Fig. 1. Synapse formation between soma–soma paired Lymnaea neurons. ( A ) Individually identifiable, presynaptic (visceral dorsal 4 [VD4]) and postsynaptic (left pedal dorsal 1 [LPeD1]) were soma–soma paired overnight. ( B ) Specific synapses similar to those seen in vivo reformed overnight between the paired cells. An action potential in VD4 (at arrow ) generated 1:1 excitatory postsynaptic potentials in LPeD1.