Shufflebrain

by Paul Pietsch

  When I arrived the next morning, the first thing I did was check out the fasting guppies in the main lab. They went into a frenzy when I held worms above the beaker. When I released the squirming ball, it vanished almost as soon as it hit the surface of the water, as though attacked by a school of piranhas. The control fish kept at 20 degrees were hungry indeed, I noted.

  Next, I went into the cool room to see what had happened there during the night. All the tubifexes in the dishes with Buster and the chilled guppies had survived. Everybody was still lively and healthy, by every criterion I could apply. But Buster and the guppies simply were not taking worms. Again, I checked feeding among the stock and the guppy-heart recipients. They attacked the worms immediately.

  But wait! I wanted more data. Now came a critical test. For the next step was like back checking addition with subtraction. I transferred Buster and the guppies into the main lab, placed them in fresh water--20.4 degrees centigrade--from a carboy there, gave each a fresh worm, set the entire bunch on my desk, recorded the time in my notebook, and then sat down to watch.

  Sixty-one minutes from the time I changed his water, Buster devoured his worm. It took 101 minutes for a guppy to make the first nibble; by 111 minutes, not a worm was left in any of the experimental bowls. Warming the water had revived their chilled appetites.

  But like a crapshooter on a hot streak, I just couldn't stop. I added to the experiment some salamanders with guppy flank muscle transplanted to their abdominal cavities. I added some new guppies. And I transferred the group back to the cool room, where I fasted them for forty-eight hours before adding worms. When testing time came, all the control salamanders ate their worms. But Buster and the guppies did not. I decided to allow the trial to run an additional twenty-four hours, leaving Buster and the guppies each with a worm. Still they failed to take the prey. When I repeated the warming phase of the experiment, Buster went after his worm in 58 minutes and the guppies averaged an hour and a half.

  I set up an entire series of guppy-to-salamander cerebral transplants to answer a number of subsidiary questions about what I was now calling "temperature-dependent feeding behavior." How often would it occur? About 70 percent of the time. What was the critical temperature? I determined that it was 17-18 degrees centigrade--for the donors as well as the hosts. When, postoperatively, did temperature-dependent feeding emerge? In a little more than two weeks. (Thus, it wasn't like injecting tissue extracts, but more like the wait for a graft to take.) Checking Buster's records, I realized that had the fire drill taken place perhaps a day or two earlier, I never would have made the observation.

  Then one day, six weeks after his operation, after having fasted twenty-four hours in the cold, Buster hauled off and ate a worm. For a moment I was sick enough to cry. Had it all been just a fluke? But that same day, the transplanted guppy hearts beat their last beats. Rejection! And five to six weeks after the new batch of guppy-to-salamander hosts had been operated on, they too reverted to feeding at low temperature. I was sorry to see the trait disappear. But its disappearance made the story as complete as it could possibly have been.

  Buster exemplified the independence principle. Punky the Tadamander gave us no basis to judge it. Buster's feeding behavior was a composite of salamander and guppy traits. Punky merely used his salamander body to display his tadpole mind. Buster's failure to attack worms at low temperatures did not mean that he lacked the necessary memories. The stimulus, a cool environment, had blocked his use of those memories. His reaction in the cool was negative, but an "active" negative (like a minus sign in the check book). Punky's refusal to attack worms during those 68 days stemmed from different causes entirely: his negative response was passive. As a control for my experiment with Punky, I performed operations in which I left most of the host salamanders' brains in place and substituted only the cerebrums with those of tadpoles. These animals, like Punky, always attacked worms. Thus, I had to conclude that in preparing Punky for his transplant--in amputating his original salamander midbrain, diencephalon, and cerebrum--I had removed his carnivorous memory, which his new tadpole brain did not restore to him. Placing the active-versus-passive comparison in the context of our earlier analogy with the deck of hologramic cards, Buster's failure to attack was similar to dealing out an inappropriate hand. When Buster's environment was warmed, we found that attack was in his deck after all. But no possible deal could have turned Punky into a killer; attack was not among his tadamander cards.

  ***

  Are Buster and Punky too remote from us to suggest anything about the human condition? During embryonic life, we develop through stages in which we look and act like fish, salamanders and tadpoles. Embryonic development provides convincing evidence for the theory of evolution. One principle of embryology, von Baer's law, holds that ontogeny recapitulates phylogeny, meaning that as we develop, we go through our own individual mini-evolutions, revealing our close kinship to other vertebrate creatures. Behavior doesn't start up when we slide out of the birth canal onto the obstetrics table. We're live cargoes in Mom's womb. And we're behaving long before we're born.

  An old-time Georgia country obstetrician, Richard Torpin, used to show up every year at the meetings of the American Association of Anatomists with all sorts of novel and ingenious exhibits of human behavior in utero. From stillbirths and detailed records on his patients, Doc Torpin would reconstruct what led to a particular fetus's undoing. Using rubber bands and plaster of Paris, he produced models to illustrate various prenatal problems. One year he demonstrated how a restless fetus could get its fingers and toes tangled and, cut off from a blood supply at a period of intense growth, eventually lost in loops of umbilical cord. (He had found bits of detached fingers in the inner wall of the placenta.) In another exhibit, he showed how a swimming fetus had found and swallowed its own umbilical cord, much as a salamander or a guppy would down a worm. At birth, as the child tried to shift breathing air, it strangled on its own umbilical cord, Doc Turpin explained.

