By Paul Pietsch
| BRAIN SWAPPING1 By Paul Pietsch | |
Adapted from Science Digest, February 1982
But the mind perpetually defies its would- be cartographers. Throughout history, the battle-ax, shrapnel, tumors, infections, even the deliberate stroke of the surgeon's knife have paralyzed, blinded, deafened, muted and numbed human beings via the brain, without necessarily destroying cognition, erasing memory or breaking the mind into pieces. Karl Lashley, the father of physiological psychology, began searching in the 1920s for the site of memory storage. He ran rats with specifically injured brains through complex mazes. Predictably, injury dulled performance, and an animal's errors correlated well with the extent of its wounds. Yet the location of the damage did not affect maze skill. And even massive brain- cell destruction failed to expunge the memory totally. It was as if we had torn this page to bits and still found the faded, but nevertheless whole, message on each of the scraps....
In the 1960s, two engineers named Emmett Leith and Juris Upatnieks developed a non-living memory system, based on light, that exhibits many startling properties of human memory. Building on the discoveries of the father of holography, the late Dennis Gabor, they produced the diffuse- light hologram. Holograms are eerie, lifelike, three-dimensional pictures. Smash the holographic plate (the negative) and every piece is capable of reconstructing the whole scene. Although an image from the tiniest fragments can fade and lose detail, owing to the small amount of light that passes through the plate, the image is still whole--whether the piece comes from the middle, bottom or top of the hologram.
Leith and Upatnieks said nothing publicly about minds or brains. But others began to look toward the hologram as a well- understood analog for the poorly understood brain. Psychologists and biologists began to talk about the hologramic mind...
It is easy to understand the public fascination with holograms. As Gabor observed in 1971 when he accepted a Nobel Prize for his work, no optical test can distinguish a real object from its hologramic image. Indeed, when first faced with a hologram of a dissected brain, I held my breath, anticipating the stench of formaldehyde fumes. I tried to touch the specimen to prove to myself that it wasn't really there.
But the hologram is no creature of the supernatural. It is a phenomenon of waves. Everyone is familiar with the ability of properly placed waves to create pictures. Photographic film produces pictures simply by recording the amplitude (i.e., intensity) of the light waves that impinge upon its surfaces. But waves possess another important property, called phase, that photographs can't capture. As proved by the holographer, Alexander Metherell, phase is the essence of all holograms.
Objects can produce a characteristic warp in a wave's amplitude and phase. Warps in light waves relay to the human eye the specificity of the image in transit.
Holography re- creates the relative phase variations once carried by a wave and hence can re- create an image precisely as one originally perceived it. Hologramic plates distort the incoming laser waves in the same way that the original object warped the light waves.
Every piece of a hologram--and by analogy, the mind--can potentially perform the function of the whole because phase is without absolute size. Two breakers at Waikiki can be out of phase to the same degree as two wavelets in your bathtub if, for example, the trough of wave A aligns with the crest of wave B. The relative phase information contained in both situations is the same. In theory, a code of phase may be recorded simultaneously in space as tiny as a quark or as large as the Universe. Clearly, the hologramic model can explain how the small amount of brain left in Lashley's rats could direct full behavior in the maze. But living brains have more than one task to perform and must store a multitude of memories. Could multiple phase codes be incorporated into a single hologramic plate?
Leith and Upatnieks found that multiple holograms could indeed be constructed. The angle between the photographic plate containing the hologram and the laser light source is crucial for projecting holograms; if the angle is not correct, the hologram does not appear. Leith and Upatnieks predicted that they could make multiple holograms by tilting the recording plate to slightly different angles during the construction of each scene. When the plate was completed, they found that rotating their "negative" in the projection beam (hence changing the angles) caused one whole scene to flash off and a different one to flash on. The hologram behaved like a mortal, instantaneously forgetting last night's beer bust and remembering the sales figures for the morning's business meeting.
Some even more impressive hologramic mimicry is possible: suppose we reconstruct a multiple hologram simultaneously with several beams. With the correct angles, we could make the hologram simultaneously project objects that had never existed together in physical reality--your mother projected into a gangster movie, for instance.
There is much more going for the neural hologram than I have outlined. But I must admit that even I didn't believe in it at first. I was convinced that each part of the brain was different, that structure was intimately tied to function, and started my shufflebrain experiments to prove it.
