Some thoughts on moving your arm

As someone whose teenage consumption consisted of ShadowrunGhost in the Shell,  and William Gibson novels (as opposed to a well-balanced breakfast), it’s obvious that I’m big on cyberpunk. My library checkout record could attest to that.

Our interfacing with machines and computers seem rather mundane: keyboards, touchscreens, mice, trackballs, tablets, sledgehammers, assault rfiles, etc. It seems mundane now, but computers were operated by punch cards and magnetic tape once upon a time. You couldn’t even let loose with three-second bursts of semi-automatic fire at your earliest computers, probably because they were under heavy government security. But what if our brains could directly interface with computers? If you think (tee hee) about it, the fact that we have to use the aforementioned means to operate our computers means that our brains are still a few degrees separated from the operating system. Brain sends signal to motor neurons in the arm, activating certain muscles to punch keys or move the mouse so that it sends an instruction to the operating system. So there’s lag between what you want to do and what you end up doing, and that assumes there’s no interference in between. On a more serious note, what about people with prostheses? Sure they may have robotic limbs but what’s the point of a robotic limb if you don’t have direct control over it?

Wikimedia Commons/Public Domain, Author: Daderot (2013)

Then again, what is the brain ‘doing’ other than sending electrical signals from one part of the brain to another? This is the whole idea behind ‘trodes’, likely started from William Gibson’s Neuromancer: using electrodes to detect these electrical signals to, among other things, access the internet (well, in his universe it’s ‘the Matrix‘ – yes, that Matrix) and maybe even work your cyberware. And wouldn’t you know it, a new study (late last year) from Scientific Reports looks at exactly that. Moving an arm around is one thing, but moving the arm in order to reach out and grab something requires some much finer control, probably some better programming on the (oh, let’s just call it what it is) cyberarm’s end. It’s all about syncing the machine circuitry with brain waves – yes, all that alpha and delta brain wave stuff that may sound hokey is from neurobiology, it’s just the frequency of neural activity. You’re welcome to give it a read if you’re so inclined – it’s open access.

13 human subjects (who have both of their arms), one at a time, were hooked up to some ‘trodes and a computer and put through a series of tests, including moving a mouse cursor around on the screen (which isn’t new), which gives them practice ‘imagining’ moving an arm around; the authors show that there’s one particular brain wave pattern (mu) that is most involved with cursor control. As they got better at it, they got to use the arm in order to move it and have it hover over some target blocks. The authors notice that there was a blind spot somewhere in the testing area, where the subjects didn’t seem to be as accurate. One of the last tasks required each subject to move the arm to the block, grab it, and place it on the shelf; they were accurate for the most part save for that pesky blind spot.

There are a few things that the authors are concerned about, mainly about how consistent ‘motor imagination’ and ‘trode control is. Quite a few things can affect it, such as the position of the electrode cap (you’re not thinking of wearing it all the time, are you?) or mental status. However, this is still big stuff, considering that the alternative is invasive electrodes (as in they’re in your brain), and the fact that they can get decent performance with a ‘trode cap and some learning sessions, that’s not bad and probably much, much, MUUUUUUCH less painful. Although I would imagine that as the cyberpunk generation grows up, someone’s going to find a way for you to plug into the web off the base of your neck. I hope you’ve got a good data plan…

Featured Article: Meng J, Zhang S, Bekyo, A, Olsoe J, Baxter B, He B. (2016) Noninvasive Electroencephalogram Based Control of a Robotic Arm for Reach and Grasp Tasks. Scientific Reports. doi: 10.1038/srep38565.

Featured Image: Wikimedia Commons/Public Domain (Author: Antoine Lutz)



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