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.