Running rewires the aging brain: exercise protects memory function

Resume: Physical activity, particularly running, has been found to rewire the aging brain, preserving memory functions.

Researchers revealed that prolonged running retains older neurons, potentially preventing age-related memory loss and neurodegeneration. This effect is believed to be especially beneficial for neurons born during early adulthood, whose circuitry can be altered by midlife exercise.

The findings underscore the importance of regular exercise for maintaining cognitive health as we age.

Main facts:

  1. Prolonged running significantly increases the number of mature neurons and improves their connection to the neural network, preserving memory functions.
  2. Neurons born during early adulthood that are thought to be temporally important can remain integrated into neural networks and their circuits can be altered by physical activity in middle age.
  3. Chronic exercise beginning in young adulthood and continuing into middle age helps preserve memory function during aging, emphasizing the need for exercise in daily routine.

Source: FAU

Aging is often accompanied by cognitive decline. One of the first structures of the affected brain is the hippocampus and adjacent cortices, areas essential for learning and memory.

Deficits in cognitive ability are associated with decreased hippocampal volume and degradation of synaptic connectivity between the hippocampus and the (peri)entorhinal cortex.

There is growing evidence that physical activity can slow or prevent these structural and functional declines in older adults. A new study from Florida Atlantic University and CINVESTAV, Mexico City, Mexico, provides new insight into the benefits of exercise, which should motivate adults to keep moving throughout their lives, especially in middle age.

For the study, researchers focused on the effects of prolonged running on a network of new hippocampal neurons generated in young, middle-aged adult mice. These “mice on the run” show that running in middle age keeps old, born-grown neurons wired, which may prevent or delay aging-related memory loss and neurodegeneration.

Mature neurons are believed to contribute to hippocampus-dependent memory function and to be important temporarily, during the so-called ‘critical period’ at about three to six weeks of cell age, when they can transiently exhibit increased synaptic plasticity.

However, these new neurons persist for many months, but it was unclear whether those born in early adulthood remain integrated into neural networks and whether their circuits can be altered by physical activity in middle age.

To answer these questions, researchers used a unique rabies virus-based circuit tracing approach with a long time interval between the initial labeling of new neurons and the subsequent analysis of their neural circuits in rodents.

More than six months after tagging the adult-born neurons with a fluorescent reporter vector, they identified and quantified the direct afferent inputs to these adult-born neurons in the hippocampus and (sub)cortical regions, when the mice were middle-aged.

Results of the study, published in the journal eNeuro, long-running threads show ‘old’ new neurons, born during early adulthood, in a network relevant to the maintenance of episodic memory encoding during aging.

“Prolonged exercise has major benefits for the aging brain and may prevent aging-related decline in memory function by increasing survival and modifying the network of adult-born neurons born during early adulthood, thereby facilitating their participation in cognitive processes, said Henriette van Praag, Ph.D., corresponding author, associate professor of biomedical sciences in the FAU’s Schmidt College of Medicine and a member of the FAU Stiles-Nicholson Brain Institute.

Findings of the study showed that prolonged running significantly increased the number of mature neurons and enhanced the recruitment of presynaptic (sub)cortical cells into their network.

“Prolonged running may improve pattern separation ability, our ability to distinguish between very similar events and stimuli, a behavior closely related to neurogenesis in adults, which is among the first to show deficits indicative of age-related amnesia,” said Carmen Vivir. , Ph.D., Corresponding Author, Department of Physiology, Biophysics and Neurosciences, Centro de Investigacion y de Estudios Avanzados del IPN in Mexico.

Aging-related decline in memory function is associated with the degradation of synaptic inputs from the perirhinal and entorhinal cortex to the hippocampus, brain regions essential for pattern separation, and contextual and spatial memory.

“We show that running also significantly increases backprojection from the dorsal subiculum to old mature granule cells,” van Praag said. “This connectivity may provide navigation-related information and mediate the long-term running-induced improvement in spatial memory function.”

Results of the study show that running not only rescued perirhinal connectivity, but also increased and altered the entorhinal cortex’s contribution to the network of old adult neurons.

“Our study provides insight into how chronic exercise, beginning in young adulthood and continuing through middle age, helps preserve memory function as we age, highlighting the relevance of incorporating exercise into our daily lives,” said Vivar.

Study co-authors are Ben Peterson, Ph.D., currently a postdoctoral fellow at UC Davis; Alejandro Pinto, FAU’s Schmidt College of Medicine and Stiles-Nicholson Brain Institute; and Emma Janke, a recent graduate of the University of Pennsylvania.

financing: This research was supported in part by the FAU Stiles-Nicholson Brain Institute and the Jupiter Life Sciences Initiative (awarded to van Praag), and by the Cinvestav Scientific Research and Technological Development Fund (SEP-Cinvestav Projects), (awarded to Vivar). ).

About this exercise and research news about neurogenesis

Author: Gisele Galoustian
Source: FAU
Contact: Gisele Galoustian – FAU
Image: The image is credited to Neuroscience News

Original research: Open access.
“Running through medieval times traps old, mature born neurons” by Henriette van Praag et al. eNeuro


Running through the Middle Ages traps old, mature neurons

Exercise can prevent or delay age-related memory loss and neurodegeneration. In rodents, running increases the number of mature neurons in the dentate gyrus (DG) of the hippocampus, in association with improved synaptic plasticity and memory function.

However, it is unclear whether mature neurons remain fully integrated into the hippocampal network during aging and whether prolonged running affects their connectivity.

To address this issue, we labeled proliferating DG neural progenitor cells with retrovirus expressing the avian TVA receptor in two-month-old sedentary and walking male C57Bl/6 mice. More than six months later, we injected EnvA pseudotyped rabies virus into the DG as a monosynaptic retrograde tracer, to selectively infect TVA expressing “old” new neurons.

We identified and quantified the direct afferent inputs to these mature neurons in the hippocampus and (sub)cortical regions. Here we show that sustained running significantly alters the network of neurons generated in middle-aged young adult mice.

Exercise increases input from hippocampal interneurons to “old” mature neurons, which may play a role in reducing aging-related hippocampal hyperexcitability. In addition, running prevents the loss of innervation of mature neurons from the perirhinal cortex, and increases input from subiculum and entorhinal cortex, brain regions essential for contextual and spatial memory.

Thus, long-duration running maintains the wiring of “old” new neurons, born during early adulthood, within a network that is important for memory function during aging.

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