A theory of how brain function is integrated is presented comprising the following features:-
1) The method of handling distributed information in holography is examined in order to see if something comparable occurs in the brain. It is concluded that this is so.
2) Memory is seen to reside in diffuse patterns of neurons and synapses, some with increased and some with reduced excitability. These patterns become written in by a Hebbian process.
3) The comparison with holography shows that this would provide a distributive associative memory.
4) It is noted that in certain primary sense areas, such as the primary visual cortex, information is stored in "Topographic Form". At a higher level this information is represented in "Distributed Form" as a result of a "Scrambling network". One of the main functions of the brain is as a "Topographic Form Analyzer" which can convert scrambled information into topographic form.
5) A reciprocal network exists between levels and this feeds information back to the primary cortex. Over time, as a result of multiple oscillatory circuits and Hebbian rules, this network gradually changes and ultimately forms an unscrambling network which is able to unscramble the information, restoring it to topographic form. Then the information fed back is the association formed by the impact of the ascending signal upon the associative memory.
6) The feedback system is stabilized by a considerable amount of negative feedback. There is also positive feedback in many places.
7) The positive feedback results in the formation of many oscillatory loops which are able to reverberate for about 300 milliseconds, corresponding to the timing of an individual conscious thought. Oscillations are in the range of 40 - 50 Hz. They last for about 0.3 seconds or so, corresponding with the rate of passage of individual thoughts.
8) As a result of habituation in the synapses, after a short time the loop gain falls below unity and the oscillation stops. New oscillatory loops form somewhere else and the flow of thought goes on.
9) The unscrambling network performs the same function as does the wavefront reconstruction in holography.
10) The principal ideas embodied in the above have been presented previously in a communication to Nature by me - Feb. 1968 Vol 217 No. 5130 pp.781-782 under Chopping P. T. "Holographic Model of Temporal Recall", supplemented and expanded by me in seminars in Sept 1969 at Stanford Medical Center, Harvard and MIT. (Unpublished communications.)
11) The present communication is an expansion of the above, dealing with the way in which the unscrambling network is formed spontaneously by a learning process and going on from this, how the conscious mind might be related to electromagnetic fields set up by currents in these oscillatory loops.
12) The possibility of consciousness being related either to microwaves or to electromagnetic induction is reviewed. The effect of the saltatory (Leaping) of electric charge in medullated nerves between the nodes of Ranvier does result in a net current along the nerve. These currents cause alternating magnetic fields due to currents flowing in feed back loops modulated at a frequency of about 40Hz. These in turn produce induced currents in any nervous tissue within the range of a few centimeters. This has the same effect as an actual physical connection to all of the cells and synapses of any adjacent part of a neural net, essentially connecting up cells which do not connect directly. This phenomenon must be taken into account whenever one is looking at the CNS as a neural net. We have here the equivalent of lateral connections. This may play a part in the integrating function required to bring together the diverse modes involved in such modalities as color, form, and position, which are found in separate locations in the visual pathways.
13) Electrical synapses may play an important part in the flow of current in feedback loops.
14) The nature of mind is explored on the basis that it must be explained within the framework of physical law. It is concluded that if the mind is able to control the body, then mind has to exert a force on molecules. The only feasible forces which could do this are electromagnetic. The basis of mind are therefore electromagnetic. The weirdness of some aspects of the quantum theory are examined and it is argued that these properties, relating to electromagnetic fields and to wave functions, are probably the key to understanding the basis of consciousness. Consciousness is undoubtedly an emergent property of magnetic field and it is related to the non locality and uncertainty inherent in quantum theory.
15) Some ways of testing the theory are explored.
16) We have several separate areas of consciousness within our brains rather than the unconscious mind of Sigmund Freud.