Figure 1.

Experiments in neuron cultures. (A) Membrane potential responses of cultured neurons to injection of current steps or fluctuating currents were recorded in a whole-cell configuration. (B) Example of combined DAPI nuclear staining (blue) and ankyrin-G staining with antibodies labeled with Alexa Fluor Red in the axons of cultured neurons (17 days in culture). Arrows indicate presumable axon initial segments of cultured neurons. Note that a region with small number of clearly isolated axons was selected for illustration and axons of some neurons may be outside of this region; some of the DAPI-staining may also be due to glial cells. (C) Distribution of the lengths of axon initial segments measured using ankyrin-G staining in N = 63 cultured neurons. Mean length 27.7 ± 0.4 μm.