Scientists use many different experiments to study what happens in the brain in people with stress. It is not clear to what extent the different ways in which subjects are weighed against each other. In a meta-analysis, a biopsychology team from Ruhr-Universität Bochum compared 31 previous studies that had examined weight using magnetic resonance imaging (fMRI) imaging.
The team worked out which regions of the brain are activated as normal during stress and which stress tests stimulate similar activation patterns. They report the results in the journal Neuroscience and Biobehaviolog Reviews, published online on February 5, 2021.
To do the work, Gesa Berretz, Dr. Julian Packheiser and Professor Sebastian Ocklenburg from the Department of Biopsychology collaborated with Professor Robert Kumsta, Genetic Psychology, and Professor Oliver Wolf, Science Cognitive-mind.
Comparative implementation patterns from 31 studies
“We know that stress affects the entire information processing pathway, for example attention, working memory and long-term memory,” says Gesa Berretz. “But so far there has been no consensus on how these different conditions trigger the same sense of stress and what happens in the brain.”
Many researchers are trying to clarify this question and use different methods to promote stress in their study partners. In doing so, they measure the brain activity of subjects using fMRI. The activation patterns are reported in the form of coordinates in a three-dimensional space, representing regions of the brain that were active during the stress test.
The Bochum-based team evaluated 31 studies using an estimated probability of implementation. During this, the researchers compared the coordinates of the activation patterns from all the studies and performed a statistical analysis to what extent the patterns were similar. Data from 1279 subjects were included. The result: a range of areas of the brain, including the insula, the claustrum, the lentiform nucleus and the lower frontal gyrus, were always activated, regardless of the pressure test applied. engaged. “These areas of the brain seem to play a key role in stress,” summarizes Gesa Berretz.
The potential role of brain regions in stress
The insula is, among other things, associated with pain perception, self-awareness and social understanding, and it contains sensory and internal emotional information. It is also involved in controlling the hormonal response. The claustrum is also responsible for the integration of different information and is important for sensation. The activity of these regions reveals, according to the researchers, that the study participants direct their attention toward their emotional processes when under stress.
The lower frontal gyrus is responsible for semantic and phonological processing and for working memory. “Activity seems to occur because many of the methods involve the solicitation of mental functions,” the authors acknowledge.
The lentiform nucleus is associated with movement and coordination. It is not known what its role is in the context of stress. “We hypothesize that excessive weight leads to an increase in overall muscle tension and preparation for a possible fight-or-flight response,” Gesa Berretz explains.
Two weight tests appear as outliers
The analysis also found that the methods used largely achieved consistent results and thus appeared very suitable for the study of stress. Only two methods, called Cyberball and aversive view, represented exceptions. In the first place, subjects were socially excluded during a meaningful ball game. The pattern of brain activity induced by this stress test showed less oversupply with the activation patterns from other methods.
When viewed through confusion, the subjects watch difficult film scenes with brutal content, while showing neutral film material under controlled conditions. In some experiments incorporating this approach, the meta-analysis found no differences between the stress and control conditions. As a result, according to the researchers, care should be taken when interpreting studies that use these methods.
Berretz, G., et al. (2021) The Brain Under Brain – A systematic review and functional meta-analysis of changes in BOLD signal associated with exposure to high stress. Neuroscience and Biobehaviolog Reviews. doi.org/10.1016/j.neubiorev.2021.01.001.