Afferent connections of the ectostriatum and visual wulst in the zebra finch (Taeniopygia guttata castanotis Gould)--an HRP study.

Afferent connections of the two main areas in the telencephalon, the visual wulst and the ectostriatum, were traced in the zebra finch by injection of horseradish peroxidase and staining with tetramethylbenzidine (TMB). Nuclei projecting to the hyperstriatum accessorium (HA) or the HIS region (lamina hyperstriatica intercalatus superior) were: (1) ipsilaterally the n. dorsalis anterior pars lateralis (DLL) with its two subdivisions DLLd and DLLv, the n. dorsolateralis anterior pars magnocellularis (DLAmc), and the area pretectalis (AP); (2) bilaterally the nucleus of the septomesencephalic tract (SPC) with the ipsilateral component coming from the medial, the contralateral component from the lateral part of the nucleus. As in the pigeon or the owl the ectostriatum of the zebra finch receives massive input, which is topographically ordered, from the n. rotundus. In addition to this pathway the ectostriatum receives additional visual input from the ipsilateral area pretectalis, the n. subrotundus and eventually a bilateral projection from the n. tegmenti pedunculopontinus pars compacta (TPC).