PMC

A, Power spectral density (PSD) analysis identifies three frequency bands during slow wave activity before (blue trace) and after carbachol (red trace) injection: slow (SO; 0.3–3 Hz), spindles (sp; 6–15 Hz) and gamma (30–70 Hz) oscillations (black dashes denote frequency bins where significant differences between conditions were found, ). B, Raw ECoG traces and their corresponding decomposition for the predominant three bands mentioned above. Cortical UP states are defined by the largest energy in the slow oscillation band that correlate with increases in the amplitude of spindles and gamma activity. The episodic increases in the amplitude in both frequency bands are coupled to the slow wave activity. C, D, Following a carbachol injection into the PPN, there is a significant decrease in the spindle amplitude () and an increase in the gamma band energy (), while the slow oscillations maintain their temporal structure and have a tendency to increase their energy ().

Structure of the figure is the same as . Comparison of HF power changes in spike sets with and without slow waves. All HF power changes are more frequent and of larger extent in the spikes with slow waves than those without. The occurrence of postspike HF decreases however is not dependent on the occurrence of a slow wave.

3D spatial structure of evanescent wave field in air above PVC film.

a Example traces of NREM for the different species showing both slow waves and spindle band activity. Top row, signal filtered in the delta range (0.5–4 Hz) superimposed upon the wideband, shaded area, (0.5–45 Hz) signal. Arrows denote slow wave events. Bottom row, the same signal, but filtered in the spindle range (10–16 Hz), with arrows indicating spindle events. Note the co-occurrence of slow waves and bursts of spindle band activity. b Group averaged distribution of the coupling event across species, rats n = 5, tree shrews n = 4, humans n = 5. Histograms show the group average distribution of slow wave-spindle coupling events in percentages over the time course of NREM sleep divided in 40 bins per recording (error bars indicate ±SEM). Note the black line represents the section of the first five bins containing coupling events during the beginning of the sleep period that were used for statistical comparison. Error bars reflect the standard error of the mean.