Star-coupled Hindmarsh–Rose neural network with chemical synapses

2018 ◽  
Vol 29 (03) ◽  
pp. 1850023 ◽  
Author(s):  
K. Usha ◽  
P. A. Subha
Keyword(s):  
Communication Networks ◽  
Coupled System ◽  
Chemical Synapse ◽  
Bidirectional Coupling ◽  
Existence And Stability ◽  
Chemical Synapses ◽  
Fast Ion ◽  
Synchronized Region ◽  
Lyapunov Exponent Spectrum ◽  
Insight Into

We analyze the patterns like synchrony, desynchrony, and Drum head mode in a network of Hindmarsh–Rose (HR) neurons interacting via chemical synapse in unidirectional and bidirectional star topology. A two-coupled system has been studied for synchronization by varying the coupling strength and the parameter describing the activation and inactivation of the fast ion channel. The transverse Lyapunov exponent spectrum is plotted to observe the point of transition from desynchrony to synchrony. The synchronized, desynchronized, and drum head mode regions are observed when the neurons are connected in unidirectional and bidirectional coupling configurations. A detailed analysis about the time evolution of membrane potential corresponding to each region is presented. The annihilation of synchronized region and the expansion of drum head mode region in bidirectional coupling is discussed using parameter space. Our work provides finer insight into the existence and stability of Drum head mode and is useful for designing communication networks.

scholarly journals Synaptic polarity and sign-balance prediction using gene expression data in the Caenorhabditis elegans chemical synapse neuronal connectome network

2020 ◽  
Vol 16 (12) ◽  
pp. e1007974
Author(s):  
Bánk G. Fenyves ◽  
Gábor S. Szilágyi ◽  
Zsolt Vassy ◽  
Csaba Sőti ◽  
Peter Csermely
Keyword(s):  
Gene Expression ◽  
Caenorhabditis Elegans ◽  
Gene Expression Data ◽  
Receptor Gene ◽  
Directed Network ◽  
Chemical Synapse ◽  
Expression Data ◽  
Chemical Synapses ◽  
Theoretical Analyses ◽  
Receptor Gene Expression

Graph theoretical analyses of nervous systems usually omit the aspect of connection polarity, due to data insufficiency. The chemical synapse network of Caenorhabditis elegans is a well-reconstructed directed network, but the signs of its connections are yet to be elucidated. Here, we present the gene expression-based sign prediction of the ionotropic chemical synapse connectome of C. elegans (3,638 connections and 20,589 synapses total), incorporating available presynaptic neurotransmitter and postsynaptic receptor gene expression data for three major neurotransmitter systems. We made predictions for more than two-thirds of these chemical synapses and observed an excitatory-inhibitory (E:I) ratio close to 4:1 which was found similar to that observed in many real-world networks. Our open source tool (http://EleganSign.linkgroup.hu) is simple but efficient in predicting polarities by integrating neuronal connectome and gene expression data.

Unravelling the complex interactions between root development and soil moisture profiles in the soil-root-system

2020 ◽  
Author(s):  
Debora Cynthia Maan ◽  
Marie-claire ten Veldhuis ◽  
Bas van de Wiel
Keyword(s):  
Soil Moisture ◽  
Root System ◽  
Coupled System ◽  
Rooting Depth ◽  
Infiltration Capacity ◽  
Complex Interactions ◽  
Trade Offs ◽  
Typical Behaviour ◽  
Moisture Profiles ◽  
Insight Into

<p>We  study  the coupled  action of  water  uptake  and root  development  of  maize  in Rhizotrons under greenhouse conditions. Questions we aim to answer are: What is the effect of a vertical soil moisture gradient on the root growth? How does the root structure in turn influence soil moisture? Do constant  irrigation  quantities and depths eventually lead  to  constant  root  distributions and soil moisture profiles?</p><p>We apply highly controlled subsurface irrigation schemes in potting soil-sand mixtures and measure the real-time response of the interdepending soil moisture fields and root structures.</p><p>Following a top-down approach, in which the overall behaviour of the coupled system is carefully investigated and described, we aim to unravel the complex soil-root-interaction system. Looking at the occurrence of steady states and continuities sheds light on the type of the underlying feedback loops, which in turn provides insight into the fundamental processes that underlie the typical behaviour. We are particularly interested in trade-offs between the development of rooting depth and rooting density (including its dependency on soil moisture profiles) and the coupled effect of roots and root structures on the infiltration capacity of the soil-root-system. Preliminary results suggest the possibility of an enhancing feedback loop between these processes. </p><p>The next step will be to develop a numerical model that incorporates the interactions that were identified experimentally. The model will allow us to study the behavior and sensitivities of the system in more detail.</p><p> </p>

