eYFP-labeled neurons exhibit numerous dendritic spines throughout the dentate hilus, but the spine morphology differs at dorsal and ventral levels. A, In the dorsal hilus, numerous complex spines are evident along the dendrites, and many resemble the thorny excrescences (arrowheads) that characterize some MCs. B, In the ventral hilus, labeled spines are abundant (arrows) but are generally less complex than those of labeled neurons in the dorsal hilus. Scale bars: 10 µm (A, B).