Electrophysiological characterization reveals three functionally distinct classes of Shh -lineage cells in the posterior medial amygdala. (A-F) Representative examples of three classes of ShhCre; RYFP+neurons recorded by patch-clamp in current-clamp mode (A,C,E), filled with biocytin (B,D,F; green) and immunostained for nNos (B,D,F; red) and FoxP2 (B,D,F; blue). (B'-B''', D'-D''',F'-F''') Single optical sections from high-power confocal imaging of biocytin, nNOS or FoxP2 immunohistochemistry. Each neuron was recorded at its resting membrane potential, as given at the left of each group of traces. Neurons were subjected to a hyperpolarizing step (A,C,E; black) to test for the presence of sag current and rebound firing, a small depolarizing step corresponding to the rheobase of the neuron (A,C,E; red) and the minimal depolarizing step able to induce firing at a maximum frequency (A,C,E; grey). Current injection step values are indicated in the bottom of each recording and accordingly colored. The fraction and percentage of ShhCre; RYFP+neurons corresponding to each class are indicated on the top of each group of traces. Scale bar: 80 μm (A-H); 40 μm (B'-E''').