Functional neuroanatomy of altered states of consciousness: The transient hypofrontality hypothesis

Altered states of consciousness—such as dreaming, endurance running, meditation, daydreaming, hypnosis, and drug-induced states—are primarily caused by temporary reduced activity in the prefrontal cortex, a brain region supporting higher-order cognitive functions. This transient hypofrontality is proposed as the unifying feature across all altered states, while the unique qualities of each state arise from which specific frontal circuits remain more or less active. Consciousness is conceptualized as a hierarchy of cognitive functions, with the prefrontal cortex at the top contributing the most sophisticated content. The framework generates testable hypotheses about how subtle prefrontal changes produce diverse conscious experiences.

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Abstract

It is the central hypothesis of this paper that the mental states commonly referred to as altered states of consciousness are principally due to transient prefrontal cortex deregulation. Supportive evidence from psychological and neuroscientific studies of dreaming, endurance running, meditation, daydreaming, hypnosis, and various drug-induced states is presented and integrated. It is proposed that transient hypofrontality is the unifying feature of all altered states and that the phenomenological uniqueness of each state is the result of the differential viability of various frontal circuits. Using an evolutionary approach, consciousness is conceptualized as hierarchically ordered cognitive function. Higher-order structures perform increasingly integrative functions and thus contribute more sophisticated content. Although this implies a holistic approach to consciousness, such a functional hierarchy localizes the most sophisticated layers of consciousness in the zenithal higher-order structure: the prefrontal cortex. The hallmark of altered states of consciousness is the subtle modification of behavioral and cognitive functions that are typically ascribed to the prefrontal cortex. The theoretical framework presented yields a number of testable hypotheses.