Effect of slow-wave sleep deprivation on topographical distribution of spindles

Spindle activity, visually scored in the 12-15 Hz range over antero-posteri or midline derivations, has been assessed in ten normal subjects during a b aseline and a recovery sleep after 2 nights of selective slow-wave sleep (S WS) deprivation. The recovery sleep, characterized by a significant increas e of stage 4 and SWS as compared to the baseline, revealed that sleep spind les are reduced in the first NREM sleep cycle. The size of this reduction i n spindle density progressively decreased in the course of the night, paral leling the depletion of SWS rebound. Topographical distribution of spindle activity showed a global linear increase over consecutive NREM-REM sleep cy cles, regarding to the whole antero-posterior midline EEG derivations excep t the occipital one. It is concluded that the SWS rebound after 2 nights of selective SWS deprivation is associated with a reduction of spindles durin g stage 2. (C) 2000 Elsevier Science B.V. All rights reserved.