Direct Evidence Of Role Of Sleep In Memory Formation Is Uncovered(sciencedaily.com)

  ...we tested the role of SPW-Rs on memory consolidation.
  Three groups of rats (test group, n = 7; stimulated 
  controls, n = 7; unimplanted controls, n = 12) were 
  trained to find food rewards ... . 

  During post-training rest and sleep, all of the online-
  detected ripples were suppressed by commissural 
  stimulations in test rats (average online detection rate 
  was 86.0 ± 1.3% (s.e.m.) of post hoc detected SPW-Rs;
  ...). Stimulated control rats underwent the same 
  protocol, except that a random delay (80–120 ms)
  was introduced between SPW-R detection and stimulation, 
  ensuring that the stimulations occurred mainly outside of 
  the ripple episodes.

  Thus, these control rats received the same number of 
  stimulations as test rats, but their hippocampal
  ripples were left largely intact. The global architecture 
  of sleep and the local field potential power in distinct 
  sleep stages were not modified by the suppression of 
  SPW-Rs ... .  As stimulation outside SPW-Rs had
  no detectable effect on task performance ..., the two 
  control groups were pooled and compared with test rats. 
  Performance of the test rats was significantly impaired 
  ... .