Ventral Hippocampal and Septal Neuronal Cultures

The cultures were prepared as described previously (Zhong et al., 2015 (link)). Briefly, for ventral hippocampal micro-slice cultures, the ventral CA1 and subiculum area (vHipp) from WT (+/+) or α7 knockout (−/−) mice (postnatal days 0–3, P0–P3) was dissected, sliced into ∼150 μm × 150 μm pieces, and then plated onto poly-D-lysine/laminin-coated glass coverslips (12 mm, BD Sciences) in 24-well plates with a minimal volume (50 μl) of culture media [Neurobasal, 2% B-27 (GIBCO) and 20 ng/ml of brain-derived neurotrophic factor (Invitrogen)]. After the micro-slices attached to the substrate, 100 μl of additional culture media was added. For medial septum/diagonal band (MS/DB) cultures, the MS/DB area (Bakker et al., 2015 (link); Staib et al., 2018 (link)) from ChAT-tau-eGFP or ChAT-IRS-Cre mice (P0–P3) was dissected, sliced and plated on coverslips as described before (Zhong et al., 2015 (link)) and above for vHipp cultures.
For vHipp-nucleus accumbens (nAcc) synaptic co-cultures, nAcc (ED18-P1) from WT mice (C57BL/6J) were dissected out and dispersed with 0.25% trypsin (GIBCO) for 15 min at 37°C, followed by gentle trituration in culture media. Dispersed nAcc neurons were plated onto poly-D-lysine/laminin-coated glass coverslips at 0.25 ml/coverslip. The next day vHipp micro-explants [prepared as described above and in Zhong et al. (2008) (link)] were added to the same coverslips.