scholarly journals Episodic Bouts of Activity Accompany Recovery of Rhythmic Output By a Neuromodulator- and Activity-Deprived Adult Neural Network

2003 ◽  
Vol 90 (4) ◽  
pp. 2720-2730 ◽  
Author(s):  
Jason A. Luther ◽  
Alice A. Robie ◽  
John Yarotsky ◽  
Christopher Reina ◽  
Eve Marder ◽  
...  
Keyword(s):  
Neural Network ◽  
Neuronal Network ◽  
Recovery Process ◽  
Stomatogastric Ganglion ◽  
Cancer Borealis ◽  
Pyloric Network ◽  
Underlying Mechanisms ◽  
Over Time ◽  
Phase Relationships ◽  
Pyloric Rhythm

The pyloric rhythm of the stomatogastric ganglion of the crab, Cancer borealis, slows or stops when descending modulatory inputs are acutely removed. However, the rhythm spontaneously resumes after one or more days in the absence of neuromodulatory input. We recorded continuously for days to characterize quantitatively this recovery process. Activity bouts lasting 40–900 s began several hours after removal of neuromodulatory input and were followed by stable rhythm recovery after 1–4 days. Bout duration was not related to the intervals (0.3–800 min) between bouts. During an individual bout, the frequency rapidly increased and then decreased more slowly. Photoablation of back-filled neuromodulatory terminals in the stomatogastric ganglion (STG) neuropil had no effect on activity bouts or recovery, suggesting that these processes are intrinsic to the STG neuronal network. After removal of neuromodulatory input, the phase relationships of the components of the triphasic pyloric rhythm were altered, and then over time the phase relationships moved toward their control values. Although at low pyloric rhythm frequency the phase relationships among pyloric network neurons depended on frequency, the changes in frequency during recovery did not completely account for the change in phase seen after rhythm recovery. We suggest that activity bouts represent underlying mechanisms controlling the restructuring of the pyloric network to allow resumption of an appropriate output after removal of neuromodulatory input.

scholarly journals Circuit robustness to temperature perturbation is altered by neuromodulators

2017 ◽  
Author(s):  
Sara A. Haddad ◽  
Eve Marder
Keyword(s):  
High Temperatures ◽  
Temperature Perturbation ◽  
Seasonal Temperature ◽  
Cancer Borealis ◽  
Temperature Changes ◽  
Animal Diversity ◽  
Effects Of Temperature ◽  
Work Done ◽  
Phase Relationships ◽  
Pyloric Rhythm

SUMMARYIn the ocean, the crab, Cancer borealis, is subject to daily and seasonal temperature changes. Previous work, done in the presence of descending modulatory inputs, had shown that the pyloric rhythm of the crab increases in frequency as temperature increases, but maintains its characteristic phase relationships until it “crashes” at extreme high temperatures. To study the interaction between neuromodulators and temperature perturbations, we studied the effects of temperature on preparations from which the descending modulatory inputs were removed. Under these conditions the pyloric rhythm was destabilized. We then studied the effects of temperature on preparations in the presence of oxotremorine, proctolin, and serotonin. Oxotremorine and proctolin enhanced the robustness of the pyloric rhythm, while serotonin made the rhythm less robust. These experiments reveal considerable animal-to-animal diversity in their crash stability, consistent with the interpretation that cryptic differences in many cell and network parameters are revealed by extreme perturbations.

Restoration of descending inputs fails to rescue activity following deafferentation of a motor network

2012 ◽  
Vol 108 (3) ◽  
pp. 871-881 ◽  
Author(s):  
Jebun Nahar ◽  
Kawasi M. Lett ◽  
David J. Schulz
Keyword(s):  
Time Course ◽  
Critical Role ◽  
Stomatogastric Ganglion ◽  
Homeostatic Plasticity ◽  
Projection Neurons ◽  
Cancer Borealis ◽  
Compensatory Response ◽  
Pyloric Network ◽  
Motor Network ◽  
Network Output

