4 ms·

So I totally want this to actually happen. However, they gloss over all of the actually hard parts. Cool, DEKA's built a sweet anthropomorphic robotic arm.

by frisco 16y ago

So I totally want this to actually happen. However, they gloss over all of the actually hard parts. Cool, DEKA's built a sweet anthropomorphic robotic arm. I have no doubt that part works. But you don't just jump to running a human study from that: first, you do it in non-human primates and show that they can effective control the arm with the implant. Then you show that they can interpret feedback from the arm stimulated into their brain. Then you show that the implant is stable and immunologically accepted over a long period of time (warning: deep, hard unsolved problem). Then you show that they continuously integrate it into their body representation (not necessarily hinted by the prior control study). Then you cautiously do a human surgery and see if they can control it, and the brain doesn't reject the implant after a year. Then five patients. Then apply for FDA approval, expedited or otherwise. AFAIK there's never been an implant study done using the Luke arm. Therefore we've never tried to build control models from cortical activity for it. That's a hard problem in and of itself. Jumping straight to a 5-person human study is insane. Furthermore, the idea that human patients are going to get intracortical feedback from the arm is crazytalk. It's just not happening. Electrical stimulation cooks the brain and causes seizures, and optical stimulation requires gene therapy (!) and has all kinds of long-term problems right now. TL;DR: awesome I hope it works. They'll bring a needed device to market and solve about 10-15 of the hard problems of brain-machine interfacing for us at the same time!

deleted 16y ago
[deleted]
nooneelse 16y ago
Indeed. I have no idea why they would want to include solving the "don't cook the neurons" problem in their road-map to a usable product; there are other feedback methods available. A haptic display of some flavor would certainly be plenty to close the loop in controlling the important variables like "are any of the motors encountering resistance" and "how much pressure am I putting on this thing I'm squeezing in my robot hand." A more advanced haptic display should allow enough feedback signals to hold much more than that. Heck, if one is going to go electrically stimulating neurons, better to do that to sensory neurons in the user's skin than in their skull.
sp332 16y ago
Electrical stimulation cooks the brain and causes seizures From Wikipedia: deep brain stimulation has been FDA-approved for tremor since 1997. More treatments have been approved since, like Parkinson's, dystonia, major depression, and chronic pain. https://secure.wikimedia.org/wikipedia/en/wiki/Deep_brain_stimulation#Potential_complications_and_side_effects https://secure.wikimedia.org/wikipedia/en/wiki/Deep_brain_st... Then you show that they continuously integrate it into their body representation This part is easy, isn't it? People integrate tools into their body image innately and easily. I don't think that will be very difficult.
- frisco 16y ago
  Deep-brain stimulation is different than cortical microstimulation. DBS is injected into the basal ganglia and excites an area of the brain that's effectively atrophied. This can be done relatively safely for things like Parkinsons, even though it's definitely not your first choice of treatment. It's still somewhat cooking the brain, however; in the cases where DBS is used that just doesn't outweigh the benefits. Cortical stimulation into primary sensory cortex is a totally different animal, and tends to cause seizures much more frequently. The brain is kind of wired to seize, when you look at it, and it's amazing it doesn't more often. Also, you can't map receptive fields -- which specific areas of cortex correspond to what sensation in what part of the body -- if your patient is an amputee, and there's no "master map" that's precise enough since it varies between individuals widely. Further, DBS is just designed to grossly "drive" an area of the brain; in ICMS you'd want to precisely excite a few cells to create a sensation. ICMS in practice just floods its surroundings with current in a rather blunt way. Optogenetics are a solution but have their own problems (i.e., requires genetic transfection) that make them unacceptable for use in humans today. This part is easy, isn't it? People integrate tools into their body image innately and easily. Yes -- but as a patient lives with a prosthetic full time, as opposed for a few hours at a time like in most monkey studies, the brain will adapt to the prosthetic and the neural representations shift. You need to be able to deal with this and understand what that learning looks like, which we can sort of do right now, but no one's really done a long-term-continuously-living-with-a-prosthetic study. You generally don't try to solve complete unknowns like that for the first time in humans. Humans would be a poor platform, anyway, since you can't observe and record from them 24/7 in a controlled environment.
stevenrace 16y ago
>> first, you do it in non-human primates and show that they can effective control the arm with the implant... Then you show that the implant is stable Uncited, I'm not sure my reply is worth much - but such studies have already taken place. Non-human primates have shown dexterity with such devices - but the 'interface' has a life of around 6 months due to prolonged , subtle vibrations in the 'brain probe' and scarring. EEG inputs, while non-invasive, are susceptible to interference and work best with additional triggers such as speech to extend ones 'vocabulary' of movements. The reason being it's hard to to calibrate. Lastly, electrocorticography (ECoG), seems a happy medium: picking up high frequency signals within the skull and atop the brain. So no issues with scarring and the signals are easier to map to brain regions. 'Google Tech Talk' on the subject (1hr)[1]: http://www.youtube.com/watch?v=mFWnTONOvVo http://www.youtube.com/watch?v=mFWnTONOvVo [1] Includes footage of monkeys + robotic arms @ 9m30s

