The possibilities of neural holographic processes within the brain.

A theory of brain functioning is proposed based upon an analogy to optical holographic processes. There are many properties which holography potentially offers to neurophysiology. Chief among these is the property of distributedness, which is displayed only by holographic processes. This property, an attribute of certain types of holograms, permits any small portion of the hologram to reconstruct the entire original scene recorded by the hologram. Because of this fact and other supporting evidence, neural versions of the holographic processes appear as most promising candidates for the coding of sensory and memory processes. It is demonstrated that mathematical models based on known elementary neurophysiological processes can embrace “neural-holographic processes”. This is done in terms of equations from optical holography which are discretized in space and time and are suitably transformed to account for the substitution of neural-pulse waveforms in the place of the sinusoidal oscillations involved in optical holography. The possible or probable differences between optical and neural holographic processes are then examined in detail. The various types of holographic processes are considered as to their suitability as paradigms for the neural processes. Fourier-transform holography appears to be the most suitable type for initial neural holographic models. An exploration of the possible correspondences or isomorphisms between the state space of the holographic process and the plausible state spaces of the neural coding process has been initiated. The most probable pairing at the level of the hologram appears to be: first, the correspondence of the electromagnetic oscillation phase with the neural interspike interval; and second, the correspondence of amplitude with neural impulse height. If necessary, the impulse height at the neural hologram could be restricted to binary values of pulse-no pulse, still permitting a coding of the complete intensity scale of “grays” present in the reconstructed image of the original stimulus object. There is neurophysiological evidence indicating the possibility that the impulse height present in the stimulus object plane could be coded in terms of the impulse coherence-incoherence dimension, which would fit nicely into neural-holographic processes. Additional holographic properties are detailed and examined. When this is done collectively, it is concluded that: This hypothesis is discussed in terms of previously-formulated wave interference theories of brain functioning. It is pointed out that the holographic point of view is basic to a complete discussion of any waveinterference theory. Some psychophysical and neurophysiological evidence for this hypothesis is examined. The principal evidence for such a hypothesis comes from: 0) recordings of single cell activity from Area 17 of the monkey; 1) animal brain lesion work (this work presents some of the evidence that visual and auditory processes are “distributed” in at least one stage of the processing); 2) examination of brain-damaged human beings (it is pointed out that neural-holographic processes offer possible explanations formacular sparing andpolyopia); 3) general evidence for coherent pulse activity; and 4) some evidence of neural connectivity which would be suitable for neural holographic processes. Further approaches to experimental verification are suggested.