EEG consumer BCIs spanked by the Schwartzinator

Forbes has a fun little story on the state of consumer BCIs that hits on the major consumer players, but also throws real BCIs researchers John Wolpaw and Andy Schwartz into the fray. Each echos the officially sanctioned position of their respective scalp electrode versus implanted microwire/fancier probe electrode camp.

I prefer to call this the Head-Computer Interface versus Brain-Computer Interface debate. I try to be even keeled on the subject. EEG is obviously a worthwhile endeavor because there's none of that messy surgery involved, and thus appeals to a very large audience (at least in the near term). Hey, if you get a signal that can be controlled by the user reliably and with an acceptable level of precision, you have something useful. BUT, EEG is a degraded, garbled, sloppy signal prone to nearly limitless interference sources. Anything that can bork an implanted BCI can bork an EEG-based system, but EEG throws the doors open to the world because you are essentially wearing an antenna (or several).

One major problem with EEG is the fallacy that somehow destroyed information can be recovered by some form of fancy filtering. This is simply not so. Think of the electrode as a point of convergence for all electromagnetic signals of a measurable intensity. Even after narrowing frequency bands and implementing funky probabilistic decoders, any squiggle can be the convergence of several squiggles of indeterminable sources. In other words, at a specific time, a signal of amplitude +5 can be two signals of +4 and +1, -2 and +7, or 5 signals of +1-4-2+3+7. And don't even start with harmonics.

The second problem is population size. I know we like to think that motor cortex responds to only movement. It makes life easier. What life? Life in La-La-Land. MI responds to visual stimuli, movement preparation, auditory stimuli, imagined movements, movement related words (heard, internally rehearsed or spoken), reward, attention, cutaneous and proprioceptive feedback, and a bunch of other factors I'm not even mentioning. Until the impact of these influences is understood and quantified, there will not be any BCI that translates the neural activity for "move my arm to point x,y,z". EEG will never have the fidelity to isolate the differences feedback has at the single neuron level, so the nature of the recorded signal will never allow the 'direct' mapping of neural activity to output. That is, the activity that once gave rise to movement can never be harnessed with an acceptable degree of control to recreate the movement. Yes, I am using the word never. Never. There, I said it again.

Like I said, this isn't an attack on EEG, just reality. Different uses for different technologies. I can drive a car on a road. That doesn't mean I can drive a road, or that a road has no use.

Hochberg article in NEJoM

Leigh has an article in this month's New England Journal of Medicine related to The Project. Required reading, of course.

Monkey self feeding BCI control

Alright, I get it. Several people have sent along links to Andy Schwartz's Nature publication, so here's the info. Thanks to Remy Wahnoun and Natalia "Get Moose and Squirrel" Bilenko for doing my work for me and compiling the links, and being the first to send info along.



http://www.nature.com/nature/journal/vaop/ncurrent/full/nature06996.html
http://news.bbc.co.uk/2/hi/science/nature/7423184.stm
http://technology.newscientist.com/channel/tech/dn14000-robomonkeys-use-brain-power-to-grab-a-bite.html?feedId=online-news_rss20

The work reported involves real time decoding to drive a robot arm, which fed the monkey. I haven't had time to run through the whole thing, so here's the "shoot from the hip" version of my thoughts. I'll update these

Interesting points:

- The monkey was trained to use the arm with a joystick, and followed by, the part I thought was very interesting, various levels of pre-programmed control assistance while using brain signals. I will expand on this later, but it is an interesting task design for several reasons.

- Having seen some of the raw video at the Neurobotics 2007 workshop, there is much more obviously correlated arm motion. They have an entire, substantial paragraph devoted to this, since they probably knew it would be a criticism.

The three points they make are:
1) Movements were with the arm ipsilateral to the electrodes.
2) The movements were delayed by up to a second.
3) Moving is required, since BCI control has been demonstrated before without it.
They cite some supplementary info and write, "... monkey’s hand movement was only loosely coupled to prosthetic control." The video I saw before tells a slightly different story. There was a pulling movement 100% of the time (every trial), and when the arm didn't reach the monkey's mouth it would 'paw' or 'dig' (repeated movements similar to pulling an invisible object toward the body) repeatedly until the arm reached the monkey's mouth. You can see this pretty clearly in the video linked above (watch the hand in the plexiglass tube). Yes, there is a delay, but the whole situation would be interesting to examine. It may not require the 'pulling' at onset, but monkeys very often use both hands to eat. Those of you with monkeys, go give them a treat. They will grab it with they right hand (usually), and then pull it towards their body and engage their left hand as they do so. Feeding it almost always a bimanual task for macaques, explaining the ipsilateral activation and the delay. Reason #3 above is kind of a brush off reason - hey, movement is needed to use a BCI, so no big deal. The three cited papers are all in humans, all were tetraplegic, all lacked some degree of propriocentive feedback, two didn't use PVA or multielectrode arrays, none used an arm, none had confirmed the lack of covert movements with EMG, and the list goes on.

