Comments on: Mental Control of a Robotic Arm

By: elmer mccurdy

elmer mccurdy — Thu, 24 May 2012 23:32:31 +0000

Anyway, I’m still a bit curious. Which trophic factors from nerves affect muscle growth? I’m afraid Wikipedia isn’t very helpful on this.

By: londonskeptic

londonskeptic — Wed, 23 May 2012 23:52:16 +0000

I love the whole field of BMIs and studied them during my Neuroscience Masters.

This tech is moving so fast, pretty soon we’ll really be able to help quadriplegics and people with locked in syndrome.

Resolution is still a major problem with scalp sensors and finding the right materials which will not cause scarring and deterioration of signal over time is a major problem with implanted sensors.

However, one day we may be able to feed back to the somatosensory cortex.

Then we’ll really have taken the next step!

London Skeptic

By: LivingWithMormons

LivingWithMormons — Tue, 22 May 2012 20:37:13 +0000

In 2003 I was struck by lighting. The current traveled from the top left side of my body, including my left arm, down to my right leg. I have experienced numbness on my right foot ever since (among other symptoms) but more interestingly, my left triceps, which contains a large area of superficial scarring from the (2nd degree) burn, does not respond to growth from resistance training as it used to.
I’ve searched high and low for an explanation to this but the best answer I’ve got so far is that it must be due to some scar tissue in the muscle.

I’m wondering if this is in any way related to what you wrote above, Steve, regarding the release of trophic hormones from the nerve cells. Is there a test a specialist could do that would show this?

By: etatro

etatro — Tue, 22 May 2012 18:04:25 +0000

I wonder whether the visual feedback of seeing the robotic arm move serves as feedback to strengthen the connection. Along with the visual feedback that the robotic arm had moved, comes the sense of satisfaction and reward (via dopamine in the caudate / putamen), in order to strengthen the networks that lead to the initial executive function – decision/desire to move the arm; so that eventually, the basal ganglia will create a shortcut sufficient for the robotic arm-moving to bypass the frontal cortex the way it can with our own arm. Our brain gets feedback from our own arms through various nerve-muscle connections, but this processed through the spinal cord and medulla. We only really know that our arms are in the correct position when we see it in the correct position, feel a landmark. It is possible to have sufficient experience to remember (our caudate remembers, and we might not be conscious of it) what the result of the movement would be, we also get feedback in the form of muscle strain & tension; however the feedback from the result of a motion (seeing your arm in the right position, feeling the stair step on your foot, feeling the lightswitch on your fingers), are quite powerful.

I would think that the visual stimulus and reward for having achieved the goal would be powerful enough to strengthen the brain-machine connection to make it easier for the user over time.

I suppose an experiment would be to blindfold the user, instruct her to move the robotic arm, not inform her of the results; and determine whether a user with our without the visual feedback performed better at the tasks over time. The predicted results seem obvious.

By: Mantiki

Mantiki — Tue, 22 May 2012 12:03:42 +0000

So when the command to move the robotic arm is issued, is it freewill or an illusion of freewill?

By: Jared Olsen

Jared Olsen — Tue, 22 May 2012 09:50:49 +0000

Very cool. More evidence of the coming robotic revolution…

By: Captain Quirk

Captain Quirk — Tue, 22 May 2012 00:26:17 +0000

This is really cool. Is there anything robots can’t do? *Homer Simpson-esque awe*

By: BillyJoe7

BillyJoe7 — Mon, 21 May 2012 21:43:53 +0000

SARA: “I’m not sure how long it takes for atrophy to set in, but if it’s more than 3 or 4 months…”

My uneducated answer: about 7 days.
When training for a race, it doesn’t matter what I do in the last week before the race (the two months before that is of course vitally important).

By: naveed.ejaz

naveed.ejaz — Mon, 21 May 2012 20:20:56 +0000

Thanks for the short review on the recent BMI studies Steven. One aspect of BMIs that you overlooked was that the limiting factor in invasive studies comes from neural tissue forming around the implanted electrodes which over a period of time degrades the signals recorded from the individual neurons. This both reduces the spatial resolution as well as the quality of the recordings for motor control. I don’t have references off the top of my head but I believe that currently electrodes are able to provide stable recordings over a time period of 5-10 years.

By: SARA

SARA — Mon, 21 May 2012 18:33:15 +0000

Once the tech is developed enough, why would we wait long enough for the muscle to atrophy before implanting?

I’m not sure how long it takes for atrophy to set in, but if it’s more than 3 or 4 months, surely we could implant and all that would be needed is training and rehab.

In fact, in the case of an obvious permanent injury, it could be implanted much much sooner, right?

If not, I suppose we would start to seriously look at amputation for the useless living limb and replace it with a useful robotic limb.