Non-spiking local interneurones mediate abdominal extension related descending control of uropod motor neurones in the crayfish terminal abdominal ganglion

1997 ◽  
Vol 180 (5) ◽  
pp. 463-472 ◽  
Author(s):  
Hisaaki Namba ◽  
Toshiki Nagayama ◽  
Masakazu Takahata
Keyword(s):  
Abdominal Ganglion ◽  
Motor Neurones ◽  
Spiking Local Interneurones ◽  
Descending Control

Serotonergic modulation of nonspiking local interneurones in the terminal abdominal ganglion of the crayfish

2002 ◽  
Vol 205 (19) ◽  
pp. 3067-3076 ◽  
Author(s):  
Toshiki Nagayama
Keyword(s):  
Sensory Stimulation ◽  
Inhibitory Effect ◽  
Motor Neurone ◽  
Abdominal Ganglion ◽  
Membrane Hyperpolarization ◽  
Bath Application ◽  
Motor Neurones ◽  
Sensory Responses ◽  
Spiking Local Interneurones ◽  
Excitatory Responses

SUMMARY The modulatory effect of serotonin on local circuit neurones forming the uropod motor control system of the crayfish Procambarus clarkiiGirard was analysed electrophysiologically. Bath application of 10 μmol l-1 serotonin caused a decrease in the tonic spike activity of the exopodite reductor motor neurone. The inhibitory effect of serotonin on the motor neurone was dose-dependent and its spike discharge was completely suppressed for long periods by 1 mmol l-1 serotonin perfusion. Nonspiking local interneurones in the terminal abdominal ganglion showed either a membrane depolarization (N=6) or hyperpolarization(N=9) of 10-30 mV in amplitude when 100 μmol l-1serotonin was perfused for 3-5 min. By contrast, spiking local interneurones and intersegmental ascending interneurones showed no observable excitatory responses to the perfusion of serotonin but instead some showed a small membrane hyperpolarization of 2-5 mV. These results indicate that the nonspiking interneurones could contribute substantially to the level of tonic excitation of the uropod motor neurones. Sensory stimulation elicited depolarizing or hyperpolarizing potentials in the nonspiking interneurones and excitatory postsynaptic potentials (EPSPs)and spikes in the spiking interneurones. The sensory responses of spiking interneurones increased during bath application of serotonin and were reduced after 20-30 min of washing with normal saline. In the nonspiking interneurones, the amplitude of both depolarizing and hyperpolarizing potentials increased without any direct correlation with the serotonin-mediated potential change. This effect of serotonin was long-lasting and continued to enhance the responses of the nonspiking interneurones after washing. This postserotonin enhancement persisted for over 1 h.

CENTRALLY GENERATED RHYTHMIC ACTIVITY AND MODULATORY FUNCTION OF THE OVIDUCTAL DORSAL UNPAIRED MEDIAN (DUM) NEURONES IN TWO ORTHOPTERAN SPECIES (CALLIPTAMUS SP. AND DECTICUS ALBIFRONS)

1993 ◽  
Vol 174 (1) ◽  
pp. 123-138 ◽  
Author(s):  
E. Kalogianni ◽  
G. Theophilidis
Keyword(s):  
Firing Rate ◽  
Firing Pattern ◽  
Anterior Part ◽  
Motor Pattern ◽  
Egg Laying ◽  
Abdominal Ganglion ◽  
Muscle Fibres ◽  
Motor Neurones ◽  
Rhythmic Firing ◽  
Dorsal Unpaired Median

The rhythmic firing pattern of the putatively octopaminergic dorsal unpaired median (DUM) neurones supplying the oviductal system of female orthopterans, Calliptamus sp. and Decticus albifrons, was examined. Our data provide evidence that the oviductal DUM neurones in the seventh abdominal ganglion modulate the oviductal motor pattern, both peripherally and centrally, during the inhibition of egg-laying behaviour. In a minimally dissected animal, rhythmic activation of the oviductal DUM and motor neurones can be readily elicited by isolation of the seventh abdominal ganglion from the anterior part of the nerve cord. The bursting activity of the DUM neurones is temporally correlated with the oviductal motor rhythm. Both populations of oviductal neurones retain their rhythmic firing pattern after total isolation of the genital ganglia, indicating the presence of an oviductal central pattern generator. The effects of stimulation of oviductal DUM neurones on the oviductal motor activity were monitored by recording intracellularly from oviductal muscle fibres and extracellularly from motor axons. These effects consist of a reduction in the amplitude and frequency of excitatory postsynaptic potentials (EPSPs) in the muscle fibre and in the firing rate in oviductal motor neurones. We suggest that the change in EPSP amplitude results from peripheral release of octopamine by DUM neurones. The decreased firing rate of motor neurones, however, appears to be a central effect, possibly caused by central release of octopamine by DUM neurones.

