A healthy brain is an adaptable brain—one that can respond to new information and circumstances, withstand the harmful effects of injury, disease, and stress, and repair itself following damage to, or loss of, brain cells and/or their connections. This capacity, called neuroplasticity, is essential to staying sharp in older age.
“Brain circuits aren’t static—they’re receptive to modification and re-organization,” says Amar Sahay, PhD, Principal Faculty at the Harvard Stem Cell Institute and an assistant professor at the Center for Regenerative Medicine and the Department of Psychia-try at Massachusetts General Hospital (MGH). “The brain is capable of changing in response to many factors, including environmental stimuli, learning new information, and physical exercise, to name a few, and in healthy individuals, these adaptations continue all life long.”
The processes involved in neuroplasticity include the production of new neurons, or brain cells (neurogenesis) and the formation of new connections among brain cells. These ongoing changes in brain structure and function appear to be essential to maintaining an alert and healthy mind. Learning ways to promote neurogenesis can help you ensure that your brain remains adaptable and can also help you withstand the effects of aging; recover from stroke, brain injury and the ravages of stress; resist depression; and reduce your risk for neurological diseases such as Alz-heimer’s disease.
WHAT YOU SHOULD KNOW
Researchers have found links between a number of factors and significant reductions in neurogenesis. It’s best to avoid these factors, which include:
- Physical inactivity
- Excessive alcohol consumption (three to four drinks a day)
- Exposure to neurotoxins (Wear protective gear to minimize your exposure when you come into contact with potentially neurotoxic substances, such as pesticides or spray paints.)
Boosting neurogenesis involves addressing a complex array of factors, many of which are within your control. The secret is to adopt a lifestyle in which you incorporate elements that support a healthy brain and avoid elements that harm it. No one element can promote neurogenesis on its own—it’s a balance of many elements. The following factors are among those that have been shown to promote healthy neurogenesis:
▶ Exercise. Regular aerobic exercise has been linked with improved cognition. It also increases brain growth factors and promotes neurogenesis in the hippo-campus, an important memory region that is especially impacted by this process. With your doc-tor’s permission, aim for at least 30 minutes of daily exercise, five days per week.
▶ Meditation. Research suggests that spending at least 20 minutes a day meditating—sitting quietly, focusing on your breathing, and being mindful of thoughts and sensory perceptions, but remaining detached—helps increase connections among brain cells and boosts the volume of brain regions involved in memory, sensory processing, and attention.
▶ Good health care. Get regular checkups and follow your doctor’s advice on managing any medical problems. Proper care can help you avoid health problems that adversely affect the brain. For example, obesity is associated with high levels of in-flammation and the stress hormone cortisol that can interfere with neurogenesis. Research with animals suggests that diabetes mellitus may also adversely affect neuroplasticity.
▶ Adequate sleep. Healthy amounts of sleep—seven to nine hours per night—are important for brain health and mental alertness. Studies suggest that sleep helps prevent brain atrophy, a sign of reduced neurogenesis, and also strengthens con-nections responsible for transmitting information across brain networks.
▶ Stress reduction. Chronic stress is associated with re-duced neurogenesis, atrophy of important brain regions, and increased risk for dementia. When stress is unavoidable, reduce its negative effects on the brain through lifestyle changes and by us-ing relaxation techniques such as yoga, meditation, and visualization, pursuing soothing activities such as listening to music, or enjoying positive and active relationships with friends, family and even pets.
▶ Treatment of major depressive disorder (MDD). Depression has been shown to slow neurogenesis and interfere with memory and cognition. For individuals diagnosed with mood disorders such as depression or anxiety, getting professional treatment is important. An added bonus: Antidepressants that affect levels of neurotransmitters such as norepinephrine, serotonin and dopamine have been associated with increased neurogenesis.
▶ Intellectual stimulation. Research studies suggest that keeping your brain occupied with new and challenging tasks may help foster new neuronal growth and connections. Make an effort to learn new skills, such as speaking a foreign language, and try to surround yourself with a stimulating, complex environment that includes sensory activities (such as listening to music) and exposure to new routines, unfamiliar places, and novel ideas. Maintain an active social life. Social activities can be challenging and stimulating to the brain.
▶ Fasting. Research has linked the practice of fasting with increases in nerve growth factors that promote neurogenesis, and with decreased risk for neuro-degenerative disease. It is advisable to consult a medical care provider before undertaking a fast.
▶ Consumption of omega-3 fatty acids. A healthy, well-balanced and nutritious low-calorie diet should include plenty of these important fatty acids found in foods such as cold-water fish, flaxseed oil, and walnuts. Research suggests that omega-3s help to reduce pro-inflammatory factors that may interfere with repair processes in the brain.
Dr. Sahay and his colleagues at MGH’s Laboratory of Adult Hippocampal Neurogenesis, Cognition and Mood (http://www.sahaylab.com) recently published results of a ground-breaking animal study in which they used a novel procedure to improve memory function in adult mice by in-creasing neurogenesis in the hippocampus. In younger individuals, new stem cells produced by neurogenesis grow and integrate themselves into networks of connections among existing neurons, but as the brain ages, neurogenesis slows down.
To address this problem, the scientists turned on a gene with which they could prune back some of the connections of old neurons in aged mice. This disruption stimulated the production of new neurons and enhanced the integration of these new cells into neural circuits, resulting in improved memory function. When the gene was turned off, the connections of the old neurons came back without affecting the extra new neurons that had became incorporated into the circuit, according to an online report published Sept. 21, 2016 in Neuron.
“Because we can do this reversibly, at any point in the animals’ life we can reju-venate the hippocampus with extra, new encoding units,” Dr. Sahay said. The findings raise the possibility that similar processes might be developed for humans that would one day help aging brains adapt, learn and heal.