title: Brain morphology correlates of interindividual differences in conditioned fear acquisition and extinction learning.
abstract: The neural circuits underlying fear learning have been intensively investigated in pavlovian fear conditioning paradigms across species. These studies established a predominant role for the amygdala in fear acquisition, while the ventromedial prefrontal cortex (vmPFC) has been shown to be important in the extinction of conditioned fear. However, studies on morphological correlates of fear learning could not consistently confirm an association with these structures. The objective of the present study was to investigate if interindividual differences in morphology of the amygdala and the vmPFC are related to differences in fear acquisition and extinction learning in humans. We performed structural magnetic resonance imaging in 68 healthy participants who underwent a differential cued fear conditioning paradigm. Volumes of subcortical structures as well as cortical thickness were computed by the semi-automated segmentation software Freesurfer. Stronger acquisition of fear as indexed by skin conductance responses was associated with larger right amygdala volume, while the degree of extinction learning was positively correlated with cortical thickness of the right vmPFC. Both findings could be conceptually replicated in an independent sample of 53 subjects. The data complement our understanding of the role of human brain morphology in the mechanisms of the acquisition and extinction of conditioned fear.
authors.affiliation: Department of Cognitive and Clinical Neuroscience, Medical Faculty Mannheim, Central Institute of Mental Health, Heidelberg University, Square J 5, 68159, Mannheim, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Winkelmann
authors.affiliation: Department of Cognitive and Clinical Neuroscience, Medical Faculty Mannheim, Central Institute of Mental Health, Heidelberg University, Square J 5, 68159, Mannheim, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Grimm
authors.affiliation: Department of Cognitive and Clinical Neuroscience, Medical Faculty Mannheim, Central Institute of Mental Health, Heidelberg University, Square J 5, 68159, Mannheim, Germany.
authors.forename: Sebastian T
authors.initials: ST
authors.lastname: Pohlack
authors.affiliation: Department of Cognitive and Clinical Neuroscience, Medical Faculty Mannheim, Central Institute of Mental Health, Heidelberg University, Square J 5, 68159, Mannheim, Germany.
authors.forename: Frauke
authors.initials: F
authors.lastname: Nees
authors.affiliation: Department of Cognitive and Clinical Neuroscience, Medical Faculty Mannheim, Central Institute of Mental Health, Heidelberg University, Square J 5, 68159, Mannheim, Germany.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Cacciaglia
authors.affiliation: Department of Cognitive and Clinical Neuroscience, Medical Faculty Mannheim, Central Institute of Mental Health, Heidelberg University, Square J 5, 68159, Mannheim, Germany.
authors.forename: Ramona
authors.initials: R
authors.lastname: Dinu-Biringer
authors.affiliation: Department of Cognitive and Clinical Neuroscience, Medical Faculty Mannheim, Central Institute of Mental Health, Heidelberg University, Square J 5, 68159, Mannheim, Germany.
authors.forename: Frauke
authors.initials: F
authors.lastname: Steiger
authors.affiliation: Department of Cognitive and Clinical Neuroscience, Medical Faculty Mannheim, Central Institute of Mental Health, Heidelberg University, Square J 5, 68159, Mannheim, Germany.
authors.forename: Manon
authors.initials: M
authors.lastname: Wicking
authors.affiliation: Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Michaela
authors.initials: M
authors.lastname: Ruttorf
authors.affiliation: Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Lothar R
authors.initials: LR
authors.lastname: Schad
authors.affiliation: Department of Cognitive and Clinical Neuroscience, Medical Faculty Mannheim, Central Institute of Mental Health, Heidelberg University, Square J 5, 68159, Mannheim, Germany. herta.flor@zi-mannheim.de.
authors.forename: Herta
authors.initials: H
authors.lastname: Flor
mesh_terms: D000328:Adult; D000679:Amygdala / Q000033:anatomy & histology* / Q000502:physiology; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology; D003214:Conditioning, Classical / Q000502:physiology*; D005108:Extinction, Psychological / Q000502:physiology*; D005239:Fear / Q000502:physiology*; D005260:Female; D005712:Galvanic Skin Response; D006801:Humans; D007206:Individuality; D008279:Magnetic Resonance Imaging; D008297:Male; D017397:Prefrontal Cortex / Q000033:anatomy & histology* / Q000502:physiology; D055815:Young Adult
keywords: Amygdala; Brain structure; Cortical thickness; Extinction learning; Fear conditioning; vmPFC