PHYSIOLOGY 32: 410 – 424, 2017.
Published October 11, 2017

Exercise is a simple intervention that profoundly benefits cognition. In rodents, running increases neurogenesis in the hippocampus, a brain area important for memory. We describe the dynamic changes in new neuron number and afferent connections throughout their maturation. We highlight the effects of exercise on the neurotransmitter systems involved, with a focus on the role of glutamate and acetylcholine in the initial development of new neurons in the adult brain.

The mammalian brain can modify itself in response to new stimuli, behaviors, diet, and environment. Exercise elicits a robust effect on neural plasticity. In rodents, voluntary wheel running results in structural and functional changes in brain regions important for cognition, such as the hippocampus and cortex. In humans, physical activity benefits hippocampus-dependent memory and prefrontal cortex-mediated executive function, and may maintain neural gray and white matter volume over the lifespan. The onset of effects of exercise on the brain and behavior is rapid and evolves over time. Initially, neurotransmitter levels and blood flow are changed, followed by an upregulation of growth factors in the brain [e.g., brain-derived nerve growth factor (BDNF)] and the genesis of new neurons in the hippocampus. In this review, we evaluate how 1 wk and 1 mo of wheel running in rodents influences adult hippocampal cell genesis, neuronal morphology, neural circuitry, and synaptic plasticity. We also discuss the effects of exercise on other brain areas and the potential implications for human brain function.

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