scholarly journals Computation is concentrated in rich clubs of local cortical neurons

2018 ◽  
Author(s):  
Samantha P. Faber ◽  
Nicholas M. Timme ◽  
John M. Beggs ◽  
Ehren L. Newman
Keyword(s):  
Cortical Neurons ◽  
Effective Connectivity ◽  
Neural Computation ◽  
Information Propagation ◽  
Cortical Circuits ◽  
Amount Of Information ◽  
Rich Club ◽  
The Rich ◽  
Do So ◽  
Spiking Activity

ABSTRACTTo understand how neural circuits process information, it is essential to identify the relationship between computation and circuit topology. Rich-clubs, highly interconnected sets of neurons, are known to propagate a disproportionate amount of information within cortical circuits. Here, we test the hypothesis that rich-clubs also perform a disproportionate amount of computation. To do so, we recorded the spiking activity of on average ∼300 well-isolated individual neurons from organotypic cortical cultures. We then constructed weighted, directed networks reflecting the effective connectivity between the neurons. For each neuron, we quantified the amount of computation it performed based on its inputs. We found that rich-club neurons compute ∼200% more information than neurons outside of the rich club. Indeed, the amount of computation performed in the rich-club was proportional to the amount information propagation by the same neurons. This suggests that, in these circuits, information propagation drives computation. Comparing the computation-to-propagation ratio inside versus outside of the rich club showed that rich clubs compute at a slightly, though significantly, reduced level (∼4% lower). In total, our findings indicate that rich club topology in effective cortical circuits supports not only information propagation but also neural computation.AUTHOR SUMMARYHere we answer the question of whether rich club topology in functional cortical circuits supports neural computation as it has been previously shown to do for information propagation. To do so, we combined network analysis with information theoretic tools to analyze the spiking activity of hundreds of neurons recorded from organotypic cultures of mouse somatosensory cortex. We found that neurons in rich clubs computed significantly more than neurons outside of rich clubs, suggesting that rich-clubs do support computation in cortical circuits. Indeed, the amount of computation that we found in the rich club was proportional to the amount of information they propagate suggesting that, in these circuits, information propagation drives computation.

scholarly journals Computation is concentrated in rich clubs of local cortical networks

2019 ◽  
Vol 3 (2) ◽  
pp. 384-404 ◽  
Author(s):  
Samantha P. Faber ◽  
Nicholas M. Timme ◽  
John M. Beggs ◽  
Ehren L. Newman
Keyword(s):  
Neural Circuits ◽  
Effective Connectivity ◽  
Neural Computation ◽  
Information Propagation ◽  
Cortical Circuits ◽  
Amount Of Information ◽  
Rich Club ◽  
The Rich ◽  
The Relationship ◽  
Do So

To understand how neural circuits process information, it is essential to identify the relationship between computation and circuit organization. Rich clubs, highly interconnected sets of neurons, are known to propagate a disproportionate amount of information within cortical circuits. Here, we test the hypothesis that rich clubs also perform a disproportionate amount of computation. To do so, we recorded the spiking activity of on average ∼300 well-isolated individual neurons from organotypic cortical cultures. We then constructed weighted, directed networks reflecting the effective connectivity between the neurons. For each neuron, we quantified the amount of computation it performed based on its inputs. We found that rich-club neurons compute ∼160% more information than neurons outside of the rich club. The amount of computation performed in the rich club was proportional to the amount of information propagation by the same neurons. This suggests that in these circuits, information propagation drives computation. In total, our findings indicate that rich-club organization in effective cortical circuits supports not only information propagation but also neural computation.

scholarly journals Task-related effective connectivity reveals that the cortical rich club gates cortex-wide communication

2017 ◽  
Author(s):  
Mario Senden ◽  
Niels Reuter ◽  
Martijn P. van den Heuvel ◽  
Rainer Goebel ◽  
Gustavo Deco ◽  
...  
Keyword(s):  
Information Exchange ◽  
Effective Connectivity ◽  
Functional Integration ◽  
Brain Regions ◽  
Rich Club ◽  
State Dependent ◽  
Gating Mechanism ◽  
The Rich ◽  
Cortical Regions ◽  
Peripheral Regions

