RUI: The Role of Multiple Modulators in a Small Neural System: A Comparative Approach

Bowdoin College, Brunswick ME

Investigators

Abstract

Animals must alter their behavior to meet the demands of a changing environment. One mechanism that allows such behavioral flexibility in the pattern generators that drive rhythmical movements, such as locomotion and chewing, is the functional reconfiguration of neural networks by neuromodulators. The stomatogastric system, which contains the pattern generators that drive the pyloric filter and the gastric mill in the crustacean foregut, provides an ideal system in which to study neuromodulation. Both the pattern generators and the modulatory inputs in the stomatogastric system have been extensively characterized. More than 20 modulatory substances have been identified in this ganglion, raising the following question: Why are so many modulators involved in modulating such a relatively simple system? This project asks whether a comparative approach can shed light on this question and thus provide insights into the fundamental mechanisms and effects of neuromodulators. The pyloric pattern and its responses to modulators have been studied to some extent in a number of different species of decapod crustaceans. The present study will further examine the responses of six species - two closely related species of crab, two related lobster species, the California spiny lobster, and a kelp crab - to a test group of four neuromodulators. Using standard recording techniques, the basic pyloric pattern and its responses to these substances will be recorded and characterized qualitatively and quantitatively. Additionally, some of the mechanisms involved in modulation will be compared, as will the effects of these four modulators on muscle activity and contraction in the six species.