Figure 4.

Impact of axonal length on AP properties. A, Confocal images of layer 5 pyramidal neurons (Alexa 568) with axons of the indicated lengths. Note the characteristic bulbous end of the severed axon. B, Double differentiation of the somatic AP voltage in the neurons illustrated in A. All neurons exhibited two distinct components, presumably resulting from the separate charging of the initial segment and the soma. C, The voltage change required to reach AP threshold (top) and AP amplitude (bottom) measured from threshold in neurons with different axon lengths (21–968 μm; n = 108). APs evoked by somatic current injection.