Towards a Holistic Model of Time Dependent Stress Effects on Working Memory I: Investigating the Effects of Naturalistic Interventions Targeting Central Noradrenaline and Cortisol

• Applicant: Dr. Christoph Geißler
• Subject Area: Biological Psychology and Cognitive Neuroscience
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 550639314

Acute stress affects cognition. One of the cognitive processes affected by acute stress is working memory. Working memory is a central executive function that allows us to uphold, manipulate, and update information internally. This allows us to develop action plans and adapt to our environment. Acute stress commonly leads to a deactivation of such higher cognitive abilities in favor of instinctive or reflexive behavior. However, in humans, previous experimental findings regarding acute stress effects on working memory are mixed. Some previous studies reported positive, some negative, and some no effect of acute stress on working memory. In addition to a number of person-inherent factors, the time between stress and working memory task plays a crucial role in the quality of the effects found. In a systematic literature review, we were able to show that negative stress effects on working memory occur primarily within the first ten minutes after acute stress, as well as in a time interval of more than 25 minutes after acute stress. These time intervals coincide with the activity window of two key cerebral active stress hormones. Thus, cerebral norepinephrine levels are elevated within the first ten to fifteen minutes after acute stress, and cerebral cortisol levels reach their maximum between 25 and 45 minutes after acute stress. Studies employing drugs to artificially increase hormone levels could show that both significantly elevated norepinephrine and significantly elevated cortisol levels have impair neural processing in prefrontal brain regions central to working memory. However, it is questionable how well external drug application mimics natural changes in norepinephrine and cortisol levels. Studies that map the specific role of norepinephrine and cortisol in stress-induced changes in prefrontal processing, as well as working memory performance, are lacking to date. A series of five experiments is planned in which cerebral norepinephrine and cortisol activity will be targeted with different stress interventions and the effect on working memory performance and related prefrontal activity will be examined. The aim of the research project is to establish a holistic model of acute stress effects on human working memory. In particular, we aim to specify the reciprocal relationship between acute stress, prefrontal neuronal activity, and endogenous norepinephrine and cortisol activity in this context.

• DFG Programme: Research Grants
• Co-Investigators: Professor Dr. Gregor Domes; Professor Dr. Christian Frings