title: Sleep promotes generalization of extinction of conditioned fear.
abstract: OBJECTIVE
  To examine the effects of sleep on fear conditioning, extinction, extinction recall, and generalization of extinction recall in healthy humans.
  
  
  METHODS
  During the Conditioning phase, a mild, 0.5-sec shock followed conditioned stimuli (CS+s), which consisted of 2 differently colored lamps. A third lamp color was interspersed but never reinforced (CS-). Immediately after Conditioning, one CS+ was extinguished (CS+E) by presentation without shocks (Extinction phase). The other CS+ went unextinguished (CS+U). Twelve hours later, following continuous normal daytime waking (Wake group, N=27) or an equal interval containing a normal night's sleep (Sleep group, N=26), conditioned responses (CRs) to all CSs were measured (Extinction Recall phase). It was hypothesized that the Sleep versus Wake group would show greater extinction recall and/or generalization of extinction recall from the CS+E to the CS+U.
  
  
  METHODS
  Academic medical center.
  
  
  METHODS
  Paid normal volunteers.
  
  
  RESULTS
  Square-root transformed skin conductance response (SCR) measured conditioned responding. During Extinction Recall, the Group (Wake or Sleep) x CS+ Type (CS+E or CS+U) interaction was significant (P = 0.04). SCRs to the CS+E did not differ between groups, whereas SCRs to the CS+U were significantly smaller in the Sleep group. Additionally, SCRs were significantly larger to the CS+U than CS+E in the Wake but not the Sleep group.
  
  
  CONCLUSIONS
  After sleep, extinction memory generalized from an extinguished conditioned stimulus to a similarly conditioned but unextinguished stimulus. Clinically, adequate sleep may promote generalization of extinction memory from specific stimuli treated during exposure therapy to similar stimuli later encountered in vivo.
authors.affiliation: Harvard Medical School, Department of Psychiatry, Center for Sleep & Cognition, Beth Israel Deaconess Medical Center Boston, MA 02215, USA. epacesch@bidmc.harvard.edu
authors.forename: Edward F
authors.initials: EF
authors.lastname: Pace-Schott
authors.forename: Mohammed R
authors.initials: MR
authors.lastname: Milad
authors.forename: Scott P
authors.initials: SP
authors.lastname: Orr
authors.forename: Scott L
authors.initials: SL
authors.lastname: Rauch
authors.forename: Robert
authors.initials: R
authors.lastname: Stickgold
authors.forename: Roger K
authors.initials: RK
authors.lastname: Pitman
mesh_terms: D000293:Adolescent; D000328:Adult; D001143:Arousal; D001245:Association Learning; D003214:Conditioning, Classical; D004597:Electroshock; D005108:Extinction, Psychological; D005239:Fear; D005260:Female; D005712:Galvanic Skin Response; D005795:Generalization, Stimulus; D006801:Humans; D008297:Male; D011939:Mental Recall; D012890:Sleep; D014851:Wakefulness; D055815:Young Adult