By 12 weeks, spontaneous neuronal firing could be observed in these cultures. Lithium pretreatment of BP neurons significantly decreased their calcium transient (101. 65±31. 64 vs 290. 22±0.52 sec; P⩽0.007) and wave amplitude (0.76±0.07 vs 1.89±0.26 ΔF/F0; P⩽0.004) compared with lithium-exposed control neurons (Supplementary Figure 5). We also observed that clusters of soma were capable of clearing Ca2+ more rapidly than axon- and dendrite-rich regions.
