It is certainly no newsflash to suggest exercise is beneficial for brain health, but exactly how physical activity confers cognitive enhancements is still not entirely clear. Compelling new research from Oregon Health & Science University has discovered a single session of exercise can enhance the expression of a gene that promotes synaptic growth in the hippocampus.
"Previous studies of exercise almost all focus on sustained exercise," explains Gary Westbrook, co-senior-author on the new study. "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."
The goal of this new study was to home in on any specific neuronal changes that occur in the minutes and days following a single period of exercise. The researchers exposed a cohort of otherwise sedentary mice to a two-hour exercise session on a running wheel. The single bout of exercise was estimated as having a human equivalent of a weekly game of basketball, or a 2-mile (3.2-km) run.
As soon as one-hour post exercise the mice displayed enhanced synaptic activity in the hippocampus, a brain area linked to memory and learning. Further analysis then revealed a surprising new discovery – the expression of a particular gene called Mtss1L was enhanced in single neurons following the acute exercise session.
This is the first time scientists have detected activity-dependent Mtss1L expression in single neurons. The gene is known to be involved in cerebellar synapse formation, and in this context was found to enhance the growth of dendritic spines, an action that promotes new synaptic connections between neurons.
What this all suggests is that a short burst of exercise seems to prime the brain for new synaptic connections, implying learning may be enhanced when preceded by physical exercise. While this particular study only involved mice, there is an interesting body of prior work to show exercise improving cognition in humans. From a longer six-week study linking exercise to improved memory, to a shorter experiment finding just 10 minutes of vigorous activity enhances cognitive performance, there is strong evidence the mechanism uncovered in this new research may translate to humans.
The next step for the researchers is to more closely investigate how exercise can directly improve memory and learning via the expression of this particular gene.
The new research was published in the journal eLife.
Source: OHSU