Transcranial DC Stimulation Improves Learning

Research soon to be published in PNAS involves transcranial direct current stimulation (tDCS) of the brain to aid learning a motor skill. The findings suggest that tDCS over the motor cortex can aid the learning and long term retention of a new motor skill.

The new paper targets an area of the brain known as the primary motor cortex, which helps control muscle movements. The authors focused on a learning task, one they describe as similar in principle to the process we go through when we learn a new sport. Subjects were given a device that measured the pressure applied between the thumb and forefinger, and asked to use it to maneuver a cursor through an on-screen obstacle course. One group of subjects received a current; the controls had electrodes attached, but received no current. The subjects were asked to come in for five consecutive days to repeat the process so that researchers could track how their skill improved.

By the end of day one, those who had an anode placed near the primary motor cortex were already pulling away from their peers (a cathode had no effect), and had opened up a large and significant gap by the end of day five. As expected, stopping the training at day five resulted in a gradual decline of the skills over time. Because the two sets of subjects showed declines of roughly the same rate, the gap that opened up during training wound persisting to at least 85 days after the training sessions ended.

Between days... the control group was prone to forget some of the skills they had developed; in contrast, those receiving the current actually came back the next day in better shape than they'd left the day before.

The authors argue that this fits in nicely with our model of how memories are formed, as it involves a three-step process of learning, consolidation, and retention. Clearly, the tDCS was only affecting the consolidation portion of the process.

Although the results are startling enough on their own—the fact that something as crude as sticking an electrode on your head is enough to have such specific consequences is quite surprising—they actually have significant practical implications. Strokes and many other types of brain damage often force their victims to relearn basic motor skills, from speech to walking. Given that tDCS is noninvasive and may help speed to recovery of these patients, I'd expect to see tests of its efficacy in the near future. _arstechnica

Other non-invasive approaches to electromagnetic brain stimulation include the external magnetic coil stimulator. An Israeli company named Brainsway has recently received European approval for using its deep TMS system to alleviate depression, bipolar disease and schizophrenia (H/T Brainstimulant). The interesting thing about the Brainsway is that it can be used to either inhibit or augment neural activity in the targeted part of the brain.

The prospect of improved learning through brain stimulation is just as exciting as the prospect of better therapies for depression, stroke, and other neuro-psychiatric disorders. We are aiming for something beyond normal. The next level.