||This article or section appears to contradict itself. (April 2012)|
The term brain fitness reflects a hypothesis that cognitive abilities can be maintained or improved by exercising the brain, in analogy to the way physical fitness is improved by exercising the body. Although there is strong evidence that aspects of brain structure remain plastic throughout life, and that high levels of mental activity are associated with reduced risks of age-related dementia, scientific support for the concept of "brain fitness" is limited. The term is virtually never used in the scientific literature, but is commonly used in the context of self-help books and commercial products. It first came into play in the 1980s, and appeared in the titles of self-help books in 1989 and 1990.
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, air pollution, 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 practicing sports, 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. However, all brain training products are different and some work better than others. 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 percent decrease in memory tests after the seven-week course, while the pen and paper group saw an increase of 33 percent. Some experts are skeptical with regard to the real value of particular 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. However, other researchers underline the growing amount of studies indicating that some commercial brain training products have shown measurable results in improving various cognitive skills.
Neurogenesis is the creation of new neurons. The more active a particular brain cell is, the more connections it develops with its neighboring neurons through a process called dendritic sprouting. A single neuron can have up to thirty thousand such connections, creating a dense web of interconnected activity throughout the brain. Each neuron can then be stimulated directly through experience (real or imagined) or indirectly through these connections from its neighbors, which saves the cell from cell death.
Physical exercise boosts the brain’s rate of neurogenesis throughout life, while mental exercise increases the rate at which those new brain cells survive and make functional connections into existing neural networks. Both physical exercise and the challenge from mental exercise increase the secretion of nerve growth factor, which helps neurons grow and stay healthy.
Consistent mental challenge by novel stimuli increases production and interconnectivity of neurons and nerve growth factor, as well as prevents loss of connections and cell death. The Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) nationwide (America) clinical trial is so far the nation's largest study of cognitive training. Researchers found that improvements in cognitive ability roughly counteract the degree of long-term cognitive decline typical among older people without dementia. The results, published in the Journal of the American Medical Association in 2002, showed significant percentages of the 2,832 participants age 65 and older who trained for five weeks for about 2½ hours per week improved their memory, reasoning and information-processing speed.
Joe Verghese, M.D. found that people with higher activity score had lower risks of Alzheimer's and dementia. An open question in the field is whether people who will later develop Alzheimer's are naturally less active, or whether intervening to raise an activity score will delay or prevent Alzheimer's. If the latter hypothesis were true, people could lower their dementia risk by 7% simply by adding one activity per week (such as doing a crossword puzzle or playing a board game) to their schedule. According to the findings of that same study, subjects who did crossword puzzles four days a week had a 47% lower risk of dementia than subjects who did a crossword puzzle just once a week.
Role of neurotrophins
Brain fitness is purported to be positively influenced through mental and physical exercises that increase levels neurotrophins. Neurotrophins are a small class of proteins that are vital in neuronal development and function. In development, neurotrophins act to protect and warrant the survival of an adequate number of neurons. The survival of ample neurons is vital to ensure that they are match for target innervations. Neurotrophins also assist cell fate decisions, innervations patterns, the development of axons, dendrite pruning, etc. Neurotrophins are also important for regulating neural function and neuronal survival. Neurons are affected most predominantly by neurotrophins; however, they are important for many parts of the body in addition to the nervous system. Neurotrophins are crucial for the survival of neurons in the peripheral nervous system (PNS) as well as neurons in the central nervous system (CNS). The four most common neurotrophins are Nerve Growth Factor (NGF), Brain Derived Neurotrophic Factor (BDNF), Neurotrophic Factor-3 (NT-3), and Neurotrophic Factor-4/5 (NT-4/5). In order to understand how neurotrophins affects brain fitness, it is important to understand how they work.
