Neural complexity measures, which can distinguish conscious from unconscious states, also detect meaningful fluctuations in conscious level during normal wakefulness. Using MEG and fMRI data from healthy adults, complexity decreased as participants became drowsy, validating the approach. Complexity changed within and between tasks, and higher complexity was associated with better performance and faster reaction times on an executive task. This offers a new way to explore the cognitive and neural basis of consciousness.
People with first episode psychosis and treatment-resistant schizophrenia show reduced ability to stabilize their decision-making strategies in uncertain environments, resembling effects previously seen with the drug ketamine. In two studies, participants completed a probabilistic reversal learning task. Those with first episode psychosis made more errors and shifted strategies too often after misleading feedback. The treatment-resistant schizophrenia group also shifted strategies more, though their overall accuracy was not significantly reduced. Computational modeling revealed that only the treatment-resistant schizophrenia group showed altered confidence-based modulation of responding, similar to ketamine effects, though these modeling results are considered preliminary due to model limitations.