Hologramic theory not only stirred my prejudice, it also seemed highly vulnerable to the very experiments I was planning: shuffling neuroanatomy, reorganizing the brain, scrambling the sets and subsets that I theorized were the carriers of neural programs. I fully expected to retire hologramic theory to the boneyard of meaningless ideas.
I should have awaited Nature's answers. For hologramic theory was to survive every trial, and my own theory went down to utter defeat.
In a hologram, the carrier of meaning-- phase--exists independently of any location and cannot be reached with an eraser or a knife. The hologramic code ought to survive any anatomical changes we make. To me, herein was the hologramic theory's most astonishing prediction: shuffling the brain will not scramble the mind! How might we shuffle the brain? The salamander embodies the answer.
Salamanders are amphibians, taxonomically one step up from fishes and a half step down from frogs and toads. They begin life as aquatic creatures, and, a few species excepted, they undergo metamorphosis and become land dwelling animals. As larvae--the equivalents of toad and frog tadpoles, and before metamorphosis--salamanders of the genus I work with range down in size from the proportions of a six- year- old child's index finger.
The larva's brain, textured like lightly polished Carrara marble and narrower than the letters on this page, can slip through the eye of a needle. Nevertheless, the tiny brain has the same major anatomical subdivisions as our own: cerebrum, diencephalon, midbrain, cerebellum, medulla. And within those minuscule neuroanatomical entities, somewhere, lie the programs for a range of complex, if primitive, behaviors.
The salamander's capacity to endure massive injury has fascinated biologists ever since 1768, when Lazzaro Spallanzani published the fact that they regenerate lost appendages. In larvae, a fully functioning replica replaces an amputated leg or tail in a month to six weeks. Other organs and tissues regenerate as well. A severed optic nerve, for example, reestablishes contact with the brain, and the eye can see again. In fact, almost all nerve fibers grow back. Following an incision into the brain, new nerve fibers quickly sprout and soon re-knit a completely functional patch across the rift.
The salamander larva was an excellent candidate for shufflebrain experiments on an additional count. I knew that, after the healing period, messages would relay freely between the spinal cord and the shuffled brain. As a student trying to teach myself the art of transplanting tiny organs, I had assigned myself exercises involving the larval salamander's brain. First, I would make a tunnel in the jelly like connective tissue of the creature's dorsal fin. Then I would amputate the brain and store it in the tunnel. The animal, of course, went into a stupor. After some days, I would return the brain to the cranium. Most animals survived; in 8 to 20 days they recovered consciousness.
My first formal plunge into shufflebrain experiments involved the repetition of Lashley's basic operation. I mapped the brain into regions. Then, in an extensive series of operations, I replaced given map regions with pieces of spinal cord, which prevents brain regeneration, moving down the brain region by region.
The animals invariably fed the moment they recovered from post- operative stupor, no matter which region I removed. Massive destruction of the brain reduced feeding but did not stop it. Clearly, there was no exclusive repository of feeding programs in any single part of the salamander's brain.
My next experiments involved the exchange of brain parts. For example, I switched the diencephalon with the cerebrum. I moved the midbrain up front and either the cerebrum or the diencephalon to the rear. I performed every operation I could think up. But nothing eradicated feeding. Let me describe one series of rather drastic operations in more detail.
I decided to see what effect an extra medulla (a region between the brain and the spinal cord) would have on feeding. The best approach, I thought, would be to take the entire brain of one animal, down to and including its medulla, and fuse it to the medulla of the host. The available space inside my prospective host's cranium, however, wasn't sufficient to accommodate this amount of brain if I used a sibling as a donor. Therefore I decided to use a large tiger salamander larva (Amblystoma tigrinum) as the transplant host, and a little marble salamander larva (Amblystoma opacum) as the donor. The operations went well. A week to 10 days later, all five of the animals in the group were awake and feeding again. And no facet of their behavior even hinted at the bizarre contents of their craniums.
I suspect that most experimentalists suffer, from time to time, from what I call janitor- induced paranoia--the certainty that in the middle of the night the janitor, or someone, has exchanged the labels on test tubes, cages or salamander dishes. I certainly suffered a bad case of the syndrome while observing the behavior of members of the tiger- marble salamander experiments. I repeated the operations and got identical results. But my disbelief simply would not go away. Here was a brain in a foreign head, plugged into the medulla of a different species -- a brain with two medullas, no less. And yet the beast behaved like a normal salamander.
