Just about everyone wishes they were better at math. But studying and practicing is so difficult and boring that very few people do it. If only there were an easier way.

Now there may be, suggests a new study in which scientists stimulated volunteers' brains with mild electric current while they learned new arithmetic operations based on made-up symbols. People who received brain stimulation during training sessions on five consecutive days learned two to five times faster than those who received sham stimulation, and they retained a 30 to 40 percent performance edge six months later.

The study is not the first to show improvement in mathematical cognition with brain stimulation. In 2010, scientists reported that people can learn a new set of numbers based on arbitrary symbols more quickly when a mild current is applied to the right parietal lobe of the brain, a region implicated in previous number-comprehension studies.

The new research goes a step farther by showing that electrical stimulation can also improve the ability to perform calculations, says cognitive neuroscientist Roi Cohen Kadosh of the University of Oxford, who led both studies.

The new study also uses a different type of stimulation. In the 2010 study, Cohen Kadosh and colleagues used transcranial direct current stimulation (tDCS), which delivers a weak but constant current to the brain via electrodes placed on the skull. In the new study, they used transcranial random noise stimulation (TRNS): current that fluctuates randomly within certain bounds. People sometimes feel a slight tingling on the scalp with tDCS, Cohen Kadosh says, but with TRNS they usually feel nothing.

They may also get a different kind of cognitive boost.

The researchers applied TRNS to a different brain region thought to play a role in mathematical cognition, the left dorsolateral prefrontal cortex. When people received TRNS during training sessions spread across five days, they memorized new "facts" more quickly (such as 4 # 12 = 17, an arbitrary equation that had to be learned by rote). Compared to subjects who got sham stimulation, those who received TRNS also learned more quickly to do calculations with novel operands (the symbols like + and - that tell you what to do with the numbers on either side, but in this case the new symbols required somewhat more complicated operations).

The researchers also monitored blood flow in the stimulated region of cortex with a non-invasive method called near-infrared spectroscopy. TRNS appeared to make metabolism more efficient, co-author Jackie Thompson wrote in an email to Wired: "That is, metabolic levels in the TRNS group were actually lower whilst doing the same mental calculations (the same amount of "work") as the sham group."

That physiological change, as well as the improved calculation performance, persisted 6 months after training, the researchers report today in Current Biology. (The improved memory performance did not).

"If I put my sci-fi hat on, what I can imagine coming down the road is even more sophisticated combinations of stimulation and cognitive training," said Peter Reiner, a neuroscientist and neuroethicist at the University of British Columbia in Vancouver. Reiner sees the performance improvements reported in the new study as a nice incremental advance over what's been shown previously, but he predicts that bigger things are on the way. "There's a huge amount of potential there."

But before you run off to RadioShack and fire up the soldering iron in an attempt to build a TRNS kit, Cohen Kadosh has a few words of caution. "Do not try this at home," he said. Although tDCS is fairly simple, TRNS requires more sophisticated equipment and protocols. The electrodes have to be attached in just the right place and the cognitive training has to be done right too, Cohen Kadosh says.

Also, although his team didn't see any adverse effects in this study, they recently discovered that tDCS can cause cognitive impairments as well as benefits in some cases.

Study and practice is still the surest and safest way to kick your brain into a higher math gear. At least for now.