[Striopallidum projections to the pedunculopontine tegmental nucleus in the dog mesencephalon]

Using the method based on the retrograde axonal transport of the horseradish peroxidase, striopallidal afferent projections to the pedunculopontine tegmental nucleus (PPN) of the dog brain were studied. It was shown that the main source of these projections was pallidum, since the projections were directed both to the compact and diffuse parts of this nucleus from all its structures: nucleus entopeduncularis, globus pallidus and ventral pallidum. In the striatal complex, namely in the nucleus accumbens, only single labeled neurons projecting exceptionally to the compact part of the PPN, were detected Since in the distribution of the projection fibers, originating from the functionally various territorries of the striopallidum and directed to the individual substructures of the PPN, no topical elements were detected, the separation of the functionally specific (motor and limbic) regions in the PPN, on the basis of findings obtained, appears impossible.