One persistent myth in popular culture about the human brain is that we only use 10% of it. In fact, scientists have found that most of the human brain is actively in use over the course of a normal day. But that doesn’t mean we can’t improve brain function with simple practices like regular exercise, a healthy diet, and adequate sleep. Now advances in technology have made it possible to stimulate the brain to increase learning speed.

In a research study funded by the Defense Advanced Research Projects Agency (DARPA), scientists demonstrated that stimulating the brain non-invasively using transcranial direct current stimulation (tDCS) improved cognitive performance.  The results of the study, published in the journal Current Biology, describe how tDCS was used to “modulate neural activity via weak, externally applied electric fields.” This was done with a non-invasive cap that stimulates parts of the brain through the use of electrical currents. The brain device was tested on macaque monkeys by stimulating their prefrontal cortex. Afterwards, the monkeys were prompted to perform tasks based on associative learning to get a reward. Scientists observed a noticeable increase in the monkey’s ability to perform these tasks when compared to the control group of macaques who were not wearing the tDCS cap.  Monkeys wearing the brain device needed 12 trials to learn how to get the reward, while the control group of monkeys needed 22 attempts to produce the same result. The brain device accounted for a 40 percent increase in learning speed, according to the researchers. As one of the DARPA researchers noted, the prefrontal cortex is the area that controls executive functions including “decision-making, cognitive control, and contextual memory retrieval. It is connected to almost all the other cortical areas of the brain, and stimulating it has widespread effects.” The DARPA researchers pointed out that their device is less costly than other similar non-invasive methods to improve learning.

Researchers concluded that the test results “are consistent with the idea that tDCS leads to widespread changes in brain activity and suggest that it may be a valuable method for cheaply and non-invasively altering functional connectivity in humans.” While we’d all probably like to have access to a device that makes us smarter, that’s not the goal of this research. Future applications could include treating patients with neural degeneration that causes memory loss, such as during a stroke rehabilitation, or in other healthcare applications where cognitive enhancement could improve a person’s life.