The clinical syndromes described with lesions of the hypothalamus are summarized in Table 9.5-9.7. The anterior hypothalamic syndrome consists of insomnia and loss of thirst regulatory mechanisms. In occasional larger lesions which interrupt the output from the supraoptic and paraventricular nuclei, diabetes insipidus has been noticed. In the tuberal region of the hypothalamus the most prominent findings are those that are caused by the disruption of the final common pathway to the pituitary. This results in endocrinopathy, most often the syndrome originally reported by Frohlich, with failure of sexual maturation and obesity. In the tuberal region, differences between lesions of the medial and lateral portions are quite marked. Medial lesions result in obesity while bilateral lesions result in anorexia and emaciation. The diencephalic syndrome of infancy with it's severe emaciation in young years and obesity in later years clearly indicates a different organizational pattern in the neonatal hypothalamus. Emotional disorders may be seen with lesions either in the medial or lateral hypothalamus at the tuberal level. Finally, in the posterior hypothalamic region, which includes the greatest effector apparatus, hypersomnia, apathy, and poikilothermia have been reported. Emotional disturbances and the Wernicke-Korsakoff syndrome also seemed to be associated with lesions in this area. The hypothalamus remains the single most important integrator of vegetative and endocrinologic regulation of the body. Cushing said of the hypothalamus, "here in this hidden spot, almost to be covered with a thumb nail, lies the very main spring of primitive existence: vegetative, emotional and reproductive".