Nerve growth factor (NGF) was the first neurotrophin to be discovered and is the most famous. The effects of NGF are present in a multitude of tissues through human development as well as adulthood. NGF is associated with immunity, stress reaction, nerve maintenance and neurodegenerative diseases. NGF is known have a predominant effect on the sympathetic ganglion cells and dorsal root ganglion cells with free nerve endings and the cholinergic neurons of the basal nucleus. Sympathetic ganglion cells are masses of neuronal cell bodies in the sympathetic branch of the visceral (autonomic) nervous system. Dorsal root ganglion are masses of neuronal cell bodies in the posterior portion of the spinal cord where sensory information is processed. Cholinergic neurons are profuse in parts of the brainstem, the base of the forebrain, and the basal ganglia. They are thought to play a role in regulating the general level of activity of CNS neurons, especially during the different phases of wakefulness and sleep and also during learning. Therefore, it can be purported that increased secretion of NGF can stimulate the sympathetic nervous system, the sensory portion of the spinal cord, parts of the brainstem, the base of the forebrain, and the basal ganglia. Perhaps the roles of these individual structures can be facilitated or preserved with increased NGF.
Secretion of brain derived neurotrophic factor (BDNF) is stimulated by cortical neurons, and is essential for permanence of striatal neurons in the brain. Both patients with Alzheimer's and with Huntington disease exhibit reduced levels of BDNF. Striatal neurons are the nerve cells that make up the stratium. The stratium is an inclusive term for several structures of the midbrain. The stratium is the major point of entry for receiving input from most or all cortical areas and analyzing inhibitory outputs to the various parts of the midbrain. Therefore, it may be deduced that secretion of BDNF can have an influence on many parts of the cerebral cortex and coincidentally the functions of the areas influenced.
Spiral ganglion neurons are particularly sensitive to neurotrophic factor-3 (NT-3). The spiral ganglion neurons contain the cell bodies of the auditory primary afferent fibers. The central process of these cells collect at the base of the cochlea to form the cochlear division of the eight nerve  These afferent fibers carry auditory impulses toward the central nervous system. Therefore, it may be reasoned that healthy levels of NT-3 can preserve the function of these cells that are crucial for processing auditory information in the brain.
An article entitled “Neurotrophin 4/5 is a trophic factor for mammalian facial motor neurons” summarizes a study that was conducted on the researchers’ findings in 1993. The research suggests that NT-4/5 prevents injuries that cause death of facial motor neurons in neonatal rats. Additionally, there is functional receptor for NT-4/5 in facial motor neurons that can be serviceable thought embryonic development and even postnatal life. Thus, both NT-4/5and brain-derived neurotrophic factor (BDNF) may be physiological survival factors for facial motor neurons and may serve as restorative means for motor neuron disease.
Activities presumed to promote brain fitness
Not all brain activity exercises the brain in the same way.
- Activities that require you to use all your senses, break your routines and engage in novel experiences which can create BDNFs(neurotrophins) as explained in the book Keep Your Brain Alive, Workman Publishing.
- Activities that involve planning ahead, like chess, stimulate the frontal lobe area of the brain.
- Activities like ballroom dance and basketball, train short range spatial skills, used when one walks through a short limited space, like the interior of a house.
- Activities that combine intellectual and physical demands improve spatial and reasoning skills 
- Activities like learning a new language or painting require the coordinating of multiple regions of the brain.
- Physical exercise promotes BDNF.
- Reading books, and writing
- Cognitive training games
A significant issue in brain fitness work has been establishing that brain training exercises have impacts on brain function that exist outside the context of the training task. For example, in the ACTIVE studies, subjects were trained only in one of these three modalities: speed of processing, reasoning, or memory. Subjects did not significantly improve in non-trained modalities.
Other studies, however, have looked at changes in tests of everyday function that occur after brain-based training. In a review of these studies, the following significant effects were noted. Improvements on speed of processing training tests were related to improvements in the Timed Instrumental Activities of Daily Living test (TIADL). Evidence of ceiling effects were also noted, indicating that subjects who were further below normal at the beginning of training had the largest expected gains. Further, the effect sizes may be related to customizing the training difficulty to the performance level of the trainee. Subjects trained with one training strategy, the Useful Field of View test (UFOV), showed significant improvements in an on-the-road driving test designed to evaluate driver response during potential dangerous situations. Specifically, subjects trained with UFOV made fewer dangerous maneuvers after training. In another study, the researchers have found that action video game experience is shown to improve trainees’ probabilistic inference. These results were established both in visual and auditory tasks, indicating generalization across modalities. In a study performed with Air force flight cadets it has been shown that training addressing attention control processes yielded significant transfer of skills from the training environment to actual flight.
