<P> Extracellular recordings of action potential propagation in axons has been demonstrated in freely moving animals . While extracellular somatic action potentials have been used to study cellular activity in freely moving animals such as place cells, axonal activity in both white and gray matter can also be recorded . Extracellular recordings of axon action potential propagation is distinct from somatic action potentials in three ways: 1 . The signal has a shorter peak - trough duration (~ 150μs) than of pyramidal cells (~ 500μs) or interneurons (~ 250μs). 2 . The voltage change is triphasic. 3 . Activity recorded on a tetrode is seen on only one of the four recording wires . In recordings from freely moving rats, axonal signals have been isolated in white matter tracts including the alveus and the corpus callosum as well hippocampal gray matter . </P> <P> In fact, the generation of action potentials in vivo is sequential in nature, and these sequential spikes constitute the digital codes in the neurons . Although previous studies indicate an axonal origin of a single spike evoked by short - term pulses, physiological signals in vivo trigger the initiation of sequential spikes at the cell bodies of the neurons . </P> <P> In addition to propagating action potentials to axonal terminals, the axon is able to amplify the action potentials, which makes sure a secure propagation of sequential action potentials toward the axonal terminal . In terms of molecular mechanisms, voltage - gated sodium channels in the axons possess lower threshold and shorter refractory period in response to short - term pulses . </P> <P> The development of the axon to its target, is one of the six major stages in the overall development of the nervous system . Studies done on cultured hippocampal neurons suggest that neurons initially produce multiple neurites that are equivalent, yet only one of these neurites is destined to become the axon . It is unclear whether axon specification precedes axon elongation or vice versa, although recent evidence points to the latter . If an axon that is not fully developed is cut, the polarity can change and other neurites can potentially become the axon . This alteration of polarity only occurs when the axon is cut at least 10 μm shorter than the other neurites . After the incision is made, the longest neurite will become the future axon and all the other neurites, including the original axon, will turn into dendrites . Imposing an external force on a neurite, causing it to elongate, will make it become an axon . Nonetheless, axonal development is achieved through a complex interplay between extracellular signaling, intracellular signaling and cytoskeletal dynamics . </P>

What does the axon do in the nerve cell