Evolutionary Model Linking Exercise, Cognition, & Brain Health

[Michael Scally MD]

Trends

· Recent work has shown that exercise can significantly improve brain structure and function in adults, especially during aging.

· We currently lack a comprehensive theoretical model to explain why exercise can lead to improved brain function.

· Taking an evolutionary neuroscience approach suggests that physiological systems, including the brain, respond to activity-related stress by expanding capacity, and that reductions in capacity represent an energy-minimizing strategy in response to inactivity.

· From an evolutionary neuroscience perspective, physical activity stresses brain function because of the cognitively demanding foraging context in which our ancestors engaged in aerobic physical activity.

· The ACM links evolutionary theory with cognitive neuroscience to show that cognitively demanding exercise is beneficial to brain structure and function, and that we can take advantage of this adaptation to help prevent declines due to aging and to developing neurological disease.

Raichlen DA, Alexander GE. Adaptive Capacity: An Evolutionary Neuroscience Model Linking Exercise, Cognition, and Brain Health. Trends in Neurosciences. http://www.cell.com/trends/neurosciences/fulltext/S0166-2236(17)30089-9

The field of cognitive neuroscience was transformed by the discovery that exercise induces neurogenesis in the adult brain, with the potential to improve brain health and stave off the effects of neurodegenerative disease.

However, the basic mechanisms underlying exercise–brain connections are not well understood. We use an evolutionary neuroscience approach to develop the adaptive capacity model (ACM), detailing how and why physical activity improves brain function based on an energy-minimizing strategy.

Building on studies showing a combined benefit of exercise and cognitive challenge to enhance neuroplasticity, our ACM addresses two fundamental questions:
(i) what are the proximate and ultimate mechanisms underlying age-related brain atrophy, and
(ii) how do lifestyle changes influence the trajectory of healthy and pathological aging?

 

[Michael Scally MD]

Mechanisms Underlying the Adaptive Capacity Model (ACM).

(A) Cognitively challenging physical activity, traditionally experienced during for aging, represents the evolutionary origins of the ACM. During for aging bouts, individuals must combine aerobic activity with control of motor systems, spatial navigation and memory, executive functions including decision-making and planning, and control of sensory and attentional systems.

This combination makes for aging a cognitively-complex behavior, requiring an adaptive neural response to processing demands that can be further amplified when moving through novel environments and at increasing speeds.

(B) Acute effects of aerobic exercise. At the acute level, cognitively challenging aerobic activity (e.g., during foraging) begins with a neurogenic trigger (physical movement). Movement initiates the upregulation of neurotrophins and increased brain perfusion.

In turn, the effects may induce hippocampal neurogenesis as well as synaptogenesis and myelin remodeling with associated white matter(WM) and cortical brain effects. These non-specific effects are referred to as on-demand potential that may be realized when combined with cognitive challenges during or immediately following the aerobic activity.

If these challenges occur, the acute effects of cognitively challenging exercise lead to neuronal survival in the hippocampus as well as strengthened connections and myelination in key white matter tracts and associated cortical brain regions.

(C) Lifetime effects of cognitively challenging exercise. Combining aerobic exercise and cognitive challenges across the life span leads to the maintenance of brain structure and associated function during aging.

Inactivity over the lifespan leads to an adaptive brain response that reduces structure (i.e., brain atrophy), potentially leading to the expression of cognitive decline or neurodegenerative disease.

However, increasing cognitively challenging physical activity (Ex + Cog) after a lifetime of inactivity can alter the trajectory of cognitive aging and potentially reduce the risk of developing neurodegenerative disease.

 

[BBC3]

So are they saying that at the right age... A little Adderall will do the trick...?!?!???

 

[Redrum42]

I tell all the old people I care about: chug water all day, and lift weights 3x/week, it is truly the fountain of youth. With those two things pretty much every single disease and ailment has reduced probability. Old people are frail because they're sedentary, not because they're old. The thought that being feeble and weak in old age is inevitable is b.s. for 99% of people, and brings our society down in so many ways.

People are always looking for such a complicated answer when a simple one is staring them straight in the face. It doesn't help that they actually have to WORK to save their own lives instead of taking some magical pill.