Shufflebrain

A nerve impulse shows up on the physiologist's oscilloscope as a traveling electronic wavelet. What is on the scope represents a wavelike voltage flux on the exterior of the neuron's membrane, and is often called a "spike." Now the impulse obeys what is called the all-or-none law. This means, first of all, that the cell must absorb stimulation at or above a particular threshold, or else it won't fire an impulse, per se; second, that the impulse travels at a constant rate and maintains uniform amplitude throughout its passage along the membrane; third, that increasing the stimulus above threshold will not make the impulse move faster or become stronger. Also, immediately after the appearance of the spike, and for a brief duration as the cell recocks itself, the membrane won't carry an impulse. This interval is called the absolute refractory period. The refractory period prevents impulse additions. With threshold in the van and the refractory period in the wake, the impulse becomes a wave of constant amplitude. What's left to turn impulses into signals? The answer is the number of impulses per unit of time--the frequency. FM or phase modulation, which is the fundamental principle in hologramic theory.

Groups of neurons, some firing (ON), others inhibited (OFF), can produce arrays of ON-OFF in the nervous system. This is very conspicuous on the retina and in the LGB. Some time ago, Karl Pribram, going counter to conventional thinking, analogized such ON-OFF arrays to interference patterns--implicating phase modulation, and, of course, the hologram. In more recent years, physiologists have been finding what Pribram suggested. Today, phase has become a major topic in sensory physiology, especially in vision research.[3]

Thus we do not have to search very far or long to make analogies between the generic principle of the hologram, wave phase, and the physiology of the brain.

***

My purpose is not to oversimplify the mind. The pivotal question is: Do we find nonliving analogs of ourselves out there? The answer is yes.

But analogy is too causal and conjectural a process to suit scientific verification. To an empirical scientist, which I am, theory must justify itself in experiments. And this is where shufflebrain enters the story.

RETURN TO CONTENTS PAGE

Internet contact:[email protected]

chapter five

Shufflebrain

HOLOGRAMIC THEORY can explain the otherwise paradoxical body of facts about brain damage. The theory also accounts for Lashley's findings. But neither his experiments nor the volumes of anecdotal information on the injured brain provide critical tests of hologramic theory's most important predictions. Let me illustrate this important point with an imaginary experiment. Envisage three or four transparent plastic sheets on which we have photocopied and reproduced a message, say ANATOMY. As in a diffuse hologram, our message would be redundant. But the message we have just created is not at all hologramic--not truly "distributed" as in an interference pattern. ANATOMY is "anatogramic," as I once thought memory was.

Think of the space each letter occupies as a specific, independent "set" on the sheet. The meaning of our message devolves from the relationship among a sheet's sets. We can even define "meaning" from the organization--the anatomy--of the sheet: What's in each set? How do the sets interrelate? The specific answers define the specific message. (I used to believe the genes for organ development, in principle, came on in this manner.)

How do we simulate the brain with our ANATOMY sheets? More specifically, what can we do to model structural order among the several redundant sheets? The simplest way is to stack all sheets in exact correspondence or, as the printer says, perfect register.

Next, we want to observe our system--look at its output or readout, as information theorists call the display. The output, our analog of behavior, is what we see on the surface. With the sheets of the stack in perfect register, the output obviously is ANATOMY. But how many messages do we have in the system? We already know the answer for our imaginary system. But the real brain is an unknown.

What happens if we remove the first sheet from our model? Obviously, we still read ANATOMY at the surface; a little lighter, perhaps, but with its meaning quite intact. Does it make any difference which sheet we remove? Obviously not, as long as we keep the register constant. Suppose we erase or snip off the "TOMY" on the first sheet? Suppose we take "ANA" away from the bottom and "TOMY" away from the second? Our deletions may introduce subtle variations in intensity, but the meaning of our message survives as long as we maintain the equivalence of a sheet's worth of ANATOMY. Deleting, we can only destroy meaning at the surface if we clean out every last well of a particular sheet.