by frisco 16y ago

deleted 16y ago

[deleted]

nooneelse 16y ago

Indeed. I have no idea why they would want to include solving the "don't cook the neurons" problem in their road-map to a usable product; there are other feedback methods available. A haptic display of some flavor would certainly be plenty to close the loop in controlling the important variables like "are any of the motors encountering resistance" and "how much pressure am I putting on this thing I'm squeezing in my robot hand." A more advanced haptic display should allow enough feedback signals to hold much more than that. Heck, if one is going to go electrically stimulating neurons, better to do that to sensory neurons in the user's skin than in their skull.

sp332 16y ago

Electrical stimulation cooks the brain and causes seizures From Wikipedia: deep brain stimulation has been FDA-approved for tremor since 1997. More treatments have been approved since, like Parkinson's, dystonia, major depression, and chronic pain. https://secure.wikimedia.org/wikipedia/en/wiki/Deep_brain_stimulation#Potential_complications_and_side_effects https://secure.wikimedia.org/wikipedia/en/wiki/Deep_brain_st... Then you show that they continuously integrate it into their body representation This part is easy, isn't it? People integrate tools into their body image innately and easily. I don't think that will be very difficult.

frisco 16y ago
Deep-brain stimulation is different than cortical microstimulation. DBS is injected into the basal ganglia and excites an area of the brain that's effectively atrophied. This can be done relatively safely for things like Parkinsons, even though it's definitely not your first choice of treatment. It's still somewhat cooking the brain, however; in the cases where DBS is used that just doesn't outweigh the benefits. Cortical stimulation into primary sensory cortex is a totally different animal, and tends to cause seizures much more frequently. The brain is kind of wired to seize, when you look at it, and it's amazing it doesn't more often. Also, you can't map receptive fields -- which specific areas of cortex correspond to what sensation in what part of the body -- if your patient is an amputee, and there's no "master map" that's precise enough since it varies between individuals widely. Further, DBS is just designed to grossly "drive" an area of the brain; in ICMS you'd want to precisely excite a few cells to create a sensation. ICMS in practice just floods its surroundings with current in a rather blunt way. Optogenetics are a solution but have their own problems (i.e., requires genetic transfection) that make them unacceptable for use in humans today. This part is easy, isn't it? People integrate tools into their body image innately and easily. Yes -- but as a patient lives with a prosthetic full time, as opposed for a few hours at a time like in most monkey studies, the brain will adapt to the prosthetic and the neural representations shift. You need to be able to deal with this and understand what that learning looks like, which we can sort of do right now, but no one's really done a long-term-continuously-living-with-a-prosthetic study. You generally don't try to solve complete unknowns like that for the first time in humans. Humans would be a poor platform, anyway, since you can't observe and record from them 24/7 in a controlled environment.

stevenrace 16y ago

>> first, you do it in non-human primates and show that they can effective control the arm with the implant... Then you show that the implant is stable Uncited, I'm not sure my reply is worth much - but such studies have already taken place. Non-human primates have shown dexterity with such devices - but the 'interface' has a life of around 6 months due to prolonged , subtle vibrations in the 'brain probe' and scarring. EEG inputs, while non-invasive, are susceptible to interference and work best with additional triggers such as speech to extend ones 'vocabulary' of movements. The reason being it's hard to to calibrate. Lastly, electrocorticography (ECoG), seems a happy medium: picking up high frequency signals within the skull and atop the brain. So no issues with scarring and the signals are easier to map to brain regions. 'Google Tech Talk' on the subject (1hr)[1]: http://www.youtube.com/watch?v=mFWnTONOvVo http://www.youtube.com/watch?v=mFWnTONOvVo [1] Includes footage of monkeys + robotic arms @ 9m30s