Neurotransmitters, Neuromodulators, and Behavior in Simpler Nervous Systems
Motor programs stored in the CNS control many innate, species-specific patterns of animal behavior. Examples include rhythmic activities such as walking, swimming, flying, feeding, and respiratory activity. We are attempting to map neural circuits that generate such patterns of behavior, and to clarify the roles of neurotransmitters and neuromodulators acting in these circuits. For example, we have shown that an isolated central nervous system of the horseshoe crab Limulus contains circuitry that produces the appropriate pattern of motor output for feeding behavior. When octopamine is perfused into the isolated nervous system, it activates this feeding motor program; moreover, octopamine injections into intact animals induce feeding behavior. Octopamine in this case could be acting as a neurotransmitter, as a hormone, or as a local neuromodulator (i.e. acting at a distance and time course intermediate between that of a hormone and a transmitter). We are exploring the actions of octopamine and other neuroactive agents on neurons and simple neural circuits, as well as attempting to determine the behavioral roles of these agents in caterpillar feeding, Limulus sensory receptor sensitivity, and cricket reproduction. These studies employ techniques of electrophysical recording, anatomy of identified neurons (by dye fills and by immunohistochemistry), pharmacology, and behavior.
Wyse, G.A. 2010. Central pattern generation underlying Limulus rhythmic behavior patterns. Curr. Zool., 56: 537-549.
Hill, R.W., G.A. Wyse, and M. Anderson. 2008. Animal Physiology (2nd ed.). Sinauer Associates, Sunderland, MA.
Bowdan, E. and Wyse, G.A. 2000. Temporally patterned activity recorded from mandibular nerves of the isolated subesophageal ganglion of Manduca. J. Insect Physiology 46: 709-719.
Bowdan, E. and Wyse, G.A. 1997. Removing antennae and maxillae has little effect on feeding on normal host plants by two species of caterpillar. J. Insect Physiol. 43: 1053-1063.
Bowdan, E. and Wyse, G.A. 1996. Finding Food: Neuroethological Aspects of Foraging. Introductioin, and Sensory Ecology: Introduction. Biol. Bull. 191: 57-59; 122-123.
Bowdan, E. and Wyse, G.A. (eds.) 1996. Finding Food: Neuroethological Aspects of Foraging. Proceedings of a symposium in honor of Vincent Gaston Dethier (1915-1993). Biol. Bull. 191: 55-138.
Lee, H.M. and G.A. Wyse. 1991. Immunocytochemical localization of octopamine in the central nervous system of Limulus polyphemus: A light and electron microscopic study. J. Comp. Neurol. 307: 683-694.