Lately, brain training games have been actively marketed as a "magic bullet" for Alzheimer's and Dementia. While there are few studies showing effectiveness of brain training for older adults, it has to be noted that many brain training games are purely commercial and have no scientific footing. To address growing public concerns with regard to aggressive online marketing of brain games to older population, a group of neuroscientists published a letter warning general public that there is a lack of research showing effectiveness of brain games in elderly. Authors of this letter suggest that many popular computerized training programs are not very effective and some other interventions, such intense physical exercise, may have greater benefits. With regard to research studies supporting benefits of brain training games for older adults, there is a strong evidence that participants only gain in the trained task and that there is limited transfer of skills to the real life activities.
- Sandra Aamodt, Sam Wang (November 8, 2007). "Exercise on the brain". New York Times.
- Vernon Mark, Jeffrey P. Mark (1989). Brain Power: A Neurosurgeon's Complete Program to Maintain and Enhance Brain Fitness Throughout Your Life. Houghton Mifflin. ISBN 978-0-395-49861-3.
- M. Le Poncin-Lafitte, Monique Le Poncin, Michael Levine (1990). Brain Fitness. Fawcett Columbine. ISBN 978-0-449-90348-3.
- Gopher, D; Weil M; Bareket T (1994). "Transfer of skill from a computer game trainer to flight". Human Factors 36: 1–19.
- Scarmeas, N; Y Stern (2003). "Cognitive reserve and lifestyle". J Clin Exp Neuropsychol 25 (5): 625–33. doi:10.1076/jcen.25.5.625.14576. PMC 3024591. PMID 12815500.
- Kramer, AF; Erickson KI; Colcombe SJ (2006). "Exercise, cognition, and the aging brain". J Appl Physiol 101 (4): 1237–42. doi:10.1152/japplphysiol.00500.2006. PMID 16778001.
- Stern, Y; B Gurland; TK Tatemichi et al. (1994). "Influence of education and occupation on the incidence of Alzheimer's disease". JAMA 271 (13): 1004–10. doi:10.1001/jama.271.13.1004. PMID 8139057.
- Verghese, J et al. (2003). "Leisure activities and the risk of dementia in the elderly". The New England Journal of Medicine 348 (25): 2508–16. doi:10.1056/NEJMoa022252. PMID 12815136.
- Willis, SL; SL Tennstedt; M Marsiske et al. (2006). "Long-term effects of cognitive training on everyday functional outcomes in older adults". JAMA 296 (23): 2805–14. doi:10.1001/jama.296.23.2805. PMC 2910591. PMID 17179457.
- Wilson, RS et al. (2002). "Participation in cognitively stimulating activities and risk of incident Alzheimer disease". JAMA 287 (6): 742–8. doi:10.1001/jama.287.6.742. PMID 11851541.
- Hairston, IS; Little MT; Scanlon MD; Barekat MT; Palmer TD; Sapolsky RM; Heller HC (2005). "Sleep restriction suppresses neurogenesis induced by hippocampus-dependent learning". J Neurophysiol 94 (6): 4224–33. doi:10.1152/jn.00218.2005. PMID 16014798.
- Mirescu, Christian; Jennifer D. Peters; Liron Noiman; Elizabeth Gould (2006). "Sleep deprivation inhibits adult neurogenesis in the hippocampus by elevating glucocorticoids". PNAS 103 (50): 19170–19175. Bibcode:2006PNAS..10319170M. doi:10.1073/pnas.0608644103. PMC 1748194. PMID 17135354.
- MacLennan, AH; Henderson VW; Paine BJ et al. (2006). "Hormone therapy, timing of initiation, and cognition in women aged older than 60 years: the REMEMBER pilot study". Menopause 13 (1): 28–36. doi:10.1097/01.gme.0000191204.38664.61. PMID 16607096.
- Elder, GA; De Gasperi R; Gama Sosa MA (2006). "Research update: neurogenesis in adult brain and neuropsychiatric disorders". Mt Sinai J Med 73 (7): 931–40. PMID 17195878.
- Bos, I et al. (2011). "No exercise-induced increase in serum BDNF after cycling near a major traffic road". Neuroscience Letters 500 (2): 129–132. doi:10.1016/j.neulet.2011.06.019. PMID 21708224.
