Abstract

The study of the brain mechanisms of mnemonic traces has recently been given substantial impetus by the development of various advanced techniques that can be used in humans and animals. The message of such studies is that the mnemonic traces or engrams of specific experiences are now being identified. This message, however, misrepresents what has actually been accomplished. None of the studies provides evidence that engrams of specific memories such as fear of shock are identified, exclusive of brain activation patterns corresponding to the operations of encoding or consolidation and/or retrieval. This note is meant to rectify that false impression by placing the otherwise impressive findings in their proper perspective: Thus far only the broad outlines of traces of the mnemonic operations combined with those of sensorimotor tasks in animals have been discerned. While this is a major accomplishment, to view it as equivalent to the discovery of engrams of specific experiences is to indulge in hyperbole that is counterproductive to inquiry and undermines the authority of science in the eyes of the general public.