Fig. 3.

Pursuit ratio scores for perception, dreaming and imagination tracking. a Median values of normalized pursuit ratio scores in horizontal line tracking (Line tracking), horizontal (H comp circle), vertical (V Comp Circle) and joint (Circle tracking) components of circle tracking during imagination (I, red line and symbols), perception (P, blue line and symbols) and dreaming (D, green line and symbols). Symbols designate medians for individual subjects. Green stars to the right of D indicate pursuit ratio z-score values for the non-lucid REM sleep dream tracking trial. Given that the data were not normally distributed and contained varied numbers of repeated observations within subjects, data were analyzed using a linear mixed model and nonparametric bootstrapping (two-sided, paired test) was used to compare P (circle tracking: N = 5, trials = 28; line tracking: N = 2, trials = 3), D (circle tracking: N = 5, trials = 21; line tracking: N = 3, trials = 5) and I (circle tracking: N = 5, trials = 28; line tracking: N = 2, trials = 3) conditions (replications = 1), *P < 0.001, *P < 0.0001, ***P < 0.00001. Error bars show s.e.m. b Boxplot showing pursuit ratio z-scores during horizontal line tracking task for imagination (I), imagination in the dream (I in D), perception (P) and dreaming (D) conditions. The bottoms and tops of the boxes show the 25th and 75th percentiles (the lower and upper quartiles), respectively; the inner band shows the median; and the whiskers show the upper and lower quartiles ± 1.5 × the interquartile range (IQR). c Area under the ROC curve (AUC) for perception versus imagination (PvI) H (horizontal EOG) (thin blue solid line) and V (vertical EOG) (thin blue dotted line) and dreaming versus imagination (DvI) H (thick green solid line) and V (thick green dotted line) components of eye movements