Transfer operators for coupled map lattices

1992 ◽  
Vol 12 (2) ◽  
pp. 297-318 ◽  
Author(s):  
Gerhard Keller ◽  
Martin Künzle
Keyword(s):  
Lattice Site ◽  
Broad Class ◽  
Coupled System ◽  
Coupled Map Lattices ◽  
Absolutely Continuous ◽  
Transfer Operators ◽  
Finite Dimensional ◽  
Nearest Neighbours ◽  
Existence And Stability ◽  
Stability Results

AbstractLet L denote a finite or infinite one-dimensional lattice. To each lattice site is attached a copy of a dynamical system with phase space [0, 1] and dynamics described by a transformation τ: [0, 1] → [0, 1], which is the same on each component. Denote the direct product of these identical systems by T: X → X where X = [0, 1]L. From this product system we obtain a coupled map lattice (CML) Sε: X → X, if we introduce some interaction between the components, e.g. by averaging between nearest neighbours. The strength of the coupling depends upon some parameter ε.For a broad class of piecewise expanding single-component-transformations τ we study such systems via their transfer operators and treat the coupled system as a perturbation of the uncoupled one. This yields existence and stability results for T-invariant measures with absolutely continuous finite-dimensional marginals.

scholarly journals Silicon Eye

2009 ◽  
Vol 3 (2) ◽  
Author(s):  
S. Thuvvakkadan ◽  
V. J. Nair
Keyword(s):  
Effective Interaction ◽  
Drainage System ◽  
Modern Medicine ◽  
Primary Circuit ◽  
Retinal Layer ◽  
Chemical Synapse ◽  
Secondary Circuit ◽  
Chemical Synapses ◽  
Effective Drainage ◽  
Electrical Impulses

Silicon eye can be otherwise called as a complete eye implant. The project overview is given in brief by the description of main components. Here in the silicon eye, a biconcave gel lens is used in connection with a micro controller. A porous silicon nano photodiode is placed before the gel lens. This specially designed transparent diode will help in identifying the intensity of light receiving in the beginning of the processing chain. An effective drainage system (with the help of two valves) will control the working of gel lens. All these components together form the primary circuit to enable the process of auto focusing. The micro controller is connected with all components of the system. The primary circuit is connected to a secondary circuit which consists of an artificial silicon retina and a chemical synapse. By the combined and co-ordinate working of both these will enable vision. The power supply, which all the electrical components here need is given by a series of nano paper batteries placed beneath the retinal layer (carbon nano tubes can also be implemented instead or along with it). The converted electrical impulses (from intensity of light received) will be carried to the visual area of brain through optic nerve by the effective interaction with a number of artificial chemical synapses. Finally this silicon eye will be an effective implant for the damaged eye. And we are sure that this will be a great breakthrough in the modern medicine.

scholarly journals Theoretical Analysis of Coupled Modified Hindmarsh-rose Model Under Transcranial Magnetic-acoustic Electrical Stimulation

2022 ◽  
Vol 16 ◽  
pp. 610-617
Author(s):  
Liang Guo ◽  
Shuai Zhang ◽  
Jiankang Wu ◽  
Xinyu Gao ◽  
Mingkang Zhao ◽  
...  
Keyword(s):  
Nervous System ◽  
Electrical Stimulation ◽  
Modulation Frequency ◽  
Ultrasonic Waves ◽  
Neuronal Firing ◽  
Electrical Synapse ◽  
Discharge Frequency ◽  
Neural Network Modeling ◽  
Chemical Synapse ◽  
Chemical Synapses

