- Researchers have investigated the cellular mechanisms behind how exercise improves cognition.
- They discovered that contracting muscle cells release chemical signals that increase the growth and firing of neurons.
- They also found that supporting cells known as astrocytes prevent neurons exposed to chemical signals from muscle cells from excessive electrical signaling.
- Further research is needed to see if these findings apply to humans.
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Understanding more about how exercise increases the size and function of the hippocampus could allow researchers to reverse engineer treatments for cognitive conditions such as dementia.
Recently, researchers conducted a series of in vitro experiments—experiments in cell cultures—to understand how exercise changes hippocampal cells.
They found that chemical signals from contracting muscle cells cause hippocampal cells to grow and release more electrical signals. They also found that supporting cells known as astrocytes regulate the growth and activity of neurons for optimal brain function.
“The implications support previous findings from other studies that exercise, including muscle-strengthening exercises such as resistance training, can have a positive effect on brain function,” Ryan Glattsenior brain health coach and director of the FitBrain program at the Pacific Neuroscience Institute in Santa Monica, CA, who was not involved in the study, said Medical news today.
The study was published in Neuroscience.
For the study, the researchers isolated small samples of muscle precursor cells from mice and grew them in Petri dishes. Once they matured, they began to contract and release chemical signals into the cell culture.
The team then added chemicals containing a culture of mature muscle cells to another dish containing hippocampal neurons and astrocytes.
They used immunofluorescence and calcium recording to monitor cell growth, as well as multi-electrode arrays to record neuronal activity.
Finally, they found that exposure to chemical signals from muscle cells increased the amount of hippocampal neurons and astrocytes by 1.4 and 4.4 times, respectively.
The addition of muscle cell cultures also accelerated the formation of mature hippocampal neuronal networks – cells that fire synchronously.
Next, the researchers tried to investigate how astrocytes affect the mixture. To do this, they looked at the effects of removing astrocytes from cell cultures containing hippocampal cells and mature muscle cells.
In doing so, they noticed that the neurons fired even more electrical signals, suggesting that astrocytes may help moderate and coordinate the patterns of activation between neurons.
From further tests, the researchers found that muscle contractions were necessary for the observed changes in hippocampal cultures.
When the muscle cells were prevented from contracting, hippocampal cells no longer showed the same levels of neuronal firing, although synchronous firing remained unchanged.
The researchers noted that this means that muscle contractions—or exercise—release factors that stationary cells do not.
They concluded that their findings provide new insights into how exercise can support hippocampal function.
MNT asked Dr. Rong Zhanga neurologist at the UT Southwestern O’Donnell Brain Institute, who was not involved in the study, how exercise can reduce the risk of dementia.
He noted that this case has yet to be tested in large clinical trials and that further research should also explore the underlying molecular mechanisms.
Meanwhile, Dr Bennett pointed out that previous research shows that exercise reduces the risk of dementia in the following ways:
MNT also talked to Dr. Romnesh de Souzaconsultant neurologist and interventional neurologist at Health City Cayman Islands, was not involved in the study.
He said:
“Regular aerobic exercise of 20 to 30 minutes a day which can be achieved by walking, brisk walking, swimming or using an exercise bike. Aim for a heart rate of 70% of your maximum heart rate. To estimate your age-related maximum heart rate, subtract your age from 220. This practice has been shown to reduce dementia by 30-35%.”
“This was an in vitro study on rodents, using cell culture. Additional research will be needed to see if these findings are applicable to humans,” confirmed Dr. Zhang, commenting on the study.
Dr. Lauren Bennettdirector of neuropsychology at the Pickup Family Neurosciences Institute at Hoag Memorial Hospital Presbyterian, who was not involved in the study, added that the research “was only conducted for a short time and it is not clear whether the findings will be the same over a longer period of time.”
Nevertheless, “the results of this study provide further evidence for the importance of exercise, at any point in life, in supporting hippocampal plasticity in combating hippocampal atrophy, a hallmark of Alzheimer’s disease,” noted Dr. Bennett.
“In the future, studies like this could play a key role in helping us optimize exercise regimens to support cognitive health,” she explained.
dr. de Souza added that the findings may also help develop new treatments for cognitive impairment.
“These findings indicate that there is potential in the future to ‘reverse engineer treatments to recapitulate the pro-cognitive effects of exercise in the absence of physical activity.’ What is also exciting is whether this can be used to reverse or halt the progression of cognitive decline in dementia patients,” he said.
