From the Wikipedia article.
"Brain fitness is the capacity of a person to meet the various cognitive demands of life. It is evident in an ability to assimilate information, comprehend relationships, and develop reasonable conclusions and plans. Brain fitness can be developed by formal education, being actively mentally engaged in life, continuing to learn, and exercises designed to challenge cognitive skills. Healthy lifestyle habits including mental stimulation, physical exercise, good nutrition, stress management, and sleep can improve brain fitness. On the other hand, chronic stress, anxiety, depression, aging, decreasing estrogen, excess oxytocin, and prolonged cortisol can decrease brain fitness as well as general health.
Brain fitness can be measured physically at the cellular level by neurogenesis, the creation of new neurons, and increased functional connections of synapses and dendrites between neurons. It can also be evaluated by behavioral performance as seen in cognitive reserve, improved memory, attention, concentration, executive functions, decision-making, mental flexibility, and other core capabilities.
Like physical fitness, brain fitness can be improved by various challenging activities such as playing chess or bridge, dancing regularly, practicing yoga and tai chi and also by engaging in more structured computer based workouts. Some research shows that brain stimulation can help prevent age-related cognitive decline, reverse behavioral assessment declines in dementia and Alzheimer’s, and can also improve normally functioning minds. In experiments, comparing some computer based brain boosting exercises to other computer based activities, brain exercises were found to improve attention and memory in people over age 60. . Other studies have evaluated other brain boosting exercises and not found improvements. A study of 67 schoolchildren aged 10 compared 7 week Nintendo brain training to engaging in pen and paper puzzles. The study found that the brain training group suffered a 17 per cent decrease in memory tests after the seven week course, while the pen and paper group saw an increase of 33 per cent. Many experts are skeptical with regard to the real value of different commercial brain boosting products. For example, a panel of experts gathered by Which? Magazine have concluded that ‘Dr Kawashima’s Brain Training’ for the Nintendo DS will not enhance brainpower at all." 
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When a deep, immersive calm is achieved and stressors are reduced, the brain can produce the neurochemical cocktail that enables formation of new neuronal connections. The brain and body are not separate. We have one nervous system, not two. The specific kind of concentration to achieve a deep, immersive calm requires the same level of effort as when learning a new language.
50ten40 curriculum engages your awareness using a physical tools. Using the physical to train the mental produces better results. Real change is difficult and unexpected. Prepare to be suprised.