One Sunday morning I finally gave up, pickled some of these animals and dissected their brain cases. There was no question about it. Each had two medullas, one plugged into the other. I could trace the host's optic nerve into the transplanted brain. But I still clung feebly to the hope of impugning hologramic theory by some ingenious anatomical transformation.
Preliminary to shufflebrain experiments, I had conducted a systematic investigation of the salamander larva's medulla. When I destroyed the medulla, the animals became unconscious and died within two weeks. If I left the medulla intact and amputated the brain immediately in front of it, the animals went into permanent stupor but remained alive for many months. So in all shufflebrain experiments, the host animal's medulla had remained in the body.
As a last- ditch working hypothesis, I speculated that the medulla is the seat of the feeding programs. Clearly, I needed another experiment. I had to eliminate feeding memories from the graft but at the same time revive the host so the effect of its medulla could show up. And so I turned my attention to the frog.
The adult leopard frog is a notorious carnivore. Yet as a young tadpole it is a vegetarian. When the tadpole bothers a tubifex at all, it is only to suck algae and fungi from the worm's wriggling flanks.
I called the first member of this series Punky. He had the body of a salamander (Amblystoma punctatum), but the brain in front of his medulla had come into this world in a frog (Rana pipiens). Punky was a combination of tadpole and salamander, a tadamander!
By 17 days after surgery, Punky had fully regained his ability to stand and swim. Within a few days after that, he had become the liveliest animal in my colony. (Tadpoles are more active than salamanders.) He was blind, but his sonar and sense of touch were in splendid working order for feeding. When I dropped a pebble into his bowl, the clink would alert him and bring him swimming over immediately. And so would a tubifex worm.
But the worm was completely safe. Punky would inspect the squirming crimson thread for perhaps a minute or two. Then he would execute a crisp about-face and swim away. And this continued for the next 68 days while I virtually camped at the edge of his dish. A conscious, alert and responsive little fellow he remained throughout. But not once during that time did Punky even hint at an attack, despite the fact that a fresh worm was always available. Worms were now objects of lively curiosity, not of furious assault. If feeding programs were present in Punky's medulla, their presence would have to be accepted on the strength of divine revelation, not experimental fact. My hypothesis failed the pragmatic test of truth: it didn't work.
I had performed an even dozen tadamander operations. No tadamander fed. One morning I arrived at the lab to find all the active tadamanders except Punky displaying signs of transplant rejection. Fortunately, Punky was still healthy. But I doubted he would last long, and I could not risk losing the critical anatomical data to be found inside his cranium.
The first and most obvious question about Punky was whether or not a frog's brain would even connect, anatomically, with a salamander's medulla. To answer this question, I stained slides of Punky's tissues with Bodian's protargol stain, which deposited silver salts on very fine nerve fibers, fibers that otherwise do not show up under a microscope. And the moment these slides were ready, I selected one at random merely to check quality. That very slide had the answer I sought. A cablework of delicate nerve fibers connected the tadpole brain to the salamander medulla. It is irrational, I confess, but I date my belief in hologramic theory from that first look at Punky's brain.
Before I describe another set of experiments, let's do an imaginary experiment. Imagine a deck of cards. Let's begin with a conventional, nonhologramic message, using a single card as a set for storing one letter. The meaning of our message--let's use DOG-- depends on the relationships among our cards: where each card lies in relation to the others when the deck is at rest, or when a card turns up during the deal. If we shuffle the deck, we obviously run the risk of scrambling the meaning of our message; DOG might become GOD.
The hologramic deck of cards is far different. Here each card contains a whole message. And if the same message is on each card, just as the same feeding message is in each part of the salamander's brain, shuffling will not alter the deal.
But according to hologramic theory each card is an independent carrier of our hologramic code. What's to stop us from slipping in cards with new codes? Certainly not the codes per se. Cards are independent. Therefore old and new codes can coexist in the same deck without distorting each other's meanings if hologramic theory really does work. I call this the Independence principle.
The Independence principle predicts that I should be able to transplant new thoughts into the brain. An examination of this prediction of the theory was the next phase of my research....
Just as I was weaning a group of about 50 axolotl salamanders onto beef liver in preparation for a new round of experiments, a then optometry student, Calvin Yates, came around looking for a job. In Calvin's presence, living things thrived. A few days after he took over the job of weaning, the axolotls were snapping like veterans. Calvin also introduced a clever trick into his feeding technique. He would tap the rim of an axolotl's plastic dish and then pause a few seconds before presenting the liver. In a few days, tapping alone would cause the larva to look up in anticipation of the imminent reward.
