A Simulation Study Investigating the Impact of Dendritic Morphology and Synaptic Topology on Neuronal Firing Patterns

2010 ◽  
Vol 22 (4) ◽  
pp. 1086-1111 ◽  
Author(s):  
Jen-Yung Chen
Keyword(s):  
Information Processing ◽  
Computational Models ◽  
Dendritic Morphology ◽  
Neuronal Firing ◽  
Membrane Properties ◽  
Neuron Models ◽  
Spatial And Temporal Scales ◽  
Brain Functions ◽  
Scaling Analyses ◽  
The Impact

In the brain, complex information interactions among neurons span several spatial and temporal scales, making it extremely difficult to identify the principles governing neural information processing. In this study, we used computational models to investigate the impact of dendritic morphology and synaptic topology on patterns of neuronal firing. We first constructed Hodgkin-Huxley-type neuron models that possessed dendrites with different morphological features. We then simulated the responses of these neurons to a number of spatiotemporal input patterns. The similarity between neuronal responses to different patterned inputs was effectively evaluated by a novel combination of metric space analysis and multidimensional scaling analyses. The results showed that neurons with different morphological or anatomical features exhibit differences in stimulus-specific temporal encoding and firing reliability. These findings support the idea that in addition to biophysical membrane properties, the dendritic morphology and the synaptic topology of a neuron can play a significant role in neuronal information processing and may directly contribute to various brain functions.

scholarly journals The Impact of Digital Text

2020 ◽  
pp. 209-217
Author(s):  
Hye K. Pae
Keyword(s):  
Social Media ◽  
Information Processing ◽  
Digital Media ◽  
Significant Influence ◽  
Low Cost ◽  
Visual Aids ◽  
Digital Text ◽  
Advantages And Disadvantages ◽  
Brain Functions ◽  
The Impact

Abstract This chapter discusses reading on screen and in print, as the emergence of digital age has transformed our reading and attention. Digital reading reshapes the concept of reading with the use of various forms of social media that are full of acronyms and emoticons or emoji. Advantages and disadvantages of reading on screen and in print are reviewed. The effects of digitally-mediated text on information processing and reading comprehension are also discussed. Although reading online has merits, such as convenience, low cost, and easy accessibility, readers are likely to scan through an F-shaped gaze pattern. The use of digital media may have a significant influence on brain networks due to the brain’s adaptability and accommodating abilities. Digital text that includes more images and visual aids than hardcopy text may lead to more balanced brain functions. This may have implications for reduced script relativity in the future.

Altered dendritic complexity affects firing properties of cortical layer 2/3 pyramidal neurons in mice lacking the 5-HT3A receptor

2012 ◽  
Vol 108 (5) ◽  
pp. 1521-1528 ◽  
Author(s):  
Luuk van der Velden ◽  
Johannes A. van Hooft ◽  
Pascal Chameau
Keyword(s):  
Firing Pattern ◽  
Neuronal Excitability ◽  
Pyramidal Neurons ◽  
Dendritic Morphology ◽  
Neuronal Firing ◽  
Specific Class ◽  
Postnatal Maturation ◽  
Layer 2 ◽  
The Impact ◽  
Dendritic Complexity

We have previously shown that the serotonergic input on Cajal-Retzius cells, mediated by 5-HT3 receptors, plays an important role in the early postnatal maturation of the apical dendritic trees of layer 2/3 pyramidal neurons. We reported that knockout mice lacking the 5-HT3A receptor showed exuberant apical dendrites of these cortical pyramidal neurons. Because model studies have shown the role of dendritic morphology on neuronal firing pattern, we used the 5-HT3A knockout mouse to explore the impact of dendritic hypercomplexity on the electrophysiological properties of this specific class of neurons. Our experimental results show that hypercomplexity of the apical dendritic tuft of layer 2/3 pyramidal neurons affects neuronal excitability by reducing the amount of spike frequency adaptation. This difference in firing pattern, related to a higher dendritic complexity, was accompanied by an altered development of the afterhyperpolarization slope with successive action potentials. Our abstract and realistic neuronal models, which allowed manipulation of the dendritic complexity, showed similar effects on neuronal excitability and confirmed the impact of apical dendritic complexity. Alterations of dendritic complexity, as observed in several pathological conditions such as neurodegenerative diseases or neurodevelopmental disorders, may thus not only affect the input to layer 2/3 pyramidal neurons but also shape their firing pattern and consequently alter the information processing in the cortex.

scholarly journals Modulation of voltage-dependent K+ conductances in photoreceptors trades off investment in contrast gain for bandwidth

2018 ◽  
Author(s):  
Francisco JH Heras ◽  
Mikko Vähäsöyrinki ◽  
Jeremy E Niven
Keyword(s):  
Information Processing ◽  
Energy Consumption ◽  
Computational Models ◽  
Membrane Resistance ◽  
Functional Requirements ◽  
Low Frequencies ◽  
Contrast Gain ◽  
Shift Performance ◽  
Voltage Dependent ◽  
The Impact

