Organization and projections of the neurons in the dorsal tegmental area of the rat.

The organization and projection of the neurons in the dorsal tegmental area at the locus coeruleus level of the rat have been investigated by means of the horseradish peroxidase (HRP) method, combined with monoamine oxidase staining to identify the noradrenaline (NA) neurons. Judging from the anatomical aspects elucidated in this study, this area is composed of various different cell groups. Although the functional role of these neuronal groups remains to be determined, the present study strongly suggests that the dorsal tegmental area participates in important regulation of several brain functions.