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Memory improvement

Act of improving one's memory

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Memory function factors

Neuroplasticity

Neuroplasticity is the mechanism by which the brain encodes experience, learns new behaviors, and can relearn behaviors lost due to brain damage.

Experience-dependent neuroplasticity suggests that the brain changes in response to experiences. After the learning of London taxicab drivers, who memorize maps of the city while studying to drive taxis, was studied over a period of time, it was found that the grey matter volume increased in the posterior hippocampus, an area in the brain involved heavily in memory. The longer taxi drivers navigated the streets of London, the higher the volume of the gray matter in their posterior hippocampus. This suggests a correlation between mental training or exercise and the brain's capacity to manage greater volume and more complex information. The increase in volume led to a decrease in the taxi drivers' ability to acquire new visuo-spatial information.

Stress

Research has found that chronic and acute stress have adverse effects on memory processing systems.

  • 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. Relative to other brain regions, the hippocampus has a high concentration of glucocorticoid receptors. The anterior hippocampus of London taxi drivers 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 control processes such as selective attention reduce this competition by prioritizing where attention is distributed. In memory processing, attention enhances encoding and strength of memory traces. Memory is best when relevant information is attended to and irrelevant information is ignored.
Animal and human studies 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. 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.

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