Physiological and Phenomenological Bases of Altered States of Consciousness
Institutionalized procedures for inducing altered states of consciousness (ASCs) have been documented in virtually all societies of the world, reflecting a universal of culture and religious behavior. This usage of ASCs reflects a psychophysiological basis derived from activities and functions of basic brain structures and their homeostatic balance and integration. ASCs reflect the operation of a mode of consciousness, a fundamental aspect of human nature. The nature of this mode of consciousness is illustrated by its relationships to brain structures and functions. A neurophenomenological approach identifies the four major modes of consciousness -- deep sleep, dreaming, waking, and integrative (or "transpersonal"). These different modes of consciousness reflect cyclic systemic operations of brain structures, in adaptation to external and internal environments.
Societies have a number of adaptations to the integrative mode of consciousness, which is manifested in conditions labeled soul flight, possession, obsession, vision quests, enlightenment, samadhi, and others. Cultures relate to ASCs in different ways, some deliberately