The Integration of the Patterned Output of Buccal Motoneurones During Feeding in Tritonia Hombergi

1979 ◽  
Vol 79 (1) ◽  
pp. 23-40
Author(s):  
A.G. M. BULLOCH ◽  
D. A. DORSETT
Keyword(s):  
Feeding Activity ◽  
Electrical Coupling ◽  
Cell Activity ◽  
Giant Cells ◽  
Posterior Border ◽  
Buccal Ganglion ◽  
Synaptic Inputs ◽  
Proprioceptive Input ◽  
Buccal Ganglia ◽  
Feeding Cycle

Three phases of activity may be recognized in the buccal mass of Tritonia hombergi during the feeding cycle. These have been termed Protraction, Retraction and Flattening. Each phase is driven by a group of motoneurones along the posterior border of the buccal ganglia. The patterned bursting observed in the motoneurone groups during feeding activity is phased by synaptic inputs which are common to two or more groups. Evidence is presented which indicates these inputs are derived from three unidentified multi-action interneurone sources within each buccal ganglion, and whose action primarily determines the patterned output of the motoneurones. Electrical coupling between between synergistic motoneurones and, in one case, post-inhibitory rebound, contribute to the synchronization of group activity. Proprioceptive input to the motoneurones was not identified, but may project to the interneurones. Some small neurones having synaptic inputs on the motoneurones appropriate to two of the interneurones were found, but require confirmation in this role. The cerebral giant cells synapse on representatives of three motoneurone groups, and also activate the buccal interneurones driving the feeding cycle. The patterned activity of the motoneurones can occur in the absence of cerebral cell activity.

The Morphology and Physiological Properties of the Small White Neurones in the Buccal Ganglia of Tritonia Hombergi

1986 ◽  
Vol 122 (1) ◽  
pp. 237-256
Author(s):  
D. A. DORSETT
Keyword(s):  
Phase I ◽  
Feeding Activity ◽  
The Other ◽  
Inhibitory Input ◽  
Cyclic Activity ◽  
Buccal Ganglia ◽  
Physiological Properties ◽  
Feeding Cycle ◽  
F Cells ◽  
P Cells

The two small white (W) cells in the buccal ganglia of Tritonia hombergi can initiate and modulate cyclic activity in the pattern generating neurones which drive feeding activity in the buccal mass. They also make extensive monosynaptic connections with the buccal motoneurones, generating EPSPs on protractor (P) cells, IPSPs on retractor (R) cells, and EIPSPs on the small radula flattener (F) cells. Two F motoneurones receive a chemically mediated, facilitating EPSP from the W cells. Inactive W cells receive weak excitatory feedback from the pattern generating network interneurones (FPG) in phase I of the feeding cycle and also from some F cells. Prolonged depolarization of one W cell recruits the other. When both are active they adopt a patterned burst mode with a common inhibitory input in phase I.

Central Coordination of Buccal and Pedal Neuronal Activity in the Pond Snail Lymnaea Stagnalis

1988 ◽  
Vol 136 (1) ◽  
pp. 103-123
Author(s):  
M. A. KYRIAKIDES ◽  
C. R. MCCROHAN
Keyword(s):  
Central Pattern Generator ◽  
Body Wall ◽  
Lymnaea Stagnalis ◽  
Pattern Generator ◽  
Pond Snail ◽  
Buccal Ganglion ◽  
Buccal Ganglia ◽  
Feeding Cycle ◽  
Central Coordination

Cyclical synaptic inputs were recorded from identified giant neurones and neuronal cluster cells in the pedal ganglia of Lymnaea stagnalis. They occurred in phase with rhythmical inputs to buccal ganglion motoneurones, which have been shown to originate from interneurones of the buccal central pattern generator for feeding. In pedal neurones, the cyclical inputs were mainly inhibitory, and occurred predominantly during the radula retraction phase of the feeding cycle. Tonic depolarization of higher-order interneurones in the feeding system, to activate the buccal central pattern generator, led to the onset of cyclical inputs to pedal neurones. These inputs were abolished after cutting the cerebrobuccal connectives, supporting the hypothesis that they originate from the buccal ganglia. The possible role of these inputs in coordinating foot and body wall movements with the buccal feeding rhythm is discussed.