AbstractModulation is essential for adjusting neurons to prevailing conditions and differing demands. Yet understanding how modulators adjust neuronal properties to alter information processing remains unclear, as is the impact of neuromodulation on energy consumption. Here we combine two computational models, one Hodgkin-Huxley type and the other analytic, to investigate the effects of neuromodulation upon Drosophila melanogaster photoreceptors. Voltage-dependent K+ conductances: (i) activate upon depolarisation to reduce membrane resistance and adjust bandwidth to functional requirements; (ii) produce negative feedback to increase bandwidth in an energy efficient way; (iii) produce shunt-peaking thereby increasing the membrane gain bandwidth product; and (iv) inactivate to amplify low frequencies. Through their effects on the voltage-dependent K+ conductances, three modulators, serotonin, calmodulin and PIP2, trade-off contrast gain against membrane bandwidth. Serotonin shifts the photoreceptor performance towards higher contrast gains and lower membrane bandwidths, whereas PIP2 and calmodulin shift performance towards lower contrast gains and higher membrane bandwidths. These neuromodulators have little effect upon the overall energy consumed by photoreceptors, instead they redistribute the energy invested in gain versus bandwidth. This demonstrates how modulators can shift neuronal information processing within the limitations of biophysics and energy consumption.

scholarly journals A general principle of dendritic constancy – a neuron’s size and shape invariant excitability

2019 ◽  
Author(s):  
Hermann Cuntz ◽  
Alexander D Bird ◽  
Marcel Beining ◽  
Marius Schneider ◽  
Laura Mediavilla ◽  
...  
Keyword(s):  
Dendritic Morphology ◽  
Spike Timing ◽  
List Type ◽  
Input Output ◽  
Neuron Models ◽  
Dendrite Morphology ◽  
Synaptic Inputs ◽  
Size And Shape ◽  
Dendritic Length ◽  
The Impact

AbstractReducing neuronal size results in less cell membrane and therefore lower input conductance. Smaller neurons are thus more excitable as seen in their voltage responses to current injections in the soma. However, the impact of a neuron’s size and shape on its voltage responses to synaptic activation in dendrites is much less understood. Here we use analytical cable theory to predict voltage responses to distributed synaptic inputs and show that these are entirely independent of dendritic length. For a given synaptic density, a neuron’s response depends only on the average dendritic diameter and its intrinsic conductivity. These results remain true for the entire range of possible dendritic morphologies irrespective of any particular arborisation complexity. Also, spiking models result in morphology invariant numbers of action potentials that encode the percentage of active synapses. Interestingly, in contrast to spike rate, spike times do depend on dendrite morphology. In summary, a neuron’s excitability in response to synaptic inputs is not affected by total dendrite length. It rather provides a homeostatic input-output relation that specialised synapse distributions, local non-linearities in the dendrites and synaptic plasticity can modulate. Our work reveals a new fundamental principle of dendritic constancy that has consequences for the overall computation in neural circuits.In briefWe show that realistic neuron models essentially collapse to point neurons when stimulated by randomly distributed inputs instead of by single synapses or current injection in the soma.HighlightsA simple equation that predicts voltage in response to distributed synaptic inputs.Responses to distributed and clustered inputs are largely independent of dendritic length.Spike rates in various Hodgkin Huxley (HH) like or Leaky Integrate-and-Fire (LIF) models are largely independent of morphology.Precise spike timing (firing pattern) depends on dendritic morphology.NeuroMorpho.Org database-wide analysis of the relation between dendritic morphology and electrophysiology.Our equations set precise input-output relations in realistic dendrite models.

scholarly journals Reconstruction and Simulation of a Scaffold Model of the Cerebellar Network

2019 ◽  
Author(s):  
Stefano Casali ◽  
Elisa Marenzi ◽  
Chaitanya Medini ◽  
Claudia Casellato ◽  
Egidio D’Angelo
Keyword(s):  
Computational Models ◽  
Mossy Fiber ◽  
Molecular Layer ◽  
Cerebellar Nuclei ◽  
Neuronal Morphology ◽  
Inhibitory Synapses ◽  
Structural Constraints ◽  
Neuron Models ◽  
Cellular Mechanisms ◽  
The Impact

