In a study done in mice, a team of researchers found that short-term bursts of exercise — the human equivalent of a weekly game of pickup basketball, or 4,000 steps — promoted an increase in synapses in the hippocampus and prime the brain for learning. The findings were published in the journal eLife.
“Exercise is cheap, and you don’t necessarily need a fancy gym membership or have to run 10 miles a day,” said Professor Gary Westbrook, a researcher in the Vollum Institute and the School of Medicine at Oregon Health Science University.
Regular exercise promotes general brain health. However, it’s hard to untangle the overall benefits of exercise to the heart, liver and muscles from the specific effect on the brain. For example, a healthy heart oxygenates the whole body, including the brain.
“Previous studies of exercise almost all focus on sustained exercise. As neuroscientists, it’s not that we don’t care about the benefits on the heart and muscles but we wanted to know the brain-specific benefit of exercise,” Professor Westbrook said.
So the team designed a study in mice that measured the brain’s response to single bouts of exercise in otherwise sedentary mice that were placed for short periods on running wheels. The mice ran a few miles in two hours.
The authors found that short-term bursts of exercise promoted an increase in synapses in the hippocampus.
They made the key discovery by analyzing genes that were increased in single neurons activated during exercise.
One particular gene, called the metastasis-suppressor 1-like (Mtss1L), stood out.
This gene encodes a protein that causes bending of the cell membrane and had been largely ignored in prior studies in the brain.
“That was the most exciting thing,” said Dr. Christina Chatzi, also from the Vollum Institute at Oregon Health Science University.
The scientists discovered that when the Mtss1L gene is activated by short bursts of exercise, it promotes small growths on neurons known as dendritic spines — the site at which synapses form.
In effect, the study showed that an acute burst of exercise is enough to prime the brain for learning.
The team now plans to pair acute bouts of exercise with learning tasks to better understand the impact on learning and memory.
Christina Chatzi et al. 2019. Exercise-induced enhancement of synaptic function triggered by the inverse BAR protein, Mtss1L. eLife 8: e45920; doi: 10.7554/eLife.45920