Markers and Mechanisms of Individual Differences in Cortico-Cardiac Covariation

• Applicant: Professor Dr. Erik M. Müller
• Subject Area: Personality Psychology, Clinical and Medical Psychology, Methodology
• Term: from 2017 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 390764156

The mere cognitive processing of a potential threat may almost immediately accelerate cardiac activity. Although cortical and cardiac processes are known to affect each other and covary (cortico-cardiac covariation), we do not know why cortico-cardiac covariation is stronger in some individuals than in others. Individual differences in cortico-cardiac covariation relate to individual differences in anxiety and are thus particularly important for our understanding of dispositional anxiety and anxiety disorders. Here, two studies with healthy participants are proposed in an attempt to shed light on markers and mechanisms of cortico-cardiac covariation. The main goal of study 1 is to test whether previously reported within-subject correlations of time-lagged single-trial EEG and heart rate provide a stable and valid trait-marker for cortico-cardiac covariation with relevance for anxiety. N = 67 participants perform several paradigms (gambling task, time estimation task and fear conditioning paradigm) that evoke well-characterized signatures in EEG, heart rate and measures of EEG-heart rate covariation and dispositional anxiety is assessed. The same paradigms are performed 6 months later. With the collected data the re-test reliability, convergent, construct and predictive (i.e. anxiety) validity of cortico-cardiac covariation as assessed with various measures (EEG-heart rate covariation, stimulus-evoked heart rate responses, heart rate variability) and various paradigms will be assessed using multi-trait-multi-method and cross-lagged panel approaches. The main goal of study 2 is to investigate underlying mechanisms of cortico-cardiac covariation and to experimentally test whether individual differences in cortico-cardiac covariation contribute to individual differences in anxiety or vice versa. In that study, N = 148 participants perform a gambling task during threat-of-shock and control conditions. Importantly, we intend to pharmacologically alter cortico-cardiac covariation by double blind and placebo-controlled intake of escitalopram (10 mg), a substance that presumably affects cortical influences on the heart by modulating serotonin activity. By assessing whether (A) (pharmacologically induced) alterations of cortico-cardiac covariation mediate the subjective experience of anxiety during the anticipation of shocks or (B) whether (threat-of-shock induced) alterations of anxiety mediate changes in cortico-cardiac covariation, inferences about causal relationships between anxiety and cortico-cardiac covariation can be made. In combination, studies 1 and 2 thus inform, whether cortico-cardiac covariation as assessed with combined EEG-heart rate measurements reflects a stable trait and a risk factor for experiencing anxiety. Both studies will provide important insights into the general mechanisms by which the brain communicates with the heart and into the mechanisms of individual variation in cortico-cardiac covariation.

• DFG Programme: Research Grants