For the interpretation of these significant investigations, it should be remembered that reciprocal relations exist in the hypothalamus with respect to autonomic and somatic functions which are closely associated with the emotions. The feeding pain antagonism seems to be based on this reciprocal relation between the tropho -- and ergotropic systems. Furthermore, a functional antagonism exists between an aggressive attitude and a state of anxiety. Although in both emotions sympathetic symptoms are present, different autonomic somatic patterns underlie aggression and anxiety, respectively, as indicated by the rate of the excretion of the catecholamines, the state of the muscle tone, and the Mecholyl test. The psychological incompatibility of these emotional states seems to be reflected in, or based on, this marked difference.

In our attempt to interpret the emotions in their physiological and pathological range, we emphasized the importance of the degree of activity of the parasympathetic and sympathetic divisions of the hypothalamic system and their influence on the inhibitory and excitatory systems, respectively. We stressed the reciprocal relation of these systems with respect to the autonomic somatic downward discharge as well as regarding the hypothalamic cortical discharge. Although we are still far from a complete understanding of these problems, as a first approximation, it is suggested that alterations in the hypothalamic balance with consequent changes in the hypothalamic cortical discharges account for major changes in behavior seen in various moods and states of emotions in man and beast under physiological circumstances, in experimental and clinical neurosis, and as the result of psychopharmacological agents. In view of the important role which emotional disturbances play in the genesis of neurotic and psychotic disorders and the parallelism observed between autonomic states and psychological behavior in several instances, it is further suggested that a hypothalamic imbalance may play an important role in initiating mental changes.