Reviews studies that have used protein synthesis inhibitors to test the hypothesis that memory in part depends on brain protein synthesis. Evidence from learning curves, examination of short-term retention, and posttraining drug injection indicate that initial acquisition is not dependent on such synthesis, but it appears that protein synthesis, during or shortly after training, is an essential step in the formation of long-term memory. Possible side effects of protein synthesis inhibitors are considered in terms of locomotor activity, abnormal cerebral electrical activity, conditioned aversion, and catecholamine biosynthesis. Stages of memory formation are discussed, and the possibility that kindling, drug tolerance, and enzyme induction are dependent on protein synthesis is considered.(8 p ref)(PsycINFO Database Record (c) 2016 APA, all rights reserved)