scholarly journals An image-computable model of attention and texture segmentation

2021 ◽  
Author(s):  
Michael Jigo ◽  
David J. Heeger ◽  
Marisa Carrasco
Keyword(s):  
Sensory Processing ◽  
Texture Segmentation ◽  
Computable Model ◽  
Voluntary Attention ◽  
Attentional Modulation ◽  
Functional Roles ◽  
Systems Model ◽  
Proposed Model ◽  
Attention Systems ◽  
Operating Regimes

ABSTRACTAttention can facilitate or impair texture segmentation, altering whether objects are isolated from their surroundings in visual scenes. We simultaneously explain several empirical phenomena of texture segmentation and its attentional modulation with a single image-computable model. At the model’s core, segmentation relies on the interaction between sensory processing and attention, with different operating regimes for involuntary and voluntary attention systems. Model comparisons were used to identify computations critical for texture segmentation and attentional modulation. The model reproduced (i) the central performance drop, which is the parafoveal advantage for segmentation over the fovea, (ii) the peripheral improvements and central impairments induced by involuntary attention and (iii) the uniform improvements across eccentricity by voluntary attention. The proposed model reveals distinct functional roles for involuntary and voluntary attention and provides a generalizable quantitative framework for predicting the perceptual impact of attention across the visual field.

scholarly journals Reflective and Impulsive Determinants of Social Behavior

2004 ◽  
Vol 8 (3) ◽  
pp. 220-247 ◽  
Author(s):  
Fritz Strack ◽  
Roland Deutsch
Keyword(s):  
Social Behavior ◽  
Impulsive System ◽  
Dual Process ◽  
Mental Functioning ◽  
Systems Model ◽  
Proposed Model ◽  
Interacting Systems ◽  
Impulsive Model ◽  
Impulsive Processes ◽  
Behavioral Mechanisms

This article describes a 2-systems model that explains social behavior as a joint function of reflective and impulsive processes. In particular, it is assumed that social behavior is controlled by 2 interacting systems that follow different operating principles. The reflective system generates behavioral decisions that are based on knowledge about facts and values, whereas the impulsive system elicits behavior through associative links and motivational orientations. The proposed model describes how the 2 systems interact at various stages of processing, and how their outputs may determine behavior in a synergistic or antagonistic fashion. It extends previous models by integrating motivational components that allow more precise predictions of behavior. The implications of this reflective-impulsive model are applied to various phenomena from social psychology and beyond. Extending previous dual-process accounts, this model is not limited to specific domains of mental functioning and attempts to integrate cognitive, motivational, and behavioral mechanisms.

iRNAD: a computational tool for identifying D modification sites in RNA sequence

2019 ◽  
Vol 35 (23) ◽  
pp. 4922-4929 ◽  
Author(s):  
Zhao-Chun Xu ◽  
Peng-Mian Feng ◽  
Hui Yang ◽  
Wang-Ren Qiu ◽  
Wei Chen ◽  
...  
Keyword(s):  
Computational Models ◽  
Operating Characteristic ◽  
Cross Validation ◽  
Characteristic Curve ◽  
Support Vector ◽  
Final Model ◽  
Rna Sequence ◽  
Functional Roles ◽  
Proposed Model ◽  
User Friendly

Abstract Motivation Dihydrouridine (D) is a common RNA post-transcriptional modification found in eukaryotes, bacteria and a few archaea. The modification can promote the conformational flexibility of individual nucleotide bases. And its levels are increased in cancerous tissues. Therefore, it is necessary to detect D in RNA for further understanding its functional roles. Since wet-experimental techniques for the aim are time-consuming and laborious, it is urgent to develop computational models to identify D modification sites in RNA. Results We constructed a predictor, called iRNAD, for identifying D modification sites in RNA sequence. In this predictor, the RNA samples derived from five species were encoded by nucleotide chemical property and nucleotide density. Support vector machine was utilized to perform the classification. The final model could produce the overall accuracy of 96.18% with the area under the receiver operating characteristic curve of 0.9839 in jackknife cross-validation test. Furthermore, we performed a series of validations from several aspects and demonstrated the robustness and reliability of the proposed model. Availability and implementation A user-friendly web-server called iRNAD can be freely accessible at http://lin-group.cn/server/iRNAD, which will provide convenience and guide to users for further studying D modification.