Transcranial magnetic-acoustic electrical stimulation (TMAES) is a new technology with ultrasonic waves and a static magnetic field to generate an electric current in nerve tissues to modulate neuronal firing activities. The existing neuron models only simulate a single neuron, and there are few studies on coupled neurons models about TMAES. Most of the neurons in the cerebral cortex are not isolated but are coupled to each other. It is necessary to study the information transmission of coupled neurons. The types of neuron coupled synapses include electrical synapse and chemical synapse. A neuron model without considering chemical synapses is not comprehensive. Here, we modified the Hindmarsh-Rose (HR) model to simulate the smallest nervous system—two neurons coupled electrical synapses and chemical synapses under TMAES. And the environmental variables describing the synaptic coupling between two neurons and the nonlinearity of the nervous system are also taken into account. The firing behavior of the nervous system can be modulated by changing the intensity or the modulation frequency. The results show that within a certain range of parameters, the discharge frequency of coupled neurons could be increased by altering the modulation frequency, and intensity of stimulation, modulating the excitability of neurons, reducing the response time of chemical postsynaptic neurons, and accelerating the information transferring. Moreover, the discharge frequency of neurons was selective to stimulus parameters. These results demonstrate the possible theoretical regulatory mechanism of the neurons' firing frequency characteristics by TMAES. The study establishes the foundation for large-scale neural network modeling and can be taken as the theoretical basis for TMAES experimental and clinical application.

scholarly journals Perceived Centrality in Social Networks Increases Women’s Expectations of Confronting Sexism

2020 ◽  
Vol 46 (12) ◽  
pp. 1682-1701
Author(s):  
Raina A. Brands ◽  
Aneeta Rattan
Keyword(s):  
Gender Bias ◽  
Communication Networks ◽  
Perceived Risk ◽  
Order Effects ◽  
Network Centrality ◽  
Additional Mechanism ◽  
Employed Women ◽  
Occupy Central ◽  
Equal Power ◽  
Insight Into

This article integrates the study of intergroup relations and social network cognition, predicting that women who occupy central (vs. peripheral) advice network positions are more likely to confront a coworker’s gender-biased comment. Study 1 offers correlational evidence of the predicted link between perceived advice network centrality and confronting among employed women, uniquely in advice (but not communication) networks. Study 2 replicates and investigates two possible mechanisms—perceptions of the situation as public and perceived risk of confronting. Study 3 rules out order effects and tests an additional mechanism (expectations of the network members). Study 4 is an experiment that shows people expect central (vs. peripheral) women to confront more, even when she is lower (vs. equal) power. Study 5 replicates the core hypothesis in retrospective accounts of women’s responses to real workplace gender bias. Study 6 compares multiple potential mechanisms to provide greater insight into why centrality reliably predicts confrontation.

Human Mobility Patterns

2014 ◽  
pp. 245-273
Author(s):  
Ali Diab ◽  
Andreas Mitschele-Thiel
Keyword(s):  
Information System ◽  
Communication Networks ◽  
Mobile Communication ◽  
Collective Intelligence ◽  
Human Mobility ◽  
Physical World ◽  
Mobility Models ◽  
Mobility Patterns ◽  
Community Based ◽  
Insight Into

It is well accepted that the physical world itself, including communication networks, humans, and objects, is becoming a type of information system. Thus, to improve the experience of individuals, communities, organizations, and societies within such systems, a thorough comprehension of collective intelligence processes responsible for generating, handling, and controlling data is fundamental. One of the major aspects in this context and also the focus of this chapter is the development of novel methods to model human mobility patterns, which have myriad uses in crucial fields (e.g. mobile communication, urban planning, etc.). The chapter highlights the state of the art and provides a comprehensive investigation of current research efforts in this field. It classifies mobility models into synthetic, trace-based, and community-based models, and also provides insight into each category. That is, well-known approaches are presented, discussed, and qualitatively compared with each other.

