Figures and data
Experimental design.
a) Artificial words consist of two vowels and two consonants according to four different sequences. b) The phonotactic probabilities (PP) for single phonemes (left panel) and biphone probabilities (right panel) averaged over the four sets (40 words per set) and pairing of the sets with respect to two distinct levels of PP in high-(black) and low-PP (grey). c) Schematic trial structure of the learning task with screen images and the durations in milliseconds. d) Feedback matrix with the four answer types (hits, CR = correct rejections, misses and FA = false alarms) regarding to response and reward assignment of the word. Note, subjects could receive and lose money points dependent on correct and incorrect responses. e) Experimental procedure with experimental tasks and phases in temporal order. TMR took place in the non-REM sleep stages 2 & 3. Error bars reflect standard errors of the mean (SEM).
Distinct levels of encoding between high- and low-PP words.
a) Learning curves showing encoding performance over presentations of high-(black) and low-PP (gray) words. Note significant greater performance of high- in comparison to low-PP over the second and third presentations. b) Grand average time-frequency plots time-locked to word presentations. The gray rectangle within the top panel borders time and frequency range of interest (0.7 to 1.9s; 8-13Hz). Three different panels from top to down regarding to the three presentations. Solid and dotted lines within plots representing stimulus onset and averaged offset respectively. Note, increases of oscillatory desynchronization in alpha range (8-13Hz) over the three presentations. b) (Top, right) Topographic map shows power values averaged over the time window and frequency range of interest. c) (Top) Time-frequency representation of t-values (merged over Pz and P3 electrodes) shows significant greater changed desynchronization in alpha oscillations of high- in contrast to low-PP during the third presentation. Below, topographic map indicates significant cluster of electrodes of comparison between PP conditions of the third presentation (0.7 to 1.9s; 8-13Hz). d) The bar chart shows mean changes across subjects in alpha power (merged over Pz and Cz electrodes) of the second and third presentation by subtracting the first presentation in high-(black) vs. low-PP (gray). Statistical analyses revealed significant higher desynchronization of high-compared to low-PP and a significant decrease in alpha power under 0 of high-PP at the third presentation. Error bars reflect standard errors of the Mean (SEM); *p<0.05, **p<0.01.
TMR affects the memory performance of the easy to learn words.
Bar charts show mean overnight changes of sensitivity (a) and c-criterion (b) values of high- and low-PP and cued (green) vs. uncued (gray) conditions. Note, statistical analyses revealed significant overnight increases only in the high-PP cued condition. Error bars reflect SEM; *p<0.05.
Increased spindle power during SW up-states in TMR of the easy to learn words.
a) Top and bottom panel, two example EEG traces of auditory cueing during sleep (−2 until 6s to stimulus onset). Top rows, in blue, signal filtered in the SW range (0.5-3 Hz) superimposed upon the broadband (0.5-35 Hz) signal in black. Vertical black lines with speaker symbols on top mark onsets of auditory presentations. Black arrows point to spindle activity during SW up-states. Bottom rows, in red, the same signal, but filtered in the spindle range (9–16 Hz). Note, elevated SW following cueing presentations with various spindle band activity nested during SW up-states. b) Grand average baseline corrected curve of increased SW density after TMR in percentage. Shaded gray areas mark time windows (0 to 0.5s, 0.5 to 1s and 1.5 to 2s) of significant increased SW density. c) Grand average time-frequency plots time-locked to the troughs of SW with averaged signals plotted as black lines. Two different panels (left and right) according to high- vs. low-PP cueing conditions. The rectangle within the left panel borders time (0.3 until 0.6s to SW troughs) and frequency range of up-state fast spindle band activity (12-16Hz). Corresponding topographic map at right shows elevated fast spindle power over mid-parietal electrodes. d) Time-frequency representation of t-values time-locked to SW shows significant greater spindle band power during SW up-states for high- vs. low-PP (merged over Pz, P3 and P4 electrodes). Right, topographic map of t-values shows corresponding significant cluster of electrodes (0.3 to 0.8s; 11-14Hz), *p<0.05.
Gender, age and performance rates
