EXTRATECTAL PROJECTIONS TO THE NUCLEUS ISTHMI IN AMPHIBIANS
两栖类峡核的顶盖外投射

The extratectal projections to the nucleus isthmi (NI) were studied by using horseradish peroxidase tracing method in Chinese toads (Bufo bufo gargarizans). The adults indicate that (1) the anterodorsal tegmental nucleus, nucleus profundus mesencephali and superfidel isthmal reticular nucleus project bilaterally to NI, and the contralateral projation crosses the mjdline through the decussatio veti; and (2) these tegmental nuclei projeCt to the whole NI, and there does not exist any topography between the tegmental and isthmic nuclei. The putative functional significance of these tegmento-isthmic projections is also discussed.