title: Modeling fear-conditioned bradycardia in humans.
abstract: Across species, cued fear conditioning is a common experimental paradigm to investigate aversive Pavlovian learning. While fear-conditioned stimuli (CS+) elicit overt behavior in many mammals, this is not the case in humans. Typically, autonomic nervous system activity is used to quantify fear memory in humans, measured by skin conductance responses (SCR). Here, we investigate whether heart period responses (HPR) evoked by the CS, often observed in humans and small mammals, are suitable to complement SCR as an index of fear memory in humans. We analyze four datasets involving delay and trace conditioning, in which heart beats are identified via electrocardiogram or pulse oximetry, to show that fear-conditioned heart rate deceleration (bradycardia) is elicited and robustly distinguishes CS+ from CS-. We then develop a psychophysiological model (PsPM) of fear-conditioned HPR. This PsPM is inverted to yield estimates of autonomic input into the heart. We show that the sensitivity to distinguish CS+ and CS- (predictive validity) is higher for model-based estimates than peak-scoring analysis, and compare this with SCR. Our work provides a novel tool to investigate fear memory in humans that allows direct comparison between species.
authors.affiliation: Department of Psychiatry, Psychotherapy, and Psychosomatics, University of Zurich, Zurich, Switzerland.|Neuroscience Centre Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Castegnetti
authors.affiliation: Department of Psychiatry, Psychotherapy, and Psychosomatics, University of Zurich, Zurich, Switzerland.|Neuroscience Centre Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Athina
authors.initials: A
authors.lastname: Tzovara
authors.affiliation: Department of Psychiatry, Psychotherapy, and Psychosomatics, University of Zurich, Zurich, Switzerland.|Neuroscience Centre Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Staib
authors.affiliation: Department of Psychiatry, Psychotherapy, and Psychosomatics, University of Zurich, Zurich, Switzerland.|Neuroscience Centre Zurich, University of Zurich, Zurich, Switzerland.|Department of Psychology, Dresden University of Technology, Dresden, Germany.
authors.forename: Philipp C
authors.initials: PC
authors.lastname: Paulus
authors.affiliation: Department of Psychiatry, Psychotherapy, and Psychosomatics, University of Zurich, Zurich, Switzerland.|Neuroscience Centre Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Hofer
authors.affiliation: Department of Psychiatry, Psychotherapy, and Psychosomatics, University of Zurich, Zurich, Switzerland.|Neuroscience Centre Zurich, University of Zurich, Zurich, Switzerland.|Wellcome Trust Centre for Neuroimaging, University College London, London, UK.
authors.forename: Dominik R
authors.initials: DR
authors.lastname: Bach
mesh_terms: D000293:Adolescent; D000328:Adult; D001341:Autonomic Nervous System / Q000502:physiology*; D001499:Bayes Theorem; D001919:Bradycardia / Q000523:psychology*; D003214:Conditioning, Classical / Q000502:physiology*; D004562:Electrocardiography; D005239:Fear / Q000502:physiology*; D005260:Female; D005712:Galvanic Skin Response; D006339:Heart Rate; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D008960:Models, Psychological; D010092:Oximetry; D011601:Psychophysics / Q000379:methods*; D055815:Young Adult
keywords: Delay conditioning; Heart period; Psychophysiological model; Skin conductance; Trace conditioning