Summary of the main findings
| Experiment | Knock-out | MRR excitation | MRR inhibition | |
|---|---|---|---|---|
| Mobility | OF | Ø | Ø | ↓ |
| EPM | Ø | Ø | Ø | |
| Y-maze | Ø | Ø | Ø | |
| Anxiety | OF | ↑ | Ø | Ø |
| EPM | ↑ | ↓ | Ø | |
| Social behavior | Social interest | ↑ (sociability, tendency in SDT) | ↓ (indirect during sociability) | ↑ (in SDT) |
| Friendly behavior | Ø | Ø | ↓ in aggressive context (RIT) | |
| Aggressive behavior | ↑ in anxiogenic context (SIT) | Ø | Ø | |
| Memory | SDT | ↓ 24 h SDT | Ø | Ø |
| Y-maze | Ø | Ø | Ø | |
| c-Fos activity | ↓ in anterior cingulate, infralimbic cortex and medial septum | ↑ in the MRR | - | |
The results are presented in comparison with their respective control groups: that is, VGluT3 wild-type littermates for knock-out mice and control group (expressing only RFP in the VGluT3+ neurons in the MRR) for the excitatory (Gq DREADD + RFP) and inhibitory (Gi DREADD + RFP) chemogenetically manipulated groups. Ø, no difference compared with respective control group; -, not applicable; DREADD, designer receptors exclusively activated by designer drugs; EPM, elevated plus maze; MRR, median raphe region; OF, open field; RFP, red fluorescent protein; RIT, resident intruder test; SDT, social discrimination test; SIT, social interaction test; VGluT3, vesicular glutamate transporter 3.