Near-death experience is a unique consciousness, a self-related, mysterious and unexplainable experience, which occurs in life-threatening and non-life-threatening situations, and could be classified as"classical near-death experiences"and"near-death-like experiences (NDEs-like)", respectively. The classical near-death experience corresponds to the internal awareness experienced in unresponsive conditions, which can be used to explore the disconnected states of consciousness of human beings. Meanwhile, the near-death-like experience is a more heterogeneous state, which brings more possibilities for future research. This article reviews the research progress of near-death experiences in different situations, such as cardiac arrest, syncope and meditative state, etc. Researchers found that people with rapid eye movement invasion are more likely to have NDEs and ketamine-induced general anesthesia can be used as a reversible and safe experimental model. Although many physiological and psychological explanations of near-death experiences have been proposed, the definition of the phenomenon, the mechanisms by which it occurs and the identification of near-death experiences remain controversial. Research on near-death experiences in China is still in its infancy. As a field of consciousness research, near-death experiences can be used to explore the mechanism of human consciousness in an unresponsive state, and to provide a new direction for the scientific research of clinical consciousness.

Consciousness; Awareness; Near-death experiences; Near-death-like experiences; Near-Death Experience Content scale