A Love of Memory

When I got back home from Australia I took the opportunity to reread some of my favourite books. These included Kim Stanley’s Mars Trilogy, which are probably up there in my top ten of rereadable books (Cryptonomicon sits at the pole position, having withstood at least a couple of years of sustained rereading).

I’ve forgotten how much I enjoy the Mars Trilogy. It gets bashed so often for apparently being too dry, political and sometimes boring, but consider this – the first two books won the Nebula and Hugo awards, and the trilogy as a whole was singlehandedly responsible for getting me interested in Mars. There are few (if any) events in my life that I can point to and say, this changed everything, but that fateful day when I spotted the trilogy in a book club brochure must be one of them.

The last book in the trilogy, Blue Mars, is not considered to be as good as the first two, which is a fair claim to make but it certainly doesn’t mean it’s not a good read. In Red Mars, the first book, a group of scientists develop a longevity treatment that results in people regularly living to over 200 years old by the time of Blue Mars. This is all very well and good, but said geriatrics are having a really hard time with their memory.

Accordingly, one of the main characters joins an effort to develop a memory boosting drug. At this point, most authors would be happy to say, ‘…and then after much work they made the drug,’ or if they were feeling particularly generous, they might throw in a few choice words like ‘dopamine’ or ‘serotonin’. If you were really lucky, they might take the time to look up a diagram of the brain and mention the hippocampus.

But this isn’t enough for KSR, and it’s part of the reason why I love his books. He spends over seven full pages on a monologue/stream of consciousness that dives right into the way that memory works and how you might enhance it. That’s over two thousand words of detailed information and informed speculation, none of which is wildly wrong. In fact, most of it is right, it’s only the speculation that I have a problem with and even then I have to give him a lot of respect for giving it a good try. I would say that to have written that monologue, KSR must have read at least a few reviews on the subject and perhaps a book.

Here is the bit which I love and hate (and yes, the first paragraph is that long):

The original Hebb hypothesis, first proposed by Donald Hebb in 1949, was still held to be true, because it was such a general principle; learning changed some physical feature in the brain, and after that the changed feature somehow encoded the event learned. In Hebb’s time the physical feature (the engram) was conceived of as occuring somewhere on the synaptic level, and as there could be hundreds of thousands of synapses for each of the ten billion neurones in the brain, this gave researchers the impression that the brain might be capable of holding some 10^14 data bits; at the time this seemed more than adequate to explain human consciousness. And as it was also within the realm of the possible for cmoputers, it led to a brief bogue in the notion of strong artificial intelligence, as well as that era’s version of the ‘machine fallacy’, an inversion of the pathetic fallacy, in which the brain was thought of as being something like the most powerful machine of the time. The work of the twenty-first and twenty-second centuries, however, had made it clear that there were no specific ‘engram’ sites as such. Any number of experiments failed to locate these sites, including on in which various parts of rats’ brains were removed after they learned a task, with no part of the brain proving essential; the frustrated experimenters concluded that memory was ‘everywhere and nowhere’, leading to the analogy of brain to hologram, even sillier than all the other machine analogies; but they were stumped, they were flailing. Later experiments clarified things; it became obvious that all the actions of consciousness were taking place on a level far smaller even than that of neurons; this was associated in Sax’s mind with the general miniaturization of scientific attention through the twenty-second century. In that finer-grained appraisal they had begun investigating the cytoskeletons of neuron cells, which were internal array of microtubules, with protein bridges between the microtubules. The microtubules’ structure consisted of hollow tubes made of thirteen columns of tubulin dimers, peanut-shaped globular protein pairs, each about eight by four by four nanometres, existing in two differen configurations, depending on their electrical polarization. So they dimers represented a possible on-off switch of the hoped-for engram; but they were so small that the electrical state of each dimer was influenced by the dimers around it, because of van der Waals interactions between them So messages of all kinds could be propagated along each microtubule column, and along the protein bridges connecting them. Then most recently had come yet another step in miniaturization; each dimer contained about four hundred and fifty amino acids, which could retain information by changed in the sequences of amino acids. And contained inside the dimer columns were tiny threads of water in an ordered state, a state called vicinal water, and this vicinal water was capable of conveying quantum-coherent oscilliations for the length of the tubule. A great number of experiments on living monkey brains, with miniaturized instrumentation of many different kinds, had established that while conscousness was thinking, amino acid sequences were shifting, tubulin dimers in may different places in the brain were changing configuration, in pulsed phases; microtubules were moving, sometimes growing; and on a much larger scale, dendrite spins then grew and made new connections, something changing synapses permanently, sometimes not.

So now the best current model had it that memories were encoded as standing patterns of quantum-coherent oscillations, set up by changes in the microtubules and their constituent parts, all working in patterns inside the neurons. Although there were now researchers who speculated that there could be significant action at even finer ultramicroscopic levels, permnanetly beyond their ability to investigate (familiar refrain); some saw traces of signs that the oscillations were structured in the kind of spin networks that Bao’s work described, in knotted nodes and networks that Sax found eerily reminiscent of the palace of memory plan – rooms and hallways – as if the ancient Greeks by introspection alone had intuited the very geometry of timespace.

The reason why I hate it (and hate is too strong a word) is because I don’t happen to think that his explanation for memory and consciousness is true at all. It has a very Penrosian feel about it, and I’ve never really thought that it was possible for there to be a working quantum computer residing in our neuron microtubules; and neither have I seen the necessitity for it. Plus, the idea that you would use alterations in the tubulin dimer amino acid sequence is really not workable (although I suppose that enzyme-mediated residue methylation or ubiquitination wouldn’t be out of the question).

I love this passage because it almost makes sense. KSR clearly understands what he’s talking about, and I’m pretty sure that he realises it’s extreme speculation. The rest of the monologue is much like this, discussing terms that neuroscientists bandy about regularly but don’t actually understand fully, like LTP and glutamate receptor sensitizers.

In a way, to most readers it doesn’t matter if the science makes any sense. What matters is the flow of the words and the beautiful progression from one magical concept to the next that science seems to make effortlessly; in this passage, KSR has managed to convey some of the feeling that you experience when you understand (or think you understand) a horribly complicated system; the feeling when everything shifts, just so, and interlocks into place.

The fact that it also happens to largely make sense is something that I truly appreciate; it would have been simple enough for KSR to just make all of it up, but I think KSR must have actually enjoyed learning about how memory might work for him to have written this.

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