Fig. 4

Noradrenergic neurons in the LC of htau mice display an irregular firing pattern at 4 months. A Confocal image of biocytin-labeled cells (red) in the LC that express TH (green) B Schematic of patch clamp recordings in the LC and representative traces of spontaneous action potential (AP) firing at resting membrane potential (RMP). Intracellular recordings with histograms indicating C RMP, D Input resistance at RMP, E Firing rate at RMP, F Action potential (AP) amplitude, and G Coefficient of variation of the inter-event interval (IEI). H Representative traces of voltage ramps to compute rheobase and AP-current plot at the 190 pA current step from a holding potential of − 55 mV. I Rheobase at − 55 mV and J Current (0–200 pA)-induced spiking from − 55 mV. Action potential kinetics showing the K Antipeak amplitude, L Maximum rise slope, M Time to maximum rise slope, N Event frequency, and O Instantaneous frequency at 0–200 pA current steps from a holding potential of − 55 mV. *p < 0.05, ***p < 0.001