Sensory Consciousness, Jhāna Consciousness, and the Role of the Upper Brain Stem

A perspective report describes a form of consciousness called jhāna consciousness, developed through Buddhist meditation, which differs fundamentally from ordinary sensory consciousness. An EEG study showed that as practitioners disengage from sensory awareness toward jhāna absorption, brain activity in most cortical networks gradually simplifies and fades, leaving only intense infraslow wave activity at the vertex. This suggests jhāna consciousness is not an altered state of everyday consciousness but a distinct mode, experienced as clear embodied presence. Comparing the two modes points to the upper brain stem as a likely basis for consciousness in both.

Study at a glance

Abstract

Most if not all research into consciousness in neuroscience and philosophy has dealt with the consciousness we all live within from birth, which in Dennison (2019) I termed the “human default sensory consciousness”. This was to contrast this mode to a quite different form of consciousness that develops in the Buddhist practice of jhāna meditation. This little known practice implicitly requires practitioners to disengage, temporarily, from their habitual sensory consciousness towards progressively deeper stages of what in Buddhist terminology is termed jhānic absorption or jhāna consciousness (Dennison, 2022), as a basis for developing insight into the human condition. The 2019 EEG study demonstrated that jhāna consciousness is not an altered state (ASC) or subset of our familiar everyday consciousness, but is a different form of consciousness in its own right, experienced as clear embodied presence. This perspective report describes the profound changes in brain activity as a practitioner disengages from sensory consciousness towards jhāna consciousness. In contrast to task-based studies that attempt to identify neural correlates of consciousness amongst the many complex neural networks, the EEG study of this form of meditation reveals a gradual simplification and fading of activity in the bulk of those cortical networks during this transition, until only an intense focus of infraslow wave activity remains at the vertex. Comparison of these two modes of consciousness allows new insights into the nature of consciousness itself, including the key role of the upper brain stem as the likely basis of consciousness for both modes.