by Paul Pietsch
During the early and middle phases of his career, Penfield was a staunch advocate of the anatomical point of view. In some of his last written words, he related how he had spent his left trying "to prove that brain accounts for the mind." But he had seen too many paradoxes over the years.
Take, for example, a patch of cerebral cortex you're probably using this very moment as your eyes scan this page. The patch is the size of a postage stamp, on the rear of your frontal lobe, about where a Viking's horn emerges from the side of his helmet. It's in a place called area 8 alpha, beta, gamma; or, alternatively, the frontal eye fields; or just plain area 8 for short. Penfield explored area 8 with electrodes and found that it is indeed associated with voluntary eye movements. What do you suppose happens if area 8 is cut out? The person may lose the ability to move his or her eyes, willfully, toward the opposite side of the head (smooth, involuntary eye movements are handled by the occipital lobes). But the voluntary eye movements usually return a few days after surgery. And sometimes the function doesn't disappear at all.
Memory is even more puzzling. Penfield could often elicit vivid recollections of scenes from his patient's distant past by stimulating the temporal lobe. Had Penfield tapped the seat of long-term memory? Removal of the area frequently had no demonstrable effect on the person's memory.
For Penfield, the discrepancies eventually became overwhelming. Shortly before he died, he came to the conclusion that "our being consists of two fundamental elements."[10] For him, those elements had become "brain and mind" (my italics). Even the most faithful of the faithful have had trouble with mind-brain.
***
Holism does not rest its case on the structuralist's dubious dialectical position, but on prima facie evidence from some of the finest research ever conducted in psychology or biology--thirty furious years of exhaustive, imaginative, and carefully controlled laboratory investigations by Karl Lashley, the founder of the entire field of physiological psychology.
Lashley investigated memory in a wide variety of species, ranging from cockroaches to chimpanzees. But his favorite subject was the rat. His basic experiment was to train an animal to run a maze. Then he would injure the animal's brain at a particular location and in a specific amount. Finally, he would retest the animal's ability to run the maze postoperatively, comparing its performance with that of control rats whose skulls had been opened but whose brains hadn't been injured.
Lashley found that destruction of 20 percent or more of a rat's cerebrum could dim its memory of the maze. And increasing the damage would proportionately decrease the animal's recall. But (and this is the single biggest "but" in the history of brain research!), the critical thing was not where he made the wound but how much of the area he destroyed. Lashley got the same results by destroying the same percentages of different lobes. Anticipating hologramic theory, he even analogized memory to interference patterns.[11] He had borrowed the name of his cardinal principle--equipotentiality--from the embryologist Hans Driesch The term, which I'll expand on shortly, means that engrams, or memory traces, are distributed all over the region.
From chemistry, Lashley borrowed the principle of mass action[12 ]to explain how increased brain damage dulled performance. The less engram the brain had to work with, the dumber the animal seemed.
Equipotentiality and mass action became Lashley trademarks. He and his students and followers produced, reconfirmed, and extended their evidence. More recently, the physiologist, E. Roy John, has developed an extensive new line of evidence to support the principle equipotential distribution of memory.
John and his colleagues, working with cats, perfected electrophysiological methods to monitor the learning brain. Electrical activities in the animal's brain assume the form of waves on the recording device. As an animal learns to distinguish flickering lights of different frequencies, the waves begin to change form; and after the animal has learned, the harmonic features of the waves assume distinctive characteristics, which John and his colleagues take to signify memory. And these same waves--and presumably the memory underlying the animal's reaction--show up throughout widely dispersed regions of the brain.[13]
There is always some extraneous "noise" associated with electronic waves--"blips" that are independent of the main waves. Information theorists call the main waves the signal, and an important aspect of electronic communications is the signal-to-noise ratio. John and his group have found that although the main waves are the same all over the brain, signal-to-noise ratio varies. John believes that variations in signal-to-noise ratio account for specific functions of different regions of the brain and explain why, for example, the occipital lobe works in vision and the temporal lobe works in hearing.
How might a structuralist explain John's research One way is to argue that he really did not tap stored memory but instead tapped communications from long-term to short-term compartments. Another is to assume that the alleged noise is really the memory, and that the signals represent some nonspecific nerve-cell activity. I'm not faulting John's work here, incidentally, but merely giving examples of structuralist explanations of his findings.
***
Lashley did not resolve the mind-brain conundrum. His work sharpened its intensity, extended its dimensions, and made a whole generation of psychologists afraid even to think of behavior along physiological lines.
As I mentioned before, Lashley took the term (and the concept of) equipotentiality from Hans Driesch. Driesch espoused equipotentiality because dissociated two- and four-celled frog and salamander embryos don't form half or fractions of animals but whole frogs or salamanders. Driesch's research led him to embrace entelechy, the doctrine of vitalism, or the belief that the first principles of life cannot be found in nonliving matter.