I paid only the most casual attention to Calvin during that time. For I had learned that my favorite species of salamander, Amblystoma opacum, lived in the area to which I had just moved. Fortunately, I met a man who happened to have 50 eggs he was willing to let go for two dollars. By the time Calvin was weaning the axolotls, the opacum larvae had grown to just the right size for me to put the finishing touches on my shufflebrain project.
One afternoon at the tail end of an operating session, I realized that I had anesthetized one too many opacum larvae. It is against my standard procedures to return such animals to stock. Yet I don't like to waste a creature, make- do budget or not. On impulse, I decided to see how well an axolotl's forebrain would work when attached to an opacum's midbrain. And I took an animal from Calvin's colony to serve as the donor.
The fateful moment came 10 days later.
To check a salamander's reflexes, I flick the edge of its dish. When an animal has recovered from postoperative stupor, it usually jumps in response to the noise. As I placed the opacum larva with the axolotl brain on the stage of the dissecting microscope, I noticed that he had righted himself and was standing on the bottom of the dish. I gave a light flick, expecting him to give a little jump and then swim out of the microscopic field. Instead, he slowly arched his little back and looked directly up into the barrel of the microscope, right into my eyes. My heart missed a beat. I had observed this looking- up reaction in only one other place-- among Calvin's axolotls, where the donor had come from. I jumped up and flicked every dish on the axolotl table. Every axolotl there looked up in response. Next I checked the stock opacum larvae; flicking only caused them to scurry around. Not one looked up.
The trained cerebral donor animals were interesting, too. As soon as the effects of anesthesia wore off, these animals demonstrated that they remembered the signal to look up. In other words, looking- up memories existed in the donated as well as the retained parts of these animals' brains. What was true of innate feeding behavior worked for looking up: memory wasn't confined to a single location in the brain.
Unwittingly, I had discovered that a learned response could be added to the hologramic deck.
I am still unwilling to declare hologramic theory true. Do I believe the theory? Yes, of course, or I wouldn't be writing about it. But belief has an irrational component built in. And if I correctly judge the reader by my own feelings, there's too much [[pi]] in the abstract sky for us to move directly from hologramic theory to a description of mind that will ring true to our intuitions. Let's imagine an experiment.
Let's reach into the distant technological future and invent a new holography. Let's invent a hologram of a play, but one whose reconstructed characters are life-size, full color, warm, moving and endowed with "holophonic" sound.
Now let's enter the theater while the play is in progress with the mission of finding out whether the actors are at work or if they've taken the night off and are letting their holograms carry the show. What test can we use? Suppose we sent a 515- pound gorilla up to the stage. What would live actors do? We could never specifically predict. But there would be a change in their behavior. What about the holographic images? We can accurately predict their responses with a single word: nothing! With the holographer on the job, the show will go on, gorilla or no!
What's the theoretical difference between our live players and their holograms? Both depend upon the same basic abstract principle--relative phase. Yet the informational universe in our physical hologram is like a cake that has already been baked. If we want the gorilla in the scene, we must make up our minds about that during construction--before the abstract dough congeals in the theoretical oven. The hologram's coordinate system has already been defined; it is what the philosopher would call determinate.
Our live players? Their informational universe is still being calculated; it is still fluid. Their coordinates are not yet defined. Our live actors' minds are continuously indeterminate. And it is this indeterminacy that is the principal feature of intelligence!
Should holographers somehow give holograms continuous indeterminacy, it won't make any difference whether we perceive a particular person or a hologram of him or her--except to that person. For then holograms would be as unpredictable as we are. My hunch on this is that it will always make a difference whether we see a person or a holographic reconstruction--but that's pure hunch.#
1Based on excerpts from Shufflebrain by Paul Pietsch, Houghton Mifflin, Boston, 1981; copyright Paul Pietsch,1981; now available through the Books On-Demand program of University Microfilms International (UMI), 300 North Zeeb Road, Ann Arbor, MI 489106, USA, 1-800-521-0600 (cat. number AU00447).
Click to find revised editions of Shufflebrain: The Quest for the Hologramic Mind on the web.
Web contact:pietsch@indiana.edu