Fear Extinction in Rodents

Chun‐hui Chang1, Ewelina Knapska1, Caitlin A. Orsini1, Christine A. Rabinak1, Joshua M. Zimmerman1, Stephen Maren1

1 University of Michigan, Ann Arbor, Michigan
Publication Name:  Current Protocols in Neuroscience
Unit Number:  Unit 8.23
DOI:  10.1002/0471142301.ns0823s47
Online Posting Date:  April, 2009
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Pavlovian conditioning paradigms have become important model systems for understanding the neuroscience of behavior. In particular, studies of the extinction of Pavlovian fear responses are yielding important information about the neural substrates of anxiety disorders, such as phobias and post‐traumatic stress disorder (PTSD) in humans. These studies are germane to understanding the neural mechanisms underlying behavioral interventions that suppress fear, including exposure therapy in anxiety disorders. This unit describes detailed behavioral protocols for examining the nature and properties of fear extinction in laboratory rodents. Curr. Protoc. Neurosci. 47:8.23.1‐8.23.17. © 2009 by John Wiley & Sons, Inc.

Keywords: extinction; fear; rat; anxiety; phobia

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Table of Contents

  • Introduction
  • Strategic Planning
  • Basic Protocol 1: Fear Extinction in Rats
  • Alternate Protocol 1: Context‐Specific Fear Extinction and Renewal
  • Alternate Protocol 2: Spontaneous Recovery of Fear Memory in Rats
  • Alternate Protocol 3: Reinstatement of Fear Memory After Extinction
  • Commentary
  • Literature Cited
  • Figures
  • Tables
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Basic Protocol 1: Fear Extinction in Rats

  • 1% ammonium and 1% acetic acid solution for cleaning chambers (odors from these solutions are also used to establish unique olfactory contexts)
  • Rats (e.g., adult, male Long‐Evans)
  • Med‐Test software (MED Associates)
  • Shock calibration tool (MED Associates or equivalent) or an oscilloscope with alligator clips
  • A computer that will run MED‐PC software and interface with the chambers for stimulus delivery and data acquisition
  • Decibel meter
  • Load‐cell platforms (see )
  • Observation/conditioning chambers (30 × 24 × 21–cm; MED Associates; see )
  • Video camera mounted on the ceiling of the sound‐attenuating cabinet facing down into the observation chamber (see )
  • White and black plastic boxes
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Literature Cited

Literature Cited
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   Bouton, M.E. 1993. Context, time, and memory retrieval in the interference paradigms of Pavlovian learning. Psychol. Bull. 114:80‐99.
   Bouton, M.E., Westbrook, R.F., Corcoran, K.A., and Maren, S. 2006. Contextual and temporal modulation of extinction: behavioral and biological mechanisms. Biol. Psychiat. 60:352‐360.
   Bruchey, A.K., Shumake, J., and Gonzalez‐Lima, F. 2007. Network model of fear extinction and renewal functional pathways. Neuroscience 145:423‐437.
   Corcoran, K.A., Desmond, T.J., Frey, K.A., and Maren, S. 2005. Hippocampal inactivation disrupts the acquisition and contextual encoding of fear extinction. J. Neurosci. 25:8978‐8987.
   Corcoran, K.A. and Maren, S. 2001. Hippocampal inactivation disrupts contextual retrieval of fear memory after extinction. J. Neurosci. 21:1720‐1726.
   Corcoran, K.A. and Maren, S. 2004. Factors regulating the effects of hippocampal inactivation on renewal of conditional fear after extinction. Learn. Mem. 11:598‐603.
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   Maren, S. and Chang, C.H. 2006. Recent fear is resistant to extinction. Proc. Natl. Acad. Sci. U.S.A. 103:18020‐18025.
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   Woods, A.M. and Bouton, M.E. 2006. D‐cycloserine facilitates extinction but does not eliminate renewal of the conditioned emotional response. Behav. Neurosci. 120:1159‐1162.
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