An Introduction

Lots of other people manage to have quite capable "work blogs", where they can work ideas out and refer to them later in an online forum that allows for comments by interested parties. I think I can, too!

So, I'm a first year graduate student at the Department of Cognitive & Neural Systems at Boston University. I have no idea what I'm going to study here, but I (oh so modestly) want to, you know, figure out how this consciousness thing works, and then come up with ways to utilize this knowledge that don't involve evil government mind control and tacky consumer products. I'm going to do my best to keep things at a legible level, although I'm sure that this will be pretty much exclusively for my benefit anyhow.

I studied Cognitive Science and Electrical Engineering & Computer Science at UC Berkeley, where I took a very good class by John Kihlstrom on Scientific Approaches to Consciousness. I very nearly went to graduate school at the University of Pittsburgh, to work with Andy Schwartz on neuroprosthetics, and that's still one of my central interests, academically. Neuroprosthetics is exciting because it manages to restore lost function in a profound way (via a mentally controllable prosthetic arm, in Schwartz's case) and also addresses some key features of internal motor representation, how this representation changes over time and how it relates to our own conscious experience.

One tough question though regards what is the best way to restore lost function to people who have lost a limb. Of course, a chronic neural implant is an option, and is being pursued by a pretty large number of labs (Schwartz, Donoghue, Nicolelis), but there are a huge number of issues that arise here. First off, how long does an implant last? Signal decays over time when it comes to such implants, keeping a microelectrode array in the brain for a decade and expecting to get strong signals from even a quarter of the electrodes is most likely a pipe dream. What does this mean for Matthew Nagle, then, who has a permanent array in place, and has for around a year, if not longer?

If an array dies, do you do brain surgery and implant another one? I think there are probably a lot of lessons to be learned here from cochlear implants, and probably also pacemakers, which are presently beyond my ken. Also, how can such an implant be wireless? How does it get power? Of course, these are all implementation details, but that's really the guts of any sort of neural engineering scheme. I have a hunch that if you could record from pretty much any population of neurons and use this to, say, control a race car, your subject would figure out how to control it, and find it quite natural to do so. Of course, what do I know, but still - the brain is good at things like that. Look at development - you basically take all sorts of neurons and randomly hook them up to each other (or do you?) and when you're born you spend a few years tuning the system, figuring out how to control things, and you end up doing a remarkable job. There's no instruction manual here, everything is embedded, and there is no innate "this is visual input" kind of information tagged to the retina, LGN, V1, whatever.

So, let's say you have a system that is a hybrid biological and neural system, such as a neuroprosthetic, or something even more fundamental like DeWeerth is doing at Georgia Tech. If I recall, he managed to teach neurons ex vivo to perform some sort of task, which is pretty remarkable, really. First off, wow, how can we use this, and second, what are the implications of this with respect to consciousness? DeWeerth is also special because he graduated from a program similar to mine at Caltech (Computational & Neural Systems), and he's trying to put his models to good use in biological systems, which is pretty fantastic.

Also, it looks like some of his models deal with the spinal cord as opposed to the brain itself, which ties in to other questions of neuroprosthetics. Is it better to go at the brain directly, or try to tap into the spinal cord, which is where a biological arm would have synapsed anyway? Certainly, a lot of the neural structure is still intact, and if you can harness that at a lower level, then you have a lot to gain. Doing surgery on your arm five times is OK, but doing surgery five times on your brain is probably not so hot. And plus, if your surgery goes horribly wrong, you don't destroy any brain tissue at all, ever. Of course, damaging the spinal cord is also really heinous, but there could be ways to try and access the sensory and motor fibers that remain in what is left of the limb.

For example, could sensory input from an arm be given by direct electrical stimulation, such as through explorations by Paul Bach-y-Rita in terms of sensory substitution? For those who aren't aware, Bach-y-Rita managed to provide visual input to blind subjects through electrical stimulation on the tongue. Subjects report visual phenomena, and are able to identify and interact with objects in the world. And this isn't even an invasive technique, putting a chip on the tongue. But how could this be integrated into something long term? Again, this is the sort of thing that could be very appealing for a neuroprosthetic device.

I should probably do some real chatting with Robert Ajemian, who shares many of my interests, and also graduated from my program here at BU.

Anyway, there's some food for thought. Later on I'll figure out consciousness. Yep.