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The Brain as Hologram 27

by some amputees that a missing arm or leg is still present. Such 
The Mathematical Language of the Hologram

individuals often feel eerily realistic cramps, pains, and tinglings in 

these phantom appendages, but maybe what they are experiencing is While the theories that enabled the development of the hologram were 

the holographic memory of the limb that is still recorded in the inter- first formulated in 1947 by Dennis Gabor (wholater won a Nobel Prize 

ference patterns in their brains.
for his efforts), in the late 1960s and early 1970s Pribram's theory 

received even more persuasive experimental support. When Gabor 

first conceived the idea of holography he wasn't thinking about lasers. 

His goal was to improve the electron microscope, then a primitive and 

Experimental Support for the Holographic Brain
imperfect device. His approach was a mathematical one, and the math- 

ematics he used was a type of calculus invented by an eighteenth- 

For Pribram the many similarities between brains and holograms century Frenchman named Jean B. J. Fourier.

were tantalizing, but he knew his theory didn't mean anything unless Roughly speaking what Fourier developed was a mathematical way 

it was backed up by more solid evidence. One researcher who provided of converting any pattern, no matter how complex, into a language of 

such evidence was Indiana University biologist Paul Pietsch. Intrigu- simple waves. He also showed how these wave forms could be con- 

ingly, Pietsch began as an ardent disbeliever in Pribram's theory. He verted back into the original pattern. In other words, just as a televi- 

was especially skeptical of Pribram's claim that memories do not pos- sion camera converts an image into electromagnetic frequencies and 

sess any specific location in the brain.
a television set converts those frequencies back into the original 

To prove Pribram wrong, Pietsch devised a series of experiments, image, Fourier showed how a similar process could be achieved math- 

and as the test subjects of his experiments he chose salamanders. In ematically. The equations he developed to convert images into wave 

previous studies he had discovered that he could remove the brain of forms and back again are known as Fourier transforms.

a salamander without killing it, and although it remained in a stupor Fourier transforms enabled Gabor to convert a picture of an object 

as long as its brain was missing, its behavior completely returned to into the blur of interference patterns on a piece of holographic film. 

normal as soon as its brain was restored.
They also enabled him to devise a way of converting those interference 

Pietsch reasoned that if a salamander's feeding behavior is not patterns back into an image of the original object. In fact the special 

confined to any specific location in the brain, then it should not matter whole in every part of a hologram is one of the by-products that occurs 

how its brain is positioned in its head. If it did matter, Pribram's theory when an image or pattern is translated into the Fourier language of 

would be disproven. He thenflip-floppedthe left and right hemispheres wave forms.

of a salamander's brain, but to his dismay, as soon as it recovered, the Throughout the late 1960s and early 1970s various researchers con- 

salamander quickly resumed normal feeding.
tacted Pribram and told him they had uncovered evidence that the 

He took another salamander and turned its brain upside down. 
visual system worked as a kind of frequency analyzer. Since fre- 

When it recovered it, too, fed normally. Growing increasingly frus- quency is a measure of the number of oscillations a wave undergoes 

trated, he decided to resort to more drastic measures. In a series of per second, this strongly suggested that the brain might be function- 

over 700 operations he sliced, flipped, shuffled, subtracted, and even ing as a hologram does.

minced the brains of his hapless subjects, but always when he replaced
But it wasn't until 1979 that Berkeley neurophysiologists Russell 
what was left of their brains, their behavior returned to normal. and Karen DeValois made the discovery that settled the matter. Re- 

These findings and others turned Pietsch into a believer and at- search in the 1960s had shown that each brain cell in the visual cortex 

tracted enough attention that his research became the subject of a is geared to respond to a different pattern—some brain cells fire when 

segment on the television show 60 Minutes. He writes about this the eyes see a horizontal line, others fire when the eyes see a vertical 

experience as well as giving detailed accounts of his experiments in his
line, and so on. As a result, many researchers concludedthat the brain 

insightful book Shufflebrain.
takes input from these highly specialized cells called feature detec-

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