Encoding Difficulty Promotes Postlearning Changes in Sleep Spindle Activity during Napping

• DOI: 10.1523/jneurosci.2464-06.2006
• Publication Date: 2006-08-31T00:39:46Z
• Authors: Christina Schmidt; Philippe Peigneux; Vincenzo Muto; Maja Schenkel; Vera Knoblauch; Mirjam Münch; Dominique J.-F. d...; Anna Wirz-Justice; Christian Cajochen
• Keywords: Nap; Sleep; Cued speech; Sleep spindle

Learning-dependent increases in sleep spindle density have been reported during nocturnal immediately after the learning session. Here, we investigated experience-dependent changes daytime EEG activity declarative of unrelated word pairs. At weekly intervals, 13 young male volunteers spent three 24 h sessions laboratory under carefully controlled homeostatic and circadian conditions. approximately midday, subjects performed either one two word-pair tasks or a matched nonlearning control task, counterbalanced order. The lists differed level concreteness words used, resulting an easier more difficult associative encoding condition, as confirmed by performance at immediate cued recall. Subjects were then allowed to for 4 h; afterward, delayed recall was tested. Compared with spectral low frequency range low-frequency spindles (11.25–13.75 Hz) both significantly increased left frontal cortex but not easy condition. Furthermore, found positive correlations between these memory pre-nap post-nap sessions. These results indicate that, like sleep, oscillations including are modified demonstrate here that nature material is determinant factor sleep-related alterations learning.