by Paul Pietsch
Continuity is essential to the theory of evolution. Try to imagine a tree whose branches are not and never were continuous, back to the main trunk. Continuity in fact during embryonic development is our prima facie evidence for continuity in theory among the species. Evolution is inconceivable in a simple, discontinuous arithmetic system. In the light of Bitterman's turtle, a straight-line theory of the natural history of intelligence would predict discontinuity among the species and render the theory of evolution itself no more defensible on formal grounds than the events depicted in Genesis. Bitterman's investigations deny a simple, linear progression from fish to human and provide experimental evidence for the evolution of intelligence.
We have not constructed hologramic theory along linear lines. If we had, we wouldn't be able to reconcile what we find. We would be forced to ignore some facts in order to believe others. Without the continuum, we would be unable to explain not only the differences and similarities of the species, but also those in ourselves at various stages of our own embryonic development.
The hologramic continuum, by nature, allows new dimensions to integrate harmoniously with those already present. It lets us explain how our biological yesterday remains a part of today within a totally changed informational universe. Even though we share the same elemental rule--the phase code--with all other life forms, we're not reducible to what we once were, nor to bacteria or beheaded bugs. We are neither a linear sum of what we were nor a linear fraction of what we used to be. And our uniquely human inner world begins to unfold with the advent of the cerebral cortex.
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Physiologically, the cerebral cortex was a near-total enigma until comparatively recent times. But two physiologists, David Hubel and Torsten Wiesel spent decades exploring pattern recognition in the visual cortex, first of cats and eventually monkeys.[13] They identified three basic types of neurons there, cells that would respond to visual targets of different degrees of complexity. Hubel and Wiesel called these neurons simple, complex and hypercomplex cells:
Simple cells fired in response to a barlike image in a fixed position with a particular orientation; those that would fire in response to, say, a horizontal target would quite immediately if the bar were tilted or if Hubel and Wiesel substituted it with a vertical or bar.
Complex cells were those that went on firing to a basically two-dimensional target. But the complex cells would not fire if the target's pattern became still more complicated.
That's where hypercomplex cells come into the picture: they were cells that kept on discharging when complex cells stopped.
The visual system must handle a great deal of information in addition to patterns: it must deal with color, motion, distance, direction--with a variety of independent abstract dimensions that have to be compiled into a single, composite picture, as do bars and rectangles and edges to make unified percept. Hubel and Wiesel analogized the problem to a jigsaw puzzle: the shape of the pieces is independent of the picture or potential picture they bear. We recognize a checkerboard whether it's red and black or black and blue. And we don't usually confuse a Carmen-performing diva flitting around the stage in a red and black dress with the red-black checkerboard.
We're always assembling informational dimensions into a single composite scene. If we go to a three-dimensional object, or if the object is moving, or if we attach some emotional significance to the input, we must either integrate the data into a percept or keep the subsets sorted into groups. And the integration (or segregation) must be quick. Vary the beast's capability for handling dimensions and we change its perception in a nonlinear way, as Bitterman did when he took the knife to his rat's cortex. Interestingly, it was not until Hubel and Wiesel began studying the monkey (versus the cat) that they discovered hypercomplex cells in sufficient numbers to analyze their complicated physiological details.
What we hear, touch, taste and smell may also be multidimensional. For instances, we may recognize a melody from The Barber of Seville, but our understanding of the lyrics may depend on a knowledge of Italian. And whether we're enthralled or put to sleep will depend on factors other than just the words or the music.
We also harmoniously integrate diverse sensory data. Thus silent movies disappeared quickly after talkies came along. We not only have the capacity to combine sight and sound, but we like (or hate) doing it which is a whole other constellations of dimensions.
The cerebral cortex is far from the only dimensional processor in the brains of organisms (although it may very well be the most elegant one in there). The frog, for instances, has a well developed roof on its midbrain--the tectum I mentioned in chapter 3: the part that helps process visual information among non-mammalian vertebrates. While the tectum comes nowhere close to the capabilities of a primate visual cortex, it nevertheless integrates different dimensions of the frog's visual perception.[14]
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Another structure I mentioned in chapter 3 was the zucchini-shaped hippocampus, lesions of which induce short-term memory defects and make it difficult for persons so afflicted to repeat newly presented phrases or sequences of numbers. In rats, however, the hippocampus appears to assist navigation.
The function of the rat's hippocampus became evident in studies involving what is called the radial maze.[15] This kind of apparatus consists of typically a dozen alleys leading off a central choice point like the spokes radiating from the hub of a wagon wheel. To win a reward, the rat must go through the alleys in a predetermined sequence. To carry out the task, the rat must remember which alley he's in and which turn to take for the next one. The rat must compile at least two sets of memories: one of positions, the other of direction. Lesions in the hippocampus erode the animal's efficiency at the radial maze.
Now think of what happens when we recite the lines of a poem. We must remember not only the individual words but, so as to place correct emphases, their location in the sequence.[16] Although the task assumes verbal form in a human being, its informational aspects seem quite like those a rat uses to organize memories of geographic locations and sequences.
