Bill Shain is a neural engineer now, but that isn’t what he started out to be. For one thing, when Shain was deciding what he wanted to be when he grew up, neural engineering didn’t exist. There were people doing some proto-neural engineering, but Shain started out on a different track entirely. As an undergraduate at Amherst College he developed an interest in embryology, which as you may have guessed, is the science of how an embryo develops.
Brains need blood, and plenty of it. Brain cells use up a lot of calories and oxygen, and the only place they can get them from is the blood. If the blood supply to the brain is disrupted, the brain tissue starts to die, and that is a bad thing. We call it a stroke. A stroke happens when a blood vessel in the brain either bursts or gets clogged; either way, the result is dead brain cells. How this affects the person who had the stroke depends on where in the brain stroke occurred and how much of the brain was damaged as a consequence. There is no such thing as a good stroke, but some strokes are worse than others. A brainstem stroke is particularly nasty because almost all of the signals going into and coming out of the brain have to go through the brainstem. Thus, damage to the brainstem can impair or completely prevent communication between the brain and the rest of the body. If this happens, the brain has no way to tell the body when and how to move and the body has no way to tell the brain what is happening to it. The result is complete paralysis.
There are lots of engineers out there, wandering loose in the world doing their engineering thing. You have probably heard of them, you may have even met one, or seen one on television. As a result, even if you don’t know exactly what engineering is, you may have some sort of an idea.
Is “sensorimotor” a real word? Yes, actually, it is. It’s a compound word; the two root words are “sensory” and “motor.” It is an adjective, and it just means “having to do with both sensory and motor functions,” which is easy enough to remember. One caveat, though: it is only a word in the context of neuroscience. The rest of the time it doesn’t count, and you can’t use it in Scrabble (unless you’re playing with neuroscientists). Everyone else in the world gets along just fine without it, and that’s why you may never have heard it before, and why most people don’t think it is a real word when first they hear it.
In the last post I talked a little bit about what neurons are, in this post I want to talk about where neurons live. They are not uniformly distributed throughout your body, they are highly organized into a system - the nervous system. On the highest level of organization the nervous system is split into two parts, central and peripheral. The central nervous system, or CNS, includes your brain and your spinal cord. Sometimes the retinas are also included, but for now we’ll leave them out. We call it the “central” nervous system not because it is in the center of your body (your brain is in your head, after all) but because it functions like a central command station.
If your intuition tells you that the adjective "neural" can be roughly translated as "having something to do with the brain," then your intuition has brought you very close to the truth (thanks, intuition). In fact, "neural" means "having something to do with neurons." Neurons are a type of cell, and the majority of those cells live in the semi-solid, three-pound lump of tissue between your ears and behind your eyes - your brain. Your brain houses about 100 billion neurons, which is quite a few. But while most of your neurons are in your brain, most is not the same as all. The neurons outside of your brain are in the minority, but they perform some critical functions, especially in the context of Sensorimotor Neural Engineering. They are still a part of the nervous system, so, when we say “neural”, those guys are invited to the party too.
What exactly is Sensorimotor Neural Engineering? That is a very good question, and one that I get asked frequently. Inevitably when you meet someone you get to talking about what you do for a living, and if you work at the Center for Sensorimotor Neural Engineering, it’s only natural for people to wonder what on Earth that is. Some people are polite about this, while others are more direct. A friend of mine, when I told him about the Center, asked, “Is that a real thing?” It might be interesting at some point to contemplate why my friends would accuse me of fabricating an entire field of study, but I’ll leave that exercise for some later date. For now, I will only say that, yes, in fact, Sensorimotor Neural Engineering is a real thing. Saying what exactly it is will take a little bit longer. Fortunately, that’s the sort of thing that I get paid to do, so I can afford to provide a description that is more than rearranging the word order.