Figure 2.

Two hypothetical modes for mossy cell-driven feed-forward inhibition of granule cells. Based on our findings, dentate granule cells appear to be inhibited by two distinct categories of interneurons in light of fast- or slow-rise kinetics of postsynaptic GABA_A receptors. We propose that granule cells located in the same lamellae receive inhibition from interneurons (In A; interneuron A) which display slow-rise time kinetics of sIPSCs at the granule cell dendrites. Conversely, granule cells translamellar to the mossy cells may receive perisomatic inhibition from interneurons (In B; interneuron B) that display fast-rise time kinetics. While the nature of those interneurons is uncertain, we suspect interneurons translamellar to the mossy cells are basket cell-like cells. For simplicity, the dendrites of mossy cells and interneurons are omitted. GC, granule cell; GCL, granule cell layer; MC, mossy cell; ML, molecular layer; PL, polymorphic layer.