Victoria Booth Layman's abstract for proposal titled "A dendritic origin of bistability of motoneuron firing patterns" (proposal #: IBN- 9722946) In response to stimuli from the rest of the nervous system, neurons in the spinal cord, called motoneurons, generate an electrical signal called an action potential that is transmitted to muscle fibers and induces contraction. In this way, the pattern of action potential firing by motoneurons regulates muscle movement. In the presence of the naturally-occuring neurotransmitter serotonin, experimentalists have observed motoneurons firing complex patterns of action potentials that are believed to affect muscle activity. The cell mechanisms within motoneurons responsible for the generation of action potentials are sufficiently well known to allow the development of mathematical models that replicate motoneuron behavior. The goal of this proposal is to investigate the cell mechanisms underlying the generation of the serotonin-induced complex firing behaviors by studying mathematical models of motoneurons. Of particular interest is the suggestion that the complex behaviors are a result of the interaction of mechanisms located in different segments of the neuron, where one segment was previously thought to be uninvolved in action potential generation.
