Selective rostral transection of the fornix spares the hippocampal commissural pathway in the rat: a Phaseolus vulgaris leucoagglutinin tracing study.

This study describes an approach for disconnecting the septal region from the hippocampus by fimbria-fornix lesions while sparing the commissural projections. After a frontal cut through the rostral fornix, commissural fibres were labelled with the anterograde tracer Phaseolus vulgaris leucoagglutinin. The commissural fibre bundle located in the posterior-basal fornix (ventral hippocampal commissure) remained unaffected by the rostral fornix transection, whereas the absence of septal fibres in the hippocampus could be verified using AChE histochemistry. Thus, using this approach, selective studies of the septo-hippocampal projection can be performed while leaving the overwhelming portion of the commissural fibre system intact.