[Interconnections of the pallidum, pedunculopontine nucleus, zona incerta, and deep mesencephalic nucleus--the structures of the basal ganglia morpho-functional system].

Method of anterograde and retrograde axonal transport of horseradish peroxidase was used to study the organization of projections of different substructures of zona incerta (ZI), pedunculopontine nucleus (PPN), deep mesencephalic nucleus (DMN) complex, and functionally distinct structures of the pallidum of dog brain (n=20). It was found that pallidum and nucleus entope-duncularis are connected by reciprocal projections with dorsal, ventral and caudal sectors of ZI, as well as with DMN, lateral segment of the pars dissipata, and the pars compacta of PPN. The rostral sector of ZI, cuneiform and subcuneiform nuclei of DMN complex, the medial region of PPN pars dissipata are connected by ipsilateral projections with the same pallidal nuclei. Among all the structures studied, the presence of reciprocal connections with the ventral pallidum was found only in the lateral segment of the pars dissipata and pars compacta of PPN. The possible pathways of transfer of functionally different information and its integration in the investigated projection systems, are discussed.