[Central nervous system control for maximal alertness in danger].

A survey is given of the various "emotional" neuro-hormonal response patterns, organised at the limbic-hypothalamic level of the brain and specialised in dealing with the multiplicity of challenging environmental stimuli that all organisms, including man, have to cope with. Typically they involve all three efferent links of body control--i e, the somatomotor system, governing behaviour, the visceromotor (autonomic nervous) system, adjusting inner organs to suit behavioural response, and the hormonal system, adjusting metabolism, nutritional depots and water-electrolyte balance, again to provide optimal support for behavioural response. Special emphasis is put on the visceromotor and hormonal adjustment of the cardiovascular system, affecting blood pressure, cardiac output and blood flow distribution, particularly in stressful situations, where such responses as the "defence reaction", the "defeat reaction" and the "playing-dead reaction", are virtually the same in all species. It is discussed how in humans such age-old response patterns are also elicited by a variety of artificial or symbolic challenges typical of hectic modern society; and how, if provoked too often or too long, they may constitute crucial determinants of such serious cardiovascular disorders as hypertension and atherosclerosis. In this context, the defence and defeat reactions would seem to be particularly relevant, and the importance is stressed of animal studies of such complex systemic adjustments, for the understanding and hence future prevention of certain particularly serious disorders common in modern society.