Exercise Boosts Brain Wiring in Mice
Exercise—it’s well-known for building muscles, but it seems it’s also enhancing the way neurons work. A recent study published in Neuron has found that multiple treadmill sessions can actually strengthen the connections in a mouse’s brain. This “rewiring” allows certain neurons to activate more quickly, which is important for improving their running endurance.
The findings suggest that the brain plays a key role in building endurance, as pointed out by Nicholas Betley from the University of Pennsylvania, who co-authored the study. He noted that while running, various bodily functions improve—it gets easier over time, which is often expected. Yet, he didn’t anticipate that the brain was managing all these changes.
Understanding Brain Function During Exercise
Betley and his team were curious about how exercise leads to strength gains in the brain.
They focused on the ventromedial hypothalamus, an area linked to appetite and blood sugar regulation. Specifically, they examined a group of neurons there that create a protein called steroidogenic factor 1 (SF1), which is known to influence metabolism. Interestingly, previous research had shown that removing the gene for SF1 hampers endurance in mice.
While observing SF1 neurons in mice running on treadmills, the researchers found that these neurons did respond to exercise. A surprising detail was that a subset of these neurons became active only after the running sessions concluded. As the training sessions continued, both the quantity of neurons excited post-exercise and their overall activation increased.
When the researchers analyzed brain slices from mice that had undergone consistent training over three weeks, they noticed changes in the electrical properties of the SF1 neurons. These differences suggested that the neurons from trained mice were now easier to activate. Furthermore, they discovered that repeated exercise doubled the number of excitatory synapses—those that are prepared to transmit electrical signals—between the neurons.
