Chronic masturbation is often considered an addiction, and like substance abuse, can lead to profound and irreversible changes in the masturbator's brain. In this audio program we consider the cause and impact of those changes in "This is Your Brain, on Masturbation". The program is in four parts. The first two deal with internal structural differences between normal male brains and the brains of chronic masturbators. We explain these changes by the development of "the masturbation circuit" resulting from continued prolonged masturbatory over-stimulation of the sexual pleasure centers.  The third part examines behavioral and mental dysfunctions following recruitment or consumption of other brain resources to support the masturbation circuit. And the fourth concludes with guided edging, to help the listener experience and assess the strength of the masturbation circuit in his own brain. For the comfort of the listener, ejaculatory relief is granted at the ends of parts 1, 2, and 4.