A new method called Temporal Experience Tracing captures aspects of conscious experience continuously over time, allowing computational reconstruction of common experience states. Analyzing 852 meditations from 20 novice and 12 experienced meditators practicing Breathing, Loving-Kindness, and Open-Monitoring meditation, four recurring experience states were identified, averaging 6 minutes 46 seconds each. Three states matched the three meditation styles, and a fourth represented a low-motivational off-task state. Both groups spent more time in the task-related state during Loving-Kindness meditation and were less likely to transition to the off-task state compared to Breathing meditation. The method transforms the time dimension of subjective experience from narrative to measurable.
Neural complexity, measured by the Lempel-Ziv compression algorithm, is lowest during NREM sleep and similar during REM sleep and wakefulness in cats with intracranial electrodes. Under subanesthetic doses of ketamine (5, 10, and 15 mg/kg), complexity follows an inverted U-shaped curve in some electrodes, especially in prefrontal cortex, rising at low doses and falling as doses approach anesthetic levels. Variability in the ketamine dose-response across cats and cortices is larger than sleep-stage differences, revealing distinct local dynamics. These results replicate findings in humans and other species, showing neural complexity is sensitive to conscious state changes and dose-dependent ketamine effects.