Figure 3.

GABA immunostaining of rabies-labeled neurons indicate that mossy cells receive inputs from both GABAergic and non-GABAergic neurons in local circuits. A, Rabies virus-labeled neurons (mCherry expression only, red) in the DG are direct presynaptic neurons of targeted hilar mossy cells. B, DAPI staining (blue) shows the anatomic structure of the DG, and nuclear EGFP label (small white box) shows a mossy starter neuron with AAV helper virus infection. C, GABA immunostaining (gray) shows GABAergic cells. D, The overlay image shows rabies-labeled hilar cells that are immunopositive for GABA (indicated by the white arrows). The white arrowhead points to a rabies-labeled neuron that is GABA immunopositive from the dentate granule cell layer. The small white box shows the hilar mossy starter neuron that lacks GABA staining. Scale bar, 200 μm.