At the same time, clinical and laboratory evidence don't prove that the hippocampus is the exclusive seat of such short-term memory processing. Lesions do not totally nullify the rat's ability to run the radial maze: performances dropped from 7 correct turns out of 8 to 5 or 6, a statistically significant drop but far from the total loss of the ability that follow from destruction of the seat of the neural information. [17] I once watched a record film of a man with a damaged hippocampus. He made errors when repeating phrases, but he wasn't always wrong. In addition, he often employed subtle tricks to recall items. When he was allowed to count on his fingers, he could often correctly repeat phrases that he couldn't handle without them. Other parts of the brain can compile memories of position and distance but would seem to do with much less efficiency than the hippocampus.
The success or failure of a particular behavior may depend on how fast an organism can assemble different memories. Out in the wild, the navigational problems a rat confronts are much more difficult--and potentially perilous--than anything in the laboratory. Ethologist are students of behavior in the wild. And ethologists Richard Lore and Kevin Flanders, undertook the frightening job digging up a rat-infested garbage dump in New Jersey to see how the beasts live out there. To Lore and Flander's surprise, they found that wild rats live in family groups, each with its own burrow. The dump wasn't honeycombed with one communal rat flop, the animals randomly infesting a labyrinth and eating, sleeping or mating wherever the opportunity presented itself. Now the wild rat is one vicious creature, as a child of the inner city can often testify first hand. A strange rat who ends up in the wrong hole isn't welcomed as an honored dinner guest but may very well become the piece de résistance. Thus when the rat ventures into the night and turns around to bring home a half-eaten pork chop, it by-god better know which burrow to choose out of hundreds in a multidimensional array. It would quickly succumb to its own social psychology if not for the s
uperb navigational system resident in its hippocampus. The use to which a rat puts its hippocampus seems at least as complicated as ours. Appreciate, though, that while the qualitative features of the behaviors mediated by the homologous brains structures can differ greatly between them and us, the abstract attributes--the analogous logic-- can be quite similar. Let's remind ourselves of this from hologramic theory.
We can construct two continua that have identical numbers of dimensions yet produce different universes. How? The shape of a universe depends not only on how many dimensions it has, but on how they connect up and which part connects with what. Recall in the last chapter we envisaged adding a dimension by converting a figure 8 into a snowman.
What if we take a snowman apart and reassemble it with the members in a different order. Call our initial snowman A and our reshuffled one B. Now let's send an imaginary insect crawling on each figure at the same time and at the same speed. Of course, both insects will complete the round-trip excursion together. But relative to the starting point (the phase variation between the two), the two bugs will never once have traveled an equal distance until both have arrived back at the start-finish point. The similarities and differences don't trick us. Likewise, the differences between our hippocampus and the rat's shouldn't mask the similarities.
As I mentioned earlier, some psychologists conceptualize short-term or working memory by means of an idealized compartment.[18] The hippocampus, as I've suggested, may be a location of a portion of that compartment, at least in higher animals. Of course, as evidence from, for instance, decerebrated cats and many other sources indicates, we can't consider the hippocampus as the exclusive repository of short-term memory. But hippocampal functions may yet reveal critical details about the dynamics of perception and reminiscence in higher animals. Circumstantial evidence from rats as well as humans indicates that an active memory in the hippocampus is short term. Now short-term memory in general is very sensitive to electroconvulsive shock (ECS). And relatively mild electrical stimulation of the hippocampus or the surrounding brain can evoke a violent convulsive seizure.[19]
A temporary and erasable working memory would be valuable to us as well as to rats. When we no longer need a telephone number, for example, we simply expunge. Yet we wouldn't want to forget all telephone numbers. After a journey from the garbage pile, the neural map in the rat's hippocampus could become a liability. But the rat wouldn't want to have to relearn every map. ("That's the pipe were the coyote got my brother!") What might control the shift from short-term to long-term storage? I raise the latter question not to signal a final answer. But a little speculation from a few facts will allow me to illustrate how we can use hologramic theory to generate working hypotheses (the kind from which experimentation grows). Also, the hippocampus exhibits an important feature of the brain that Norbert Wiener predicted many years ago.
The human hippocampus interconnects with vast regions of the central nervous system. Its most conspicuous pathways lead to and from subdivisions of what is called the limbic system. The limbic system is most conspicuously associated with emotions. One hippocampal circuit in particular connects the hippocampus to a massive convolution called the cingulate gyrus. Draped like a lounging leopard on the corpus callosum, the cingulate gyrus was the first part of the limbic system ever designated [20] and became a favorite target of psychosurgery in the post-prefrontal lobotomy era. The hippocampal-cingulate circuit has (among other many things) three features that are highly germane to our discussion.
- First, a number of relay stations intervene between the hippocampus and the cingulate gyrus. These relay stations are locations where the signal can be modified; where messages can be routed to and from other areas of the brain and spinal cord and blended (or removed) with (from) other data.
