4 mEq/kg LiCl were found to cause only minor motivational changes as indicated by a computer system which continuously monitored activity, eating, and drinking. Using this dosage in Experiment II, Li and control animals were taught to run in a radial arm maze for a food reward in two learning tasks, spatial and cue. Results indicated that while there were no significant learning differences between the Li and control groups, running times were increased for the Li animals. Although the Li administered animals did not demonstrate the expected facilitation in learning, the careful quantification of Li induced behavioral changes should prove of value in future research.