One of the many aspects of the stress response is the fight-or-flight response, whereby humankind’s survival benefited by generating a rapid response to threats in the environment. However, for the perceived threats encountered in today’s society, this response could potentially be maladaptive. As a result, many people take a medication that blocks the response of the sympathetic nervous system, part of the stress response, to allow optimal performance during public performance, or while taking exams. In our previous work, we had explored this, and induced the stress response using a well characterized public speaking and mathematical challenge- based stressor, and found impairments in performance on problem solving tasks that are associated with creativity associated with stress. However, the extent to which this cognitively impairing effect of stress manifests appears to vary based on an individual’s genetic susceptibility to stress.
In order to examine how this effect of stress on problem solving manifests in the brain, we examined 45 healthy college-age individuals, while also testing for the presence of at least one copy of a variation in the serotonin transporter gene that has been associated with susceptibility to some aspects of stress. Participants completed two types of tasks while brain activity was monitored during a functional magnetic resonance imaging (MRI) scan.
In the first task, participants were asked to generate as many items from a category after exposure to a stressor implemented within the MRI, and results were contrasted with performance without the stressor. While the number of items generated was not impacted by stress overall, stress-associated changes in the functional interaction between the brain regions activated by the language task was related to stress-associated changes in the number of words generated. This suggests that functional connectivity might serve as a marker for the effects of stress on cognition, at least during language tasks.
In the second task, participants were asked to complete verbal problem solving tasks associated with creativity after exposure to a stressor implemented within the MRI, and results were contrasted with performance without the stressor. With this task, stress-associated changes in the interaction between the middle temporal gyrus region, a critical hub in language, and other language areas, were related to stress-associated changes in performance on the task. Furthermore, the direction of this relationship differed depending on the presence or absence of the stress-related variant of the serotonin transporter gene. Since performance on such verbal problem solving tasks are susceptible to the effects of stress, this may serve as a specific brain marker associated with susceptibility to stress during cognitive tasks. This raises the question as to whether this might serve as an important marker for such effects in individuals with enhanced susceptibility to stress, such as those with test anxiety or those with post-traumatic stress disorder.
Identification of such biomarkers might help us to understand how best to mitigate the effects of stress on cognition in susceptible individuals, which can have a significant impact on quality of life and functioning. This also serves as a window into how processes such as creativity manifest in the brain, and how performance on such processes is regulated by physiological and pharmacological systems.
The lead author for both of these papers was Neetu Nair, Ph.D., with Bradley Ferguson, PhD, and Shawn Christ, Ph.D., at University of Missouri, John Hegarty, PhD, at the Stanford Autism Center; Patrick Hecht, Ph.D., and Michael Tilley, Ph.D. The study, “Effects of stress on functional connectivity during verbal processing,” was recently published in the journal Brain Imaging and Behavior. The companion study, “Effects of stress on functional connectivity during problem solving,” published in the journal NeuroImage. This research was supported by a grant from the University of Missouri Research Board and the University of Missouri Mission Enhancement Fund.