Synaptic relationships of the cerebral giant cells with motoneurones in the feeding system of Lymnaea stagnalis

1980 ◽  
Vol 85 (1) ◽  
pp. 169-186
Author(s):  
C. R. McCrohan ◽  
P. R. Benjamin
Keyword(s):  
Synaptic Input ◽  
Lymnaea Stagnalis ◽  
Giant Cells ◽  
Burst Activity ◽  
Feeding System ◽  
Postsynaptic Potentials ◽  
Buccal Ganglia ◽  
Long Latency ◽  
Burst Intensity ◽  
Feeding Cycle

1.The cerebral giant cells (CGCs) of Lymnaea have a tonic, modulatory effect on the intensity of output from feeding motoneurones in the buccal ganglia. 2. Short latency, excitatory and probably monosynaptic connexions occur between the CGCs and three identified feeding motoneurones. Unitary excitatory postsynaptic potentials in these motoneurones, following CGC spikes, are of different sizes and durations, and hence have different summation properties. 3. The CGCs make long latency, excitatory polysynaptic connexions with four other feeding motoneurone types. 4. Bursts of spikes in the CGCs, resulting from phasic synaptic input, synchronous with the feeding cycle, amplify their modulatory effect on burst intensity in feeding motoneurones. 5. Thte for reinforcing their cyclic burst activity.

The Functional Morphology and Motor Innervation of the Buccal Mass of Tritonia Hombergi

1979 ◽  
Vol 79 (1) ◽  
pp. 7-22
Author(s):  
A.G. M. BULLOCH ◽  
D. A. DORSETT
Keyword(s):  
Muscle Activity ◽  
Posterior Border ◽  
Motor Innervation ◽  
Fourth Group ◽  
Buccal Mass ◽  
Buccal Ganglia ◽  
Feeding Cycle ◽  
F Cells ◽  
Sequential Activation ◽  
Muscle Groups

The anatomy of the buccal mass and the function of nine principal muscle groups involved in the feeding movements, are described for the mollusc Tritonia hombergi. Anatomical and physiological studies on some 40 neurones along the posterior border of the buccal ganglia indicates that many are primary motoneurones to the muscles of the buccal mass. The feeding cycle may be divided into three phases of muscle activity termed Protraction, Retraction and Flattening, which are correlated with the patterned bursting observed in P, R and F motoneurone groups within the motoneurone population. A fourth group of motoneurones are thought to innervate muscles to the outer lips which are active during protraction. The patterned output of impulses in the buccal nerves during feeding cycles confirms that the motor control of the muscle groups may be explained in terms of the sequential activation of the P, R and F cells.

Interneuronal Control of Feeding in the Pond Snail Lymnaea Stagnalis: I. Initiation of Feeding Cycles by a Single Buccal Interneurone

1981 ◽  
Vol 92 (1) ◽  
pp. 187-201
Author(s):  
R. M. ROSE ◽  
P. R. BENJAMIN
Keyword(s):  
Lymnaea Stagnalis ◽  
Pond Snail ◽  
Buccal Ganglion ◽  
Synaptic Inputs ◽  
Feeding Rhythm ◽  
Interneuronal Network

The Lymnaea buccal ganglion is organized such that the basic feeding rhythm is generated by an interneuronal network which imposes its activity on a set of follower cells. In this paper we extend our earlier observations (Benjamin & Rose, 1979) on the follower cells to show that they receive four consecutive synaptic inputs. The main objective of the paper is to describe the properties of an interneurone called the ‘slow oscillator’ which is capable of initiating feeding cycles. This interneurone will be used in the following paper (Rose & Benjamin, 1981) to drive other members of the interneuronal network in order to determine how it is organized, and to understand the origin and timing of the four synaptic inputs to the follower cells.

Synaptic Actions of Oesophageal Proprioceptors in the Mollusc, Philine

1981 ◽  
Vol 94 (1) ◽  
pp. 95-104
Author(s):  
J. N. SIGGER ◽  
D. A. DORSETT
Keyword(s):  
Receptive Fields ◽  
Large Cell ◽  
The Other ◽  
Small Cells ◽  
Sensory Cells ◽  
Periodic Activity ◽  
Buccal Ganglia ◽  
Excitatory Synaptic Input ◽  
Feeding Cycle ◽  
Protraction Phase

