title: Safety signals mitigate the consequences of uncontrollable stress via a circuit involving the sensory insular cortex and bed nucleus of the stria terminalis.
abstract: BACKGROUND
  Safety signals exert a powerful buffering effect when provided during exposure to uncontrollable stressors. We evaluated the role of the sensory insular cortex (Si) and the extend amygdala in this "safety signal effect."
  
  
  METHODS
  Rats were implanted with microinjection cannula, exposed to inescapable tailshocks either with or without a safety signal, and later tested for anxiety-like behavior or neuronal Fos expression.
  
  
  RESULTS
  Exposure to the uncontrollable stressor reduced later social exploration but not when safety signals were present. Temporary inhibition of Si during stressor exposure but not during later behavioral testing blocked the safety signal effect on social exploration. The stressor induced Fos in all regions of the amygdala, but safety signals significantly reduced the number of Fos immunoreactive cells in the basolateral amygdala and ventrolateral region of the bed nucleus of the stria terminalis (BNSTlv). Inhibition of BNSTlv neuronal activity during uncontrollable stressor exposure prevented the later reduction in social exploration. Finally, safety signals reduced the time spent freezing during uncontrollable stress.
  
  
  CONCLUSIONS
  These data suggest that safety signals inhibit the neural fear or anxiety response that normally occurs during uncontrollable stressors and that inhibition of the BNSTlv is sufficient to prevent later anxiety. These data lend support to a growing body of evidence that chronic fear is mediated in the basolateral amygdala and BNSTlv and that environmental factors that modulate fear during stress will alter the long-term consequences of the stressor.
authors.affiliation: Department of Psychology and Neuroscience, Center for Neuroscience, University of Colorado, Boulder, Colorado, USA. john.christianson@colorado.edu
authors.forename: John P
authors.initials: JP
authors.lastname: Christianson
authors.forename: Joshua H
authors.initials: JH
authors.lastname: Jennings
authors.forename: Thomas
authors.initials: T
authors.lastname: Ragole
authors.forename: Johana G N
authors.initials: JG
authors.lastname: Flyer
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Benison
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Barth
authors.forename: Linda R
authors.initials: LR
authors.lastname: Watkins
authors.forename: Steven F
authors.initials: SF
authors.lastname: Maier
mesh_terms: D000679:Amygdala / Q000187:drug effects / Q000503:physiopathology; D000818:Animals; D001931:Brain Mapping / Q000379:methods; D002540:Cerebral Cortex / Q000187:drug effects / Q000503:physiopathology*; D003463:Cues; D004558:Electric Stimulation / Q000379:methods; D005239:Fear / Q000502:physiology; D046353:Immobility Response, Tonic / Q000502:physiology; D008297:Male; D008845:Microinjections; D009118:Muscimol / Q000008:administration & dosage / Q000494:pharmacology; D009434:Neural Pathways / Q000187:drug effects / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012686:Septal Nuclei / Q000187:drug effects / Q000503:physiopathology*; D012919:Social Behavior; D013315:Stress, Psychological / Q000503:physiopathology* / Q000523:psychology*; D013779:Tetrodotoxin / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D009118:Muscimol; D013779:Tetrodotoxin