Motor networks such as the pyloric network of the stomatogastric ganglion often require descending neuromodulatory inputs to initiate, regulate, and modulate their activity and their synaptic connectivity to manifest physiologically appropriate output. Prolonged removal of these descending inputs often results in a compensatory response that alters the inputs themselves, their targets, or both. Using the pyloric network of the crab, Cancer borealis, we investigated whether isolation of motor networks would result in alterations that change the responses of these networks to restored modulatory input. We used a reversible block with isotonic sucrose to transiently alter descending inputs into the pyloric network of the crab stomatogastric ganglion. Using this method, we found that blocking neuromodulatory inputs caused a reduced ability for subsequently restored modulatory projections to appropriately generate network output. Our results suggest that this could be due to changes in activity of descending projection neurons as well as changes in sensitivity to neuromodulators of the target neurons that develop over the time course of the blockade. These findings suggest that although homeostatic plasticity may play a critical role in recovery of functional output in a deafferented motor network, the results of these compensatory changes may alter the network such that restored inputs no longer function appropriately.

Neurons that form multiple pattern generators: identification and multiple activity patterns of gastric/pyloric neurons in the crab stomatogastric system

1991 ◽  
Vol 65 (1) ◽  
pp. 111-122 ◽  
Author(s):  
J. M. Weimann ◽  
P. Meyrand ◽  
E. Marder
Keyword(s):  
Motor Neurons ◽  
Activity Patterns ◽  
Gastric Mill ◽  
Cancer Borealis ◽  
Motor Patterns ◽  
Pyloric Network ◽  
Lateral Posterior ◽  
Pattern Generators ◽  
Rhythmic Behaviors ◽  
Pyloric Rhythm

1. The stomatogastric ganglion (STG) of decapod crustaceans has been characterized by its production of two motor patterns, the gastric mill rhythm and the pyloric rhythm. The period of the gastric rhythm is typically 5-10 s, whereas the period of the pyloric rhythm is approximately 1 s. 2. In the STG of the crab, Cancer borealis, we find routinely that many motor neurons are active in time with both the pyloric and gastric rhythms. We rigorously identified the motor neurons according to the muscles they innervate. Some neurons usually classified as members of the pyloric network can be active in time with the gastric rhythm. All of the gastric motor neurons except the dorsal gastric (DG) neuron can generate pyloric-timed firing patterns. 3. Two motor neurons innervate muscles found in several different regions of the stomach. The inferior cardiac (IC) neuron, usually considered part of the pyloric network, innervates cardiac sac, gastric mill, and pyloric muscles. The lateral posterior gastric (LPG) neurons innervate muscles of both the gastric mill and the pyloric chamber. 4. These data show that the gastric and pyloric networks in the crab are not separate groups of neurons that independently generate two different rhythmic behaviors. Rather, these neurons together provide a synaptically connected pool of neurons from which many different pattern-generating circuits can be assembled, under different physiological conditions.

Pharmacological dissection of pyloric network of the lobster stomatogastric ganglion using picrotoxin

1980 ◽  
Vol 44 (6) ◽  
pp. 1089-1101 ◽  
Author(s):  
M. Bidaut
Keyword(s):  
Stomatogastric Ganglion ◽  
Inhibitory Synapses ◽  
Primary Role ◽  
Panulirus Interruptus ◽  
Pyloric Network ◽  
Pyloric Dilator ◽  
Fast Rise ◽  
Later Phase ◽  
Pyloric Rhythm

1. Picrotoxin (PTX) (10(-7)-10(-6) M) completely blocked most inhibitory synapses in the pyloric pattern generator of the lobster (Panulirus interruptus) stomatogastric ganglion. The sensitivity of synapses from most classes of identified neurons was examined. Blockade was at least partly reversible with prolonged washing. 2. The synapses from pyloric dilator (PD) neurons were the only inhibitory synapses that picrotoxin failed to block completely. 3. A correlation is derived that brief, fast-rise inhibitory postsynaptic potentials (IPSPs) are picrotoxin sensitive, whereas a slow rounded component of IPSPs from PD neurons is not picrotoxin sensitive. 4. Picrotoxin caused specific changes in the pattern of the motor rhythm produced by the 16-cell pyloric network. This sheds some light on the functional role of particular synapses in the pyloric generator. 5. The endogenously bursting neurons (PD and anterior burster (AB)), which drive the pyloric rhythm, kept a similar burst rate. 6. Under picrotoxin, the pyloric "follower" neurons all moved to later phase relative to the "driver" group. Some normally antagonistic cells, related by reciprocal inhibitor connections, became in-phase. These and other pattern changes could be related to blockade of particular synapses. 7. The pyloric rhythm was still quite recognizable under picrotoxin despite the drastically altered circuitry of the synaptic network. This supports the idea that periodic inhibition from the PD driver neurons plays a primary role in creating the pyloric pattern.