  The movement within a pregnant woman's uterus can't be equated to the simple push-pull action-reaction of a hydraulic shock absorber. It is behavior. Just as the embryo's lungs, heart, eyes, face and a brain gradually develop through fishlike, froglike and ratlike stages into what we might be willing to call a "baby," so the primitive mind we start out with must gradually and continuously evolve into a human mentality. The course our development takes runs right by the junctures where our aquatic vertebrate cousins stopped evolving. And when one of us gets off course too soon, what we do en route to the formaldehyde jar is fishlike, salamanderlike, or ratlike... depending on our point of departure.

  Yet in spite of an unbroken thread running all the way back through our development, we emerge from the uterus infinitely different creatures from when we first implanted into its soft, warm, sticky inner wall. How do we become so different during development? The independence principle, remember, permits new codes to be added virtually at will to the pre-existing deck. Buster serves as a precedent for such additions.

  The independence principle also frees us from having to assume fundamentally different laws of Nature in order to explain how experience can add to our mental stores what development builds into us spontaneously. In hologramic theory, one general principle serves all the codes, whether we call them memories or instincts, learned ideas or innate thoughts, a priori or a posteriori knowledge. An examination of this prediction of the theory was the next phase of my research.

  ***

  I lost my job at the beginning of 1970, before shufflebrain was a complete story. A miniature depression had begun in the sciences during 1969. Shortly after I was fired, a staff writer for Science magazine came to the conclusion that what many scientists were calling a "Ph.D. glut" was really a myth. True, the article conceded, the really good jobs were getting hard to find. Competition had intensified, and there was no doubt that the federal government was spending significantly less on science. But the article implied that only the Willie L
omans of science were driving taxi cabs, washing dishes, freelancing, busing dishes and drawing unemployment checks. Directly or through friends, I soon contacted the anatomy department of every medical school in the United States and Canada, without success. And wherever else I looked, there were no jobs, not for me at least. Perhaps it was the Science article, which I believed at the time; perhaps it was the serious economic plight of my family (the oldest of our four children had had to miss a semester at the University of Michigan); perhaps it was my still-incomplete shufflebrain research; or the fact that my unemployment insurance was running out. In any case, when a friend eventually arranged an interview for me at Indiana University's optometry school, I found it psychologically impossible to negotiate seriously for anything. Had my pride been operative, I would have rejected their job offer, which carried lower rank and less pay than my former job. And I would never have worked as a scientist again.

  But by the autumn of 1970, I was drawing real wages again. I had a splendid office overlooking the most beautiful campus I had ever seen. Although my lab had nothing in it, my morale was high. I had applied to the university's grant committee for a few thousand dollars to tide me over until I could secure federal funds. When I got four hundred dollars instead, I was still too euphoric to bitch. And I set about doing what scientists of the generation before mine had routinely done: made do!

  Making do included scrounging salamanders from a wonderful man, the late Rufus Humphrey. Humphrey had retired to Indiana University from the anatomy department of the University of Buffalo (now the State University of New York at Buffalo). As chance had it, I'd joined that department, myself, for a period in the early 1960's. After taking over some discarded dissecting tables Humphrey had once used for his salamanders (Humphrey was a maker-do of world class rank), I'd written him to tell him that his picture still hung in the microscopic anatomy lab at Buffalo. Thus began a lasting friendly correspondence between us.

  Humphrey studied the genetics of a salamander known as the axolotl. Some of his purebred strains ran back to 1930. His colony (which continues today as the Axolotl Colony at Indiana University) is famous, worldwide, among people who work with amphibians. Even if I had not been on a scrounging mission, one of the first things I would have had to see in Indiana was Humphrey's axolotls.

  Another item I badly needed was a dissecting microscope. There wasn't one lying around in Optometry, and I couldn't afford to buy one out of my wife's tight budget. I learned of a new ecology program starting up over in Biological Sciences, however, and dissecting microscopes were part of the equipment for the forthcoming teaching lab. And (I licked my chops!) the course wasn't scheduled to begin until the first of the year. Could I arrange a loan? The answer was yes.

  Making do also meant giving up the live tubifex worm as staple for my colony. Detergents and chemical pollutants have driven these once-ubiquitous worms from all but a few waters. Since the early 1960s, I had not been able to collect them in the field, myself but had had to fly them in from New York or Philadelphia, which was totally out of the question on a make-do budget. Thus I began feeding young larvae on freshly hatched brine-shrimp embryos, which could be purchased dry by the millions for a quarter in any pet shop. When the axolotl larvae grew to about 40 millimeters in length, I weaned them onto beef liver (swiped from my wife's shopping basket).

