UrFU and Tubingen Scientists Analyze Brain Activity

09:08, October 14, 2020

Scientists have found that task success is more related to attention rather than memory size

The performance of a person's working memory is largely influenced not by the skill to hold many tasks in the head, but by the ability to structure information, manipulate it, and mentally return to the necessary components. This and other conclusions were reached by scientists from the Ural Federal University and the Institute of Medical Psychology at the University of Tübingen (Germany). They conducted a large-scale study: they analyzed electroencephalography (EEG) data of 156 people (in previous similar studies, the sample was 30–35 people), 82 of whom were women. The research results are presented in Scientific Reports (Nature publishing house).

Introducing scientists:

• Dr. Yuri G. Pavlov (UrFU, Tubingen U)
• Dr. Boris Kotchoubey (Tubingen U)

Working memory is responsible for storing and managing information in the short term. Consists of two "components": "capacity" for short-term storage of memory contents and executive components, which are responsible for controlling attention, processing and reorganizing or manipulating information in short-term storage. These executive components make working memory "work" and distinguish it from short-term memory.

In subjects, scientists examined the correlation between the ability of short-term storage of information and the ability to concentrate on this information. Using EEG, the authors studied the cortical oscillatory correlates of theta activity and central beta activity in the brain to separately assess their contribution to individual differences in working memory. In order to find out what signals the brain sends, the study participants were presented with tasks with a difficulty level above average. Some tasks required only storage of information, others - storage and mental manipulation.

“Most working memory tasks in real life require both short-term storage and execution components. For example, memorizing a telephone number before dialing it requires converting verbal information into a sequence of keystrokes. The task also involves switching attention between the current number to be dialed and pressing buttons on the phone panel. A more complex example is transforming a shopping list into an optimal shopping path. This task, in addition to translating the list into a sequence of spatial locations, also involves the constant updating of information in working memory, "- explain the authors of the article.

Existing EEG data indicate that manipulations with information in working memory are strongly associated with theta oscillations in the medial prefrontal and anterior cingulate cortex. Therefore, theta is believed to reflect the involvement of the executive components of working memory. In turn, posterior alpha activity is associated with short-term storage and may directly underlie the storage of information in working memory. Alpha activity responds to increasing stress.

As a result of the study of theta and beta components, scientists found out that not only external distractions, but also mutual interference between elements: the number of elements stored in the working memory and the presence of simultaneous tasks affect the functioning of working memory. When the work memory load is high and / or manipulation is required, a working memory executive is needed to cope with the interference. And scientists suggest that it is likely that the resources that can be used to counter interference are better represented in people with higher efficiency. That is, the ability to control attention plays a more important role in individual differences in working memory than short-term storage capacity.

“We interpreted the changes in the posterior alpha rhythm as reflecting the demand for the short-term storage component of working memory. Another interpretation sees alpha as a filtering mechanism for information by strobing only relevant sensory stimuli. If we accept this point of view, then either people with higher working memory power are no more effective at filtering non-task information than people with less power, or the alpha filtering mechanism works only at moderate levels of memory load, " researchers.

In addition, the data that scientists obtained during the study indicate a strong relationship between medial frontal theta, central beta activity and the executive components of working memory. Both indicators of executive processes, manifested in theta and beta frequency ranges, were associated with behavioral characteristics in the verbal task of working memory. The researchers also found a positive correlation between working memory performance and theta performance index. That is, the more theta activity, the better the performance. In contrast to theta, the beta index of executive control was negatively correlated with working memory performance. That is, the larger the beta, the worse the performance. And alpha activity is not related to individual differences.