Engram

The Television & Movie Wiki: for TV, celebrities, and movies.

(Redirected from Engrams)

An Engram is defined as: A physical alteration thought to occur in living neural tissue in response to stimuli, posited as an explanation for memory [1]. The root of the word comes from the Greek word for seed. The existence of engrams is posited by some scientific theories to explain the persistence of memory and how memories are stored by the brain while Dianetics uses a slightly different meaning, but both use engram as an aspect of memory.

Contents

Overview

The term engram was coined by Richard Semon and explored by Anton Pavlov. Karl S. Lashley an American behaviorist well-remembered for his influential contributions to the study of learning and memory tried to locate the engram. His failure to find a single biological locus of memory (or "engram", as he called it) suggested to him that memories were not localized to one part of the brain, but were widely distributed throughout the cortex.

Lashley argued for distributed representations as a result of his failure to find anything like a localized engram in years of lesion experiments (src: Early work, Connectionism).

Later researcher, Richard F. Thompson, sought the engram of memory in the cerebellum instead of the cerebral cortex.

Thompson and his colleagues used classical conditioning of the eyelid response in rabbits in their search for an engram. They puffed air upon the cornea of the eye and paired it with a tone. This airpuff normally causes an automatic blinking response. After a number of trials they conditioned the rabbits to blink when they heard the tone even though the airpuff was no longer administered. During the experiment, they monitored several brain cells to try to locate the engram.

One brain region that they monitored that they thought was a possible part of the memory engram was the lateral interpositus nucleus (LIP), when chemically deactivated, it resulted in the rabbits, who were previously conditioned to blink when hearing the tone, to act as if the conditioning never took place; however, when they re-activated the LIP, they responded to the tone again with an eyeblink. This gives evidence that the LIP is a key element of the engram for this behavioral response. (James W. Kalat, Biological Psychology p.391-393)

It is important to stress that this approach targeting the cerebellum, though relatively successful, only examines basic, automatic responses. Almost all animals have these (especially as defense mechanisms) and it is fairly difficult to resist them. Imagine trying to avoid blinking when someone shoots something at your eye. Ideally, research by Thompson and others could eventually lead to isolation of more complicated engrams that control more abstract, declarative memories, like how one remembers one's name or the capital of France.

The problem here is that considerable studies have shown declarative memories tend to move about the brain between the limbic system (deep within the brain) and the outer coritcal areas. This contrasts with the more "primitive" set-up of the cerebellum, which controls the blinking response and receives direct input of auditory information. Thus, it does not need to reach out to other brain structures for assistance in forming simpler memories of association.

Dianetic's use of engram

Dianetics is a practice and trademark of the Church of Scientology. Dianetics too defines engram as a memory but does not address whether a physical change has happened or not. Instead dianetics is concerned with memory being available for a person's recall and use, or being less available for a person's recall and use. Dianetic theory defines engram as a memory a person has which is not fully available. Moments of experience which had physical pain in them, or which had an emotional pain are called engrams. A goal of Dianetics is to convert engrams into consiously available memory, the idea being that some energy is tied up in painful memories which make a person less free.

Pseudoscientific use of the term engram

Other concepts of engram have arisen, such as NLP (Derks and Hollander 1998;Derks and Goldblatt 1985;Sinclair 1992;Drenth 2003) and EST, which also use the term in relation to the subconscious, extraordinary claims, past lives therapy, and unlimited human potential.

References

  • Derks, L. & Goldblatt, R.,(1985) The Feedforward Conception of Consciousness: A Bridge between Therapeutic Practice and Experimental Psychology The William James Foundation, Amsterdam.
  • Drenth, J.D. (2003) Growing anti-intellectualism in Europe; a menace to science Studia Psychologica, 2003, 45, 5-13

Further reading

Forgotten Ideas, Neglected Pioneers: Richard Semon and the Story of Memory, Daniel Schacter, 2001de:Engramm

Personal tools