- Oei, NY; Everaerd WT; Elzinga BM; van Well S; Bermond B (2006). "Psychosocial stress impairs working memory at high loads: an association with cortisol levels and memory retrieval". Stress 9 (3): 133–41. doi:10.1080/10253890600965773. PMID 17035163.
- "Moreau, D., & Conway, A. R. A. (2013). Cognitive enhancement: A comparative review of computerized and athletic training programs. International Review of Sport and Exercise Psychology, 6(1), 155-183. doi:10.1080/1750984X.2012.758763"
- Cassavaugh, N; Kramer, AF (2009). "Transfer of computer-based cognitive training to simulated driving in older adults". Applied Ergonomics 40 (5): 943–952. doi:10.1016/j.apergo.2009.02.001. PMID 19268912.
- de la Fuente-Fernandez, Ra?l (2006). "Impact of neuroprotection on incidence of Alzheimer's disease". PLoS ONE 20 (1): e52. Bibcode:2006PLoSO...1...52D. doi:10.1371/journal.pone.0000052. PMC 1762379. PMID 17183682.
- Spector, A; Thorgrimsen L; Woods B; Royan L; Davies S; Butterworth M; Orrell M (2003). "Efficacy of an evidence-based cognitive stimulation therapy programme for people with dementia: randomised controlled trial". Br J Psychiatry 183 (3): 248–54. doi:10.1192/bjp.183.3.248. PMID 12948999.
- Belleville, S; Gilbert B; Fontaine F; Gagnon L; Menard E; Gauthier S (2006). "Improvement of episodic memory in persons with mild cognitive impairment and healthy older adults: evidence from a cognitive intervention program". Dement Geriatr Cogn Disord 22 (5–6): 486–99. doi:10.1159/000096316. PMID 17050952.
- Whitbourne, S. (April 6, 2010). Building a better brain: Strengthening your mental muscle. Psychology Today. Sussex Publishers.
- "A cognitive training program based on principles of brain plasticity: results from the Improvement in Memory with Plasticity-based Adaptive Cognitive Training (IMPACT) study." J Am Geriatr Soc. 2009 Apr;57(4):594-603
- "Memory enhancement in healthy older adults using a brain plasticity-based training program: A randomized, controlled study" PNAS USA. 2006 August 15;103(33):12523-8
- "Brain Training under attack".
- [dead link]
- Cognitive Training and Brain Fitness Computer Programs: Interview with Dr. Elkhonon Goldberg
- Cognitive Training for Basketball Game-Intelligence: Interview with Prof. Daniel Gopher
- Memory training and attention deficits: interview with Notre Dame’s Bradley Gibson
- Ernst, C; Olson AK; Pinel JP; Lam RW; Christie BR (2006). "Antidepressant effects of exercise: evidence for an adult-neurogenesis hypothesis?". J Psychiatry Neurosci 31 (2): 84–92. PMC 1413959. PMID 16575423.
- Wolf, SA; Kronenberg G; Lehmann K; Blankenship A; Overall R; Staufenbiel M; Kempermann G (2006). "Cognitive and physical activity differently modulate disease progression in the amyloid precursor protein (APP)-23 model of Alzheimer's disease". Biol Psychiatry 60 (12): 1314–23. doi:10.1016/j.biopsych.2006.04.004. PMID 16806094.
- Chaturvedi, RK; Shukla S; Seth K; Agrawal AK (2006). "Nerve growth factor increases survival of dopaminergic graft, rescue nigral dopaminergic neurons and restores functional deficits in rat model of Parkinson's disease". Neurosci Lett 398 (1–2): 44–9. doi:10.1016/j.neulet.2005.12.042. PMID 16423459.
- Ball, K; Berch DB; Helmers KF et al. (2002). "Effects of cognitive training interventions with older adults: a randomized controlled trial". JAMA 288 (18): 2271–81. doi:10.1001/jama.288.18.2271. PMC 2916176. PMID 12425704.
- Huang, E. J.; Reichardt, L. F. (2001). "Neurotrophins: Roles in neuronal development and function". Annual Review of Neuroscience 24: 677–736. doi:10.1146/annurev.neuro.24.1.677. PMC 2758233. PMID 11520916.
