The Journal of Neurophysiology Vol. 78 No. 6 December 1997, pp. 3415-3427
Copyright ©1997 The American Physiological Society

Behavior-Dependent Activities of a Central Pattern Generator in Freely Behaving Lymnaea stagnalis

Rene F. Jansen, Anton W. Pieneman, and Andries ter Maat

Graduate School Neurosciences Amsterdam, Research Institute Neurosciences Vrije Universiteit, 1081 HV Amsterdam, The Netherlands

Jansen, Rene F., Anton W. Pieneman, and Andries ter Maat. Behavior-dependent activities of a central pattern generator in freely behaving Lymnaea stagnalis. J. Neurophysiol. 78: 3415-3427, 1997. Cyclic or repeated movements are thought to be driven by networks of neurons (central pattern generators) that are dynamic in their connectivity. During two unrelated behaviors (feeding and egg laying), we investigated the behavioral output of the buccal pattern generator as well as the electrical activity of a pair of identified interneurons that have been shown to be involved in setting the level of activity of this pattern generator (PG). Analysis of the quantile plots of the parameters that describe the behavior (movements of the buccal mass) reveals that during egg laying, the behavioral output of the PG is different compared with that during feeding. Comparison of the average durations of the different parts of the buccal movements showed that during egg laying, the duration of one specific part of buccal movement is increased. Correlated with these changes in the behavioral output of the PG were changes in the firing rate of the cerebral giant neurons (CGC), a pair of interneurons that have been shown to modulate the activity of the PG by means of multiple synaptic contacts with neurons in the buccal ganglion. Interval- and autocorrelation histograms of the behavioral output and CGC spiking show that both the PG output and the spiking properties of the CGCs are different when comparing egg-laying animals with feeding animals. Analysis of the timing relations between the CGCs and the behavioral output of the PG showed that both during feeding and egg laying, the electrical activity of the CGCs is largely in phase with the PG output, although small changes occur. We discuss how these results lead to specific predictions about the kinds of changes that are likely to occur when the animal switches the PG from feeding to egg laying and how the hormones that cause egg laying are likely to be involved.

This article has been cited by other articles:

				C. J. H. Elliott and A. J. Susswein Comparative neuroethology of feeding control in molluscs J. Exp. Biol., April 1, 2002; 205(7): 877 - 896. [Abstract] [Full Text] [PDF]

				J. Koene, R. Jansen, A Ter Maat, and R Chase A conserved location for the central nervous system control of mating behaviour in gastropod molluscs: evidence from a terrestrial snail J. Exp. Biol., January 3, 2000; 203(6): 1071 - 1080. [Abstract] [PDF]

				R. F. Jansen, A. W. Pieneman, and A. t. Maat Pattern Generation in the Buccal System of Freely Behaving Lymnaea stagnalis J Neurophysiol, December 1, 1999; 82(6): 3378 - 3391. [Abstract] [Full Text] [PDF]

				M. DE JONG-BRINK, C. N. REID, C. P. TENSEN, and A. TER MAAT Parasites flicking the NPY gene on the host's switchboard: why NPY? FASEB J, November 1, 1999; 13(14): 1972 - 1984. [Abstract] [Full Text]