AbstractHigher cognition may require the globally coordinated integration of specialized brain regions into functional networks. A collection of structural cortical hubs - referred to as the rich club - has been hypothesized to support task-specific functional integration. In the present paper, we use a whole-cortex model to estimate directed interactions between 68 cortical regions from fMRI activity for four different tasks (reflecting different cognitive domains) and resting state. We analyze the state-dependent input and output effective connectivity of the structural rich club and relate these to whole-cortex dynamics and network reconfigurations. We find that the cortical rich club exhibits an increase in outgoing effective connectivity during task performance as compared to rest while incoming connectivity remains constant. Increased outgoing connectivity targets a sparse set of peripheral regions with specific regions strongly overlapping between tasks. At the same time, community detection analyses reveal massive reorganizations of interactions among peripheral regions, including those serving as target of increased rich club output. This suggests that while peripheral regions may play a role in several tasks, their concrete interplay might nonetheless be task-specific. Furthermore, we observe that whole-cortex dynamics are faster during task as compared to rest. The decoupling effects usually accompanying faster dynamics appear to be counteracted by the increased rich club outgoing effective connectivity. Together our findings speak to a gating mechanism of the rich club that supports fast-paced information exchange among relevant peripheral regions in a task-specific and goal-directed fashion, while constantly listening to the whole network.

scholarly journals Rich-Club Organization in Effective Connectivity among Cortical Neurons

2016 ◽  
Vol 36 (3) ◽  
pp. 670-684 ◽  
Author(s):  
Sunny Nigam ◽  
Masanori Shimono ◽  
Shinya Ito ◽  
Fang-Chin Yeh ◽  
Nicholas Timme ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Effective Connectivity ◽  
Rich Club

scholarly journals Inhibition-Dominated Rich-Club Shapes Dynamics in Cortical Microcircuits of Awake Behaving Mice

2021 ◽  
Author(s):  
Hadi Hafizi ◽  
Sunny Nigam ◽  
Josh Barnathan ◽  
Ian Stevenson ◽  
Sotiris C Masmanidis ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Large Scale ◽  
Population Level ◽  
Inhibitory Neurons ◽  
Population Activity ◽  
Rich Club ◽  
Large Scale Network ◽  
Type Composition ◽  
Scale Network ◽  
The Rich

Functional networks of cortical neurons contain highly interconnected hubs, forming a rich-club structure. However, the cell type composition within this distinct subnetwork and how it influences large-scale network dynamics is unclear. Using spontaneous activity recorded from hundreds of cortical neurons in orbitofrontal cortex of awake behaving mice we show that the rich-club is disproportionately composed of inhibitory neurons, and that inhibitory neurons within the rich-club are significantly more synchronous than other neurons. At the population level, Granger causality showed that neurons in the rich-club are the dominant drivers of overall population activity and do so in a frequency-specific manner. Moreover, early activity ofinhibitory neurons, along with excitatory neurons within the rich-club, synergistically predicts the duration of neuronal cascades. Together, these results reveal an unexpected role of a highly connected core of inhibitory neurons in driving and sustaining activity in local cortical networks.

scholarly journals Effect of Multishell Diffusion MRI Acquisition Strategy and Parcellation Scale on Rich-Club Organization of Human Brain Structural Networks

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 970
Author(s):  
Maedeh Khalilian ◽  
Kamran Kazemi ◽  
Mahshid Fouladivanda ◽  
Malek Makki ◽  
Mohammad Sadegh Helfroush ◽  
...  
Keyword(s):  
Human Brain ◽  
Clustering Coefficient ◽  
Quality Data ◽  
B Values ◽  
Rich Club ◽  
Global Efficiency ◽  
Acquisition Strategy ◽  
The Rich ◽  
Structural Networks ◽  
Single Shell

