Different forms of post-training memory processing.

Memories are not acquired in their definitive form, but can be considerably modified in the period that follows after acquisition, both quali- and quantitatively. This may happen either by a process of consolidation or strengthening of each memory trace or by the incorporation of further information to each experience. This further information may be provided by the action of drugs, including that of endogenous substances released by each training experience, and by the addition of information provided by other tasks or events. Evidence in favor of the existence of these various post-training processes, and of their importance for memory formation, is discussed. All of these processes are time dependent, all may depend on stimulus aftereffects, each is differently affected by drugs given in the post-training period, and all may interact with each other.