By preforming measurements of electrical surface potentials of the brain via electrocorticography (ECog), researchers at the University of Washington demonstrated that using a brain-computer interface to move a mouse on a screen provides a serious workout to the organ. The brain adapts quickly to the implant and devotes a lot of energy into the process. The clinical potential of this finding is pointing to using neural interfaces to train the brain after a stroke.
The researchers first recorded brain patterns when human subjects clenched and unclenched a fist, stuck out a tongue, shrugged their shoulders or said the word “move.”
Next, the scientists recorded brain patterns when subjects imagined performing the same actions. These patterns were similar to the patterns for actual action but much weaker, as expected from previous studies.
Finally, the researchers looked at signals when subjects imagined performing the action and those brain signals were used to move a cursor toward a target on a computer screen. After less than 10 minutes of practice, brain signals from imagined movement became significantly stronger than when actually performing the physical motion.
After less than 10 minutes of training, two of the subjects also reported they no longer had to imagine moving the body part and could just think about moving the cursor.
The new findings also provide clues about which brain signals to tap. Researchers compared the patterns in low-frequency signals, usually used to control external devices, and high-frequency signals, typically dismissed as noise. They discovered that the high-frequency signals are more specific to each type of movement. Because each one occupies a smaller portion of the brain, several high-frequency signals could be tapped simultaneously to control more sophisticated devices.
Press release: Brain-controlled cursor doubles as a neural workout …
Open access article in PNAS: Cortical activity during motor execution, motor imagery, and imagery-based online feedback
Image: Top: Brain signals in the first trial, when the subject was able to hit the target just under half the time. Bottom: Brain activity after about 10 minutes of training, when the subject could hit the target with 94 percent accuracy.
