Shufflebrain

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 continuum 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.

***

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.