An Inventory of Publications on Electronic Patient Records

1999 ◽  
Vol 38 (04/05) ◽  
pp. 294-297 ◽  
Author(s):  
J. van der Lei ◽  
P. W. Moorman
Keyword(s):  
Computer Security ◽  
Communication Networks ◽  
Hospital Information Systems ◽  
Computer Interface ◽  
Patient Records ◽  
Electronic Patient Records ◽  
Computer Communication ◽  
Mesh Terms ◽  
Number Of Publications ◽  
Insight Into

AbstractThis study describes an analysis of 1832 papers dealing with electronic patient records, and indexed in NLM’s MEDLINE. Of each retrieved publication the country of origin and the journal in which it was published was determined. Furthermore, insight into the subjects of the publication was obtained by analysing the MeSH terms by which it was indexed. Since 1990 the number of publications on electronic patient records has increased. Publications originated from 43 different countries representing all continents. However, 75% stemmed from only 4 countries. The publications appeared in 379 different journals, of which 26 journals had 10 or more publications. Of all publications, 5.3% had appeared in journals with an impact factor of at least 4.5. The topics most often dealt with were: Hospital Information Systems, Computer Communication Networks, User-Computer Interface, Confidentiality and Computer Security. No obvious trends, other than an increased interest in confidentiality and computer security, were observed.

Insight into fast ion migration kinetics of a new hybrid single Li-ion conductor based on aluminate complexes for solid-state Li-ion batteries

Nanoscale ◽  
2018 ◽  
Vol 10 (13) ◽  
pp. 5975-5984 ◽  
Author(s):  
Yancong Feng ◽  
Rui Tan ◽  
Yan Zhao ◽  
Rongtan Gao ◽  
Luyi Yang ◽  
...  
Keyword(s):  
Polyethylene Oxide ◽  
Transport Mechanism ◽  
Li Ion Batteries ◽  
Ion Migration ◽  
Ion Conductor ◽  
Hopping Transport ◽  
Li Ion ◽  
Fast Ion ◽  
Kinetics Of ◽  
Insight Into

A novel hybrid single Li-ion conductor with high ion migration kinetics was prepared by mixing aluminate complexes–polyethylene glycol and polyethylene oxide. The new hopping transport mechanism was proposed.

scholarly journals Neuromodulator-evoked synaptic metaplasticity within a central pattern generator network

2012 ◽  
Vol 108 (10) ◽  
pp. 2846-2856 ◽  
Author(s):  
Mark D. Kvarta ◽  
Ronald M. Harris-Warrick ◽  
Bruce R. Johnson
Keyword(s):  
Central Pattern Generator ◽  
Spiny Lobster ◽  
Motor Pattern ◽  
Synaptic Depression ◽  
Pattern Generator ◽  
Chemical Synapse ◽  
Pyloric Network ◽  
Pyloric Dilator ◽  
Synaptic Dynamics ◽  
Chemical Synapses

Synapses show short-term activity-dependent dynamics that alter the strength of neuronal interactions. This synaptic plasticity can be tuned by neuromodulation as a form of metaplasticity. We examined neuromodulator-induced metaplasticity at a graded chemical synapse in a model central pattern generator (CPG), the pyloric network of the spiny lobster stomatogastric ganglion. Dopamine, serotonin, and octopamine each produce a unique motor pattern from the pyloric network, partially through their modulation of synaptic strength in the network. We characterized synaptic depression and its amine modulation at the graded synapse from the pyloric dilator neuron to the lateral pyloric neuron (PD→LP synapse), driving the PD neuron with both long square pulses and trains of realistic waveforms over a range of presynaptic voltages. We found that the three amines can differentially affect the amplitude of graded synaptic transmission independently of the synaptic dynamics. Low concentrations of dopamine had weak and variable effects on the strength of the graded inhibitory postsynaptic potentials (gIPSPs) but reliably accelerated the onset of synaptic depression and recovery from depression independently of gIPSP amplitude. Octopamine enhanced gIPSP amplitude but decreased the amount of synaptic depression; it slowed the onset of depression and accelerated its recovery during square pulse stimulation. Serotonin reduced gIPSP amplitude but increased the amount of synaptic depression and accelerated the onset of depression. These results suggest that amine-induced metaplasticity at graded chemical synapses can alter the parameters of synaptic dynamics in multiple and independent ways.

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