Engram

Engram, a trace left in organic matter (e.g., in nervous tissue) by excitation caused in it through the effect of a specific stimulus. According to the teaching of Semon, to whom this term belongs, the formation of engrams lies at the basis of all phenomena of the so-called mneme, to which Semon even attributes the hereditary transmission of traits. At present, this term is used only by some psychologists to denote processes of imprinting in memory and the formation of habits. The process of engram formation, according to Semon, is characterized, on one hand, by a change in the structure of the tissue receiving the impression, and on the other hand, by dynamism, i.e., the preservation in this tissue of a state, albeit significantly weakened excitation, which is an echo of that which was caused by the original stimulus. Once formed, the engram is stored as long as the structure of the corresponding tissue (brain) remains undamaged, which explains the sometimes observed revival of seemingly long-forgotten memories. The fact that not all engrams and not under all circumstances are susceptible to forgetting (see), representatives of associationist psychology (e.g. Bleuler) explain not so much by the fading or blurring of the engrams themselves, as by the difficulty of finding associative paths leading to them. For criticism of Semon's theory, see Semon's teaching and Memory.