Ectopic granule cells of hilus fasciae dentatae projecting to the ipsilateral regio inferior of the rat hippocampus.

Retrograde fluorescent tracing techniques were used in a search of projections from the hilus of fascia dentata to the Ammon's horn. We found that up to 5% of the neurons in the hilus project to the ipsilateral regio inferior. The projection originates from cells that morphologically resemble ectopic granule cells and terminates in the mossy fiber layer. We found no evidence for a projection from the hilus to the ipsilateral regio superior or the contralateral Ammon's horn.