Originally posted by DJ Delorie
Neither, really. The overall scheme is holographic, although the individual neural connections are direct wired (digital) and the signals are analog.
So technically the answer is "no" ;-) (assuming the question is "is it purely analog or digital?")
The math that can be used to describe the dynamic electrical fields from the whole body level down to the micro-cilia on the synaptic stems, is Dennis Gabor's "analog" equivalent to Shannon's "digital" Information Theory (Gabor's half wave in-any-number-dimensions "logon" vs. Shannon's linear "bit). Gabor won the 1970 Nobel for developing this math to describe holography.
This is the point Karl Pribram was making in the appendix of his book "Brain and Perception", the text (and person) that originated what people mistakenly refer to as "holographic memory".
The MATH can be used to describe it. That has no more relationship to reality than statistical/quantum mechanics has to the reality of the subatomic world, a point which Feynman delighted in making in his typical unscientific way.
Gabor's math was adpoted by Pribram with the help of David Bohm. In physics he ranks up there with Einstein and Hawking; he's less known outside because he doesn't get talked about since he tended to go off into considerations such as consciousness well before doing so was acceptable. The math and the theory to this day are being constantly rehashed by Pribram along with Basil Hiley, David Bohm's physics partner of decades.
The "appendix" to Pribram's book is almost 1/4 of its mass. There are also two Japanese phsyicists who participate in this ongoing theory building, Jibu and Yasue. It takes a physicist AND a neuroscientist working together to understand it. Trust me.
Another math that could be used is tensor calculus such as Einstein used for describing spacetime. It could be, but after having suggested it and received long stares from Pribram, Hiley, Jibu and Yasue, Basil told me I was correct, but it was far more difficult than using Gabor's function to get to the same result.
Karl Pribram was my mentor. My scientific geneology, mentor to student, goes:
Sir Charles Sherrington
Karl Lashley
Karl Pribram
me.
I did brain interfacing experiments on rats. I did it on the same lab table that Sherrington used when he sliced rats' cortices all kind of ways trying to figure out how much had to be removed to remove a learned behavior (memory). The answer was "most of it", like 90%, which formed the basis of the idea that memory was distributed, and THAT later led people to believe it was distributed equally everywhere much as the interference pattern on a hologram.
Yes, Ozy, there's a neuroscientist on board. The 'real' answer is that we have several theories and those that know them best admit we have very little clue as far as explaining. We can describe, and even interact, but the "how" is still too hard. Gabor's function describes well. It does not explain. Also, there are competing "digital" and "analog" explanations for the same things, making it seem as if there's something of the bi-character quantum world involved. This is probably due to our poor understanding and insufficient theories. As Feynman would emphasize, "the math works, that's all that means".
Karl enjoys a good rant whenever he hears someone mistaking his theory for "holographic memory". Yet that does not prevent him from enjoying the heck out of playing with a hologram to make his point. That may seem a contradiction. But if you were an 80 year old neurosurgeon/neuroscientist that looked like a cross between Santa Claus and one of his elves, and had been working for 30 years so far outside the envelope of neuroscience that few people still can grasp it, you'd be entitled to rants of your own on a whim and apparent contradictions in your behavior, and probably wouldn't care what others thought any more than Karl does. Or Richard "What Do You Care What Other People Think?" Feynman did for that matter.