Fig. 3

The ipsCA-conCA1 functional connectivity. a RV-dG-GFP and -Dsred were infused into the stratum oriens of left and right CA1, and a number of neurons were labeled in the opposite side. b In vivo study revealed that electrical stimulation at ipsCA1 evoked the excitatory postsynaptic potentials (fEPSP) in conCA1, with an onset latency of about 8-ms (c, d T2), relative to about 10-ms in the CA3-CA1 pathway (c, d T1). e Paradigm for studying TetLC effects. f Unilateral (Uni) or bilateral (Bi) CA1 expression of TetLC (AAV-Syn-EGFP-2A-TetLC-3flg) impaired generalization or the both, respectively. g–j NpHR was expressed and optogenetic stimulation was used during the retrieval tests. Silencing of Uni or Bi CA1 impaired generalization or the both, respectively. k–n When NpHR was expressed at ipsCA1 but optogenetic stimulation was applied at conCA1 to silence the ipsCA1 projection terminals onto conCA1, the ipsCA1–conCA1 fEPSP was reduced by about 20% with light on relative to light off. Light on during the retrieval tests impaired generalization, while light off during the tests had a slight enhancement effect on the both. Statistical comparisons are performed by using one-tail t-test d and two-way ANOVA (f, j, n *contrast effects; ^#parameter estimates); * or ^# P < 0.05, ** or ^## P < 0.01, *** or ^### P < 0.001. Error bars, s.e.m. EGFP or EYFP, control virus; Calibration bar: 100 µm