Humoral induction of pyloric rhythmic output in lobster stomatogastric ganglion: in vivo and in vitro studies

1992 ◽  
Vol 163 (1) ◽  
pp. 209-230
Author(s):  
E. Rezer ◽  
M. Moulins
Keyword(s):  
Blood Serum ◽  
Stomatogastric Ganglion ◽  
In Vitro Studies ◽  
In Vitro Experiments ◽  
Experimental Conditions ◽  
Pyloric Network ◽  
Pyloric Rhythm

In the lobster Jasus lalandii, 14 neurones of the stomatogastric ganglion (STG) are organized in a network that produces rhythmic pyloric outputs. In vitro experiments have shown that the STG neurones receive, via the stomatogastric nerve (stn), neuromodulatory inputs that influence the expression of the bursting properties of the neurones and the ability of the network to produce its rhythmic output. In contrast to these in vitro observations, in vivo transection of the stn does not abolish the pyloric rhythm. Rhythmic output can be recorded by electromyography immediately after stn transection and for up to 2 years afterwards. We have shown that, under these experimental conditions, the STG appears to be isolated from any neuronal input that might account for the maintenance of the rhythmic output. Experiments carried out in the 2 days after stn transection showed that an in vitro preparation of the isolated STG was unable to produce any rhythmic output, but blood serum added to the system could restore the pyloric output. These results suggest strongly that the pyloric network receives neural and humoral modulatory influences in parallel and that each type of influence alone is able to maintain the bursting capability of the pyloric neurones.

scholarly journals Allatostatin peptides in the crab stomatogastric nervous system: inhibition of the pyloric motor pattern and distribution of allatostatin-like immunoreactivity.

1994 ◽  
Vol 194 (1) ◽  
pp. 195-208 ◽  
Author(s):  
P Skiebe ◽  
H Schneider
Keyword(s):  
Nervous System ◽  
Physiological State ◽  
Motor Pattern ◽  
Stomatogastric Ganglion ◽  
Dependent Manner ◽  
Rhythmic Movements ◽  
Stomatogastric Nervous System ◽  
Cancer Borealis ◽  
Motor Nerves ◽  
Pyloric Rhythm

The effects of four Diploptera punctata allatostatin peptides on the stomatogastric nervous system of the crab Cancer borealis were studied. All of the peptides had similar actions on the activity of neurons involved in rhythmic movements of the pyloric region of the stomach, decreasing the frequency of the pyloric rhythm in a dose-dependent manner. Diploptera allatostatin 3 (D-AST-3) was slightly more effective than the others. The absolute change in the frequency of the pyloric rhythm depended on the starting frequency, demonstrating that the effect of D-AST-3 depends on the preceding physiological state of the preparation. The largest decreases were observed when the starting frequency was slower than 0.8 Hz. Whole-mount immunocytochemistry with anti-Diploptera allatostatin 1 antibodies demonstrated the presence of allatostatin-like peptides in the paired commissural ganglia, the unpaired oesophageal ganglion and the stomatogastric ganglion, and in their connecting and motor nerves. Dense processes were labeled in the stomatogastric ganglion, 12-19 cell bodies and neuropil staining were found in each commissural ganglion, two cell bodies were stained in the oesophageal ganglion and two pairs of cell bodies, the gastropyloric receptor neurons, were stained in peripheral nerves.

scholarly journals Overexpression of neuregulin 1 in GABAergic interneurons results in reversible cortical disinhibition

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yao-Yi Wang ◽  
Bing Zhao ◽  
Meng-Meng Wu ◽  
Xiao-Li Zheng ◽  
Longnian Lin ◽  
...  
Keyword(s):  
Neural Network ◽  
Intellectual Disabilities ◽  
Sodium Channel ◽  
Susceptibility Gene ◽  
Gabaergic Interneurons ◽  
Neuregulin 1 ◽  
Neuropsychiatric Diseases ◽  
Underlying Mechanisms ◽  
Gabaergic Function ◽  
Schizophrenia Susceptibility