scholarly journals Processing of mechanosensory signals in local reflex pathways of the locust

1989 ◽  
Vol 146 (1) ◽  
pp. 209-227 ◽  
Author(s):  
M. Burrows
Keyword(s):  
Receptive Fields ◽  
Sensory Information ◽  
Afferent Input ◽  
The Other ◽  
Reflex Pathways ◽  
Motor Neurones ◽  
The Central Nervous System ◽  
Local Reflex ◽  
Spiking Local Interneurones ◽  
The Stability

The processing of mechanosensory signals responsible for the reflex adjustment of the posture or movement of the legs of the locust is described in terms of the actions and connections of identified neurones. Signals can be followed from the major classes of exteroceptors of a leg, through their various integrative stages in the central nervous system to their emergence as specific patterns in known motor neurones. Particular emphasis is placed on the integrative roles of two classes of local interneurones. The spiking local interneurones map the leg as a series of overlapping receptive fields and reverse the sign of the afferent input. The nonspiking local interneurones control the output of the motor neurones by the graded release of chemical transmitter and can adjust the gain of a local reflex depending on the position and movements of the joints of that leg. The reflex movements of one leg must not impair the stability of the animal and must therefore be influenced by events at the other legs. Populations of intersegmental interneurones convey sensory information from one segment to another to ensure such coordination. These interneurones do not produce stereotyped intersegmental reflexes but, instead, alter the performance of a local reflex in a distant leg by making synaptic connections with nonspiking local interneurones. These connections change the effectiveness of the outputs to the motor neurones and consequently the local reflex. The local interneurones therefore play a crucial role both in the production of local reflexes and in the integration of these actions with the movements of the other legs.

scholarly journals The Identification of Motor and Unpaired Median Neurones Innervating the Locust Oviduct

1992 ◽  
Vol 168 (1) ◽  
pp. 177-198 ◽  
Author(s):  
E. KALOGIANNI ◽  
H.-J. PFLÜGER
Keyword(s):  
Action Potentials ◽  
Motor Pattern ◽  
Abdominal Ganglion ◽  
Cell Group ◽  
Posterior Median ◽  
Posterior Group ◽  
Motor Neurones ◽  
The Common ◽  
Anterior Group ◽  
Lateral Oviduct

The different classes of neurones supplying the locust oviduct were individually identified by intracellular recording and staining. We could thus show that different regions of the oviduct are innervated by different sets of neurones. Three motor neurones (oviductal neurones 1–3, OVN1-3) supply the oviduct via nerve N2B of the seventh abdominal ganglion. Whereas all three motor neurones innervate the junctional area of the lateral and the common oviduct (OVN1, 2 and 3), the lateral oviduct is innervated by only one motor neurone (OVN2) and the common oviduct by two motor neurones (OVN1 and 2). The cell bodies of all three motor neurones lie ventrally, near the origin of the sternal root, and their neuropilar branches are confined to the seventh abdominal ganglion. The neuropilar branches of OVN1 and 2 extend mainly in the ipsilateral half of the ganglion; those of OVN3 reside exclusively in the contralateral half. The oviductal motor neurones, produce a phasic motor pattern, the oviductal rhythm, which causes neurogenic contractions of the junctional area and the common oviduct. These contractions serve to retain eggs in the lateral oviduct. The oviduct is also supplied by a large number (16–20) of median neurones with bilateral axons. All of these appear to innervate the lateral oviduct, but only two project to the junctional area and the common oviduct. The cell bodies of the median neurones are situated in the seventh abdominal ganglion and are arranged in two groups: a posterior group made up of 10–12 cells and an anterior group with 6–8 cells. Their primary neurites run towards the centre of the ganglion in the dorsal plane, where they bifurcate, sending a secondary neurite through each oviductal nerve. Their neuropilar branches are confined to the seventh abdominal ganglion, but some also possess thin axon collaterals projecting to the terminal abdominal ganglion. The anterior and posterior median neurones show considerable differences in their branching pattern within the ganglion. The posterior cells are all likely to be neurones of the well-known DUM cell group, but the anterior median cells probably represent a different class of neurone. Posterior median neurones support overshooting soma action potentials of 60–80 mV amplitude, with a characteristic undershoot of 6–15 mV. Orthodromic stimulation of these neurones results in a reduction of the amplitude and frequency of the oviductal contractions, suggesting that they have a modulatory role. Note: To whom reprint requests should be sent.