The buccal ganglia of Philine each contain a group of mechanoreceptors, consisting of 1 large and 3 small cells, with receptive fields in the oesophagus. Synaptic contacts occur between the receptors; the large cell providing an EIPSP input to its contralateral partner and to the two groups of smaller receptors. The small receptors make weak excitatory contacts with both the large receptors. The sensory cells synapse with other buccal motoneurones and interneurones, some of which show periodic activity associated with the feeding movements. Protraction phase neurones are divisible into two groups, one of which receives EPSPs from the receptors, while the other group receives IPSPs. Retraction phase neurones receive a biphasic EIPSP. The receptors provide excitatory synaptic input to a pair of interneurones which ‘gate’ the feeding cycle. A third class of neurones which are not rhythmically active during feeding receive a predominantly inhibitory EIPSP.

Modulation of Fictive Feeding by Dopamine and Serotonin inAplysia

2000 ◽  
Vol 83 (1) ◽  
pp. 374-392 ◽  
Author(s):  
Evgeni A. Kabotyanski ◽  
Douglas A. Baxter ◽  
Susan J. Cushman ◽  
John H. Byrne
Keyword(s):  
Feeding Activity ◽  
Neural Correlates ◽  
Neural Circuitry ◽  
Pattern Generator ◽  
Synaptic Connections ◽  
Rhythmic Movements ◽  
Motor Programs ◽  
Dopaminergic Cells ◽  
Buccal Ganglia ◽  
Bath Application

The buccal ganglia of Aplysia contain a central pattern generator (CPG) that mediates rhythmic movements of the buccal apparatus during feeding. Activity in this CPG is believed to be regulated, in part, by extrinsic serotonergic inputs and by an intrinsic and extrinsic system of putative dopaminergic cells. The present study investigated the roles of dopamine (DA) and serotonin (5-HT) in regulating feeding movements of the buccal apparatus and properties of the underlying neural circuitry. Perfusing a semi-intact head preparation with DA (50 μM) or the metabolic precursor of catecholamines (l-3–4-dihydroxyphenylalanine, DOPA, 250 μM) induced feeding-like movements of the jaws and radula/odontophore. These DA-induced movements were similar to bites in intact animals. Perfusing with 5-HT (5 μM) also induced feeding-like movements, but the 5-HT-induced movements were similar to swallows. In preparations of isolated buccal ganglia, buccal motor programs (BMPs) that represented at least two different aspects of fictive feeding (i.e., ingestion and rejection) could be recorded. Bath application of DA (50 μM) increased the frequency of BMPs, in part, by increasing the number of ingestion-like BMPs. Bath application of 5-HT (5 μM) did not significantly increase the frequency of BMPs nor did it significantly increase the proportion of ingestion-like BMPs being expressed. Many of the cells and synaptic connections within the CPG appeared to be modulated by DA or 5-HT. For example, bath application of DA decreased the excitability of cells B4/5 and B34, which in turn may have contributed to the DA-induced increase in ingestion-like BMPs. In summary, bite-like movements were induced by DA in the semi-intact preparation, and neural correlates of these DA-induced effects were manifest as an increase in ingestion-like BMPs in the isolated ganglia. Swallow-like movements were induced by 5-HT in the semi-intact preparation. Neural correlates of these 5-HT-induced effects were not evident in isolated buccal ganglia, however.

Feeding CPG in Aplysia Directly Controls Two Distinct Outputs of a Compartmentalized Interneuron That Functions as a CPG Element

2007 ◽  
Vol 98 (6) ◽  
pp. 3796-3801 ◽  
Author(s):  
Kosei Sasaki ◽  
Michael R. Due ◽  
Jian Jing ◽  
Klaudiusz R. Weiss
Keyword(s):  
Action Potentials ◽  
Electrical Coupling ◽  
Motor Program ◽  
Pattern Generator ◽  
Synaptic Connections ◽  
Buccal Ganglion ◽  
Full Size ◽  
Program Generation ◽  
Functional Aspects ◽  
Protraction Phase

