Intrinsic electrophysiological properties and morphologies of 5-HT3AR-expressing cortical interneurons. A, Representative traces of voltage responses to 500 ms step current injection in current-clamp whole-cell configuration of six major subtypes of 5-HT3AR interneurons. B, Examples of morphologies of different subtypes reconstructed using Neurolucida tracing. Dendrite and soma are shown in blue and axon in red. LS1, Late spiking 1; LS2, late spiking 2; bNA1, burst nonadapting 1; bNA2, burst nonadapting 2; IS, irregular spiking; fAD, fast adapting; POA, preoptic area. Scale bar, 100 μm.