Regular exercise is often recommended as a way to boost both emotional and physical well-being. But more than that, according to studies conducted by the Beckman Institute for Advanced Science and Technology, it may also indirectly boost brain health.
Understanding the 'Brain-Exercise' Connection
In a featured report by Neuroscience News, researchers looked at how muscular exercise triggers the production of chemical signals that stimulate neuronal development in the brain. Their findings have been published in the journal Neuroscience.
During exercise, muscular contractions release a number of chemicals into circulation. This is especially true for the biceps when they are attempting to raise a large weight. It is possible for these chemicals to reach the brain and other organs. Scientists were particularly fascinated by the hippocampus and its relationship to physical activity.
Ki Yun Lee, a doctoral candidate in mechanical science and engineering at the University of Illinois Urbana-Champaign and the study's primary author, explained why the hippocampus is so important for learning and memory and how that relates to overall cognitive health.
He said determining the precise mechanisms by which physical activity improves hippocampal function may pave the way for developing exercise-based therapies for illnesses as diverse as Alzheimer's disease.
Indeed, understanding the chemical route between muscular contraction and hippocampus cell development and regulation is only the beginning of understanding how exercise improves brain health.
How was the experiment carried out?
Researchers took samples of mouse skeletal muscle and cultivated them in cell culture plates to extract the chemicals generated by contracting muscles and test them on hippocampus neurons. After reaching maturity, muscle cells spontaneously contract and secrete chemical signals into the cell culture.
A second culture comprising hippocampus neurons and astrocytes was supplemented with the culture containing the mature muscle cells and their chemical signals.
The scientists looked into the effects of these chemicals on hippocampus cells using a variety of techniques, such as immunofluorescent and calcium imaging to monitor cell development and multi-electrode arrays to record neuronal electrical activity.
Those findings really stood out. Hippocampal neurons exposed to the chemical signals from contracting muscle cells responded by sending out more and stronger electrical impulses, an indicator of healthy development and growth.
For only a few days, the neurons began firing these electrical impulses more synchronously, a pattern that is characteristic of a fully developed network of neurons and an attempt to replicate the brain's intrinsic network architecture.
One More Mystery
The researchers still wondered how these chemical signals caused hippocampus neuron growth and development. Next, they looked at astrocytes as a potential mediator of the positive effect of exercise on brain health.
Before the molecules from the muscles reach the neurons, "astrocytes are the first responders in the brain," Lee said. It is possible that they assisted in signal processing by neurons.
The researchers observed that removing astrocytes from cell cultures led neurons to generate even more electrical impulses, indicating that without them, the neurons continued to grow, perhaps to an intolerable level.
