There was an interesting paper in Cell Development that shows how a single neuron the C. elegans worm can provide proprioceptive information that coordinates wiggling behavior, but also can respond to harsh touch and evoke a different behavioral response from the worm. How can a neuron with just a single axon code for these different behaviors?

It appears that the proprioceptive signaling is handled completely by the dendrites using calcium signaling without involving the neurons’s cell body or generating an action potential. The nociceptive response, however, does involve the cell body and the generation of an action potential in the axon.

This is quite a departure from the cell doctrine concepts we discussed in class and adds to the growing list of deviations from the canonical “dendrite – axon hillock – axon” sequence.