Simultaneous whole cell recordings from pyramidal cell bodies and axons reveal that synaptic activity propagates long distances down the axon
Figure 9. The ratio of amplitude of synaptic potentials in the axon versus those occurring in the soma reveal that the axon has a long length constant of approximately 400 microns. On the right is a picture of a labeled layer 5 pyramidal cell. The white arrowheads are the location of presynaptic boutons. Note that many of these are electrotonically close to the soma, indicating that the membrane potential of these release sites will be influenced by synaptic activity propagating down the axon.