  Feeding animals on beef liver does take time. The animals must first be taught to strike. Even after they acquire the necessary experience, though, you still can't fling a hunk of meat into the dish and forget it, as you can a ball of live tubifex worms. The liver rots at the bottom of the dish, while even the experienced feeder starves.

  Now there was a federal program called Work-Study, whereby the government paid all by 20 percent of the wages for students who had university-related jobs. Just as I was weaning a group of about fifty axolotls onto liver, an optometry student, Calvin Yates, came around looking for a Work-Study job. One duty I assigned him was feeding liver to the axolotls.

  Calvin--Dr. Yates--later practiced optometry in Gary, Indiana. If his treatment of people matched the care he gave my salamanders, I am sure he was an overwhelming success. Calvin had what Humphrey once called a "slimy thumb"--the salamander buff's equivalent of the horticulturist's green thumb. In Calvin's presence, living things thrived. A few days after he took over the weaning job, the axolotls were snapping like seasoned 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, half-amused attention to Calvin's routine during that time. For I had learned that my favorite species of salamander, Amblystoma opacum, lived in the area. Opacum (the marble salamander) was one of the three principal species I had been using in my shufflebrain experiments. Luckily, the opacum female lays her eggs during the autumn. Finding them can be tricky, though. Now gregarious my wife happened to meet an old country gentleman, a retired farmer who reminded her of her grandfather. In the course of casual conversation salamanders somehow came up. The man just happened to know where he could lay his hands on about 50 opacum eggs, which he let me have for a couple dollars. And by the time Calvin was weaning the axolotls, the opacum larvae had grown to just the perfect size for me to put the finishing touches on my shufflebrain project.

  Opacum belongs to the same genus as does the axolotl (Amblystoma mexicanum). As a larva opacum is a shrewd, little animal, the smallest member of the genus but easily the most elaborate and efficient hunter. And what a fascination to watch! But its small size made liver-feeding quite impractical, which was also very lucky for me.

  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 animals to stock. Yet I don't like to waste a creature, make-do budget or no. 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 ten days later. I had taken my time getting to the lab that morning, walking slowly through the crisp autumn air, admiring the trees, saying "good mornings" to students along the way, and had perfunctorily seated myself at the operating table, thinking much more about the world in general than about science. I usually keep recuperating animals near the microscope and check their reflexes daily until they come out of postoperative stupor. That morning, I came in merely to take a routine daily record.

  To check a salamander's reflexes, I flick a fingernail on the rim of the dish. When an animal has recovered from stupor, it usually jumps in response to the flick. As I placed the opacum larva with the axolotl brain on the stage of the 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 response in only one other place--over on the table among Calvin's axolotls, where the donor had come from. Immediately I jumped up, went over and flicked every last dish on the axolotl table. Every axolotl there looked up in response.

  Next, I checked out the stock opacum larvae. Flicking only caused them to scurry around in their dishes. Not one stock opacum looked up.

  Now back to the operating table! Again, I flicked. Again the opacum with the axolotl brain looked up. I tested the other subjects that had had operations. They did not look up. Again I tried the axolotl recipient. Again it worked. Unwittingly, I had discovered that a learned response can be added to the hologramic deck.

  ***

  My looking-up little animal reminded me of a sermon I had heard decades earlier in a down-at-
the-heel, no longer extant church at the corner of 111th Street and Lexington Avenue in New York City. The sermon had been about gratitude, and the preacher had used an anecdote from his Ohio farm boy youth to illustrate the theme. His father used to let hogs into the apple orchard to clean up windfall fruit, the preacher said. It always amazed him that the hogs would devour every last apple on the ground but never once look up at the trees, the source. Looking up! I haven't practiced the religion of my boyhood for a long time. Nature has taken its place. But often, very often, in the laboratory, at the moment of a new discovery, I have felt intense gratitude, not for being right--for I've had the emotion when I was completely wrong--but simply for being there. Looking down at my talented opacum, I felt that same gratitude, to an almost overwhelming degree. And thus I gave this new paradigm the name: "Looking-up."

  ***

  Before I had the chance to carry out a decisive investigation of Looking-up, my general good fortune seemed to disappear. The Looker-upper died of a fungus infection. Something happened to the tap water, and the brine shrimp were hatching in minuscule quantities, forcing me to abandon the opacum stock just to sustain the experimental subjects in good health. Then the time came to surrender the borrowed dissecting microscope. The optometry school had rooms full of junked optical equipment from which I jury-rigged a substitute. But under it, I committed butchery. Then the National Institutes of Health rejected my application for research funds. I finally began to lose confidence, and I would have closed the lab permanently had not Calvin's job depended on feeding the axolotls. But I could not go near the lab.

  ***

  Although I could not yet make a public case for "Looking-up," I was now privately convinced that hologramic theory applied to learned as well as instinctive behaviors and that the abstract rules were indeed the same for both. I felt that the time had come to make the main part of the shufflebrain story known. And I was convinced that my days in the laboratory were over. If what I wrote was going to be a swan song, why say it in the stiff, lifeless prose of science and bury it in unread archives? If the story was as interesting as it seemed to me, perhaps a popular magazine would take it. Harper's eventually accepted my article and published it in their May 1972 issue.