Brains in Silicon
Whoa. Just back from the most recent Palo Alto Colloquia over at Lockheed Martin’s Advanced Technology Center.
For those who have seen and heard Michael Chorost’s astounding presentation on cochlear implants, you may be equally interested in Kwabena Boahen’s videos of a self-configured silicon retina at work. Just as Chorost’s low-resolution sound samples helped us to better understand the first hand experience of the artificial cochlea, so did Boahen’s 30x50 very low res imagery demonstrate the earliest exciting results of his team’s work. Unlike the cochlear implant, this work is not yet ready for human implantation.
Nevertheless, Dr. Kwabena Boahen, Stanford University, is an extraordinarily articulate man of humble demeanor, possessed of some of the most noble goals in this segment of industry. “We have two synergistic goals: We wish to understand how brains work; this will enable us to replace damaged neural tissue. And we want to build computers that work like brains; this will enable us to increase computational power a million fold.”
The talk began with a fundamental initial observation: reliance upon abstraction as the primary means of managing circuit complexity is approaching the boundaries of its useful limits as, “Nanoelectronic technology promises to cram a trillion transistors onto a 1 cm2 chip.”
The good news is, nature provides instructive alternatives for managing such complexity.
A couple of pivotal conceptual breakthroughs that caught my attention:
- Don't morph neural circuits into silicon, morph the rules that build the circuits.
- Once a chip leaves the fab, no circuit changes are possible. Softwires make post-production self-configuring circuits possible.
I might briefly and crudely describe softwires as RAM gates, but the slides do a much better job of illustrating this innovation. The slides are going up on internal Lockheed site in the next day or so, but public access won’t be available until next week, so be sure to check back for them. This is mostly pre-hippocampal emulation in silicon, but the NeuroGrid project will significantly expand applied understanding and emulation of the brain’s processes that create meaning and context from received stimuli.
At least, that’s how I understood the talk.
After the presentation, I wandered up front to listen to the one-on-one q & a, one of my personal favorite activities at such gatherings. Much additional insight-can be gained by simply listening to the questions and answers among the inevitable groupies. It’s worth being patient with the goofy groupies to hear the interactions with the good groupies: those who know how to ask good questions, of course.
One interesting sidebar discussion had to do with the biological phenomenon of decreasing neuro-plasticity with increasing age. On the drive home, I began to wonder, could there be any measurable effect of a cognitive commitment to resisting that default effect? How would such an experiment be devised?
Boahen reminded a questioner that, as we age, the value of archival brain information tends to outweigh the value of forging new neural circuits; so we old men begin telling more stories than advancing new theories, in general. But how much of this due to A.) an historical lack of awareness of the tendency, and B.) lack of conscious intention brought to bear upon resisting that natural tendency?
On an evolutionary scale, external storage, publications, films, etc., have not long replaced the intergenerational neural processing baton-passing role of oral traditions; nevertheless, why not at least begin attempting to extend the years of new neural-circuit building on humans? After all, somebody had to be the first crazy fishies to flop up on the beach and stretch their fins in counter-natural ways, right?
Perhaps recruiting and admitting 50 year-olds to masters programs, or 62 year olds to PhD programs – without financial aid discrimination – could be part of such research with humans. In general, we are getting better at paying lip service to the ideas of radical life extension, but what are we doing in terms proactive, practical enhancement of individual social and academic utility?