- Second, the circuit consists of parallel pathways (co- and multi-axial) all the way around. The significance of this is that when activated the circuit preserves phase information in principle in the way Young and Fresnel did when making interference patterns--by starting from the same source but varying the specific course between the referencing waves. The hippocampal-cingulate circuitry looks designed to handle phase differentials, and on a grand scale!
- Third, the overall circuit makes a giant feedback loop. Feedback is at the heart of the communications revolution Norbert Wiener touched off in 1947 with the publication of his classic, Cybernetics and that you're living through as you read these very words.
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Biofeedback became a popular subject a couple of decades ago when people were hooking electrodes to the their heads and stopping an starting electrical trains by altering their thoughts. "EEG with electric trains," a friend of mine used to call what seemed to him a stunt wherein amplified electrical signals from the scalp are fed into the transformer of an electric train set instead of a polygraph. However one wants to characterize feedback, it is central to much that goes on chemically and physiologically in our bodies--including the brain.
Wiener spent World War Two trying to develop methods for anticipating where a German bomber was headed so that an Allied aircraft gun crew could aim properly to shoot it down, evasive actions and the trembling ground notwithstanding. The problem led Wiener began to appreciate the importance of the feedback loop in controlling the output from a system where the output device itself is subject to continual changes. Feedback became the central notion in his cybernetic theory.
What a feedback loop does is relate input to output in a dynamic instead of static way. With moment-to-moment monitoring, tiny corrections can be made in the output to compensate for last minute changes not only in a target but also in the readout mechanisms.
Wiener the mathematician used to joke about his ignorance of the brain. Nevertheless, in 1947 from pure cybernetic theory, he predicted one of the brain's (or computer's) most important functional attributes: reverberating circuits. (Reference to "reverberating circuit" is to be found in even standard textbooks.[21] ) Even though he'd never even seen the cerebellum before, he predicted both its function and the effects of damage to it (dysfunction in dynamic motor control).[22]
In a system like that conceived by Wiener, a short-term memory would reverberate around the feedback loop and remain active until other input modified it or shut it off. The hippocampus seems elegantly designed for just that kind of activity.
The specific types of memories associated with the human hippocampus are especially susceptible to emotions. Tell a class of students that a particular fact will appear on the final examination and it's almost as though their limbic systems suddenly opened the gates to the permanent storage compartment. On the other hand if you become scared or angry or amorous just before you dial a newly looked-up telephone number, you'll probably have to consult the directory again before putting in the call.
Karl Pribram has suggested that neural holograms exist in microcircuits within neurons. A cogent argument can be made for his thesis, but not in the short-term memory on the hippocampus. The evidence suggests that short-term hippocampal memory depends on a vast number of neurons, perhaps even the entire feedback loop. Let me repeat an important maxim of hologramic theory: the theory won't predict the biochemical or physiological mechanisms of memory; the absolute size of a whole phase code is arbitrary, meaning that it may be (but doesn't have to be) tiny, as Pribram's microcircuits, or in oscillations within a pair of molecules on a cell membrane; or gigantic as in the entire hippocampus, or even with the whole nervous system. Recall that the same code may exist simultaneously in many different places or sizes and in many specific mechanisms. To make the memory of a telephone number permanent, what has to transform is not a protein or a voltage but a set of variational relationship--the tensors of our hologramic continuum.
In 1922, Einstein wrote The Meaning of Relavity. In it, he demonstrates that his special relativity theory (E=mc2) can be derived from the tensors of his general relativity theory, from his four-dimensional space-time continuum. Although the hologramic con
tinuum is not the same as Einstein's theory, we do use Riemann's ideas, as did Einstein. The logic is similar. Einstein demonstrated the same relative principle in both the very small atom and in the universe at large. Hologramic theory, too, tells us that the same elemental rules operate in mind in the small or the large. If we find a memory in, say, the resonance of two chemical bonds within a hormone molecule, we should not throw up our hands in disgust abandon science for magic simply because someone else discovers the same code in the entire feedback loop of the hippocampus. Thus if microcircuits turn out to play no role in the short-term memory on the hippocampus, they could still very well exist elsewhere.
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The cortex on the cerebrum's frontal lobe may also be essential to the uniquely human personality, and some of the data collected with reference to it are not only useful to our discussion but also rather interesting in their own right. One of the most important contributors to knowledge about the frontal lobe is no less than Karl Pribram.
Human beings who have undergone prefrontal lobotomy often cannot solve problems consisting of many parts. Pribram, who was familiar with these clinical signs as a neurosurgeon, had a hunch about why, a hunch he pursued in the lab as a neurophysiologist.
Signals from the frontal lobes often have an inhibitory effect on other areas of the brain. (One theory behind prefrontal lobotomy was that it relieved the uptights.) Pribram began wondering if such inhibitory activity might represent something akin to parsing a message-- breaking a sequence of letters or words into meaningful chunks. Maybe to lobotomized patients words such as "hologramic theory" seem like "ho logramichteory"; or "ho log ram ich teory."