What is NEPTUNE, and why examine its limitations?

NEPTUNE proposes a neuroscientific framework for features of near-death experiences. A model can organize existing observations and suggest testable mechanisms without having directly measured each mechanism in each person’s experience. Critical questions include whether findings from other physiological or experimental settings transfer to cardiac arrest, how the timing of remembered experience can be established, and which predictions distinguish the model from competing explanations. These are methodological cautions, not a claim that a published model has been disproved. The supplied register identifies correspondence by O’Grady and Varghese questioning explanatory scope and the model authors’ reply. Both should be read together; publisher-preview or catalog-level access does not justify a full-text verdict. Neither a neural model nor disagreement with it independently verifies an afterlife.