Demonstration of caudally directed hippocampal efferents in the rat by intracellular injection of horseradish peroxidase.

Axonal projections of rat hippocampal neurons were demonstrated by intracellular injections of horseradish peroxidase. The data indicated a prominent caudally directed projection from pyramidal neurons of hippocampal field CA1, provided evidence that the subiculum is one of its targets, and suggested that the caudally directed efferents from CA1 are more numerous than rostrally directed ones.