Neural and Pavlovian influences on immunity.

The traditional view that the nervous and immune systems are functionally independent (aside from general stress effects and autoimmune disorders of the nervous system) is being challenged by a new view that the nervous system regulates the activity of the immune system. If this is true, it should be possible to change the activity of the immune system by means of Pavlovian conditioning, just as it is possible to condition other physiological events influenced by the autonomic nervous system or neuroendocrine substances. Evidence for autonomic and neuroendocrine modulation of immune activity is briefly reviewed; and, the various studies reporting conditioned immune effects, the physiological mechanisms most likely involved, and their possible significance are discussed.