scholarly journals Local Interneurones and Local Interactions in Arthropods

1984 ◽  
Vol 112 (1) ◽  
pp. 253-281
Author(s):  
M. V. S. SIEGLER
Keyword(s):  
Local Interactions ◽  
Visual Inputs ◽  
Modelling Studies ◽  
Motor Neurones ◽  
Spiking Local Interneurones ◽  
Specialized Region ◽  
Local Circuits ◽  
Spike Initiation ◽  
Graded Release ◽  
The Brain

As their name implies, local interneurones arborize within anatomically restricted regions of a nervous system, and the connections that they make establish local circuits. In arthropods, they may arborize wholly within a segmental ganglion, or within a specialized region of the brain. Local interneurones can be divided into two physiological types: spiking and nonspiking. In segmental ganglia, spiking local interneurones are largely responsible for the local processing of primary sensory inputs, whereas non-spiking ones play a major role in the control and coordination of motor neurone activity at the segmental level. By contrast, in the brain, primary visual inputs are processed mainly by non-spiking interneurones. Local interactions between neurones may occur in three ways: by the graded release of transmitter, by the presynaptic modulation of spike-evoked PSPs and by the ‘conventional’ mechanism where spike frequency is translated across a synapse as the summed amplitude of discrete spike-evoked PSPs. Although graded synaptic transmission is the only mechanism so far described for the local interactions of non-spiking interneurones, it is not limited to them. It may occur also in non-spiking neurones specialized to transmit graded signals over long distances, or in local, intraganglionic regions of motor neurones or long interneurones. The ability of spiking neurones to exert graded effects may depend upon input and output synapses being intermingled on their fine branches, at sites relatively distant from the region of spike initiation. Since these synapses are widely distributed over the neurones, local intraganglionic interactions can be seen as the summed effect of many, yet more restricted local interactions. Restricted local interactions also may occur within parts of non-spiking interneurones, but this is a conjecture, based on modelling studies, and upon considerable EM evidence for serial and reciprocal synapses in most other types of arthropod neurones.

The motor innervation of the oviducts and central generation of the oviductal contractions in two orthopteran species (Calliptamus sp. and Decticus albifrons)

1995 ◽  
Vol 198 (2) ◽  
pp. 507-520 ◽  
Author(s):  
E Kalogianni ◽  
G Theophilidis
Keyword(s):  
Motor Function ◽  
Action Potentials ◽  
Motor Pattern ◽  
Pattern Generator ◽  
Abdominal Ganglion ◽  
Muscle Fibres ◽  
Descending Inhibition ◽  
Metathoracic Ganglion ◽  
Motor Neurones ◽  
Orthopteran Species

