Gudden's tegmental nuclei and their connections to the hypothalamus and the reticular formation. II. An experimental study using retrograde double labelling with HRP and iron-dextran in the rat.

12 rats in double experiments were studied for the simultaneous retrograde transport of HRP and Dextran-fer from injections in the mamillary body and in the reticular formation or in selected diencephalic structures into the cells of Gudden's tegmental nuclei. The results of this particular study corroborated the findings of retrograde transport in single experiments (see Part I) showing all the cells of ventral Gudden's nucleus as projecting into the mamillary body, the cells of its peripheral parts as projecting also via a collateral to the lateral hypothalamus, and the cells of its central parts as projecting, in addition, via a collateral to the reticular formation (ncl. pedunculo-pontinus and ncl. pontis oralis). Cells of the ventral part of the ncl. dorsalis tegmenti Guddeni project into the lateral mamillary body and some of then also through a collateral into the whole of the hypothalamus. Part of its cells project independently into the RF (ncl. pontis oralis). The dorsal part of the ncl. dorsalis tegmenti Guddeni projects bilaterally to the ncl. pontis oralis.