How moderate exercise improves memory and learning
Just 20 weeks of twice-weekly exercise had significant effects on memory and learning among over 55s, research found.
An ever-increasing body of research, as previously reported on Maverick Life, has consistently confirmed the connection between exercise and the mitigation or prevention of age-related memory deficits as people get older.
Drawing on that body of research, as well as recent advances in neuroscience, a team of researchers from the Center for Molecular and Behavioral Neuroscience at Rutgers University-Newark, and the Center for the Neurobiology of Learning and Memory, Department of Neurobiology and Behavior at the University of California, conducted a study to test the effects of moderate aerobic exercise on what they describe as, “dynamic rearrangement of modular community structure — a measure of neural flexibility — within the medial temporal lobe (MTL) network.”
Simply put, to see if exercise improves the nerve connections in the specific parts of the brain that play a role in memory and learning, specifically, the medial temporal lobe.
First, a brief neuroscience jargon recap: What is the medial temporal lobe?
Although neuroscientists continue to research and update their body of knowledge, the current understanding of the medial temporal lobe is that of a system of structures that affects, among other things, learning and memory. Specifically, with regards to the latter, it is the home of the hippocampus, described here as, “a complex brain structure embedded deep into the temporal lobe. It has a major role in learning and memory.” According to research cited in the study, “The [medial temporal lobe] is one of the earliest brain regions impacted by Alzheimer’s disease.”
Whereas previous research has largely focused on connections between different networks in the brain, what made this January 2021 study unique, was the focus on nerve connections within the MTL network. As the researchers put it: “No prior studies have investigated the effects of an exercise intervention on intra-MTL connectivity.”
A total of 34 (31 female, three male) participants took part in the study, 17 of which were put through a 20-week long programme of two 60-minute dance-based aerobic exercise sessions per week, which consisted of a ten-minute warm-up, 45 minutes of aerobic exercise and five minutes of cooling down and stretching. All were healthy, African-American, and over 55 years old; the average age being 65.
Prior to their participation, “all participants received an extensive cognitive battery, and, health, fitness, and lifestyle assessments… People who were diagnosed with or self-reported MCI or dementia, and/or people who were taking medication known to affect cognition, were informed that they did not qualify for participation… Other exclusion criteria included: excessive alcohol and/ or drug use, psychiatric disorders (including bipolar disorder and schizophrenia), seizure disorders (such as epilepsy), and significant cerebrovascular or cardiovascular diseases,” the researchers write.
During the study, participants were given a range of standardised tests to see the effects of the exercise intervention.
These ranged from testing for fitness and Body Mass Index (BMI), to those that tested for improvements in memory and learning ability. For example, in some tests, participants were trained to associate dissimilar items, such as specific human faces with a certain coloured fish, to be later tested on their ability to retain the information.
In addition, equivalent fish faces were introduced, sometimes in a different order, to test them for “generalisation” capability. They also had functional magnetic resonance imaging (fMRI) scans to see the effects directly on the brain.
“Following a 20-week aerobic exercise intervention, the exercise group showed an increase in neural flexibility within the MTL network, together with an increase in mnemonic flexibility, measured by improvements in generalisation on the behavioural paradigm,” the researchers report.
Meanwhile, the 17 who participated in the learning and memory test, as well as the scans, but not in the 20 weeks of exercise, showed no behavioural or neural network changes. Further, “following the intervention period, the exercise group made significantly fewer generalisation errors, while the control group showed an increase in generalizsation errors on the behavioural paradigm.”
The researchers also noted that while their intervention gave them convincing evidence that the bi-weekly dance-based aerobic exercise had a significant impact on memory and learning, it did not significantly affect fitness and body mass index, stating, “we did not observe any significant exercise-related improvements in either physical health or aerobic fitness at the end of the 20-week intervention.”
However, they do note previous studies that compared the effects of exercise between African-American and Caucasian women, found that when it comes to equivalent aerobic exercise, African American women burnt fewer fatty acids in comparison to Caucasian women. Hence the same exercise done on different ethnicities and genders might result in different effects of BMI.
They concluded that “importantly, our data show that brain health may improve following exercise, even in the absence of observable changes in aerobic fitness. Ultimately, these results reinforce the neuroprotective value of aerobic exercise: even if an exercise regimen is undertaken later in life, it may still mitigate cognitive decline.” DM/ML