Figure 1

Long-time step pulses initiate sequential spikes at the soma of cortical pyramidal neurons, but the fluctuated signals induce spikes at the axon. A) Top panel shows the images of dual recording on the soma and axonal bleb under fluorescent (left)/DIC (right) microscope. Bottom panel shows an image of neurobiotin-labeled pyramidal neuron. B) Long-time step depolarization (middle black trace) induces more spikes at the soma (red trace) than at the axon (blue). C) shows the number of spikes vs. stimulus intensities at the soma (red symbols) and axon (blues) of this pyramidal neuron. D) illustrates input–output curves at the soma (red symbols) and axon (blues; n = 20, p < 0.05). E) The fluctuated signal (a cosine wave, middle black trace) induces more spikes at the axon (blue trace) than at soma (red). F) shows the ratio of spikes to cosine-waves vs. stimulus intensities at the axon (blue symbols) and the soma (reds) of this pyramidal cell. G) shows input–output curves for the axon (blue symbols) and the soma (reds; n = 20, p < 0.05).