Hypothalamic projection to the pulvinar-LP complex in the cat: a study by the silver impregnation method.

This study was designated to determine the exact terminal portion of the hypothalamo-thalamic projection found in our previous study by the HRP method [7]. Electrolytic lesions were made in the brains of 13 adult cats, and the ensuing degenerating fibers were impregnated with Nauta-Gygax and Fink-Heimer methods. Following the lesions of the hypothalamic small nucleus which had been reported to receive abundant HRP transport from the pulvinar-LP complex, terminal degeneration concentrated in the dorsolateral marginal area of LP, forming a well-defined and dorsomedially stretched slim column along the medial border of the pulvinar. The level of its appearance approximately corresponds with the stereotaxic coronal plane, Fr. 7.0. In the contralateral same thalamic area the degenerating fibers were also traced though they were much fewer.