Newer concepts of the autonomic system's role derived from reductionist and behavioral studies of various animal species.

The evolution of newer concepts, many from old precursors, are elaborated. Among the bases for new thought has been the realization that all body tissues receive autonomic innervation and that this system affects all functions. It is involved in the minutia or reactions studied by their reductionists and in activity of the total organism studied by behaviorists. Newer knowledge suggests that the system's functions can be subdivided into 2 major categories: (1) a role in basic metabolic or vegetative functions. There are 3 realms of such involvement: in energy storage and release; in control of endocrine and neuroendocrine secretions; and in control of exocrine secretion and thus intake, conservation or loss and transformation of energy. The hypothalamus is most highly involved in these autonomic system functions; (2) a role in behavior. The hypothalamus is also highly involved, especially in alerting and defense reactions, concepts relating to Cannon's ideas of emergency function and Selye's concepts of stress. It can be said that the normal, phasic functions of the autonomic system and its involvement in organ and body reactivity are controlled in parallel with the regulation of somatic performances. The several newer interpretative ideas originating from studies of reflexes, reflex patterns and sequences, and of general behavior are the integrative role, the supportive role, the modulatory and finally the anticipatory or determinative role in behavior. The similarity of the role of the autonomic nervous system function in all species, from birds to man, has caught the attention of investigators. This rather than the specializations of the system that are appropriate to the peculiar characteristics of individual species has been emphasized; but species specializations do exist and these should be worthy of future investigation. New concepts of the system's role are evolving from old ideas and new discoveries. Newer concepts of transmitter genesis and tissue receptors are developing that add more detail to our major channels of thought concerning the autonomic system's function. There is a new realization of the system's involvement in pain. Its' directives affect and integrate organ and tissue activity; it determines behavior and expresses the sympathy and judgements of man.