Effects of acute stress on cognitive and neuronal dynamics of learning and retrieval processes in episodic memory
(Dr. Pastötter, Prof. Frings)
Acute stress can have both positive and negative effects on episodic memory. Positive effects typically appear when acute stress is induced prior to encoding or prior to the consolidation of information. In contrast, negative effects often manifest themselves when stress is induced before information is remembered. This project examines the extent to which active retrieval can protect against such negative stress effects compared to repetitive learning of material. In a series of behavioral and EEG experiments, the cognitive and neuronal dynamics of learning and retrieval processes are examined with special reference to the protective effect of retrieval exercises in various experimental paradigms.
Prefrontal neuromodulation of action control
One of the brain regions most affected by acute stress is the prefrontal cortex. This region also plays a central role in action control. Therefore, it is not surprising that even though the connection between stress and cognitive performance is still poorly understood, it is assumed to be mediated by modulations of the prefrontal cortex (PFC). One method for isolating the activation of the PFC is transcranial direct current stimulation (tDCS). Therefore, tDCS will be combined with established experimental paradigms of action control in order to reveal, in detail, the (probably U-shaped) connection between stress and action control.
Psychobiological validation of a virtual variant of the Trier Social Stress Test (TSST)
(Prof. Walther, Prof. Domes)
In the field of experimental stress research in the laboratory, it is essential to have standardized stress induction methods that can reliably generate stress in subjects on a cognitive, emotional, physiological and behavioral level. To achieve optimal standardization and cost-effectiveness, a well-researched method for experimental stress manipulation ("Trier Social Stress Test", Kirschbaum et al., 1992) is to be transferred to a virtual environment and evaluated for its effectiveness. In addition to subjective parameters, the main focus is on how virtual reality stress induction affects endocrine and psychophysiological markers of the psychobiological stress response.
Effects of acute stress on social attention and mimicry in emotion recognition
Psychosocial stress is associated with a variety of stress-related disorders and leads to specific response types at the behavioral level. In addition to the classic "fight-or-flight" reaction postulated by Cannon, the concept of "tend-and-befriend" behavior has become increasingly important in the context of stress research in recent years. Thus, the effects of acute psychosocial stress on social-cognitive correlates of both response tendencies (e.g., social attention and emotion recognition) and the mediating role of psychobiological mechanisms will be investigated.
Effects of an acute laboratory stressor on interoceptive accuracy in preschool children
The perception of the body's own processes (interoception) is not only relevant for emotional and cognitive theories. Dysfunctional interoceptive processes, such as increased interoception in people with panic disorder, are now being discussed as relevant processes for the development and maintenance of mental disorders, such as anxiety disorders and chronic pain. How functional and dysfunctional interoceptive processes develop during childhood has not yet been investigated. Exposure to early environmental stressors (abuse, but also early onset of pain) and altered HPA activity are discussed as potential mechanisms for dysfunctional interoceptive processes.
The aim of the project is to compare the influence of an acute child-appropriate laboratory stressor (cognitive matching task and unfriendly experimenter) on the interoceptive accuracy of healthy preschool children (4-6 years) and preschool children with early pain experiences by premature birth or surgical intervention. Thus, insights can be generated a) on the validity of the child-appropriate laboratory stressor, b) on the effects of induced stress on interoceptive accuracy and the influence of physiological arousal and stress hormones, and c) on altered stress responsiveness and interoception in preschool children with early onset pain experiences.
Modulation of the neuro-cognitive mechanisms of item vs. associative memory encoding after an acute psychosocial stressor
(Jun.-Prof. Dr. Siri-Maria Kamp)
Ample evidence suggests that the experience of an acute stressor around the time of learning modulates how successful we are in learning, retaining and subsequently retrieving new information. However, the extent and manner to which neuro-cognitive mechanisms specific to episodic encoding of item- and associative information are differentially affected by stress is to date poorly understood. In the present project, we examine how event-related potential (ERP) components that have been shown in previous studies (e.g. Kamp, Bader & Mecklinger, 2017, 2018; Kamp & Donchin, 2015, Kamp, Potts & Donchin, 2015; Kamp & Zimmer, 2015) to be relevant to episodic encoding, with a focus on the P300 and the slow wave component of the ERP, change due to a preceding stressor. The first experiments in this series examine modulations of these ERP components due to stress in relatively simple experimental paradigms, as changes in these components are assumed to underlie differences in learning outcomes after an acute stressor. In subsequent experiments, this assumption is tested more directly by examining, firstly, whether stress differentially affects episodic encoding of item vs. associative information on a behavioral level, and secondly, how neuro-cognitive processes reflected in ERP components account for potential differential stress effects of item vs. associative memory. We also examine modulations of these stress effects due to the content of the learned material and focus on stimulus material varying in valence and social relevance. The results of this project promise to enhance our understanding of the mechanisms that result in modulated learning outcomes when we are under stress.
Effects of hydrocortisone on social behavior
(Dr. von Dawans; Prof. Domes)
With the prominent theoretical framework of “fight-or-flight” stress was always expected to prompt aggressive rather than prosocial behavior. With the introduction of the “tend-and-befriend” response a few decades later an alternative theoretical framework was stated. Empirical evidence is yet inconclusive as studies show both positive and negative effects on social behavior. Although there are various studies concerning acute stress, the underlying biological mechanisms are yet not clarified. Therefore, a pharmacological approach is chosen to examine the effects of varying doses of hydrocortisone (cortisol) through a single application on different facets of social behavior in a game theoretical, behavioral economic setting.
Further projects to follow…