Spikes of GABAergic neuron pairs are more synchronized than in ChAT/ChAT or GAD2/ChAT pairs. A: examples of cell-attached recordings of a pair of ChAT neurons and their respective cross-correlogram. Scale bar, 2 s/1 mV. B: same as A for a pair composed of a GAD2 (top) and a ChAT (bottom) cell. C: same as A for a pair of GAD2 cells. Scale bar, 2 s/1 mV. D: box plots showing mean synchrony index of ChAT/ChAT, GAD2/ChAT, and GAD2/GAD2 pairs (*P < 0.05, t-test).