Here are some highlights that caught my attention from the article (tl;dr): Imaging the brain first, to target the stimulation to the active region: "The MRN

Here are some highlights that caught my attention from the article (tl;dr): Imaging the brain first, to target the stimulation to the active region: "The MRN team used this software in part of their DARPA-funded research. First, they imaged volunteers’ brains to see which regions were active as they learned to spot threats. Then they applied 2 milliamps of direct current for 30 minutes to that crucial region – the inferior frontal cortex. They found that stimulation halved the time it took volunteers to learn. This was a huge surprise, says Clark. “Most tDCS studies don’t achieve a huge effect. A lot are borderline.” This is one of the criticisms that has been levelled at tDCS: the results aren’t always that good. Clark is convinced this is because a lot of the studies haven’t involved imaging the brain first, to pinpoint the regions that really need stimulation. “A lot rely on common knowledge about how the brain is meant to be organised. I’ve learned in 33 years of looking at the brain that we still have a lot to learn,” he says. Michael Weisend, who collaborated on the study, agrees – he calls the imaging work “the secret sauce”." Using both excitatory and inhibitory stimulation to increase the effectiveness of training: "Brain imaging suggested that the best way to do this would be to stimulate the motor cortex while the volunteer was doing the task. But McKinley and his team added a twist: after the stimulation, they use tDCS in reverse to inhibit the volunteers’ prefrontal cortex, which is involved in conscious thinking. The day after the stimulation, the volunteers are brought back for re-testing. “The results we’re getting are fantastic,” McKinley says. People getting a hit of both mid-test and inhibitory stimulation did 250 per cent better in their retests, far outperforming those who had received neither. Used in this way, it seems that tDCS can turbo-boost the time it takes for someone to go from being a novice at a task to being an expert." Side-effects seem to be absent from evidence up to this point: "So far, there seem to be no harmful effects of tDCS, at least, not at the levels or durations of stimulation that are routinely used. Weisend believes there’s no such thing as a free lunch, and admits there could be side-effects to tDCS that no one knows about yet."