The majority of network studies of human brain structural connectivity are based on single-shell diffusion-weighted imaging (DWI) data. Recent advances in imaging hardware and software capabilities have made it possible to acquire multishell (b-values) high-quality data required for better characterization of white-matter crossing-fiber microstructures. The purpose of this study was to investigate the extent to which brain structural organization and network topology are affected by the choice of diffusion magnetic resonance imaging (MRI) acquisition strategy and parcellation scale. We performed graph-theoretical network analysis using DWI data from 35 Human Connectome Project subjects. Our study compared four single-shell (b = 1000, 3000, 5000, 10,000 s/mm2) and multishell sampling schemes and six parcellation scales (68, 200, 400, 600, 800, 1000 nodes) using five graph metrics, including small-worldness, clustering coefficient, characteristic path length, modularity and global efficiency. Rich-club analysis was also performed to explore the rich-club organization of brain structural networks. Our results showed that the parcellation scale and imaging protocol have significant effects on the network attributes, with the parcellation scale having a substantially larger effect. Regardless of the parcellation scale, the brain structural networks exhibited a rich-club organization with similar cortical distributions across the parcellation scales involving at least 400 nodes. Compared to single b-value diffusion acquisitions, the deterministic tractography using multishell diffusion imaging data consisting of shells with b-values higher than 5000 s/mm2 resulted in significantly improved fiber-tracking results at the locations where fiber bundles cross each other. Brain structural networks constructed using the multishell acquisition scheme including high b-values also exhibited significantly shorter characteristic path lengths, higher global efficiency and lower modularity. Our results showed that both parcellation scale and sampling protocol can significantly impact the rich-club organization of brain structural networks. Therefore, caution should be taken concerning the reproducibility of connectivity results with regard to the parcellation scale and sampling scheme.

Closed Trials and Secret Allegations

2016 ◽  
Vol 80 (4) ◽  
pp. 264-277 ◽  
Author(s):  
Daniel Kelman
Keyword(s):  
United Kingdom ◽  
National Interest ◽  
Fair Trial ◽  
Amount Of Information ◽  
House Of Lords ◽  
Lower Courts ◽  
Grand Chamber ◽  
Do So ◽  
Judicial Uncertainty

The tension between an individual’s right to a fair trial and a state’s prerogative to withhold information where it is in the national interest to do so is an issue which is especially relevant in preventative detention cases. In a string of cases since 2009, lower courts have interpreted the ‘gisting’ requirement imposed by the Grand Chamber in A v United Kingdom in response to this problem. This paper will consider the jurisprudence of the lower courts and will argue that the House of Lords’ judgment in AF No. 3 imposed requirements not only in relation to the amount of information that must be disclosed, but also in relation to what that information must consist of. It will note that two irreconcilable interpretations of A have developed, and argue that one of those approaches is incompatible with AF. Finally, it will discuss the interaction between these decisions and the statutory framework of the JSA, especially ss 6(5) and 7(2), and will consider the consequences of the judicial uncertainty in this area in relation to the return of TPIMs following the CTSA.

Opposing roles for neurotrophin-3 in targeting and collateral formation of distinct sets of developing cortical neurons

Development ◽  
1999 ◽  
Vol 126 (15) ◽  
pp. 3335-3345
Author(s):  
V. Castellani ◽  
J. Bolz
Keyword(s):  
Cortical Neurons ◽  
Developmental Stages ◽  
Axonal Guidance ◽  
Cortical Circuits ◽  
Axonal Branching ◽  
Guidance Cue ◽  
Neurotrophin 3 ◽  
Cortical Membranes ◽  
Opposing Effects

Neurotrophin-3 and its receptor TrkC are expressed during the development of the mammalian cerebral cortex. To examine whether neurotrophin-3 might play a role in the elaboration of layer-specific cortical circuits, slices of layer 6 and layers 2/3 neurons were cultured in the presence of exogenously applied neurotrophin-3. Results indicate that neurotrophin-3 promotes axonal branching of layer 6 axons, which target neurotrophin-3-expressing layers in vivo, and that it inhibits branching of layers 2/3 axons, which avoid neurotrophin-3-expressing layers. Such opposing effects of neurotrophin-3 on axonal branching were also observed with embryonic cortical neurons, indicating that the response to neurotrophin-3 is specified at early developmental stages, prior to cell migration. In addition to its effects on fiber branching, axonal guidance assays also indicate that neurotrophin-3 is an attractive signal for layer 6 axons and a repellent guidance cue for layers 2/3 axons. Experiments with specific antibodies to neutralize neurotrophin-3 in cortical membranes revealed that endogenous levels of neurotrophin-3 are sufficient to regulate branching and targeting of cortical axons. These opposing effects of neurotrophin-3 on specific populations of axons demonstrate that it could serve as one of the signals for the elaboration of local cortical circuits.