Disentangling different functional roles of evoked K-complex components: Mapping the sleeping brain while quenching sensory processing

NeuroImage ◽  
2014 ◽  
Vol 86 ◽  
pp. 433-445 ◽  
Author(s):  
Marco Laurino ◽  
Danilo Menicucci ◽  
Andrea Piarulli ◽  
Francesca Mastorci ◽  
Remo Bedini ◽  
...  
Keyword(s):  
Sensory Processing ◽  
Functional Roles ◽  
Complex Components

A Theoretical and Experimental Examination of Auditory-Visual Interaction

1969 ◽  
Vol 29 (1) ◽  
pp. 23-33 ◽  
Author(s):  
Kenneth Gaarder
Keyword(s):  
Sensory Processing ◽  
Visual Information ◽  
Reaction Times ◽  
Time Sharing ◽  
Central Processing ◽  
Systems Model ◽  
Concurrent Processing ◽  
Complex Interactions ◽  
General Systems ◽  
Sense Modalities

The general systems model of central sensory processing used in this study is based on the assumption that central processing is discontinuous and raises this question: Is concurrent processing of different sense modalities serial, parallel, or independent? Since an eye-jump indicates input of visual information, if the auditory system is stimulated by clicks with fixed delays after eye-jumps, intermodality relationships are tested. Reaction times and evoked responses show complex interactions which are interpreted to suggest serial processing analogous to time sharing computers.

scholarly journals Computational Models of Neuromodulation

1998 ◽  
Vol 10 (4) ◽  
pp. 771-805 ◽  
Author(s):  
Jean-Marc Fellous ◽  
Christiane Linster
Keyword(s):  
Sensory Processing ◽  
Information Integration ◽  
Computational Models ◽  
Neural Substrates ◽  
Pattern Generation ◽  
Neural Models ◽  
Functional Roles ◽  
Modeling Studies ◽  
And Control

Computational modeling of neural substrates provides an excellent theoretical framework for the understanding of the computational roles of neuromodulation. In this review, we illustrate, with a large number of modeling studies, the specific computations performed by neuromodulation in the context of various neural models of invertebrate and vertebrate preparations. We base our characterization of neuromodulations on their computational and functional roles rather than on anatomical or chemical criteria. We review the main framework in which neuromodulation has been studied theoretically (central pattern generation and oscillations, sensory processing, memory and information integration). Finally, we present a detailed mathematical overview of how neuromodulation has been implemented at the single cell and network levels in modeling studies. Overall, neuromodulation is found to increase and control computational complexity.

scholarly journals Functional Specialization in the Attention Network

2020 ◽  
Vol 71 (1) ◽  
pp. 221-249 ◽  
Author(s):  
Ian C. Fiebelkorn ◽  
Sabine Kastner
Keyword(s):  
Spatial Attention ◽  
Cognitive Flexibility ◽  
Sensory Processing ◽  
Dynamic Environments ◽  
Brain Regions ◽  
Neural Mechanisms ◽  
Functional Specialization ◽  
Attention Network ◽  
Functional Roles ◽  
Parietal Cortices

Spatial attention is comprised of neural mechanisms that boost sensory processing at a behaviorally relevant location while filtering out competing information. The present review examines functional specialization in the network of brain regions that directs such preferential processing. This attention network includes both cortical (e.g., frontal and parietal cortices) and subcortical (e.g., the superior colliculus and the pulvinar nucleus of the thalamus) structures. Here, we piece together existing evidence that these various nodes of the attention network have dissociable functional roles by synthesizing results from electrophysiology and neuroimaging studies. We describe functional specialization across several dimensions (e.g., at different processing stages and within different behavioral contexts), while focusing on spatial attention as a dynamic process that unfolds over time. Functional contributions from each node of the attention network can change on a moment-to-moment timescale, providing the necessary cognitive flexibility for sampling from highly dynamic environments.

scholarly journals An Analysis of a Close-Type Queuing System with General Service-Time Distribution

1970 ◽  
Vol 3 (1) ◽  
pp. 77-82
Author(s):  
Yoshio Yoshioka ◽  
Tomoyuki Nagase
Keyword(s):  
Service Time ◽  
Time Distribution ◽  
Probability Distributions ◽  
Queuing System ◽  
Multiprocessor System ◽  
Service Time Distribution ◽  
Systems Model ◽  
Proposed Model ◽  
Repair Procedure ◽  
General Service

This paper presents an innovative approach to solve probability distributions of a close feed back loop type queuing system with general service time distribution. This model is applied to a multiprocessor system where some of its nodes are performed a repair procedure during a nodes malfunction condition. Our model is appropriate for a multiprocessor system that employs a common bus or for a multi-node system in computer networks. A meticulous analysis of the systems model has been conducted and numerical results have been obtained to scrutinize the proposed model.