The oviducts of the female Decticus albifrons (Orthoptera: Tettigonidae) are innervated by six bilaterally paired neurones, while those of the female Calliptamus sp. (Orthoptera: Catantopidae) are innervated by three bilaterally paired neurones, located in the seventh abdominal ganglion. Using intracellular recording and staining, five of the six oviductal neurones of D. albifrons and the three oviductal neurones of Calliptamus sp. were physiologically and morphologically identified. All three oviductal neurones of Calliptamus sp. have a motor function. In D. albifrons, however, there is evidence for motor function in only three of the five identified oviductal neurones that appear to participate in the generation of the oviductal contractions. The remaining two identified neurones of D. albifrons have a branching pattern similar to that of motor neurones, but their physiological characteristics, large overshooting soma action potentials (30­40 mV) with a long afterhyperpolarising phase, are similar to those of the oviductal unpaired median neurones, which are known to modulate the oviductal contractions. The oviductal muscle exhibits two different modes of contractions: (a) fast and slow myogenic contractions, the fast contractions being produced by spontaneous potentials (30­40 mV) generated by some oviductal muscle fibres; and (b) neurogenic contractions caused by the rhythmic spiking of the oviductal motor neurones. This motor pattern is produced by the oviductal central pattern generator, a neural network residing in the last two abdominal ganglia (seventh and terminal abdominal ganglia) of the species examined here. When isolated both anteriorly and posteriorly, the seventh abdominal ganglion generates rhythmic oviductal contractions of lower frequency and amplitude than those recorded when the connectives between the genital ganglia are intact. The oviductal pattern generator is activated through release from descending inhibition, which originates, in Calliptamus sp., from the compound metathoracic ganglion (fused metathoracic and first three abdominal neuromeres) and in, D. albifrons, from the first free abdominal ganglion (fused second and third abdominal neuromeres).

scholarly journals Motor programme switching in the crayfish swimmeret system

1985 ◽  
Vol 114 (1) ◽  
pp. 521-549
Author(s):  
W. J. Heitler
Keyword(s):  
Rhythmic Activity ◽  
Power Stroke ◽  
Intersegmental Coordination ◽  
Return Stroke ◽  
Extracellular Recordings ◽  
Sinusoidal Input ◽  
Sinusoidal Waveform ◽  
Motor Neurones ◽  
Spiking Local Interneurones ◽  
Motor Programme

Intracellular and extracellular recordings have been made from neurones of the swimmeret system in the semi-isolated abdominal ganglion of the crayfish during rhythmic activity. Extracellular recordings commonly reveal a motor programme (MP1) consisting of low-amplitude symmetrical power and return stroke activity with phase-constant posterior-to-anterior intersegmental coordination. Occasionally a different motor programme (MP2) is expressed. MP2 has higher amplitude episodic activity, with return stroke duration greater than power stroke, and with latency-constant anterior-to-posterior or near synchronous intersegmental coordination. Preparations may switch spontaneously between the two motor programmes. Intracellular recordings show that interneurones whose membrane potentials oscillate during MP1 and which can reset its rhythm usually cease to oscillate during MP2. During production of MP1, current injected into any one of a small number of interneurones can induce MP2. The polarity of current required is usually such as to drive the membrane potential towards the level normally associated with return stroke during MP1. During MP1 many motor neurones receive synaptic input with approximately sinusoidal waveform. During MP2 they may receive an episodic input with approximately sawtooth waveform, and/or input consisting of large, unitary EPSPs. The unitary EPSPs drive a ‘bursty’ mode of MP2 activity that is sometimes seen. The bursts of unitary EPSPs in MP2 appear to derive from a different source to that of the sinusoidal input in MP1. These sources are probably caudally-conducting through-interneurones and non-spiking local interneurones respectively. Thus experimental perturbation of a single neurone can induce a motor programme switch such as to change the activity of some hundreds of neurones in at least three ganglia. Neurones with this property would be convenient targets for controlling influences in the intact animal.

Does abnormal branching of inputs to motor neurones explain abnormal muscle cocontraction in cerebral palsy?

1999 ◽  
Vol 41 (7) ◽  
pp. 465-472 ◽  
Author(s):  
John Gibbs ◽  
Linda M Harrison ◽  
John A Stephens ◽  
Andrew L Evans
Keyword(s):  
Cerebral Palsy ◽  
Motor Neurones

Stimulation of cyclic AMP formation and nerve electrical activity by octopamine in the terminal abdominal ganglion of the female gypsy moth Lymantria dispar

2006 ◽  
Vol 1071 (1) ◽  
pp. 63-74 ◽  
Author(s):  
Maria C. Olianas ◽  
Paolo Solari ◽  
Luciana Garau ◽  
Anna Liscia ◽  
Roberto Crnjar ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Electrical Activity ◽  
Gypsy Moth ◽  
Lymantria Dispar ◽  
Abdominal Ganglion ◽  
Stimulation Of
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