Nicotine disrupts safety learning by enhancing fear associated with a safety cue via the dorsal hippocampus

David A. Connor, Munir G. Kutlu, Thomas J. Gould

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

Learned safety, a learning process in which a cue becomes associated with the absence of threat, is disrupted in individuals with post-traumatic stress disorder (PTSD). A bi-directional relationship exists between smoking and PTSD and one potential explanation is that nicotine-associated changes in cognition facilitate PTSD emotional dysregulation by disrupting safety associations. Therefore, we investigated whether nicotine would disrupt learned safety by enhancing fear associated with a safety cue. In the present study, C57BL/6 mice were administered acute or chronic nicotine and trained over three days in a differential backward trace conditioning paradigm consisting of five trials of a forward conditioned stimulus (CS)+ (Light) co-terminating with a footshock unconditioned stimulus followed by a backward CS- (Tone) presented 20 s after cessation of the unconditioned stimulus. Summation testing found that acute nicotine disrupted learned safety, but chronic nicotine had no effect. Another group of animals administered acute nicotine showed fear when presented with the backward CS (Light) alone, indicating the formation of a maladaptive fear association with the backward CS. Finally, we investigated the brain regions involved by administering nicotine directly into the dorsal hippocampus, ventral hippocampus, and prelimbic cortex. Infusion of nicotine into the dorsal hippocampus disrupted safety learning.

Original languageEnglish (US)
Pages (from-to)934-944
Number of pages11
JournalJournal of Psychopharmacology
Volume31
Issue number7
DOIs
StatePublished - Jul 1 2017

All Science Journal Classification (ASJC) codes

  • Pharmacology
  • Psychiatry and Mental health
  • Pharmacology (medical)

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