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Nothing says DARPA-funded science like the idea of jet fighter pilots launching missiles or unleashing the gatling cannon with nothing but their minds. While it is easy to see the potential shortcomings of such an approach, it has been hard to shake the dream of hands-free cockpit control. Researchers from the Technische Universit채t M체nchen and TU Berlin have now demonstrated that a plane can be accurately piloted without touching either pedals or stick "at least within a flight simulator.

The stated motivation for the project is to make flight accessible to more people. While that may be a noble pursuit, let's cut to the chase and examine how this might actually work. As is usually the case, we are given little about the actual methods used here to extract control commands from the pilot other than it is done noninvasively from EEG signals, with some kind of brain-computer interface. In order to shed light on this question I talked to Miguel Nicolelis about how his mind-controlled exoskeleton might use potentials from a paralyzed person to perform the opening kickoff at the 2014 World Cup in Sao Paulo.

To get the ball rolling I asked whether he would be using something akin to the fairly well-known "ereitschaftspotentials"which can be recorded over motor and premotor areas before someone makes a volitional movement "and if so, then how much averaging would be required to reliably get an unambiguous signal to kick a ball. Needless to say, like many of the new EEG mind control projects out there, details were not forthcoming.

So in this knowledge void, what other possible signals might be available? Another well-known signal is the so-called P300 waveform which can be recorded over the sensory cortex at around 300 ms after a sensory stimulus is presented. While it is sometimes possible to measure this signal with a single trial, event-related potentials"like this have the drawback that they require the stimulus to evoke them. Intriguingly, researchers have found that these signals are stronger for stimuli that has particular meaning to the person under test.

In this vein a more subtle signal known as "mismatch negativity"has been measured as a negative potential in response to novelty. For example, if the subject is presented with a series of auditory cues like, "pa, pa, pa" and then on a subsequent trial a "a" is presented, the brain's response can be seen with electrodes placed at certain areas over the frontal cortex. More practically minded efforts to select letters for a "rain to text"converter, or to move a cursor in a free-running, non-stimulated condition may require something more dramatic.

Scientists have found that one of the best ways to get a strong signal to make something happen is to imagine something provocative or arresting. Images of fear, like getting threatened with knife have proven to be effective. But with time we might expect that the brain will adapt and ever more frightful or preposterous imagery would be needed to get the same response.

Other efforts to control drones have had some success by using the covert motor signals the brain generates when imagining squeezing the hand. As in the approach used in the video above, the pilot might imagine clenching the right hand to turn right, and both hands to turn left. While not entirely obvious, playing one hand against the other, or one against both, may take best advantage of how brains actually work. In attempting this kind of an approach some details about the test subject, and the peculiarities of their brains may be helpful.

For example, left-handers and no-handers tend to do do things like speech and limb movement much differently than right-handers. In the extreme there are people like the "Rain Man"(the late Kim Peek) who could read two pages of text simultaneously "one page per eye. Scans revealed a congenital variation in Kim's brain in which the connections between the two halves of his cortex were largely absent. We might suppose that this anomaly had something to do with his unique capabilities. While Kim still moved his eyes in sync, the question can be raised whether it would even be possible to temporarily de-yoke our gaze like some reptiles. This might permit one to keep an eye on the sky and generate responses to events, while the other eye takes a glance at a Glass-like display.

One way that the control interface could be improved would be to add some kind of feedback. Pilots can feel resistance in steering which varies as loads on the wing surfaces change. The researchers are exploring ways to incorporate this into their design. At the present time pilots can follow eight out of ten targets with a deviation of just ten degrees. That is certainly an achievement, but probably not good enough for the real aviation world. Throttling a 3000 lb thrust jet engine strapped to a 1929 stunt plane already making 1500 lb of thrust with its original powerplant may be the perfect application for brain control.

Knowing what the brain really wants to do will require more invasive brain monitoring. The most esoteric thoughts ever produced by man "whether it's Einstein imagining what a flashlight beam looks like on a train or bike moving at the speed of light, Tesla playing with the rotating electromagnetic field of an AC induction motor in his mind, or Kekul's shape-shifting a snake eating its own tail in a dream to reveal the structure of benzene "all our thoughts and whims might eventually be able to be seen.

May 2014

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