MEMORY IMPROVEMENT - STRESS

Stress

Research has found that chronic and acute stress have adverse effects on memory processing systems. Therefore, it is important to find mechanisms in which one can reduce the amount of stress in their lives when seeking to improve memory.

·          Chronic stress has been shown to have negative impacts on the brain, especially in memory processing systems.The hippocampus is vulnerable to repeated stress due to adrenal steroid stress hormones. Elevated glucocorticoids, a class of adrenal steroid hormones, results in increased cortisol, a well known stress response hormone in the brain, and glucocorticoids are known to affect memory. Prolonged high cortisol levels, as seen in chronic stress, have been shown to result in reduced hippocampal volume as well as deficits in hippocampal-dependent memory, as seen in impaired declarative, episodic, spatial, and contextual memory performance.Chronic, long-term high cortisol levels affect the degree of hippocampal atrophy, resulting in as much as a 14% hippocampal volume reduction and impaired hippocampus-dependent memory when compared to elderly subjects with decreased or moderate cortisol levels. An example may be found in the London taxi drivers, as the anterior hippocampus was hypothesized to decrease in volume as a result of elevated cortisol levels from stress.

·          Acute stress: a more common form of stress, results in the release of adrenal steroids resulting in impaired short-term and working memory processes such as selective attention, memory consolidation, as well as long-term potentiation.The human brain has a limited short- term memory capacity to process information, which results in constant competition between stimuli to become processed. Cognitive contro processes such as selective attention reduce this competition by prioritizing where attentional resources are distributed. Attention is crucial in memory processing and enhances encoding and strength of memory traces. It is therefore important to selectively attend to relevant information and ignore irrelevant information in order to have the greatest success at remembering.

Animal and human studies provide evidence as they report that acute stress impairs the maintenance of short-term memory and working memory and aggravates neuropsychiatric disorders involved in short-term and working memory such as depression and schizophrenia. Animal studies with rats have also shown that exposure to acute stress reduces the survival of hippocampal neurons.One of the roles of the central nervous system (CNS) is to help adapt to stressful environments. It has been suggested that acute stress may have a protective function for individuals more vulnerable to their own stress hormones. Some individuals, for example, are not able to decrease or habituate their cortisol elevation, which plays a major role in hippocampal atrophy. This over-response of the central nervous system to stress therefore causes maladaptive chronic stress-like effects to memory processing systems.^[6]