The flotation tank was developed in 1954 by John C. Lilly, a medical practitioner and neuro-psychiatrist.[2][3][4] During his training in psychoanalysis at the US National Institute of Mental Health (NIMH), Lilly commenced experiments with sensory deprivation in combination with a psychedelic agent, mostly LSD. In neurophysiology, there had been an open question as to what keeps the brain going an