title: Switching on and off fear by distinct neuronal circuits.
abstract: Switching between exploratory and defensive behaviour is fundamental to survival of many animals, but how this transition is achieved by specific neuronal circuits is not known. Here, using the converse behavioural states of fear extinction and its context-dependent renewal as a model in mice, we show that bi-directional transitions between states of high and low fear are triggered by a rapid switch in the balance of activity between two distinct populations of basal amygdala neurons. These two populations are integrated into discrete neuronal circuits differentially connected with the hippocampus and the medial prefrontal cortex. Targeted and reversible neuronal inactivation of the basal amygdala prevents behavioural changes without affecting memory or expression of behaviour. Our findings indicate that switching between distinct behavioural states can be triggered by selective activation of specific neuronal circuits integrating sensory and contextual information. These observations provide a new framework for understanding context-dependent changes of fear behaviour.
authors.affiliation: Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland. cyril.herry@fmi.ch
authors.forename: Cyril
authors.initials: C
authors.lastname: Herry
authors.forename: Stephane
authors.initials: S
authors.lastname: Ciocchi
authors.forename: Verena
authors.initials: V
authors.lastname: Senn
authors.forename: Lynda
authors.initials: L
authors.lastname: Demmou
authors.forename: Christian
authors.initials: C
authors.lastname: Müller
authors.forename: Andreas
authors.initials: A
authors.lastname: Lüthi
mesh_terms: D000679:Amygdala / Q000166:cytology / Q000502:physiology; D000818:Animals; D003213:Conditioning, Psychological; D005108:Extinction, Psychological; D005239:Fear / Q000502:physiology*; D046352:Freezing Reaction, Cataleptic / Q000187:drug effects / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D023421:Models, Animal; D009118:Muscimol / Q000494:pharmacology; D009434:Neural Pathways; D009474:Neurons / Q000145:classification / Q000502:physiology*
chemical_list: D009118:Muscimol