The connections between the parabigeminal nucleus and the superior colliculus in the golden hamster.

The present study in hamsters shows that the horseradish peroxidase conjugated with wheat germ agglutinin (WGA-HRP) injected into the eye can be transported transneuronally in both anterograde and retrograde directions to the parabigeminal nuclei (PBN). Moreover, the patterns of labelling in the PBN are similar to those observed after introduction of horseradish peroxidase (HRP) into the superior colliculus. These results suggest that the WGA-HRP is a reliable pathway tracer for studying second-order connections at least in the visual system in mammals.