Diencephalic projections from the midbrain reticular formation.

(1) Physiologically guided stereotaxic coagulation was placed so as to avoid major through pathways in the midbrain reticular formation of 7 cats. Diencephalic degeneration resulting from this was traced by the Nauta method. (2) Preterminal degeneration was found in: the intralaminar nuclei and the posterior group (PO); the ventral group of thalamic nuclei; the ventral thalamus, including the zona incerta, subthalamus and fields of Forel; and the lateral hypothalamus. (3) The results are discussed in relation to somatomotor reactions, reticular influences on the electroencephalogram and telencephalic representation of pain.