title: fMRI fingerprint of unconditioned fear-like behavior in rats exposed to trimethylthiazoline.
abstract: Unconditioned fear plays an important yet poorly understood role in anxiety disorders, and only few neuroimaging studies have focused on evaluating the underlying neuronal mechanisms. In rodents the predator odor trimethylthiazoline (TMT), a synthetic component of fox feces, is commonly used to induce states of unconditioned fear. In this study, arterial spin labeling-based functional magnetic resonance imaging (fMRI) was applied to detect TMT-induced regional modulations of neuronal activity in Wistar rats. During TMT exposure the rats displayed increased freezing behavior and reduced exploration in the odor-associated area. Neuronal activity was selectively increased in the dorsal periaqueductal gray, superior colliculus and medial thalamus and reduced in the median raphe, locus coeruleus, nucleus accumbens shell, ventral tegmental area, ventral pallidum and entorhinal piriform cortex. This fMRI fingerprint involving distinct neuronal pathways was used to describe a schematic model of fear processing. Key brain areas known to underlie fear and anxiety-related autonomic and behavioral responses as well as centers of motivational processing were identified as being part of this functional circuitry of innate fear. Thus, preclinical fMRI studies based on unconditioned fear methods may provide a valuable translational approach to better characterize etiological and pathological processes underlying anxiety disorders.
authors.affiliation: CNS Research, F. Hoffmann-La Roche Ltd., Grenzacherstr. 124, CH-4070 Basel, Switzerland.
authors.forename: Melanie S
authors.initials: MS
authors.lastname: Kessler
authors.forename: Sébastien
authors.initials: S
authors.lastname: Debilly
authors.forename: Stephanie
authors.initials: S
authors.lastname: Schöppenthau
authors.forename: Thomas
authors.initials: T
authors.lastname: Bielser
authors.forename: Andreas
authors.initials: A
authors.lastname: Bruns
authors.forename: Basil
authors.initials: B
authors.lastname: Künnecke
authors.forename: Markus von
authors.initials: Mv
authors.lastname: Kienlin
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Wettstein
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Moreau
authors.forename: Céline
authors.initials: C
authors.lastname: Risterucci
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D005239:Fear / Q000502:physiology*; D046352:Freezing Reaction, Cataleptic / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D009474:Neurons / Q000502:physiology; D009812:Odorants; D051381:Rats; D017208:Rats, Wistar; D013844:Thiazoles / Q000494:pharmacology
chemical_list: C451263:2,4,5 trimethylthiazoline; D013844:Thiazoles