Reminiscing, Mental Health and the Aging Brain
Maintaining a Balance of Long and Short-Term Memory
May 8, 2009
A commonly held belief, particularly in Western cultures, is that aging brings inevitable memory decline and often, an unhealthy preoccupation with the past. Is reminiscence an age-related pathology that contributes to depression in the elderly, or when properly channeled, a powerful and useful means of integrating the past into the context of the present? Can a preoccupation with the past take up precious mental storage space and possibly exacerbate a waning ability to store and retrieve new memories? Research in psychology and neuroscience is uncovering more and more evidence that while memory is affected by aging, the nature of the changes and why they occur are much different than most people believe, and maintaining a healthy balance of old and new memories during later years can enhance cognitive performance and mental health.
Long-Term Memories May Be More Easily Accessed for Elderly
New discoveries and advances in the understanding of the brain have overturned the decades-old belief that widespread loss of neurons associated with memory is inevitable as one ages. While brain mass does steadily shrink during normal aging, studies show that in the absence of dementia or Alzheimer’s disease, elderly subjects who experience cognitive decline exhibit changes in the frontal lobes that can often be attributed to decreased blood flow and poor glucose utilization, perhaps due to hypertension, diabetes and cardiovascular disease.
The frontal lobes play an important role in “working” or short-term memory, which is the type of memory that relates to the ability to store task-specific information for a limited timeframe, e.g., remembering where the car is parked or a phone number for few seconds before writing it down. Short-term memory is processed through the hippocampus, the brain region responsible for learning and memory, where it is “coded” by matching and comparing or associating new sensations and experiences with previously recorded information. Working memory is then transferred for storage to other areas of the brain and becomes long-term memory.
The loss of frontal lobe function may be one explanation why short-term memory wanes and long-term memory is more active in the elderly. When an experience is remembered, rehearsed or relived, as in reminiscing, it passes through the hippocampus repeatedly, reinforcing the associations and encoding the information each time. Over a lifetime, the associations can become so strong that the other memory portions of the brain become linked to each other without needing the processing function of the hippocampus. The memory can be triggered or retrieved more easily as a result.
Reminiscing May Improve Mental Health in the Elderly
Reminiscence therapy, like memoir writing classes or memory art projects, has emerged over the past few decades as a way to understand the potential benefits of reminiscence in old age and to counteract the tendency of some to denigrate reminiscing as “living in the past.” A few research findings indicate that older adults who tend to reminisce are less likely to be depressed and possess better mental health than those who do not. The types of remembrances matter though. Glorifying the past or reflecting on negative experiences does not contribute to healthy aging, while focusing on reconciling past and present does.
Too Much Long-Term Memory May Impair Short-Term Memory
A study published in 2007 by the Proceedings of the National Academy of Sciences however, indicates that encouraging too many long-term memories might make it hard to filter and process new information, and in turn make the difficulties of retaining short-term memories even more challenging for the elderly.
Researchers had previously believed that building new cells in the hippocampus was wholly beneficial to memory. According to Gael Malleret of Columbia University Medical Center, neuroscientists were surprised to find that “… too much memory is not always a good thing, and that forgetting is important for normal cognition and behavior.” Working memory is highly sensitive to interference from information previously stored in memory as well, therefore forgetting may be necessary for performing everyday working memory tasks, such as balancing the check book or decision making.
The study goes on to suggest that a careful balance of old and new may be the best approach to maintaining memory and mental health as one ages. Statistics on whether the elderly should be encouraged or dissuaded from remembering the past as a therapeutic mental health exercise have yet to be compiled, but preliminary data indicates that engaging in a positive life review without overwhelming memory with too much old and useless mental activity can support a much healthier, happier later life.
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