- The trial was very organic and continuous, which is great. From my brief skimming, it looks like simultaneous control of the hand aperture needed to be maintained throughout the task, hinted at when they observe the the hand slowly opening along the path to the food.

In general this is a nice, brief summary with some very interesting points (perfect for a Nature Letter). Obviously they are preparing some studies, and this was released to wet out appetites. The 'organic' nature of the task will open it up to many criticisms, but more studies like this are needed in order to understand the dynamics in play when dealing with a experiences that lack built-in boundaries and environmental awareness. Definitely good thought fodder.

BCI news items

First, pointed out by the lab, Nicolelis is in the news again. Monkey brains in North Carolina controlling walking robots in Japan. Nice. Again, dissociation of neural activity and decoder performed (monkey stopped walking, but could keep the robot walking while remaining still).
No mention of a paper with some objective measures, but a pretty decent write-up available on the NYTimes site. There's even a nice schematic and video.

Interview by PhysOrg with EEG mogul Fatourechi, related to a paper published in JNE. Take a gander here.

TMR going far

And last one for tonight, Natalia pointed out that Dr. Kuiken's work in Chicago has been in the news again, thanks to some advancements that led to a J Neurophys paper. You'll remember the work (targeted muscle reinnervation) from the big media blitz a couple years ago.

Long story short, they reroute nerves that were going to an amputated limb, to muscles on the chest, side, and abdomen. Patients think about moving the non-existent limb, causing the fibers to fire, thereby eliciting a EMG detectable twitch of the new target muscle. That activity is then translated into movement of a robotic arm. The new paper discusses nerve targets, and more electrodes, making movement detection 95% accurate for 16 movements.

Paper found here.

A lickable interface

Ganked from PhysOrg, a tongue driven device that uses changes in ear air pressure (say that three times fast!), to detect tongue movements. The device is actually positioned in the ear, as shown above, and overcomes the issues of previous tongue-driven devices with attachment and comfort during use.

Nicolelis video

For those of you who haven't had a chance to see the inner sanctum of a BCI lab, here is a little video about Nicolelis' most famous experiment, complete with cheesy sound effects and British narrator. Even if you've read about it, there's something about watching the footage that adds to the experience.

Video games

Mark my words: Video games will be the biggest driving factor outside of traditional research for the BCI field. You have at the same time fine and robust input control, reward, motivation, community, and accomplishment all wrapped up in a neat little package. Add to that art, music, plot, and history, and you have a task that not only seems rewarding, but is also life enriching (things that might appear to be lacking in Pong or Super Mario Bros.).

So, I will be adding bits and pieces of video game news, as they pertain to interface and assistive technologies. If you don't like it, too bad. You'll thank me later. (Ask the people that didn't believe me in 1995 when I said the most important advancements in the internet will not be in 'finding' information, but 'filtering' it.)

First, we have One Thumb to Rule Them All, linked from Gizmodo. An inspiring story about a writer and gamer who plays mainstream games with only his thumb (due to spinal muscle atrophy).

Next, we have TecEBlog, with a mini-survey of various alternative input devices, like EOG, EMG, BCI, tongue, etc. Nice little gallery of videos.

And finally, the latest in non-neural, neural control of games, the OCZ Actuator. This has been making the rounds since the press release, and there are plenty of videos on YouTube if you're interested. If you watch carefully, you'll note that the player's muscle movements are driving the game.

Cybernetic flying poop machines

Of course, I'm referring to pigeons. Cybernetic pigeons. Should this be filed under "Because We Can"?

I can't find any info on what they are stimulating, but the story linked here to Practical Neurotechnology says it is not MFB stimulation. It is highly doubtful that this is direct motor cortex stimulation for a number of reasons (pigeons are considered to have a 'real' motor cortex, but the highly coordinated movements would be awfully tough to trigger on the fly). MFB, for those not in 'the know', is the Medial Forebrain Bundle, a collection of processes running from the ventral tegmental area to the nucleus accumbens. This pathway represents one of the biggest dopamine-carrying routes in the brain, and connects many of the areas involved in narcotic and addiction research. The earliest reward system experiments used MFB intracranial self stimulation under various environmental and drug-administration situations. Stimulating the MFB increases 'reward' sensation, and has been thought of as the site of potential 'control' signals - do the right thing and good human gets his juice.

A third method for controlling action, aside from MFB or MI stimulation, is vestibular nerve stimulation. Give a person the feeling that they are falling, and they will move to counteract that feeling. This technique is non-invasive, but pretty crude. NTT/Docomo has been working on the technology as one of their fun projects, and there's a first person account here.