Training attention for conscious non-REM sleep: The yogic practice of yoga-nidrā and its implications for neuroscience research.

The study of consciousness within cognitive neuroscience has been dominated in recent years by investigations originating from collaborations between neuroscientific investigators and Buddhist meditation practitioners. The results have been remarkable, particularly when quantitative and qualitative research methods have been combined as they are in the neurophenomenological methodology originated by Francisco Varela. The addition of qualitative data about the experience of the subject greatly enriches the interpretive potential of quantitative data and honors the ultimate subjectivity of all phenomena, if we accept consciousness as the universal first principle as some quantum physicists now do. This remarkable progress, however, has dropped a thread of inquiry begun in the late 1960s by the Menninger Foundation in Topeka, Kansas (the United States) under the leadership of Elmer and Alyce Green. Their studies of the conscious control of involuntary processes drew on collaboration with an Indian master of yoga meditation, Swāmī Rāma of the Himālayas, which opened a number of intriguing possibilities, which have yet to be followed up in detail with the most recent research tools and methodologies. Among these is the ability to enter the deepest, non-REM delta wave sleep while maintaining awareness both internally and of one's surroundings (yoga-nidrā). The particular interest in this ability lies not only in the benefits that accrue from especially deep relaxation and an especially pure experience of mindful awareness, but also from the yogi's description of this as a way to gradually learn to enter the deepest states of meditation (samādhi) and remain there even when otherwise active in the world (turīya). This chapter is one of a series hoping to elucidate that state from both traditional and contemporary descriptions of the state of yoga-nidrā, draw measurable hypotheses from these descriptions and discuss the methodological problems of conducting these investigations with sufficiently competent samples of subjects. The focus of this chapter is on training subjects who can become capable of entering the state of yoga-nidrā.