The innovative breeze of 2013 carries a particularly interesting development in the field of Neuroscience.
A joint venture funded by DARPA, composed of a group of researchers from the University of Pittsburgh and Carnegie Mellon University, revealed promising results in a recent study when monkeys were successful in moving a robotic arm using solely the power of their mind.
The practical application and climax of this study, as if it weren’t exciting enough already, finally arrived this January, when a woman was able to operate an artificial arm in a wide range of angles using her brain alone.
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For the past 11 years researchers have been conducting a series of experiments involving the motor-cortex, a part of the brain which facilitates movement. A tiny electrode array was implanted in the motor cortices of monkeys, enabling the scientists to read neural activity in the form of electrical spikes. Using a model based approach, the scientists were able to calculate the desired instantaneous hand and arm direction based on the activity of a few hundred neurons.
Reading brain-activity enabled the scientists to accurately move the artificial limb in the correct direction and angle, exactly the way the brain normally signals a healthy flesh and blood arm. In this way they trained the monkeys to move the arms through biofeedback.
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The monkeys were chosen as test subjects due to their similar brain structure to humans. However, it can’t be helped but to wonder: What is the secret for convincing a monkey to operate a robotic arm? The answer is simple: Marshmallows.
By hanging the treat just out of the monkey’s reach, far enough so that they would need to use the robotic arm to reach it, scientists were able to “train” the monkeys in moving the robotic arm in a space and they were able to teach the monkeys to grip their treat.
The next question that comes to mind is how many monkey-arms were removed due to the experiment? Animal rights fighters – rest assured; No monkeys were hurt in the process.
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After a decade of data-mining, the scientists are ready to implant a brain computer interface (BCI), an electrode array, in 53 year old Jan Scheuermann who suffers from quadriplegia; completely paralyzed from the neck down. The outcome of a not-so-simple surgery was optimistic news to all.
For many amputees, lacking an arm does not necessarily mean the brain is damaged as well. The successful experiment described above makes it very easy for a person to control a prosthetic arm, as all that needs to be done is to ‘think’ which way the arm should move, much in the same way you are operating the arm you are using to scroll down and read this article.
Jan’s reports of headaches quickly disappeared, and no sooner did she prove to be able to feed herself, and even high-five Professor Andrew B. Schwartz, a senior figure in the research. According to Jan, feeding herself was:
One small nibble for a woman, one giant bite for BCI.
While the results of the research are certainly a breakthrough, leaving neuroscientists to fantasize about a world of possibilities opening up, major flaws cannot be ignored.
Implanting the electrode array requires invasive surgery, involving a temporary removal of part of the skull. The degree of control created by the invasive BCI (Brain Computer Interface) is limited by the number of neurons recorded, currently at a few hundred. Non-invasive methods of reading brain signals, such as EEG, offer a much lower information rate and require much more training.
Another flaw that is evident by observing Ms. Scheuermann’s arm movement is a poor eye-arm coordination. Neuroscientists are still looking for a reasonable explanation for Ms. Scheuermann inability to catch a falling object while observing it. Curiously enough, she is able to do so when not looking directly at the object.
Regardless of those facts, the sweet taste of success should not be bittered: this is still the first time a human has been able to operate a robotic arm in so many degrees of freedom, using only the power of the mind.
So what’s next? Killer-coding-ninja monkeys using telepathy? Anyone?
Sources:
NYTimes: Monkeys Think, Moving Artificial Arm as Own
Lancet: Nueroprosthetic Control by Individual with Tetraplegia
Invasive BCI UPMC: Woman with Quadraplegia Feeds Herself
Nature: Cortical Control of a Prosthetic Arm for Self-Feeding
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