Figure 6.

The patterns of axonal projections of dorsal (mCherry-labeled) and ventral (eYFP-labeled) MCs differ as the fibers extend through the DG. A, B, In dorsal, coronal sections, projections from the dorsal and ventral MCs largely overlap in the molecular layer (M), adjacent to the granule cell layer (G). Dashed lines delineate the borders of the molecular layer in all panels. C, D, At ventral levels, the projections from dorsal and ventral MCs diverge and no longer overlap. A dense projection from the ventral MCs (eYFP) is present bilaterally (arrows), adjacent to the unlabeled granule cell layer (G), while a wider band of more diffuse fibers (arrowheads) from the dorsal MCs is evident in the middle molecular layer. Both projections are strongest on the ipsilateral side. At anterior ventral levels (C) a few double-labeled cell bodies (yellow) are evident in the hilus, suggesting some overlap of the dorsal and ventral transfections at this level. Scale bars: 200 µm (A–D).