Figure 1. Passive steady-state properties of layer 6 (L6) pyramidal neurons. a, L6 pyramidal neurons reconstructed from biocytin-filled neurons after the experiment or sketched from fluorescent-dye-filled neurons during the experiment (red electrodes, dendritic recording sites; black electrodes, somatic recordings). The number below each neuron indicates the distance of the dendritic electrode from the soma (in μm). The neuron shaded in gray is the cell for which data are shown in b. b, One-second-step current injections (top) to the dendrite (b1) and to the soma (b2) and resulting voltage responses (middle, red traces, dendrite; black traces, soma). Bottom, The steady-state I–V relationships at dendrite and soma for both dendritic and somatic current injection. b3, Voltage recordings with current injection at the reciprocal site for both somatic and dendritic current injection. c, Local membrane time constant (τ membrane) [black, soma, 9.1 ms; red, dendrite (Dend), 5.7 ms]. d, Steady-state voltage attenuation from soma to dendrite (black) and from dendrite to soma (red) for recordings from different cells at different distances along the apical dendrite. e, Input resistance (Rinput) at the dendrite versus soma (red circles) as a function of distance from soma. f, Sag at dendritic recording as a function of distance from soma. g, Ratio of sag at the dendrite to the soma.