1,720,971 research outputs found
To spike or not to spike: from a change of the excitability type in single neurons to exploring coding properties in network models
No full textFrom single neurons to large neural networks, the brain is constantly carrying and transforming
information. Neural coding is a core aspect of information representation, which relies on the stimulusresponse
relationship. However, the neural coding properties at a single neuron and network level are
still not fully understood.
At a single neuron level, the distinction between type 1 (integrator) and type 2 (resonator) neuron
excitability is well known and relates to what causes a neuron to spike. However, it is unclear whether
the excitability type of a single neuron can shift from type 1 to type 2 due to Acetylcholine (ACh)
neuromodulatory effects.
Pushing this further, understanding how such single neuron coding properties could arise and
interact at a network level is a great challenge considering the available network recording techniques.
Here, network modeling is crucial for understanding network behaviour in the brain. With such
models, one can study larger populations of neurons and still not lose information about single neuron
properties. For instance, with the Poisson Balanced Spiking network (Poisson BSN) model, one can
reproduce bio-like network spiking behaviour and still be able to observe single neuron properties. Yet,
how the coding properties of neurons from network models arise and are affected by network properties
is still unknown.
To study the coding properties in single neurons, we used the spike-triggered average (STA) analysis.
With this, we investigated the stimulus-response relationship from single neuron in vitro recordings
and neurons from network model simulations. From the experimental data analysis, we found that
ACh did not cause a shift from type 1 to type 2 excitability. And regarding the network modelling
we found that in the Poisson BSN model, network size, spiking cost, and time delays had an effect on
changing the neurons’ stimulus-response relationship given by the STA analysis.
Our results will allow for future research to model networks with neurons with different coding
properties (such as type 1 and type 2) and account for how the interactions between neurons might
affect these coding properties. Thus, this is one more step to developing and understanding network
models to make them more biologically plausible and more insightful for studying and reproducing
how the brain represents information
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
The Influence of Different Excitatory-Inhibitory Cell-Type Configurations on Network Dynamics of Locally Connected Balanced Networks
No full textThe principal function of neurons in the cortex is to communicate and process information. A characteristic of this communication is the high trial-to-trial spike variability. To explain this variability, balanced network models have been introduced. The interaction between excitatory and inhibitory neurons in those models, can perform active decorrelation of spike trains, resulting in uncorrelated asynchronous inputs. This asynchronous regime is important, because it can realistically mimic different types of cortical activity. Inside the asynchronous regime, classical and heterogeneous asynchrony, supporting respectively small or large fluctuations in instantaneous rate, can be distinguished. The latter is proposed to enable better separation of stimuli. Because classical balanced network models neglect the differences in network configuration between layers, this study aims to investigate the effect of different network configurations on the expressed regime of dynamics in a locally connected balanced network. The locally connected network model consisted of layer 2/3, layer 4 and a thalamus. Results showed a heterogeneous asynchronous regime of dynamics in layer 2/3, suggesting highly variable single-neuron firing rates. These findings are in line with the expectation that single-neurons in layer 2/3 would exhibit highly variable single-neuron firing rates to improve separation between stimuli. The classical asynchronous regime identified in layer 4, enables this layer to accurately transfer information to layer 2/3. Slight differences between the different network configurations in layer 2/3 were found, showing that compositions that contain fewer inhibitory neurons favor heterogeneous asynchrony. Future research should further extend the research to different network configurations, as this might provide more realistic network dynamics.Biomedical Engineering | BioMechatronic
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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