Johns Hopkins University researchers found that practicing what’s known as a “dual n-back” exercise showed a 30 percent improvement in their working memory. That was nearly double the gains made with other mental exercises. The dual n-back exercise significant changes in brain activity in the prefrontal cortex, the critical region responsible for higher learning. The “dual n-back” is a memory sequence test in which people must remember a constantly updating sequence of visual and auditory stimuli. N-Back Gym allows not just dual, but also triple and quadruple n-back - with position, sounds, colors, and images.