In an effort to improve mathematical performance using electrically stimulation in specific sections of the brain, scientists found enhancing one area collaterally impaired cognitive activity in others.
The study, published in the Journal of Neuroscience, detailed how researchers at Oxford University used a non-invasive technique called transcranial electrical stimulation (TES) to theoretically improve cognitive skills associated with mathematics.
In 2007 Roi Cohen Kadosh, a fellow at the college with a PhD in Neuropsychology, pinned down the area of the brain responsible for mathematical ability to the right parietal lobe, just above the right ear. Kadosh’s principal interests have focused on numerical cognition and the acquisition of numerical understanding.
In his more recent research, Kadosh and his colleagues recruited 19 young adults and divided them up into three groups. Using the TES method, electrodes were placed on the scalp of participants and low levels of electric currents were used to stimulate targeted regions of the brain.
One group received 20 minutes of stimulation on both sides of the head over the posterior parietal cortex (PPC). This area of the brain is critical for processing numbers as well as producing planned movements. The second group was stimulated over the dorsolateral prefrontal cortex (DLPFC), which is involved in general learning. The third group received a placebo demonstration where they were led to believe they were receiving electrical stimulus.
Over the course of six days, post TES, participants underwent two hours a day of symbol recognition training. Symbols were meant to represent specific numbers, a teaching technique associated with learning numerals in other languages.
Groups were tested on how quickly they identified one of two symbols which represented a larger number or sum. They were later asked to repeat the task, but researchers intentionally altered the font of one of the two symbols. The larger font was not always assigned to the symbol associated with the larger amount. The volunteers were then asked identify either the larger or smaller sized symbol while trying to ignore the numerical meaning.
The dual part test demonstrated two completely different aspects of learning, one involved with recognition and memorization associated with the meaning of the mathematical symbol, while the other measured automatic response.
The physical illustration of the font often clashed with the representation of the mathematical symbol, as at times the smaller font was linked to the larger sum symbol and vice versa, thus taking slightly longer to identify for some individuals.
Those having had stimulation to their PPC region were able to recognize symbols faster than those who were given fake stimulation. However it was found PPC subjects had impaired ability to respond automatically. The opposite effects were observed in the DLPFC group. Their initial learning was impaired but their automatic response had been enhanced.
The researchers determined the results demonstrated enhancing a specific cognitive ability often resulted at the expense of hindering another. It was assessed the brain compensated by shifting resources in response to the stimulation.
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