ReviewLifelong brain health is a lifelong challenge: From evolutionary principles to empirical evidence
Section snippets
Evolutionary perspective: why ‘hunger games’ bolster brainpower
Animals in the wild, particularly carnivores, survive by being able to locate and acquire food. As a corollary, evolution favored those individuals and species that were adept at outsmarting their prey and their competitors in the struggle for limited food sources. The brain is therefore geared for a high level of motivation and optimal sensory-motor and cognitive function when the individual experiences hunger/food scarcity, and the often vigorous exercise required to obtain food (Fig. 1; and
Empirical findings demonstrate that exercise, energy restriction and intellectual enrichment enhance neuroplasticity
Laboratory rats and mice are usually fed ad libitum and so eat as much and as often as desired. In addition, they are typically maintained in small cages with no running wheels or other opportunities for exercise. Moreover, each cage usually contains 4 or 5 animals, which is a relatively small social group. Thus, it is reasonable to consider control laboratory animals as ‘couch potatoes’ that, compared to rodents in the wild, are sedentary, overeat and experience little cognitive stimulation (
Signaling pathways and molecular mechanisms
There is considerable overlap in cellular and molecular mechanisms by which the challenges of exercise, energy restriction and intellectual enrichment enhance neuroplasticity and sustain cognitive performance during aging (Fig. 3). Three general mechanisms are: (1) increased synaptic activity resulting in the production and release of neurotrophic factors which then activate signaling pathways that stimulate the formation and plasticity of synapses, and neurogenesis; (2) activation of adaptive
Intermittent challenges may protect against neurodegenerative disorders
Epidemiological data suggest that individuals who exercise regularly during their adult life are at reduced risk of Alzheimer's and Parkinson's diseases. Population-based studies suggest that individuals who exercise in midlife are less likely to develop dementia later in life (Geda et al., 2010). Consistent with the possibility that regular exercise protects against Alzheimer's disease are data showing that midlife cardiorespiratory fitness is associated with a lower risk of dementia (Defina
Implications for a brain-healthy society
Advances in agriculture, food processing and transportation have contributed to a decline in the exposure of individuals in modern societies to the two major energetic challenges that sustain optimal brain health, namely, intermittent food deprivation/fasting and vigorous daily exercise. While many continue to engage in intellectual challenges that can enhance cognitive function, the available evidence suggests that such intellectual challenges are insufficient to mitigate age-related
Acknowledgements
This work was supported by the Intramural Research Program of the National Institute on Aging, and the Glenn Foundation for Medical Research.
References (124)
- et al.
Short bouts of mild-intensity physical exercise improve spatial learning and memory in aging rats: involvement of hippocampal plasticity via AKT, CREB and BDNF signaling
Mech. Ageing Dev.
(2011) - et al.
Effects of environmental enrichment and voluntary exercise on neurogenesis, learning and memory, and pattern separation: BDNF as a critical variable?
Semin. Cell Dev. Biol.
(2011) - et al.
Beneficial effects of exercise in a transgenic mouse model of Alzheimer's disease-like Tau pathology
Neurobiol. Dis.
(2011) - et al.
NT-3 and BDNF protect CNS neurons against metabolic/excitotoxic insults
Brain Res.
(1994) - et al.
Shaping neurons: long and short range effects of mature and proBDNF signalling upon neuronal structure
Neuropharmacology
(2014) - et al.
Voluntary exercise produces antidepressant and anxiolytic behavioral effects in mice
Brain Res.
(2008) - et al.
Intermittent fasting attenuates inflammasome activity in ischemic stroke
Exp. Neurol.
(2014) - et al.
Differential effects of BDNF, ADNF9, and TNFalpha on levels of NMDA receptor subunits, calcium homeostasis, and neuronal vulnerability to excitotoxicity
Exp. Neurol.
(2000) - et al.
Impact of enriched-environment housing on brain-derived neurotrophic factor and on cognitive performance after a transient global ischemia
Behav. Brain Res.
(2004) - et al.
Exercise-induced improvement in cognitive performance after traumatic brain injury in rats is dependent on BDNF activation
Brain Res.
(2009)