Computational Implications of a Serotonin-Sensitive Region of Axonal Membrane On a Dual Function Motor Neuron

Experiments on the Lateral Gastric (LG) motor neuron of the crab stomatogastric ganglion demonstrate a serotonin-sensitive region of the axonal membrane. This serotonin-sensitive region becomes a spike initiation site and propagates action potentials antidromically into the integrating regions of the stomatogastric ganglion where they do not ordinarily evoke transmitter release. A compartmental model of the neuron which includes a serotonin-sensitive slow inward current on the axon successfully simulates the physiological data. A mathematical study of axonal membranes that include slow currents provides insight into the mechanisms by which spike initiation zones can travel as waves down axons that contain slow currents.