title: Sleep shelters verbal memory from different kinds of interference.
abstract: OBJECTIVE
  Studies have shown that sleep shelters old verbal memories from associative interference arising from new, more recently acquired memories. Our objective is to extend the forms of interference for which sleep provides a sheltering benefit to non-associative and prospective interference, and to examine experimental conditions and memory strengths for which sleep before or after learning particularly affects verbal memory consolidation.
  
  
  METHODS
  Acquiring paired word associates, retention across intervening sleep and wake, training on new, interfering word associates, and test recall of both sets.
  
  
  METHODS
  University laboratory.
  
  
  METHODS
  Healthy volunteers.
  
  
  METHODS
  N/A.
  
  
  RESULTS
  Comparing recall before and after intervening periods of sleep versus wake, we found that: (i) Sleep preferentially shields weakly encoded verbal memories from retroactive interference. (ii) Sleep immediately following learning helps shelter memory from associative and non-associative forms of retroactive interference. (iii) Sleep protects new verbal memories from prospective interference. (iv) Word associations acquired for the first time in the evening after a day spent in the wake state are encoded more strongly than word associations acquired in the morning following a night of sleep.
  
  
  CONCLUSIONS
  The findings extend the known sleep protection from interference to non-associative as well as prospective interference, and limit the protection to weakly encoded word associations. Combined, our results suggest that sleep immediately after verbal learning isolates newly formed memory traces and renders them inaccessible, except by specific contextual cues. Memory isolation in sleep is a passive mechanism that can reasonably account for several experimental findings.
authors: Department of Electrical and Computer Engineering, University of Houston, Houston, TX, USA. brsheth@uh.edu
authors: Bhavin R
authors: BR
authors: Sheth
authors: Reni
authors: R
authors: Varghese
authors: Thuy
authors: T
authors: Truong
mesh_terms: D000328:Adult; D001245:Association Learning / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D011939:Mental Recall / Q000502:physiology; D012890:Sleep / Q000502:physiology*; D055815:Young Adult