QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by ROBERTS, A. Articles by SOFFE, S. R. Search for Related Content PubMed Articles by ROBERTS, A. Articles by SOFFE, S. R.

Journal of Experimental Biology 112,321-335 (1984)
Published by Company of Biologists 1984

Sustained Responses to Brief Stimuli: Swimming in Xenopus Embryos

ALAN ROBERTS ¹, N. DALE ¹, and S. R. SOFFE ¹

¹ Department of Zoology, University of Bristol Bristol BS8 1UG, U.K.

Prolonged responses to brief triggering or releasing stimuli are commonplace in animal behaviour. The initiation of locomotion is an example but hypotheses for the central nervous origin of locomotory rhythms generally do not explain how activity is sustained. After a brief review, which suggests that positive feedback excitation could be involved, evidence from Xenopus embryos is considered. Here a brief skin stimulus can evoke long episodes of swimming even in curarized embryos. Feedback excitation provides a possible explanation for sustaining fictive swimming. This hypothesis is evaluated by simulation of simple neuronal networks using a physiologically realistic digital computer modelling programme. The results from simulations suggest that: (1) positive feedback excitation could sustain activity either in central pattern generators for locomotion or in postural motor systems and (2) that the model networks tested here are not appropriate to produce the pattern of motor output from the Xenopus embryo spinal cord.

Key words: Locomotion, Xenopus, swimming

This article has been cited by other articles:

				W.-C. Li, S. R. Soffe, and A. Roberts Dorsal Spinal Interneurons Forming a Primitive, Cutaneous Sensory Pathway J Neurophysiol, August 1, 2004; 92(2): 895 - 904. [Abstract] [Full Text] [PDF]

				C. A. Reith and K. T. Sillar Development and Role of GABAA Receptor-Mediated Synaptic Potentials During Swimming in Postembryonic Xenopus laevis Tadpoles J Neurophysiol, December 1, 1999; 82(6): 3175 - 3187. [Abstract] [Full Text] [PDF]

				J. R. Lieb Jr. and W. N. Frost Realistic Simulation of the Aplysia Siphon-Withdrawal Reflex Circuit: Roles of Circuit Elements in Producing Motor Output J Neurophysiol, March 1, 1997; 77(3): 1249 - 1268. [Abstract] [Full Text] [PDF]