AbstractReconstructing neuronal microcircuits through computational models is fundamental to simulate local neuronal dynamics. Here a scaffold model of the cerebellum has been developed in order to flexibly place neurons in space, connect them synaptically and endow neurons and synapses with biologically-grounded mechanisms. The scaffold model can keep neuronal morphology separated from network connectivity, which can in turn be obtained from convergence/divergence ratios and axonal/dendritic field 3D geometries. We first tested the scaffold on the cerebellar microcircuit, which presents a challenging 3D organization, at the same time providing appropriate datasets to validate emerging network behaviors. The scaffold was designed to integrate the cerebellar cortex with deep cerebellar nuclei (DCN), including different neuronal types: Golgi cells, granule cells, Purkinje cells, stellate cells, basket cells and DCN principal cells. Mossy fiber (mf) inputs were conveyed through the glomeruli. An anisotropic volume (0.077 mm3) of mouse cerebellum was reconstructed, in which point-neuron models were tuned toward the specific discharge properties of neurons and were connected by exponentially decaying excitatory and inhibitory synapses. Simulations using pyNEST and pyNEURON showed the emergence of organized spatio-temporal patterns of neuronal activity similar to those revealed experimentally in response to background noise and burst stimulation of mossy fiber bundles. Different configurations of granular and molecular layer connectivity consistently modified neuronal activation patterns, revealing the importance of structural constraints for cerebellar network functioning. The scaffold provided thus an effective workflow accounting for the complex architecture of the cerebellar network. In principle, the scaffold can incorporate cellular mechanisms at multiple levels of detail and be tuned to test different structural and functional hypotheses. A future implementation using detailed 3D multi-compartment neuron models and dynamic synapses will be needed to investigate the impact of single neuron properties on network computation.

ON THE CLASSIFICATION OF DIGITAL TECHNOLOGIES IN CIVIL PROCESS

2019 ◽  
pp. 27-35
Author(s):  
Alexandr Neznamov
Keyword(s):  
Information Processing ◽  
Scientific Community ◽  
Digital Technologies ◽  
Significant Feature ◽  
Legal Proceedings ◽  
Civil Process ◽  
Civil Proceedings ◽  
Processing Information ◽  
The Impact

Digital technologies are no longer the future but are the present of civil proceedings. That is why any research in this direction seems to be relevant. At the same time, some of the fundamental problems remain unattended by the scientific community. One of these problems is the problem of classification of digital technologies in civil proceedings. On the basis of instrumental and genetic approaches to the understanding of digital technologies, it is concluded that their most significant feature is the ability to mediate the interaction of participants in legal proceedings with information; their differentiating feature is the function performed by a particular technology in the interaction with information. On this basis, it is proposed to distinguish the following groups of digital technologies in civil proceedings: a) technologies of recording, storing and displaying (reproducing) information, b) technologies of transferring information, c) technologies of processing information. A brief description is given to each of the groups. Presented classification could serve as a basis for a more systematic discussion of the impact of digital technologies on the essence of civil proceedings. Particularly, it is pointed out that issues of recording, storing, reproducing and transferring information are traditionally more «technological» for civil process, while issues of information processing are more conceptual.

scholarly journals Evaluation of the impact of compliance of precast discs of overlapping on the work of the frame of a multi-storey building

2019 ◽  
Vol 97 ◽  
pp. 04022
Author(s):  
Nikolay Trekin ◽  
Emil Kodysh ◽  
Alexander Bybka ◽  
Alexander Yamalov ◽  
Nikita Konkov
Keyword(s):  
Economic Performance ◽  
Computational Models ◽  
Precast Concrete ◽  
Building Frames ◽  
Frame Building ◽  
Numerical Studies ◽  
Frame Buildings ◽  
The Impact ◽  
Structural Solutions ◽  
Storey Building

The article provides an analysis and justification of the need to take into account the compliance of discs of overlapping and coatings when calculating frames from precast concrete structures. Previously conducted full-scale experiments showed that the rigidity of the precast overlapping with full filling of the seams, in comparison with the monolithic overlapping, decreases by 3-15 times due to the ductility of the joints. The use of refined computational models of structural solutions for frames, which take into account the compliance of the conjugations of elements, makes it possible to trace possible redistribution of efforts. Such an approach when reconstructing, it is possible to optimally select and calculate the enforcement of structure, and on new designing, to increase reliability and / or improve the economic performance of frame buildings. According to the results of analytical studies, formulas were adopted for the parameters that allow one to take into account the overall compliance of overlapping disks and coatings in computational models of building frames. Numerical studies on the computational model of a frame building made it possible to evaluate the effect of accounting for compliance on the stress-strain state of a multi-storey frame.

scholarly journals Moderators of the Liking Bias in Judgments of Moral Character

2021 ◽  
pp. 014616722110132
Author(s):  
Konrad Bocian ◽  
Wieslaw Baryla ◽  
Bogdan Wojciszke
Keyword(s):  
Information Processing ◽  
Moral Character ◽  
Moral Judgments ◽  
The Impact

Previous research found evidence for a liking bias in moral character judgments because judgments of liked people are higher than those of disliked or neutral ones. This article sought conditions moderating this effect. In Study 1 ( N = 792), the impact of the liking bias on moral character judgments was strongly attenuated when participants were educated that attitudes bias moral judgments. In Study 2 ( N = 376), the influence of liking on moral character attributions was eliminated when participants were accountable for the justification of their moral judgments. Overall, these results suggest that although liking biases moral character attributions, this bias might be reduced or eliminated when deeper information processing is required to generate judgments of others’ moral character.

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