Inner speech—that subjective experience of silent, self-directed verbal thought—is recognized not merely as cognitive background noise but as a core component of human cognition, self-regulation, and identity formation. How, then, does this private dialogue sustain our sense of being the same person, moment after moment, year after year?

Different anesthetics, though acting via distinct pathways, converge on a shared effect: re-aligning brain oscillations. Both ketamine and dexmedetomidine increased low-frequency synchronization across hemispheres while fragmenting within-hemisphere communication. These dose-dependent phase shifts may represent a common mechanism for loss of consciousness and offer potential biomarkers for anesthesia depth.

This article explores the NEPTUNE model, a neuroscience framework that explains near-death experiences (NDEs). Instead of mystical visions, NDEs may emerge from brain crisis responses: oxygen loss, hyperactive neural circuits, and a powerful surge of neurotransmitters. Combined with evolutionary defense strategies and psychological interpretation, these processes create the vivid, life-changing experiences survivors often describe as “more real than real life.”