Stereotaxic lesions were placed in several parasagittal planes of the lateral hypothalamus of rats at the level of the ventromedial nuclei. Both far- and mid-laterally lesioned animals developed adipsia and aphagia, with the far-lateral syndrome being more drastic in nature. The qualitatively different nature of the "failures" seen between the two groups correlated well with the additional damage to the pallidofugal fiber systems in the far-lateral lesioned group. Bilateral lesions directed to the origins of the pallidofugal fibers reproduced faithfully the far-lateral hypothalamic syndrome, histological studies in these animals revealing degeneration along the pallidofugal trajectories. It appears that the feeding and/or drinking "centers" are only convergence sites for critical fiber systems which are disjoined by far-lateral hypothalamic lesions. Thus, the medial part of the "feeding center" seems to be primarily a "motivational" system, whereas the lateral "feeding" system is more basic and depends essentially on pallidofugal circuitry. When this latter is disjoined, the failure is more than "motivational," since it is not compensated for by merely delivering food and water to the gastrointestinal tract.

The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.

In the bottlenose dolphin Tursiops truncatus, a massive retial complex is interposed between the systemic and cerebral circulations at the cervicothoracic level. Pressure measurements in the retial efferent arteries supplying the brain revealed relatively nonpulsatile pressure profiles. These measurements in the anesthetized dolphin demonstrate the pressure-damping effect of the retia mirabile.

Electrodes were implanted in the middle hypothalamus of rats to determine the neural organization of the "feeding" centers. Stimulations of the farand midlateral hypothalamic area produced feeding responses in sated animals, but only the former caused sated animals to cross an electrified grill to press a lever for food. After lesions had been made in the medial forebrain bundle, however, stimulations in the far-lateral hypothalamic area resulted in feeding in sated animals but failure to cross the electrical barrier to press a lever for food. Simultaneous far-lateral and "satiety" center stimulations produced feeding in sated animals but failed to "motivate" grill-crossing behavior.

Anatomical dissections on the cervicothoracic arterial system of the bottlenose dolphin (Tursiops truncatus) have been carried out as a necessary stage preceding certain physiological investigations in this animal. It is essential to have access to large blood vessels in these investigations, and the lack of superficial blood vessels suitable for catheterization in this species has required that a surgical approach to deeper vessels be developed. We have described a surgical technique for exposure of the A. carotis externa and V. jugularis externa and have used this method to introduce angio-catheters into both of these vessels. By these means we have been able to carry out hemodynamic, blood chemistry, and angiographic studies with successful recovery of the animals. These investigations, anatomical dissections on normal animals, and studies of vinylite vascular casts have delineated many specialized features of the cervicothoracic vascular systems in the dolphin.