Figure 9.

Electrophysiological protocols applied to NMc1 and NMc2 neurons. A, Neurobiotin-labeled NMc1/NMc2 neuron. Inset shows low-magnification image of the entire coronal NM region with the labeled NMc1/NMc2 neuron. Dorsal, top; lateral, right. Scale bar = 20 μm (200 μm in inset). B, Current clamp protocol to measure passive membrane properties. Upper trace shows the representative voltage response (average of 30 repetitive trials) recorded from an NMc1/NMc2 neuron in response to a hyperpolarizing current injection (lower trace, –10 pA). A single exponential was fitted to a 30-ms time window after the current injection (superimposed red line), to calculate time constant (tau), input resistance, and membrane capacitance. C, Population data showing membrane capacitance (C_MEMBRANE) sampled from the first (also referred as caudomost [caud-mos]) slice, second/third slices (caud), and middle to rostral slices (mid-ros, mid- to high-frequency NM; data modified from Hong et al. [2016]). Asterisk represents significance at p < 0.05. Error bars show SE. D, Metrics used to measure AP properties. Representative first APs (30 superimposed trials) were recorded from an NMc1/NMc2 neuron in response to current injections with the strength 25% above the threshold current (duration 100 ms). Several AP properties were characterized: rise rate (D), fall rate (E), half width (F), and reliability range (G). Population data of AP properties are shown in the corresponding panels in Fig. 11.