Environmental modulation of a central pattern generator in freely behaving aplysia

Eberly, Lewis B.; Kanz, James E.; Taylor, Charles P.; Pinsker, H. M.

doi:10.1016/s0163-1047(81)90227-2

Cited by 19 publications

(8 citation statements)

References 19 publications

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“…The spontaneous generation of the population burst in the R25/L25 network is mediated by endogenous pacemaker activity of the R25/L25 cells and by reverberation within the network, which results from the electrical and excitatory chemical connections between the members of the network (Byrne, 1983;Koester, 1989). The spontaneous respiratory pumping bursts are usually strong and stereotyped, but respiratory pumping occasionally occurs in a weak mode that is more variable in form (Eberly et al, 1981). I .…”

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confidence: 99%

Synaptic actions of identified peptidergic neuron R15 in Aplysia. I. Activation of respiratory pumping

1991

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The purpose of the study described in this and the following two companion papers was to determine the synaptic actions of neuron R15, an endogenously bursting neurosecretory cell in Aplysia, as a step toward determining its physiological function. The results described in this paper demonstrate that activity in R15 increases the frequency of bursting in the R25/L25 network that triggers respiratory pumping. This excitatory modulatory effect appears to be mediated by R15 alpha 1 peptide. R15 activates both strong and weak modes of respiratory pumping. In contrast, the two R20 cells, which are thought to use the neuropeptides SCPA and SCPB as transmitters, elicit only strong episodes of respiratory pumping. The synaptic actions of R15 also differ from those of the R20 cells in being longer lasting and in exhibiting profound desensitization. Chronic recording of R15 activity in vivo indicates that it does not burst spontaneously in the intact animal, so the synaptic actions of R15 are not chronically desensitized. The neuroendocrine bag cells, which initiate egg laying, had been shown by others to excite R15 and the R25/L25 network that triggers respiratory pumping. Our data indicate that the excitatory effects of the bag cells on the R25/L25 cells are mediated in part by R15.

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Synaptic actions of identified peptidergic neuron R15 in Aplysia. I. Activation of respiratory pumping

1991

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“…1. Respiratory pumping is a relatively stereotyped behavior that occurs both spontaneously and in response to tactile stimuli, anoxia, food presentation, and changes in illumination (10,20,37,39,42,43). While considerable progress has been made in elucidating the motor elements underlying this behavior, little is known regarding the cells responsible for its initiation or patterning.…”

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Identification and initial characterization of a cluster of command and pattern-generating neurons underlying respiratory pumping in Aplysia californica

Byrne

1983

Journal of Neurophysiology

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“…The most obvious and best-known of these is a spontaneous and often rhythmic FAP termed Pumping (Leonard & Lukowiak, 1986), or respiratory pumping (Koester et al, 1974 ;Eberly et al, 1981). This behaviour was first described, as spontaneous withdrawal, by Kupfermann and Kandel (1969) and Peretz (1969).…”

Section: ( B ) Whole Animal Behaviours Involving the Gillmentioning

confidence: 99%

“…More recently, studies of freely moving individuals of A. californica, in which the right parapodium has been amputated to expose the gill, have shown two types of spontaneous pumping movement, one in which the gill, siphon and mantle move approximately simultaneously and one in which the gill movement precedes the coordinated movement of the other mantle organs (Hickie, 1994 ;Hickie & Walters, 1995;Leonard, 1996). Int II activity was recorded with cuff electrodes in freely-moving A. californica in a series of studies in Harold Pinsker's laboratory, but they did not observe gill movements directly (Kanz et al, 1979 ;Eberly et al, 1981). Hickie (1994) provides a quantitative description and comparison of the two types of spontaneous movement of mantle organs.…”

Section: ( B ) Whole Animal Behaviours Involving the Gillmentioning

confidence: 99%

“…It is also clear that the threshold and amplitude for the GWR is adjusted according to behavioural requirements both in the intact animal Eberly et al, 1981) and in mantle-organ preparations where the suppressed behavioural state is associated with either copulation or satiety in the individual before dissection (Lukowiak, 1980(Lukowiak, , 1987Lukowiak & Freedman, 1983 ;Leonard et al, 1991). It seems probable therefore, that suppression of evoked gill movements serves some adaptive physiological or behavioural function.…”

Section: ( a ) Observationsmentioning

confidence: 99%

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Parallel processing in an identified neural circuit: the Aplysia californica gill‐withdrawal response model system

Leonard¹,

Edstrom²

2004

Biological Reviews

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The response of the gill of Aplysia calfornica Cooper to weak to moderate tactile stimulation of the siphon, the gill-withdrawal response or GWR, has been an important model system for work aimed at understanding the relationship between neural plasticity and simple forms of non-associative and associative learning. Interest in the GWR has been based largely on the hypothesis that the response could be explained adequately by parallel monosynaptic reflex arcs between six parietovisceral ganglion (PVG) gill motor neurons (GMNs) and a cluster of sensory neurons termed the LE cluster. This hypothesis, the Kupfermann-Kandel model, made clear, falsifiable predictions that have stimulated experimental work for many years. Here, we review tests of three predictions of the Kupfermann-Kandel model: (1) that the GWR is a simple, reflexive behaviour graded with stimulus intensity; (2) that central nervous system (CNS) pathways are necessary and sufficient for the GWR; and (3) that activity in six identified GMNs is sufficient to account for the GWR. The available data suggest that (1) a variety of action patterns occur in the context of the GWR; (2) the PVG is not necessary and the diffuse peripheral nervous system (PNS) is sufficient to mediate these action patterns; and (3) the role of any individual GMN in the behaviour varies. Both the control of gill-withdrawal responses, and plasticity in these responses, are broadly distributed across both PNS and CNS pathways. The Kupfermann-Kandel model is inconsistent with the available data and therefore stands rejected. There is, no known causal connection or correlation between the observed plasticity at the identified synapses in this system and behavioural changes during non-associative and associative learning paradigms. Critical examination of these well-studied central pathways suggests that they represent a 'wetware' neural network, architecturally similar to the neural network models of the widely used 'Perceptron' and/or 'Back-propagation' type. Such models may offer a more biologically realistic representation of nervous system organisation than has been thought. In this model, the six parallel GMNs of the CNS correspond to a hidden layer within one module of the gill-control system. That is, the gill-control system appears to be organised as a distributed system with several parallel modules, some of which are neural networks in their own right. A new model is presented here which predicts that the six GMNs serve as components of a 'push-pull' gain control system, along with known but largely unidentified inhibitory motor neurons from the PVG. This 'push-pull' gain control system sets the responsiveness of the peripheral gill motor system. Neither causal nor correlational links between specific forms of neural plasticity and behavioural plasticity have been demonstrated in the GWR model system. However, the GWR model system does provide an opportunity to observe and describe directly the physiological and biochemical mechanisms of distributed representation and parall...

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Environmental modulation of a central pattern generator in freely behaving aplysia

Cited by 19 publications

References 19 publications

Synaptic actions of identified peptidergic neuron R15 in Aplysia. I. Activation of respiratory pumping

Synaptic actions of identified peptidergic neuron R15 in Aplysia. I. Activation of respiratory pumping

Identification and initial characterization of a cluster of command and pattern-generating neurons underlying respiratory pumping in Aplysia californica

Parallel processing in an identified neural circuit: the Aplysia californica gill‐withdrawal response model system

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