Why working memory declines with age

Working memory is defined as the ability to store and process information temporally. It is connected to everyday activities such as attention, planning and reasoning. Understanding the age-related decline of our working memory is crucial for an ageing society. Tröndle and Langer from the University of Zurich conducted a study looking at data from 134 participants to investigate the change of the visual aspect of working memory with age.

Earlier evidence suggests that brain activity, known as alpha power lateralization, decreases with age during tasks involving visual working memory. However, these findings have been questioned, and no study could link the change in brain activity to the age-related decline in visual working memory performance. This led the research group to perform further investigations, adjusting for previously neglected confounding factors.

The 134 participants had to perform a lateralized color change detection task: They had to remember the visual stimuli on one side of a screen for 500 ms but ignore stimuli on the other.  An arrow, shown for a short period (200 ms), indicated which side they had to remember.

Their study design found a correlation between the decline in visual working memory performance and alpha lateralization. Since the alpha power reflects inhibition of irrelevant information, its decrease with age suggests that older people lose their ability to filter out irrelevant information. This missing filter then contributes to declines in visual working memory performance.

Interestingly, another brain activity indicated that the initial storage and early maintenance of the working memory content may not be affected in older age, further proving that age-related cognitive decline is specifically associated with the inability to prioritize the relevant information in working memory.

Tröndle, M., Langer, N. Decomposing neurophysiological underpinnings of age-related decline in visual working memory. Neurobiology of Aging 139 (2024) 30–43. https://doi.org/10.1016/j.neurobiolaging.2024.03.004

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