title: Generalization of Fear to Respiratory Sensations.
abstract: Interoceptive fear conditioning (IFC), fear generalization and a lack of safety learning have all been hypothesized to play a role in the pathogenesis of panic disorder, but have never been examined in a single paradigm. The present study aims to investigate whether healthy participants (N=43) can learn both fear and safety to an interoceptive sensation, and whether such learning generalizes to other, similar sensations. Two intensities of inspiratory breathing impairment (induced by two pressure threshold loads of 6 and 25 cm H2O) served as interoceptive conditional stimuli (CSs) in a differential conditioning paradigm. An inspiratory occlusion was used as the unconditioned stimulus (US). Generalization was tested 24h after conditioning, using four generalization stimuli with intensities in-between CS+ and CS- (GSs: 8-10.5-14-18.5 cm H2O). Measures included US-expectancy, startle blink EMG responses, electrodermal activity and respiration. Perceptual discrimination of interoceptive CSs and GSs was explored with a discrimination task prior to acquisition and after generalization. Results indicate that differential fear learning was established for US-expectancy ratings. The group with a low intensity CS+ and a high intensity CS- showed the typical pattern of differential fear responding and a similarity-based generalization gradient. In contrast, the high intensity CS+ and low intensity CS- group showed impaired differential learning and complete generalization of fear. Our findings suggest that interoceptive fear learning and generalization are modulated by stimulus intensity and that the occurrence of discriminatory learning is closely related to fear generalization.
authors.affiliation: University of Leuven. Electronic address: mathias.schroijen@ppw.kuleuven.be.
authors.forename: Mathias
authors.initials: M
authors.lastname: Schroijen
authors.affiliation: University of Leuven.
authors.forename: Meike
authors.initials: M
authors.lastname: Pappens
authors.affiliation: University of Leuven; Maastricht University.
authors.forename: Koen
authors.initials: K
authors.lastname: Schruers
authors.affiliation: University of Leuven.
authors.forename: Omer
authors.initials: O
authors.lastname: Van den Bergh
authors.affiliation: University of Leuven.
authors.forename: Bram
authors.initials: B
authors.lastname: Vervliet
authors.affiliation: University of Leuven.
authors.forename: Ilse
authors.initials: I
authors.lastname: Van Diest
mesh_terms: D000293:Adolescent; D003214:Conditioning, Classical / Q000502:physiology; D005108:Extinction, Psychological / Q000502:physiology; D005239:Fear / Q000502:physiology / Q000523:psychology*; D005260:Female; D006801:Humans; D007858:Learning; D008297:Male; D016584:Panic Disorder / Q000503:physiopathology* / Q000523:psychology; D012119:Respiration; D012677:Sensation; D055815:Young Adult
keywords: Dyspnea; Generalization; Interoceptive fear conditioning; Panic disorder; Perceptual discrimination