Context modulation of memory for fear extinction in humans

Authors

  • Mohammed R. Milad,

    1. Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
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  • Scott P. Orr,

    1. Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
    2. Research Service, Veterans Affairs Medical Center, Manchester, New Hampshire, USA
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  • Roger K. Pitman,

    1. Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
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  • Scott L. Rauch

    1. Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
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  • We thank Dr. Gregory J. Quirk for helpful discussions regarding the experimental design. The work was supported by a grant from the National Institute of Mental Health (1R21MH072156-1) to S.L.R.

Address reprint requests to: Scott L. Rauch, MD, Department of Psychiatry, 149 13th St., CNY 2618, Charlestown, MA 02129, USA. E-mail: rauch@psych.mgh.harvard.edu.

Abstract

Distinct memories are formed during fear conditioning and subsequent extinction. In animals, the expression of the latter is gated by the context. The recall of extinction memory after a long delay, and the contextual modulation thereof, has not been directly tested in humans. Mentally healthy volunteers underwent a 2-day fear conditioning and extinction protocol that examined the recall of extinction memory and its relationship to context. Conditioned stimuli were paired with an aversive electric shock in one visual context and extinguished in a different context. Extinction recall and renewal were examined 24 h after training. We found that skin conductance responses were small when the conditioned stimulus was presented in the extinction context, but responses were renewed when the conditioned stimulus was presented in the conditioning context. This finding demonstrates context dependency of extinction recall in humans.

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