Memory consolidation and reconsolidation in the rat pup require protein synthesis.

Little is known about the ontogenesis of memory, whether it appears with its full characteristics or whether they emerge progressively with development. In the adult, basic characteristics of memory processing are consolidation of memory after acquisition and reconsolidation after retrieval. Here, using a conditioned aversion paradigm and postlearning or postreactivation injection of a protein synthesis inhibitor, we show that memory acquired by rat pups as early as postnatal day 3 requires time-dependent protein synthesis after both learning and reactivation. These results present the first evidence suggesting that consolidation and reconsolidation are original properties of memory function.