Figure 2.

Slow and delta power of slow wave sleep specifically correlate with declarative memory consolidation during afternoon nap. Correlations between subject performance in the PAL task and subject total power value over the entire sham sleep interval for each spectral bands – slow, delta, theta and alpha – during the nap period. A significant positive correlation was found between the PAL task and slow and delta bands [Pearson's correlation; A, r > 0.79, P < 0.009, one-tailed, B, r > 0.69, P < 0.029, one-tailed], but not with theta, alpha, or spindle-range bands [C, r < 0.45, P > 0.26, two-tailed, D, r < 0.25, P > 0.55, two-tailed, E, r > −0.040, P > 0.91, two-tailed].