AbstractCortical disinhibition is a common feature of several neuropsychiatric diseases such as schizophrenia, autism and intellectual disabilities. However, the underlying mechanisms are not fully understood. To mimic increased expression of Nrg1, a schizophrenia susceptibility gene in GABAergic interneurons from patients with schizophrenia, we generated gtoNrg1 mice with overexpression of Nrg1 in GABAergic interneurons. gtoNrg1 mice showed cortical disinhibition at the cellular, synaptic, neural network and behavioral levels. We revealed that the intracellular domain of NRG1 interacts with the cytoplasmic loop 1 of Nav1.1, a sodium channel critical for the excitability of GABAergic interneurons, and inhibits Nav currents. Intriguingly, activation of GABAergic interneurons or restoring NRG1 expression in adulthood could rescue the hyperactivity and impaired social novelty in gtoNrg1 mice. These results identify mechanisms underlying cortical disinhibition related to schizophrenia and raise the possibility that restoration of NRG1 signaling and GABAergic function is beneficial in certain neuropsychiatric disorders.

Dopamine Modulation of Calcium Currents in Pyloric Neurons of the Lobster Stomatogastric Ganglion

2003 ◽  
Vol 90 (2) ◽  
pp. 631-643 ◽  
Author(s):  
Bruce R. Johnson ◽  
Peter Kloppenburg ◽  
Ronald M. Harris-Warrick
Keyword(s):  
Calcium Channel ◽  
Transmitter Release ◽  
Stomatogastric Ganglion ◽  
Calcium Currents ◽  
Voltage Gated ◽  
Pyloric Network ◽  
Pyloric Dilator ◽  
Voltage Dependent ◽  
Inward Currents ◽  
Dopamine Modulation

We examined the dopamine (DA) modulation of calcium currents (ICa) that could contribute to the plasticity of the pyloric network in the lobster stomatogastric ganglion. Pyloric somata were voltage-clamped under conditions designed to block voltage-gated Na+, K+, and H currents. Depolarizing steps from –60 mV generated voltage-dependent, inward currents that appeared to originate in electrotonically distal, imperfectly clamped regions of the cell. These currents were blocked by Cd2+ and enhanced by Ba2+ but unaffected by Ni2+. Dopamine enhanced the peak ICa in the pyloric constrictor (PY), lateral pyloric (LP), and inferior cardiac (IC) neurons and reduced peak ICa in the ventricular dilator (VD), pyloric dilator (PD), and anterior burster (AB) neurons. All of these effects, except for the AB, are consistent with DA's excitation or inhibition of firing in the pyloric neurons. Enhancement of ICa in PY and LP neurons and reduction of ICa in VD and PD neurons are also consistent with DA-induced synaptic strength changes via modulation of presynaptic ICa. However, the reduction of ICa in AB suggests that DA's enhancement of AB transmitter release is not directly mediated through presynaptic ICa. ICa in PY and PD neurons was more sensitive to nifedipine block than in AB neurons. In addition, nifedipine blocked DA's effects on ICa in the PY and PD neurons but not in the AB neuron. Thus the contribution of specific calcium channel subtypes carrying the total ICa may vary between pyloric neuron classes, and DA may act on different calcium channel subtypes in the different pyloric neurons.

scholarly journals Web Application for Statistical Tracking and Predicting the Evolution of Active Cases with the Novel Coronavirus (SARS-CoV-2)

2021 ◽  
pp. 70-74
Author(s):  
Iulia Clitan ◽  
◽  
Adela Puscasiu ◽  
Vlad Muresan ◽  
Mihaela Ligia Unguresan ◽  
...  
Keyword(s):  
Neural Network ◽  
Mathematical Model ◽  
Web Application ◽  
Point Of View ◽  
The Novel ◽  
End User ◽  
First Case ◽  
Novel Coronavirus ◽  
Second Wave ◽  
Over Time

Since February 2020, when the first case of infection with SARS COV-2 virus appeared in Romania, the evolution of COVID-19 pandemic continues to have an ascending allure, reaching in September 2020 a second wave of infections as expected. In order to understand the evolution and spread of this disease over time and space, more and more research is focused on obtaining mathematical models that are able to predict the evolution of active cases based on different scenarios and taking into account the numerous inputs that influence the spread of this infection. This paper presents a web responsive application that allows the end user to analyze the evolution of the pandemic in Romania, graphically, and that incorporates, unlike other COVID-19 statistical applications, a prediction of active cases evolution. The prediction is based on a neural network mathematical model, described from the architectural point of view.

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