Physiological mechanisms
underlying the basic functions of the central nervous system

Biochemical Theory of Memory

Posted: November 29th, 2009 | Filed under: Memory | Tags: , , , , , , | No Comments »

All existing theories on the memory fall into two categories. The first is the biochemical theory of memory, which suggests that the information in the brain is coded on molecules of ribonucieic acid (RNA), or on some other macromolecules. The first argument in favour of this theory is that biochemical coding allows practically unlimited amounts of information to be retained. The second argument, which is even more forcible, is that this method of storing information dates back to the very first moments of life and that Nature still employs it for handing on information from one generation to the next.

By this is meant the so-called genetic information, a set of very rigid rules and demands that defines what every individual belonging to a given species is to be like. This not only governs the appearance of an animal and the specific functions of its internal organs, but also determines the pattern of its behaviour. No one teaches ant lions how to build traps, lie in wait and catch their prey; no one shows the spider how to spin its web; the female cabbage white butterfly tells automatically males of its own species from other admirers. This innate knowledge with which the animal is endowed is as permanent as other features of its organism. It was not without reason that Wagner, a Russian zoologist, suggested classifying spiders according to their behaviour rather than tb their morphology, which is perhaps more sensible since some species are very similar in their appearance.

The pattern of behaviour in higher animals and even in man is partly inherited. Nobody teaches a newborn baby to suck; it is an innate reaction of its organism. There seem to be very many reactions of this sort, though relatively little is known about them.

Scientists were recently very surprised to find that newly hatched chicks, even those hatched from eggs laid by a hen which has never seen a bird of prey, can easily tell a predatory bird from a harmless one. When the newborn chicks were shown a moving silhouette of a flying kite (a small head drawn into the shoulders, large widely spread wings, a long, thin body and a tail), they were panic-stricken. If the silhouette was moved in the opposite direction, it looked like a duck or goose on the wing (the tail became a head on a long neck stretched forward, and the small head, a short tail), the chicks were now no longer afraid of it.

This means that the image of a predatory bird is imprinted on the mind of a tiny chick, and this information is inherited from its parents with the help of a biochemical code. If the inherited image is coded biochemically, why should an image resulting from actual experience not be coded in the same way? We have noted repeatedly that Nature seldom neglects good finds. Why should it act differently this time?