Running throughout middle age keeps 'old' adult-born neurons 'wired'
'Mice on the run:' study reveals how exercise helps maintain memory
function during aging

Date:
May 25, 2023
Source:
Florida Atlantic University
Summary:
A new study provides novel insight into the benefits of exercise,
which should motivate adults to keep moving throughout their
lifetime, especially during middle age. Long-term exercise
profoundly benefits the aging brain and may prevent aging-related
memory function decline by increasing the survival and modifying
the network of the adult-born neurons born during early adulthood,
and thereby facilitating their participation in cognitive processes.


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FULL STORY ==========================================================================
A new study provides novel insight into the benefits of exercise,
which should motivate adults to keep moving throughout their lifetime, especially during middle age. Long-term exercise profoundly benefits
the aging brain and may prevent aging-related memory function decline
by increasing the survival and modifying the network of the adult-born
neurons born during early adulthood, and thereby facilitating their participation in cognitive processes.

Aging often is accompanied by cognitive decline. Among the first
structures of the brain affected are the hippocampus and adjacent
cortices, areas essential for learning and memory. Deficits in cognitive ability are associated with reduced hippocampal volume and degradation of synaptic connectivity between the hippocampus and the (peri)-entorhinal
cortex.

Increasing evidence indicates that physical activity can delay or prevent
these structural and functional reductions in older adults. A new study by Florida Atlantic University and CINVESTAV, Mexico City, Mexico, provides
novel insight into the benefits of exercise, which should motivate adults
to keep moving throughout their lifetime, especially during middle age.

For the study, researchers focused on the effects of long-term running
on a network of new hippocampal neurons that were generated in young
adult mice, at middle age. These "mice on the run" demonstrate that
running throughout middle age keeps old adult-born neurons wired, which
may prevent or delay aging- related memory loss and neurodegeneration.

Adult-born neurons are thought to contribute to hippocampus-dependent
memory function and are believed to be temporarily important, during the so-called 'critical period' at about three to six weeks of cell age, when
they can fleetingly display increased synaptic plasticity. However, these
new neurons do remain present for many months, but it was unclear whether
those born in early adulthood remain integrated into neural networks and whether their circuitry is modifiable by physical activity in middle age.

To address 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 subsequent analysis of their neural circuitry
in rodents.

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

Results of the study, published in the journal eNeuro,show long-term
running wires 'old' new neurons, born during early adulthood, into a
network that is relevant to the maintenance of episodic memory encoding
during aging.

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

Findings from the study showed long-term running significantly increased
the number of adult-born neurons and enhanced the recruitment of
presynaptic (sub)- cortical cells to their network.

"Long-term running may enhance pattern separation ability, our ability
to distinguish between highly similar events and stimuli, a behavior
closely linked to adult neurogenesis, which is among the first to display deficits indicative of age-related memory decline," said Carmen Vivar,
Ph.D., corresponding author, Department of Physiology, Biophysics and Neuroscience, Centro de Investigacion y de Estudios Avanzados del IPN
in Mexico.

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

"We show that running also substantially increases the back-projection
from the dorsal subiculum onto old adult-born granule cells," said van
Praag. "This connectivity may provide navigation-associated information
and mediate the long-term running-induced improvement in spatial memory function." Results from the study show that running not only rescued perirhinal connectivity but also increased and altered the contribution
of the entorhinal cortices to the network of old adult-born neurons.

"Our study provides insight as to how chronic exercise, beginning in
young adulthood and continuing throughout middle age, helps maintain
memory function during aging, emphasizing the relevance of including
exercise in our daily lives," said Vivar.

Study co-authors are Ben Peterson, Ph.D., currently a postdoc 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.

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 Fondo de Investigacio'n Cienti'fica y Desarrollo Tecnolo'gico
del Cinvestav (Proyectos SEP-Cinvestav), (awarded to Vivar).

* RELATED_TOPICS
o Health_&_Medicine
# Nervous_System # Healthy_Aging # Fitness #
Chronic_Illness
o Mind_&_Brain
# Intelligence # Dementia # Neuroscience # Memory
* RELATED_TERMS
o Dementia o Anaerobic_exercise o Swimming o Neural_network
o Aerobic_exercise o Memory o Eustachian_tube o
Baldness_treatments

========================================================================== Story Source: Materials provided by Florida_Atlantic_University. Original written by Gisele Galoustian. Note: Content may be edited for style
and length.


========================================================================== Journal Reference:
1. Carmen Vivar, Ben Peterson, Alejandro Pinto, Emma Janke,
Henriette van
Praag. Running throughout Middle-Age Keeps Old Adult-Born Neurons
Wired.

eneuro, 2023; 10 (5): ENEURO.0084-23.2023 DOI: 10.1523/ENEURO.0084-
23.2023 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/05/230525140336.htm

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