The brain’s ability to predict is vital, yet it must also adapt to surprises. Emotional responses to unexpected events can significantly influence memory consolidation, with positive or negative cues shaping internal models of the world. In a study involving diverse species, including invertebrates, it was proposed that active sleep—characterized by REM—is crucial for optimizing predictive processing. This mechanism may help maintain a balance between prediction and surprise, providing insights into the evolution of consciousness across various animals.
Only 47 out of over 7,700 time-series features reliably distinguished wakefulness from anesthesia or sleep across all evaluation groups of flies. Most of these features were related to autocorrelation, indicating that signals during wakefulness remained correlated to their past for longer than during anesthesia or sleep. Features related to complexity or spectral power, often proposed as consciousness markers, failed to generalize across all datasets, though many showed consistent direction of effect. These results caution that many newly discovered potential consciousness markers may not generalize across datasets, and point to autocorrelation as a class of dynamical properties that does.