Driesch was a man of the nineteenth century. By the time Lashley came along, biology had fallen madly in love with chemistry and physics, and with the belief that life obeys the laws of Nature generally. Lashley had a thorough background in microbiology and chemistry. True to a twentieth-century scientist's view of things, he resisted vitalism and sought to explain his findings by physical and chemical examples. Yet to me, structuralist and materialist that I was, Lashley's principles seemed like dissembling--a cover-up job! I believed that he engaged in a limp form of metaphysics, disguised to sound like science but lacking the practicing metaphysician's depth and scope. Until my shufflebrain research, I thought Lashley had concocted his doctrines as a verbal means of escape from the powerful vitalistic implications of his position. Lashley's ideas seemed like substations on the way to pure vitalism. The best thing to do was ignore him, which is what I did until hologramic theory emerged.
***
As we shall see later on, though, the hologram cannot be strictly equated with equipotentiality. As I said in the first chapter, the hologram concerns that property of waves called phase. Phase makes for equipotentiality (when it is a feature of a hologram at all), not the other way around.
As a general theory, derived from the generic phase principle, hologramic theory does not make champions of the holists and chumps of the structuralists. Instead, hologramic theory breaks the mind-brain conundrum by showing that one need not choose between holism and structuralism. Hologramic theory will supply us with the missing idea--the thought that Hegel would have said allows thesis and antithesis to become synthesis.
But before we take our first glimpse at hologramic theory, let us consider holograms as such.
<---Try a little private quiz here, Doc!
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chapter three
Holograms
"It's spooky over there," one of my students said, gesturing with a thumb toward the big room across the hall from our neuroanatomy laboratory. The next student to return mumbled something about
The Exorcist
, which was a hit movie at the time. His lab partner came back next, made a quip about touching the thing but then went
mute. I had volunteered my class for an experiment in educational systems technology. But as my students kept returning, house-of-horrors look on their faces, I began wondering if I might have exposed them to a hidden danger. Then it was my turn to go.
The windowless room would have been infinitely black, except for a bright emerald rod of laser light twenty feet from where the door shut out the world behind me. "Come this way," beckoned one of the experimenters. Taking my arm like an usher at a seance, he led me to a stool opposite the laser gun. "Don't look directly into the beam," his partner warned, unnecessarily. The usher slipped a photographic plate into a frame in the beam's path. Instantly, a dissected human brain appeared in the space before me.
It was one of my own specimens, from my class demonstration collection. I'd made the dissection with great care the previous year and had loaned it to the experimenters a few weeks before. But I knew for certain that this specimen was now across the hallway, safely stored in a pickle jar and locked in a cabinet whose only key was in my pants pocket. Yet as an optical phenomenon the specimen was right here in the room with the three of us.
I had known what would be in the room. At least I'd thought I knew. I understood the technical side of what was happening, as did my students. Yet I found myself wondering, as they must have, just what "real" really means. Visually, I could make no distinction between what I was seeing and the actual object. I looked down into a complexly shadowed recess of the specimen where I'd dissected away the forward part of the temporal lobe and had pared back the cerebrum to expose the optic tract and LGB; and I saw features not even the best stereoscopic photographs can capture. When I shifted my gaze to the right, structures I hadn't seen over on the left came instantly into view. When I stood and looked down, I could see the top of the specimen. As I backed off, more structures filled my visual field, and their individual details became less distinct. As I moved in close, fewer structures occupied my field of view, but those that were there I saw much more clearly. Moving still closer, I made out gridlike indentations gauze had pressed into the soft cerebral cortex before the brain had been transferred to formaldehyde and had hardened. And I suddenly became aware that, from habit, I was holding my breath, anticipating a whiff of strong formaldehyde fumes. Finally, even though the scientist in me knew better, I was compelled to reach out and try to touch the brain, to convince myself the object wasn't there.
My students and I weren't hallucinating, observing trick photography, experiencing illusions, or skirting the edges of the occult. In the strictest technical sense we had been looking at the actual brain, even though it wasn't there. We had witnessed the decoding of an optical hologram.
***
How does a forest or a stained- glass window communicate a visible presence? How do objects let us see them? How do they impress their features onto light?
Physical theory tells us that light, emitted and absorbed as photons-- as particles--travels as waves, waves of mass-energy. Light is mass-energy in extreme motion (if Einstein was right). Except for the fleeting instant when mass-energy becomes light, or ceases to be light, it is waves. Objects change waves; they warp them. The warp is the optical message, and its specific character depends first of all on what the waves were like just before they illuminated the scene, and, second, on the nature of the objects. If the object indiscriminately absorbs waves of energy, as for example a patch of tar does, its image will appear to us to be dark, because very little light radiates away from it and into the optical environment. If the object has little capacity to absorb energy, as is the case with the fur of an albino mink, say, then light will be warped by contours and edges, but the image will appear white in white light, blue in blue light, red in red light, and so forth. If the object absorbs particular colors or wavelengths, it will subtract those energies from a mixture and will reflect or transmit the rest. White light, which is a mixture of the colors of the rainbow, contains the waves for an infinite variety of hues. The primary colors red, green, and blue, can combine to form the 500,000 or more hues a human eye can discriminate.[1] In addition, objects distort the waves relative to the sharpness, smoothness, or complexity of their contours. But the totality of the optical message travels in the form of a warp.
