Computer simulation of the enteric neural circuits mediating an ascending reflex: roles of fast and slow excitatory outputs of sensory neurons Bornstein, J. C. en_US Furness, J. B. en_US Kelly, H. F. en_US Bywater, R. A. en_US Neild, T. O. en_US Bertrand, P. P en_US 2021-11-25T13:35:13Z 2021-11-25T13:35:13Z 1997 en_US
dc.description.abstract Recent electrophysiological studies of the properties of intestinal reflexes and the neurons that mediate them indicate that the intrinsic sensory neurons may transmit to second order neurons via either fast (30-50 ms duration) or slow (10-60 s duration) excitatory synaptic potentials or both. Which of these possible modes of transmission is involved in the initiation of motility reflexes has not been determined and it is not clear what the consequences of the different forms of synaptic transmission would be for the properties of the reflex pathways. In the present study, this question has been addressed by the use of a suite of computer programs, Plexus©, which was written to simulate the activity of the neurons of the enteric nervous system during intestinal reflexes. The programs construct a simulated enteric nerve circuit based on anatomical and physiological data about the number, functions and interconnections of neurons involved in the control of motility. The membrane potentials of neurons are calculated individually from physiological data about the reversal potentials and membrane conductances for Na+, K+ and Cl−. Synaptic potentials are simulated by changes in specific conductances based on physiological data. The results of each simulation are monitored by recording the membrane potentials of up to 16 separate defined neurons and by recording the summed activity of whole classes of neurons as a function of time and location in the simulated network. The present series of experiments simulated the behaviour of a network consisting of 18 898 sensory neurons and 3708 ascending interneurons after 75% of the sensory neurons lying in the anal 10 mm of a 30 mm long segment of small intestine were stimulated once. The results were compared with electrophysiological data recorded from myenteric neurons during ascending reflexes evoked either by distension or mechanical stimulation of the mucosa. When transmission from sensory neurons to ascending interneurons was via fast excitatory synaptic potentials, the latencies and durations of the simulated responses were too brief to match the electrophysiologically recorded responses. When transmission from sensory neurons was via slow excitatory synaptic potentials, the latencies were very similar to those recorded physiologically, but the durations of the simulated responses were much longer than seen in physiological experiments. The latencies and durations of simulated and physiologically recorded responses matched only when the firing of ascending interneurons was limited to the beginning of a slow excitatory synaptic potential (in this study by limiting the duration of the decrease in K+ conductance). The simulation provided several physiologically testable predictions, indicating that Plexus© is an important tool for the investigation of the properties and behaviour of the enteric nervous system. en_US
dc.identifier.issn 0165-1838 en_US
dc.language English
dc.language.iso EN en_US
dc.rights CC BY-NC-ND 3.0 en_US
dc.rights.uri en_US
dc.source Legacy MARC en_US
dc.title Computer simulation of the enteric neural circuits mediating an ascending reflex: roles of fast and slow excitatory outputs of sensory neurons en_US
dc.type Journal Article en
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dspace.entity.type Publication en_US
unsw.identifier.doiPublisher en_US
unsw.relation.faculty Medicine & Health
unsw.relation.ispartofjournal Journal of the Autonomic Nervous System en_US
unsw.relation.ispartofpagefrompageto 143-157 en_US
unsw.relation.ispartofvolume 64 en_US
unsw.relation.originalPublicationAffiliation Bornstein, J. C. en_US
unsw.relation.originalPublicationAffiliation Furness, J. B. en_US
unsw.relation.originalPublicationAffiliation Kelly, H. F. en_US
unsw.relation.originalPublicationAffiliation Bywater, R. A. en_US
unsw.relation.originalPublicationAffiliation Neild, T. O. en_US
unsw.relation.originalPublicationAffiliation Bertrand, P. P, Medical Sciences, Faculty of Medicine, UNSW en_US School of Medical Sciences *
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