Making Class: Children's Perceptions of Social Class through Illustrations

2018 ◽  
Vol 120 (7) ◽  
pp. 1-44
Author(s):  
Adam Howard ◽  
Katy Swalwell ◽  
Karlyn Adler
Keyword(s):  
Social Class ◽  
Young People ◽  
Sixth Graders ◽  
Third Graders ◽  
Poor People ◽  
Class Differences ◽  
The Rich ◽  
And Gender ◽  
Background Context ◽  
Do So

Background/Context Though there has been attention to how class differences impact children's experiences in schools and how young people perceive racial and gender differences, very little research to date has examined how young people make sense of social class differences. Purpose In this article, the authors examine young children's conceptualizations of differences between the rich and the poor to better understand children's process of classmaking. Research Design To access young children's ideas about social class, the authors examined kindergartners’, third graders’, and sixth graders’ (N = 133) drawings depicting differences between rich and poor people and their corresponding explanations of their drawings. These children attended two schools, one public serving a majority working- class population, and one private serving a majority affluent population. Findings/Results Children understand social class to be inclusive emotions, social distinctions, and social status. Children's drawings and explanations show that perpetuated ideology-justifying status quo of poverty and economic inequality. Children have complex sociocultural insights into how social class operates that manifest themselves through four domains: material, intersectional, emotional, and spatial. Conclusions/Recommendations Educators should provide more opportunities for teaching about social class, and can do so in ways that engages students in processes of classmaking that do not reinforce stereotypes and that interrupts inequality.

scholarly journals Identification of key regulators in prostate cancer from gene expression datasets of patients

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Irengbam Rocky Mangangcha ◽  
Md. Zubbair Malik ◽  
Ömer Küçük ◽  
Shakir Ali ◽  
R. K. Brojen Singh
Keyword(s):  
Gene Expression ◽  
Prostate Cancer ◽  
Regulatory Pathways ◽  
Scale Free ◽  
Topological Parameters ◽  
Rich Club ◽  
Self Organized ◽  
Mutational Status ◽  
Interactome Network ◽  
The Rich

Abstract Identification of key regulators and regulatory pathways is an important step in the discovery of genes involved in cancer. Here, we propose a method to identify key regulators in prostate cancer (PCa) from a network constructed from gene expression datasets of PCa patients. Overexpressed genes were identified using BioXpress, having a mutational status according to COSMIC, followed by the construction of PCa Interactome network using the curated genes. The topological parameters of the network exhibited power law nature indicating hierarchical scale-free properties and five levels of organization. Highest degree hubs (k ≥ 65) were selected from the PCa network, traced, and 19 of them was identified as novel key regulators, as they participated at all network levels serving as backbone. Of the 19 hubs, some have been reported in literature to be associated with PCa and other cancers. Based on participation coefficient values most of these are connector or kinless hubs suggesting significant roles in modular linkage. The observation of non-monotonicity in the rich club formation suggested the importance of intermediate hubs in network integration, and they may play crucial roles in network stabilization. The network was self-organized as evident from fractal nature in topological parameters of it and lacked a central control mechanism.

Shaping scientific instrument collections

2018 ◽  
Vol 31 (3) ◽  
pp. 445-452 ◽  
Author(s):  
Samuel J M M Alberti
Keyword(s):  
Scientific Instrument ◽  
Scientific Instruments ◽  
Original Function ◽  
Historiography Of Science ◽  
History Of ◽  
The Rich ◽  
Do So

Abstract Many histories of scientific instruments concentrate on their manufacture and original function, but such artefacts as survive often do so in collections – many will have spent far longer in a museum than anywhere else. Alongside the rich literature on the history of scientific instruments, accordingly, there is a body of work on the histories of scientific instrument collections. This survey outlines genres and themes in the historiography of scientific instruments, focusing in particular on display and other collection-based functions. Fluid and contingent, collections are instrumental in the history, heritage, and historiography of science.

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