(A and B) Forward mapping of CA3 excitatory terminals in DLS obtained from the progeny of G32–4 bred with Ai27 (tdTomato) or Ai35 (GFP). In these mouse lines, ChR2-tdTomato or Arch-GFP is restricted mainly to CA3 (bottom panels). Note the abundance of terminals in DLS (top panels).
(C and D) Local injection of CaMKII-ChR2-eYFP in dorsal or ventral CA3 of C57B6/J mice leads to restricted expression of eYFP in the medial or lateral part of DLS, respectively. Asterisks denote the abundance of terminals in dorsal and ventral CA1, respectively.
(E) Dorsal CA3 inhibitory neurons do not innervate DLS, as evidenced by selective infection of GAD2-Cre mice with DIO-ChR2-eYFP. Asterisk denotes the presence of terminals in the medial septum. Scale bar: 100 μm.