Figure 1.

Schematic of the main aims of the study. We seek to investigate the interactions between oscillatory processes in the brain, lungs and heart, and to establish how they are affected by general anaesthesia. The interactions are assessed by reconstruction of the coupling functions. The analyses are performed on non-invasive measurements of the electroencephalogram (EEG), the respiration signal from expansion of the thorax and the electrocardiogram (ECG). Samples of raw measurements are shown adjacent to each of the organs, as are also the relevant cross-frequency intervals. (Online version in colour.)