Modeling in the Physical Domain: An Optimization-Based Approach

2002 ◽  
Author(s):  
Yong Ye ◽  
Kamal Youcef-Toumi
Keyword(s):  
Model Reduction ◽  
Dynamic Systems ◽  
Optimization Problem ◽  
Theoretical Research ◽  
Engineering Practice ◽  
Physical Domain ◽  
Systems Model ◽  
Proposed Model ◽  
Reduction Problem ◽  
Challenges And Opportunities

With the increasing complexity of dynamic systems, model reduction has become an attractive research topic. A very useful type of reduced models is obtained by removing as many physical components as possible from the original model, known as model reduction in the physical domain. Many results have been achieved in this area during past decades. Nonetheless, the newest developments in engineering practice as well as in theoretical research have brought about further challenges and opportunities. This paper expands the scope of model reduction in physical domain, and proposes a criterion based on the H∞ norm of certain error model is proposed. The model reduction problem is then formulated as an optimization problem with bilinear matrix inequality (BMI) constraints, which can be solved with various processes. Several examples are presented to illustrate the use of the proposed model reduction scheme.

scholarly journals Extracellular ribosomal RNA provides a window into taxon-specific microbial lysis

2021 ◽  
Author(s):  
Kevin Xu Zhong ◽  
Amy M Chan ◽  
Jennifer F Wirth ◽  
Curtis A Suttle
Keyword(s):  
Microbial Communities ◽  
Ribosomal Rna ◽  
Biogeochemical Cycles ◽  
Specific Cell ◽  
Sequence Variants ◽  
Viral Lysis ◽  
Functional Roles ◽  
Proposed Model ◽  
Life On Earth ◽  
Marine Microbial Communities

Microbes are by far the dominant biomass in the world's oceans and drive biogeochemical cycles that are critical to life on Earth. The composition of marine microbial communities is highly dynamic spatially and temporally, with consequent effects on their functional roles. In part, these changes in composition result from viral lysis, which is taxon-specific and estimated to account for about half of marine microbial mortality. Here we determined taxon-specific cell lysis of prokaryotes in coastal seawater by sequencing extracellular and cellular ribosomal RNA (rRNA). We detected lysis in about 15% of the 16946 prokaryotic amplicon sequence variants (ASVs) identified, and lysis of up to 34% of the ASVs within a water sample. High lysis was most commonly associated with rare but typically highly productive bacteria, while relatively low lysis was more common in taxa that are often abundant, consistent with the proposed model of "kill the winner", and the idea that less abundant taxa generally experience higher relative lysis than dominant taxa. These results provide an explanation to the long-standing conundrum of why highly productive bacteria that are readily isolated from seawater are often in very low abundance.

scholarly journals Embryonic and postnatal neurogenesis produce functionally distinct subclasses of dopaminergic neuron

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Elisa Galliano ◽  
Eleonora Franzoni ◽  
Marine Breton ◽  
Annisa N Chand ◽  
Darren J Byrne ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Sensory Processing ◽  
Dopaminergic Neuron ◽  
Initial Segment ◽  
Mammalian Brain ◽  
Postnatal Life ◽  
Postnatal Neurogenesis ◽  
Functional Roles ◽  
Long Latency ◽  
Adult Born Neurons

Most neurogenesis in the mammalian brain is completed embryonically, but in certain areas the production of neurons continues throughout postnatal life. The functional properties of mature postnatally generated neurons often match those of their embryonically produced counterparts. However, we show here that in the olfactory bulb (OB), embryonic and postnatal neurogenesis produce functionally distinct subpopulations of dopaminergic (DA) neurons. We define two subclasses of OB DA neuron by the presence or absence of a key subcellular specialisation: the axon initial segment (AIS). Large AIS-positive axon-bearing DA neurons are exclusively produced during early embryonic stages, leaving small anaxonic AIS-negative cells as the only DA subtype generated via adult neurogenesis. These populations are functionally distinct: large DA cells are more excitable, yet display weaker and – for certain long-latency or inhibitory events – more broadly tuned responses to odorant stimuli. Embryonic and postnatal neurogenesis can therefore generate distinct neuronal subclasses, placing important constraints on the functional roles of adult-born neurons in sensory processing.

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