Antidromic Spikes in Cortical Neurons Exhibit a Strong "Kink" at Spike Onset
Figure 6. It is well known that antidromic spikes in cortical neurons rise rapidly from the baseline. Here is shown three antidromic spikes in a cortical pyramidal cell initiated by stimulation of the axon. The spikes are expanded in the upper left. Note the two components - the IS or initial segment spike and the SD or somatodendritic spike. From Pare, Lang and Destexhe, Neuroscience 84: 377 (1998).
Importantly, it is well known that cortical neurons initiate spikes in their axons under normal conditions, indicating that spikes recorded in the soma are largely "antidromic" or back-propagating. (see Stuart et al., TINS 20:125; Palmer and Stuart, J. Neurosci. 26: 1854; Shu et al. J. Neurophysiol. in press.