Representative injection sites in the dorsal or ventral DG.

<p><b>A–D</b>: Nissl-stained sections with injection either in the dorsal DG at AP −3.7 (A), AP −5.2 (B), the ventral DG and CA3 region (C), or the ventral DG (D). The injection site was marked by pontamine sky blue which was co-injected with the viral vector (arrowhead). <b>E</b>–<b>G</b>: Photomicrograph of labeled neurons around the injection site. Small numbers of labeled neurons were detected in the dorsal and ventral DG injection site (E, G), whereas strong labeling was seen when the injection hit the CA3 region (F). Scale bar = 1000 µm in A (also applies to B–D) and 250 µm in E (also applies to F, G).