The Neuroscience of Aging
As one ages, every system in the body inevitably changes, including the components of the nervous system. While many consequences of such changes are unavoidable, some strategies and treatments can make a positive impact on the aging process.
Discover how the brain changes over time, learn how neuroscience offers a better understanding of the process, and discover how the medical community uses neuroscience to improve quality of life for the aging population.
The Brain Experiences Progressive Loss During Aging
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Over time, as Emeritus Professor of Neuropathology at the Nuffield Department of Clinical Neurosciences Dr. Margaret Esiri notes in The Journal of Pathology, the human brain progressively loses some of its 100 billion neurons, along with some related cells in the nervous system. This process happens relatively slowly while the average person is between 20 and 60 years old, with most people losing only 0.1 percent of their neurons during this period. As Esiri explains, the rate of neural loss increases after age 60, and upon turning 90, most people have lost an average of 11 percent of their brain mass.
For most aging adults, neural loss does not equally affect all areas of the brain. In fact, the cerebral cortex tends to experience the greatest change, specifically the prefrontal gray matter, according to research discussed in Cerebral Cortex. Other parts of the brain experience less significant but still notable neural changes. For instance, the somatic motor cortex, which manages gait and body movement, exhibits symptoms of neural atrophy in aging adults.
Aging May Cause Functional Decline, Even in Healthy Older Adults
Many older adults experience declining skills and abilities over time, even if they can avoid such diseases as Alzheimer’s or dementia. As Diane B. Howieson explains for The Dana Foundation, many older adults are capable of maintaining their intellectual abilities despite their ages, but neural loss may cause both cognitive and physical functions to slow with increased age. Eventually, that loss can result in delayed responses to stimuli and slower language recall.
In addition, adults who experience memory loss are often witnessing the first sign of aging. Short-term memory loss is common among the aging population, but it does not typically lead to long-term loss of skills. Loss of episodic memory may also present challenges for older adults as they attempt to recall the details of major life events. According to pathologist Bruce Yanker, such decline is a primary risk factor for Alzheimer’s disease and other prevalent neurodegenerative disorders.
Older Adults May Be Able to Diminish the Effects of Age
Though some amount of neural loss is inevitable, the aging population can take steps to diminish its adverse effects. For years, neuroscientists have understood that a larger brain reserve, or more brain mass and a greater number of neurons, can improve patients’ ability to recover from or manage the effects of brain injuries and diseases. A larger brain reserve does not necessarily enable older adults to improve cognitive function, however.
Instead, according to Harvard Health Publications, many neuroscientists believe that building a cognitive reserve may help older adults maintain better functionality as they age or if they encounter unexpected surgeries, stresses, or toxins. A range of factors, including holding a high-level profession, attaining an advanced level of education, and being socially active, will help older adults improve their cognitive reserve. With age, these adults can use brain reserves more effectively, due to more efficient neural connections.
Mara Mather, of the Leonard Davis School of Gerontology, notes that for older adults, remaining mentally active may stimulate neural pathways that enhance cognitive function and promote cognitive reserve for the future. Researchers have also noted that continuing to learn new skills, staying physically active, and maintaining a healthy social life will, at the very least, slow cognitive decline in the aging population.
Improved Plasticity May Impact Aging
Recent cognitive neuroscience research has suggested that the aging brain is more resilient than earlier studies have indicated. Writing for Science magazine, Angela Gutchess of the Department of Psychology and Volen National Center for Complex Systems at Brandeis University and Massachusetts General Hospital Athinoula A. Martinos Center for Biomedical Imaging explains that enhancing brain plasticity is key for older adults.
Functional magnetic resonance imaging (fMRI) technology has also shown that young adults tend to show a high level of neural specialization, meaning they often use specific parts of the brain to conduct certain cognitive functions. In contrast, older adults display a far lower level of specialization, often relying on different parts of the brain to do standard cognitive tasks.
As Gutchess explains, generating and supporting neural growth may increase brain flexibility, or plasticity, in older adults. Alternative methods, such as neurostimulation, can also enhance plasticity. Mather also mentions that regions within the aging brain specialized for emotion processing seem to decline less than regions specialized for other tasks. Older adults seem to prioritize certain emotions and use specific regions of the brain to do so, and they may also be able to alter their social strategies accordingly, although additional research is necessary to understand the full impact of socio-emotional processes on neural flexibility.
What Lies Ahead for the Neuroscience of Aging
For neuroscientists, one of the most significant challenges remains the differentiation between normal aging-related changes in the brain from changes that signify conditions such as dementia and Alzheimer’s disease. For example, episodic memory loss and neural loss are two of the primary indicators of Alzheimer’s disease, but normal brains typically experience these changes, too.
As you pursue your Master of Arts in Gerontology, you will find the equal significance of both the physical and psychological aspects of aging. According to the National Institutes of Health, managing aging-related conditions can be prohibitively expensive for many people. The health care costs surrounding dementia, for instance, average $250,000 per patient per year, making this disease the most expensive for older Americans. Reducing costs, improving overall health, and increasing quality of life for older adults could all be positive outcomes of further research.
Several emerging technologies have the potential to simplify our understanding of the aging brain. As the AAAS Science and Technology Policy Fellow at the Department of Energy Dr. Jonathan Trinastic writes in GotScience Magazine, MRI and other advanced brain imaging technology could help scientists see and analyze aging and disease-related changes in extreme detail in the near future. As supercomputers continue to advance, researchers become more capable of accurately simulating neuron networks, generating new data that offers clues about how healthy brains work and change over time.
For leaders in gerontology, understanding how the brain ages is essential, as this knowledge may enable professionals to help older adults live their best lives. Visit USC Leonard Davis School of Gerontology to learn how an online gerontology degree could help driven professionals place themselves at the forefront of the science of aging.