- Nolte, J. (2009). The human brain: An introduction to its functional anatomy. (6th ed., pp. 608–612). Philadelphia: Mosby Elsevier
- Nolte, J. (2009). The human brain: An introduction to its functional anatomy. (6th ed., pp. 608-612). Philadelphia: Mosby Elsevier
- Navis, A. R. (2007). Nerve growth factor. Embryo Project Encyclopedia, Retrieved from http://embryo.asu.edu/view/embryo:123957
- (2011). BDNF brain-derived neurotrophic factor [ homo sapiens ]. Retrieved from National Institutes of Health website: http://www.ncbi.nlm.nih.gov/gene/627
- Botstein, D.; Cayouette, M. H.; Berkemeier, L. R.; Clatterbuck, R. E.; Price, D. L.; Rosenthal, A. (1993). "Neurotrophin 4/5 is a trophic factor for mammalian facial motor neuron". Proceedings of the National Academy of Sciences of the United States of America 91 (8): 3304–3308. Bibcode:1994PNAS...91.3304K. doi:10.1073/pnas.91.8.3304. PMID 8159743.
- Grafman J (1994) Alternative frameworks for the conceptualization ofprefrontal lobe functions. In: Handbook of neuropsychology (Boller F,Grafman J, eds), pp 187–202. Amsterdam: Elsevier.
- Russo-Neustadt AA, Beard RC, Huang YM, Cotman CW; Beard; Huang; Cotman (2000). "Physical activity and antidepressant treatment potentiate the expression of specific brain-derived neurotrophic factor transcripts in the rat hippocampus". Neuroscience 101 (2): 305–12. doi:10.1016/S0306-4522(00)00349-3. PMID 11074154.
- Wilson, Robert S. et al. (July 3, 2013). "Life-span cognitive activity, neuropathologic burden, and cognitive aging (Abstract)". Neurology. Archived from the original on July 5, 2013. Explained by Koren, Marina (July 23, 2013). "Being a Lifelong Bookworm May Keep You Sharp in Old Age". Smithsonian. Archived from the original on July 5, 2013.
- Gazzaley, Adam et al. (September 5, 2013). "Video game training enhances cognitive control in older adults" (PDF). Nature.
- Kesler, Shelli et al. (May 6, 2013). "Cognitive Training for Improving Executive Function in Chemotherapy-Treated Breast Cancer Survivors". Clinical Breast Cancer.
- NY Times Op-Ed Exercise on the Brain. Sandra Aamodt and Sam Wang. Nov 8 2007.
- The Impact of Speed of Processing Training on Cognitive and Everyday Functions.
Author: Karlene Ball, Jerri D. Edwards, and Lesley A. Ross
Journal: Journals of Gerontology: SERIES B 2007, Vol. 62B (Special Issue I): 19-31
- Green, Shawn; Pouge A, Bavelier D, (September 2010). "Improved Probabilistic Inference as a General Learning Mechanism with Action Video Games". Current Biology 20 (17): 1573–1579. doi:10.1016/j.cub.2010.07.040. PMC 2956114. PMID 20833324.
- Gopher, D (1992). "Development of skill transfer based on computer games: Prospects and Issues". Proceedings of the 36th annual meeting of the Human Factors Society 2: 1284.
- Kueider, Alexandra (2010). "Computerized Cognitive Training with Older Adults: A Systematic Review". PLOS ONE. doi:10.1371/journal.pone.0040588.
- Papp, Kathryn et al. (2009). "Immediate and delayed effects of cognitive interventions in healthy elderly: A review of current literature and future directions". The Journal of the Alzheimer's Associations. doi:10.1016/j.jalz.2008.10.008.
- Lampit, Amit; Hallock H, Valenzuela M,. "Computerized Cognitive Training in Cognitively Healthy Older Adults: A Systematic Review and Meta-Analysis of Effect Modifiers". PLOS Medicine. doi:10.1371/journal.pmed.1001756.
- "A Consensus on the Brain Training Industry from the Scientific Community". 2014.
- Owen, Adrian et al. (2010). "Putting brain training to the test". Nature. doi:10.1038/nature09042.
- Melby-Lervåg, Monica; Hulme, Charles (2013). "Is working memory training effective? A meta-analytic review". Developmental Psychology. doi:10.1037/a0028228.