Over the years, there have been various unusual instances of the voluntary control over physiological functions noted in the scientific literature. Luria (1958) presented a case of a mnemonist who had remarkable control of his heart rate and skin temperature to the degree that he could abruptly alter his heart rate by 50 beats per minute, and could also raise the skin temperature of one hand while simultaneously lowering the temperature of the other hand. The modification of physiological activities such as this has been the subject of anecdotal reports for a considerable period of time. Although true empirical investigation into such self-regulation through biofeedback began in the 1960s, gaining voluntary control of various physiological activities has been a goal in many different cultures for a variety of reasons. Gatchel (1999) and Gatchel et al. (2003b) have reviewed the goals that have been traditionally sought with regard to gaining control of physiological functioning:

• In order to achieve spiritual enlightenment, yogis and other mystics of the eastern tradition have demonstrated that through certain physical exercises, or by a sheer act of will, that individuals are capable of producing significant physiochemical changes in their bodies which, in turn, produce perceived pleasant states of consciousness (Bagchi, 1959; Bagchi & Wenger, 1957).

• In order to test various theories of learning, psychologists have long debated the issue of whether autonomic nervous system responses could be operantly conditioned.

• During the 1960s, biofeedback was viewed as a potential clinical treatment procedure for modifying psychological and medical disorders.

The major focus of this present chapter is on the third category of how voluntary control of physiological activity can be used as a clinical treatment modality for medically related disorders.