In the context of motor program generation in Aplysia, we characterize several functional aspects of intraneuronal compartmentalization in an interganglionic interneuron, CBI-5/6. CBI-5/6 was shown previously to have a cerebral compartment (CC) that includes a soma that does not generate full-size action potentials and a buccal compartment (BC) that does. We find that the synaptic connections made by the BC of CBI-5/6 in the buccal ganglion counter the activity of protraction-phase neurons and reinforce the activity of retraction-phase neurons. In buccal motor programs, the BC of CBI-5/6 fires phasically, and its premature activation can phase advance protraction termination and retraction initiation. Thus the BC of CBI-5/6 can act as an element of the central pattern generator (CPG). During protraction, the CC of CBI-5/6 receives direct excitatory inputs from the CPG elements, B34 and B63, and during retraction, it receives antidromically propagating action potentials that originate in the BC of CBI-5/6. Consequently, in its CC, CBI-5/6 receives depolarizing inputs during both protraction and retraction, and these depolarizations can be transmitted via electrical coupling to other neurons. In contrast, in its BC, CBI-5/6 uses spike-dependent synaptic transmission. Thus the CPG directly and differentially controls the program phases in which the two compartments of CBI-5/6 may transmit information to its targets.

scholarly journals When two wrongs make a right: synchronized neuronal bursting from combined electrical and inhibitory coupling

2017 ◽  
Vol 375 (2096) ◽  
pp. 20160282 ◽  
Author(s):  
Reimbay Reimbayev ◽  
Kevin Daley ◽  
Igor Belykh
Keyword(s):  
Electrical Coupling ◽  
Coupled System ◽  
Underlying Mechanism ◽  
Mathematical Methods ◽  
Synaptic Inputs ◽  
Bursting Neurons ◽  
Robust Synchronization ◽  
Neuronal Mechanisms ◽  
Central Nervous Systems ◽  
Inhibitory Coupling

Synchronized cortical activities in the central nervous systems of mammals are crucial for sensory perception, coordination and locomotory function. The neuronal mechanisms that generate synchronous synaptic inputs in the neocortex are far from being fully understood. In this paper, we study the emergence of synchronization in networks of bursting neurons as a highly non-trivial, combined effect of electrical and inhibitory connections. We report a counterintuitive find that combined electrical and inhibitory coupling can synergistically induce robust synchronization in a range of parameters where electrical coupling alone promotes anti-phase spiking and inhibition induces anti-phase bursting. We reveal the underlying mechanism, which uses a balance between hidden properties of electrical and inhibitory coupling to act together to synchronize neuronal bursting. We show that this balance is controlled by the duty cycle of the self-coupled system which governs the synchronized bursting rhythm. This article is part of the themed issue ‘Mathematical methods in medicine: neuroscience, cardiology and pathology’.

scholarly journals Contralateral sprouting and compensatory innervation following the permanent lesion of a ganglionic connective in the snail

1996 ◽  
Vol 199 (12) ◽  
pp. 2631-2643
Author(s):  
M Baker ◽  
B Chiasson ◽  
R Croll
Keyword(s):  
Central Nervous System ◽  
Achatina Fulica ◽  
Buccal Ganglion ◽  
Axonal Projections ◽  
Buccal Ganglia ◽  
Electrophysiological Measurements ◽  
A Cell ◽  
The Central Nervous System ◽  
Synaptic Drive

The fate of sprouted fibres was examined following long-term recovery from lesions to the central nervous system of the snail Achatina fulica. Axonal dye-labelling of one of the cerebrobuccal connectives (CBC), following either a cut or a crush to the opposite CBC, revealed supernumerary labelling of neuronal elements in both the cerebral and buccal ganglia in the weeks following treatment. A part of this sprouting response involved the rerouting of axonal projections from injured neurones that project contralaterally into the uninjured CBC. In addition, intracellular dye-fills, immunocytochemistry for detection of serotonin and electrophysiological measurements all revealed that a contralateral, uninjured neurone, the metacerebral giant (MCG) cell, sprouted new processes to invade the buccal ganglion denervated by the lesion. The contralateral MCG also increased synaptic drive over a neurone in the denervated buccal ganglion, a cell that normally receives strong input only from the lesioned ipsilateral MCG. After 5 weeks of recovery, morphological and electrophysiological measurements returned to normal levels in animals receiving a crush to the CBC, suggesting a retraction of sprouted projections following successful regeneration across the lesioned pathway. In contrast, the measurements indicative of sprouted fibres continued for up to 5 months when the regenerative response was prevented by cutting the CBC. Together, these results suggest that both the cessation of sprouting and the eventual retraction of sprouted fibres in Achatina fulica is contingent upon successful regeneration of the damaged axonal pathway.

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