In all electromagnetic radiation, including light, the shorter the wavelength the greater the energy. Offhand, this may seem wrong. But think of the pleats of an accordion. Compressing the bellows, thereby forcing the pleats together, concentrates the train of wavelets and increases their number per inch. In electromagnetic radiation, likewise, the shorter the wavelength, the greater the frequency , or number of wavelets per second. Also, as wavelength decreases, the amplitude of each wavelet increases: the peaks become taller, the troughs deeper. You might say that compressed waves become more "ample." Physicists define amplitude as the maximum rise of the wave's crest from the horizontal surface, from the midpoint between peak and trough. The intensity of light is proportional to the amplitude, or the crest height.
According to Einstein, mass-energy has reached the maximum attainable velocity when it assumes the form of light. Conversely, when mass-energy hasn't reached that maximum speed, it isn't light. Energy is more concentrated in blue light than in, say, red light. Since the mass-energy can't move any faster or slower, and since something must accommodate the difference, blue light waves compress closer together than red ones; and, compared to red waves, blue waves exhibit greater amplitude and frequencies, and shorter wavelengths.
But not all waves move at the speed of light. Water waves certainly don't, nor do sound waves. Unlike light, the amplitude and frequency of these waves are independent of each other. This is why for example, a high-pitched squeak may be of very low amplitude, and a deep, rumbling, low-frequency bass sound may be intense enough to knock you out of your seat.
But one thing is true about any wave: put amplitude together with phase and you completely define the wave. As mathematical physicist Edgar Kraut has written, "A complete knowledge of the amplitude and phase spectra of a function [the mathematical essentials of an equation] determines the function completely."[2] Kraut uses the term spectra because phase and amplitude define not only simple waves but complex ones as well. We'll see later in the book that complex waves are made up of simple, regular waves.
What is wave phase? The formal definition of the term describes it as that part of a cycle a wave has passed through at any given instant. Engineers and physicists use the term cycle almost interchangeably with wavelet . This is because the points on a simple, regular wavelet relate directly to the circumference of a circle, or a cycle. For example, if what is known as a sine wavelet has reached its amplitude, it has passed the equivalence of ninety degrees on the circle.
----->
....
Phase also implies knowledge of the wave's point of origin, as well as every point through which the wave has passed up to the moment of observation. And the future course of a simple regular wave can be predicted when we know what phase it is in, just as we can predict how much of a circle remains the instant we reach, say, 180 degrees. Amplitude represents the bulk mass of a wave, whereas phase defines just where or when that mass will be doing what, in space or time. Phase instantly manifests to the observer the way a wave has changed since its origin, and how it will continue to change, unless outside forces intervene.
Phase, as I have said, is a sizeless entity -- sizeless in the sense that we can't measure it with a yardstick or weigh it on a scale. We speak of phase in terms of angles or their equivalents, or in terms of time. And to create an angle, or to specify it, we need more than a single entity. Phase demands a reference, something to compare it with. Because phase is relative, we cannot treat it, or even conceptualize it, as an absolute.
We can appreciate both the nature of phase and the problems in dealing with it by looking at the face of a clock. The revolutions of the hands around the dial describe the phase of the hour of the AM or PM. The hands move at different rates and exh
ibit different phases. Yet the phase difference--the relative phase--converts the seemingly abstract, invisible, untouchable, ever-beginning, never-ending dimension, time, into our time--people time! Five-thirty is the phase of the morning when we must crawl out of the sleeping bag and milk the goat. Four-fifteen is the phase of the afternoon when children will be getting off the school bus expecting warm cookies and cold orange juice. Phase on the clock has the same theoretical meaning as it does on a wavy surface. Thus relative wave phase is a part of our everyday lives.
***
In an optical hologram, such as the one my students and I experienced, the encoded message exists in a special kind of shadow, the interference pattern--alternating zones of light and dark. The densities of the shadows depend on the intensity of the light, and carry the information about amplitude. How rapidly the shadows change from light to dark depends on relative phase, and thus carries the phase code. As I mentioned earlier, objects warp light; they warp amplitude and phase. The warp, in turn, creates the shadows. In fact, the shadows are transformations of the wave's phase and amplitude warps to a kind of mathematical warp in the photographic plate. When the correct decoding beam passes through those shadows, the shadows warp beam's waves. The shadows force into the decoding beam the very phase and amplitude changes that created them in the first place. And when the decoding beam forms an image, it is, by every physical standard, completely regenerating the scene as an optical phenomenon, even though the objects may be gone.
What about photographs? They, and all conventional pictures, capture intensities of light from a scene. Photographs encode information about amplitude but not phase.
***
Optical holograms encode for amplitude as well as for phase variations in the scene. The basic reason for this has to do with the nature of light, with the waves' attainment of maximum speed. But other kinds of waves also make holograms. An acoustical holographer, Alexander Metherell, some years ago had a hunch that phase was really the generic essence of the hologram. Of course we can't have phase all by itself, except in the abstract, which Metherell , of course knew. But he wondered if he might assume just one amplitude--create a constant background din--and then encode the message strictly with phase variations. It worked. And Metherell went on the demonstrate his point with the phase-only holograms I referred to earlier.