title: Gating of fear in prelimbic cortex by hippocampal and amygdala inputs.
abstract: The prefrontal cortex (PFC) regulates emotional responses, but it is unclear how PFC integrates diverse inputs to select the appropriate response. We therefore evaluated the contribution of basolateral amygdala (BLA) and ventral hippocampus (vHPC) inputs to fear signaling in the prelimbic (PL) cortex, a PFC region critical for the expression of conditioned fear. In conditioned rats trained to press for food, BLA inactivation decreased the activity of projection cells in PL, and reduced PL conditioned tone responses. In contrast, vHPC inactivation decreased activity of interneurons in PL and increased PL conditioned tone responses. Consistent with hippocampal gating of fear after extinction, vHPC inactivation increased fear and PL pyramidal activity in extinguished, but not in conditioned, rats. These results suggest a prefrontal circuit whereby hippocampus gates amygdala-based fear. Thus, deficient hippocampal inhibition of PFC may underlie emotional disorders, especially in light of reduced hippocampal volume observed in depression and PTSD.
authors.affiliation: Departments of Psychiatry and Anatomy & Neurobiology, University of Puerto Rico School of Medicine, P.O. Box 365067, San Juan, PR 00936-5067, USA. sotres@ifc.unam.mx
authors.forename: Francisco
authors.initials: F
authors.lastname: Sotres-Bayon
authors.forename: Demetrio
authors.initials: D
authors.lastname: Sierra-Mercado
authors.forename: Enmanuelle
authors.initials: E
authors.lastname: Pardilla-Delgado
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Quirk
mesh_terms: D000161:Acoustic Stimulation; D000200:Action Potentials / Q000187:drug effects; D000679:Amygdala / Q000187:drug effects / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D004597:Electroshock / Q000379:methods; D005239:Fear / Q000187:drug effects; D058785:GABA-A Receptor Agonists / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009118:Muscimol / Q000494:pharmacology; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D017397:Prefrontal Cortex / Q000166:cytology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D055139:Sensory Gating / Q000187:drug effects / Q000502:physiology*; D018709:Statistics, Nonparametric
chemical_list: D058785:GABA-A Receptor Agonists; D009118:Muscimol