Chemical means of information storage and readout in biological systems

The correlation of genetic " informat ion" with "molecular order" has proved to be one of the most fruitful scientific ideas of the last two decades. The recent success in deciphering the genetic code and tracing the complex phenomena of cellular growth back to molecular reaction mechanisms has led a number of scientists to speculate about similar correlations between a molecular" engram ', and psychic memory. There seems to be some justification for such speculation based on the argument: If nature has invented a way to store and process information in the development of cellular life it may have made further use of this invention in later evolution. Thus, it is quite possible that the neuronal network will utilize at some level this highly developed molecular memory system, rather than using a more primitive molecular "switching" system in connection with a sophisticated electrical network. On the other hand one may also argue that the essence of psychic memory is to be found only on a higher than molecular level, represented by the "circui t ry" rather than a molecular "engram" . An understanding of the molecular mechanism of" switching" in this circuitry might then contribute to an understanding of the whole working mechanism as little as any theory explaining the nature of elementary particles would contribute to the understanding of the behavior of macromolecules. (It is, of course, necessary to suppose the existence of elementary particles and their interactions in order to explain the existence of atoms, molecules and their further interactions). This analogy may show that it is not meaningful to ask the question: Are molecular or chemical processes at all important for the understanding of psychic memory? But rather: At which level do such processes come in? And more specifically: Does psychic memory utilize the principles developed in cellular genetics and immunology in a further improved manner, or was there a splitting off at a lower level (i.e. utilizing simpler physical phenomena as it is usually the case in man-made machines possessing some resemblance to intelligent behavior) ? To answer this question certainly requires much more knowledge than we have at the present time. However, it may be worthwhile to start to analyze the situation on the basis of our present knowledge of enzymes, molecular genetics, immunology etc. Accordingly, we chose for discussion at our G6ttingen Work Session these principal subjects. Since an exhaustive discussion of any of these subjects would require much more time than is available, it was important that discussion contributions be directed towards the central problem, i.e. the mechanism of chemical processes of information storage, transfer and readout. In a pre-discussion of these problems 1 it was found that the use of terms such as memory, learning etc., with their definitions given in psychology, which usually imply abilities characteristic of the human brain, may 1earl to considerable difficulties when applied to processes on the molecular level. Since, of course, it was not intended that the entire meeting be spent on the very time consuming process of working out a suitable scheme of definitions, we therefore circulated the following proposals with the hope that they would facilitate a bet ter understanding in the discussion and save time for the t reatment of real problems. Let us start with these definitions before going into a more detailed discussion of the different subjects.