Matter over Mind: Physical exercise is central to memory formation

Looking to raise your test grades this semester?

Most students who are trying to improve their exam performance think that the answer lies in studying more. However, mounting evidence suggests that you should hop on the treadmill instead. Recent research indicates that physical exercise may be just as essential to memory formation and retention as mental training.

While many of us can attest to the benefit of exercise on our academic work habits and performance, we do not fully understand the technical basis for it. But recent research has brought us one step closer to a conclusive answer. Investigation into the scientific reasoning behind why physical exercise improves mental performance highlights one important brain development protein: brain-derived neurotrophic factor, or BDNF. This protein is expressed more during physical exercise, and may be crucial to improving both the formation and retention of human memory.

Physical exertion stimulates recognition by increasing the expression of the BDNF protein, which facilitates “synaptic plasticity.” This attribute allows neurons — brain cells — to break, form and change connections to other cells in the brain; this is an essential function for learning and memorization. In addition, the protein is found in areas of the brain where these actions occur: parts of the brain that conduct “higher thinking” such as hippocampus, cortex and basal forebrain. By aiding the development and survival of neurons in these areas, the protein impacts the brain’s capacity for learning and memory.

Although this compound was originally cited to increase short-term memory formation and retention, it also benefits long-term memory and overall brain health. Studies have established a connection between the development of neurodegenerative disease and lower levels of BDNF protein. In fact, some people in the medical community contend that regular physical exercise may do more to prevent or delay onset of neurological disease than routine mental training such as crosswords or Sudoku.

When compared to “neurobic exercises” or memory exercise programs, physical conditioning may be even more important to preventing long-term neurological problems. The BDNF protein is a neurotrophic growth factor — a molecule that facilitates growth, function and development of neurons. It is found in lower concentrations in patients with mental illnesses like Alzheimer’s disease, schizophrenia, Huntington’s disease, obsessive-compulsive disorder and Rett syndrome. Because it is so essential to brain function, the molecule has been closely associated with a number of other neurological diseases such as depression, dementia, anorexia nervosa and bulimia nervosa, and epilepsy.

But you don’t have to exercise every day to reap mental benefits. An animal study conducted at University of California, Irvine, showed that levels of BDNF increased when mice exercised only every other day, and the levels remained high several days after the exercise experience. The length of exercise time is also relatively versatile. A UCLA study found that even a short exercise period enhanced animals’ ability to navigate a maze better than sedentary controls that did not undergo physical training. In addition, when the mice began to exercise regularly after this hiatus, the BDNF protein levels jumped back up to levels close to where they left off after just a small amount of concentrated exercise exposure. Thus, prior experience of regular exercise (even after two weeks of sedentary behavior) creates a kind of molecular memory for BDNF that allows for its re-induction to previously high levels.

Significantly, it was found that BDNF concentrations continued to increase over time as the mice exercised on a regular basis; the rate of increase of molecular concentration did not taper off but rather stayed at an equally high rate, even after three months of the regimen. While it is important to note that these animal model results do not necessarily indicate the expected human metabolic responses to physical exercise, they are a starting point for future research on human exercise patterns and for encouragement of at least minimal regular exercise. So maybe instead of adding an extra hour of study time to your work schedule, scratch that for lifting at the gym, a long walk, or, heck, even sober dancing at Toad’s.

Rebecca Stern is a junior in Berkeley College.