Date of Award
Fall 2000
Document Type
Dissertation - Restricted
Degree Name
Doctor of Philosophy (PhD)
Department
Biological Sciences
First Advisor
Buchanan, James
Second Advisor
Eddinger, Thomas
Third Advisor
Fitts, Robert
Abstract
In this project I have investigated the electrophysiological properties of several types of lamprey spinal neurons and how these properties change during fictive locomotion, in an effort to understand the role of the intrinsic properties of neurons in network function. The electrophysiological properties of neurons shape the response of an individual cell to synaptic input, which influences how the cell functions within a neural network. While the properties of many invertebrate neurons have been characterized during network activity, relatively few such studies have been done in vertebrates. To understand the operation of any neural network, we must know the characteristics of its elements- electrophysiological properties of the cells. Because the central pattern generator for locomotion in the lamprey spinal cord is one of the better understood vertebrate networks, studying the properties of lamprey spinal neurons may provide us with better insight into principles that govern the operation of neural networks in general. Thus, the following questions were addressed: 1) How do the properties of lamprey spinal neurons change during fictive locomotion? 2) What substances in the spinal cord produce these changes? 3) By what ionic mechanisms are the changes produced? To answer these questions, several sets of experiments were done. First, the electrophysiological properties of single neurons were measured before, during, and after the induction of locomotor activity. Second, the same properties were measured before and after the application of serotonin and spiperone. Serotonin is a neuromodulator that is known to have effects on the electrophysiological properties of lamprey spinal neurons, and spiperone is an antagonist of serotonin. Lastly, the properties were measured in Ca2+-free extracellular solution, to investigate possible ionic mechanisms of the changes in the electrophysiological properties.