We report the first neural recording during ecstatic meditations called jhanas and test whether a brain reward system plays a rolein the joy reported. Jhanas are Altered States of Consciousness (ASC) that imply major brain changes based on subjective reports:(1) external awareness dims, (2) internal verbalizations fade, (3) the sense of personal boundaries is altered, (4) attention is highlyfocused on the object of meditation, and (5) joy increases to high levels. The fMRI and EEG results from an experienced meditatorshow changes in brain activity in 11 regions shown to be associated with the subjective reports, and these changes occur promptlyafter jhana is entered. In particular, the extreme joy is associated not only with activation of cortical processes but also with activationof the nucleus accumbens (NAc) in the dopamine/opioid reward system. We test three mechanisms by which the subject mightstimulate his own reward system by external means and reject all three. Taken together, these results demonstrate an apparentlynovel method of self-stimulating a brain reward system using only internal mental processes in a highly trained subject.