Until now, it was believed that working memory, which is used for tasks that are solved directly, is maintained by the same brain processes. Researchers have proven that this is not the case.
Scientists from the Center for the Study of Human Brain Activity at the University of Oxford have found that the areas of the brain responsible for working memory are constantly changing. Previously, experts believed that when solving a problem, constant activity is maintained in the brain. The researchers conducted a large review of previous data (over the past 50 years), including the results of experiments with monkeys. They were especially interested in the activity of the prefrontal cortex, which plays an important role in the functioning of working memory. Damage to this area leads to memory impairment and problems performing tasks. It was found that sometimes there is no activity in the brain associated with the solution of the current task, but as soon as the need arose, the period of “quiet activity” ends and activity resumes.
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Psychologist Mark Stokes, leader of the group, comments on these results: “Imagine you are looking for your cup. Previously, it was believed that in the process of searching in the brain, there is a constant activity associated with this thought. But you start walking around the rooms in search of a cup, and the brain has to also handle the task of navigating the house. The best thing to do would be to pause the activity associated with the cup, allowing the brain to focus on the task of navigating. Which is what is happening.» It is known that the brain uses about 20% of the energy that is spent by our body, and it has to be distributed among all types of brain activity. Such an algorithm of operation helps to save energy. Perhaps «working» memory functions in the same way as long-term memory. We all remember our birthdays or other significant events, but our brains don’t have the kind of constant activity that builds up our memories of those days.
For more information, see M. Stokes «Activity-silent working memory in prefrontal cortex: a dynamic coding framework», Trends in Cognitive Sciences, online publication June 4, 2015.