The brain stores image files in a "distributed" manner which is resistant to local damage and allows for correct retrieval even when variable cues or addresses are presented. One explanation is that memory, learning and real time cognitive functions are represented in the brain by interference patterns which are the convergence of two or more wave trains: signal and reference information sources (Hudspeth and Jones, 1975). Interference patterns can be dynamic, expressive, ordered or chaotic; one example is the ocean surf as an interface and monitor of the collective effects of wind, current, beach, tides, water bonds, etc. Interference patterns are used in information and imaging technologies such as interferometry, coherent processing, autocorrelation filtering, pattern recognition and many others whose capabilities are limited by their coupling medium (Dolgoff, 1975). All space in the universe is, as 17th century German philosopher Leibniz said, "the result of harmonious coexistence of forces." Consciousness as well may be described as the dynamic coexistence of forces within the brain, although the harmony may vary over time.

A method of recording and reconstructing wavefronts associated with interference patterns is call "holography," a technology whose mechanism has inspired numerous speculations of "holographic" brain function and consciousness. Holography is a method of information storage employing coherent beams of electromagnetic radiation. It was invented in the late 1940's by Denis Gabor (1948) who won the Nobel prize, and achieved technical importance with the arrival of the laser as a convenient source of coherent light in the 1950's. A hologram is a permanent record of the pattern of interference between two sources of coherent light (or any coherent waveforms) in localized regions of space, usually a photographic film plate. Subsequent reference waves unlock the patterns from storage. The record of both the original interfering waves are stored and the relevant information used as an address to retrieve patterns. Each portion of the hologram contains information about each part of both original interfering waves. Consequently reillumination of any small fragment of a hologram will recreate the entire image stored there, losing only focus or clarity. Holograms thus store image files in a "distributed" manner, much like the brain is thought to function, and are also "fractal," in that small portions are scaled down versions of the whole. By exposing a hologram to time varying sets of interfering waves, it can function as a distributed memory. These properties led to a flurry of holographic brain models (Westlake, 1970; Longuet-Higgins, 1968; Pribram, 1971). Among these, van Heerdon (1968) discussed methods of optical information storage in solids using coherent light. Van Heerdon pointed out that such systems can store large amounts of information although they require a calibrating system to maintain exact phase relations between waves. Requirements for well tuned filters or coherent resonators to maintain phase relations between patterns in the spatial domain remain a major question regarding holographic models of brain function and memory. Consequently the biological existence of holograms has been questioned, based on the assumption that the coherence and phase relation would have to be provided at the cellular or neural level. However, nanoscale coherence may have the required spatial and temporal periodicity to generate cytoplasmic holograms. Photo-refractive crystals can produce dynamic, real time holography (Gower, 1985). Conformational dynamics of the cytoskeleton could tune and generate coherent standing waves and interference patterns of calcium gradient fields, sol-gel states, and structure of the cytoskeletal microtrabecular lattice (Chapters 6 and 8). Dynamic and deterministic intracellular patterns would be useful in biological activities of all sorts. Holographic models of consciousness including a cytoskeletal approach will be described further in later chapters.

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