What if instead of giving schoolchildren hours of seemingly irrelevant math problems to solve, we equipped them with an electrode helmet that delivers (for a good cause) small electric shocks? Rest assured, this isn’t about to happen yet! But this experiment did take place, and it appears to be effective. Let’s take a look at this research that’s come back onto the scientific scene several years after its initial publication.

Until now, the benefits of non-invasive brain stimulation on cognitive function have often been deduced from behavioral observations and by carrying out basic tasks. In the present study, the team of researchers from Oxford University (UK) used Transcranial Random Noise Stimulation (TRNS), a type of transcranial electrical stimulation. Roi Cohen Kadosh and his colleagues hypothesized that this technique could help with learning and subsequent performance on complex arithmetic tasks by electrically stimulating the dorsolateral prefrontal cortex (DLPFC), which is an area of the brain that’s important for memorization and possibly mathematical cognition processes.

The scientists recruited 25 volunteers matched for age and sex for their experiment and divided them into two groups: TRNS (6 men, 7 women, average age = 20.92) and a TRNS sham control group (6 men, 6 women, average age = 21.42). Members of the TRNS group were given a helmet with electrodes and received electrical stimulations during the experiment. The (painless) current was administered for 20 minutes. Those in the TRNS sham control group were given the same helmet, but didn’t receive any stimulation. Using near-infrared spectroscopy, the researchers also measured blood flow to determine any possible variations in the participants’ metabolisms.

Each subject completed 5 consecutive days of training on arithmetic tasks (calculations and exercises), followed by a test phase (with four calculation sequences). Those in the TRNS group also completed a control phase to determine whether the stimulations that they received influenced other cognitive areas beyond mental calculations. These control tasks (focused on mental rotation and attention) were performed on the first and last day of the training.

The results of this study show that, when compared to the TRNS sham control group, the computational abilities of the TRNS group increased by 30-40%. Even during the training phase, members of the TRNS group memorized the different mathematical drills 2 to 5 times more quickly and increased their calculation speed. In addition, near infrared sprectroscopy data indicated that subjects in the tRNS group had a lower brain metabolism, meaning that their brains were more efficient and used less energy.

In the short term, tRNS appears to be an effective way to improve mathematical memory and counting skills. Note that 6 months later, the researchers had subjects return for further testing. The behavior and physiological modifications appeared to be long-lasting in the “electrified" subjects, and they remembered the operations they had carried out during the first phase of testing more easily than the sham control group. Even better: they could solve problems of similar difficulty that hadn’t been seen previously.

According to the authors, this improvement in mathematical skills could be explained by a structural modification in the cerebrovascular system (better innervation allowing for faster neuronal connections), caused by the electrical stimulations. They argue that: "The current results support TRNS as a noninvasive cognitive enhancement tool capable of improving learning in one of the most complex human faculties, mental arithmetic.” This could be particularly relevant to those struggling with dyscalculia, but the safety of the technique still needs to be further investigated…