Saturday, May 08, 2004


They're everywhere, they're everywhere!

In her senior year of high school, my oldest daughter did a research project involving factors affecting mylenization of neurons. The myelin sheath around neurons makes them transmit impulses faster; lack of it is I think mostly what Multiple Schlerosis is. The myelin sheath is composed of Schwann cells that wrap themselves around the neurons. I remember thinking and mentioning to her at the time that this seems like a relationship that may have started out parasitic and evolved to be symbiotic.

Last month's Scientific American had an article on glial cells, of which Schwann cells are a type. Glial cells make up the majority of the brain and were thought to mostly provide nutrition to the neurons. Now they have found out that they react to synapse firing and in fact moderate it. As such, they may have a role in moderating neuron activity and development, i.e., memory and learning. Really cool pictures of glial calls with tendrils wrapped around synapses, clearly they are involved in the synapses' operation. Kind of like neuron shepherds. You wonder how this relationship evolved -- this little ecosystem in our brains.

I read a few years ago "Slanted Truths", by Lynn Margulis and Dorion Sagan. One of the points of this book is that one of the techniques by which life evolves is by things merging, rather than strictly by mutation. Basic cell structure is a case in point. Mitochondria were a bacteria or something that got eaten by early cells at some point and that then got incorporated rather than digested -- they have their own DNA. Also mentioned, if I remember right, were the spindles used in mitosis, which are basically spirochetes, just as sperm tails are. So, an ecosystem in every cell.

This was also one of the coolest things of the many cool things in "Genome", already blogged -- that the genome itself is an ecosystem, with little snippets of replicating genetic code trying to make more copies of themselves, snake other sequences, and otherwise engage in Darwinian survival-of-the-fittest strategies.

So, is it surprising at all that our minds are an ecosystem? No, not at all, what else would they be? Good books on this: "Society of the Mind", by Marvin Minsky, the father of AI at MIT; and also "The Meme Machine", by Susan Blackmore, already blogged.

Read a post by Jaron Lanier at The Edge, kind of talking about how the early pioneers of computer science (Von Neumann, Wiener, Shannon) were too hung up on serial architectures and ignored surface-based (not parallel) computing. He got totally blasted on it. Still I agree with his idea, blogged previously, that current software interfaces are too brittle. It is too hard to get things to talk together, any software developer can tell you that. Re the above thoughts, it makes it too hard for software ecosystems to self-organize and evolve. If we can come up with the more approximate, organic interfaces that Lanier proposes, then our silicon children can maybe begin to evolve into something interesting. Kind of funny, Lanier is saying the Cybernetic Singularity is a pipe dream, but his idea might be a key one to make it happen.

No comments: