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https://www.readbyqxmd.com/read/29161362/the-hierarchical-organization-of-the-default-dorsal-attention-and-salience-networks-in-adolescents-and-young-adults
#1
Yuan Zhou, Karl J Friston, Peter Zeidman, Jie Chen, Shu Li, Adeel Razi
An important characteristic of spontaneous brain activity is the anticorrelation between the core default network (cDN) and the dorsal attention network (DAN) and the salience network (SN). This anticorrelation may constitute a key aspect of functional anatomy and is implicated in several brain disorders. We used dynamic causal modeling to assess the hypothesis that a causal hierarchy underlies this anticorrelation structure, using resting-state fMRI of healthy adolescent and young adults (N = 404). Our analysis revealed an asymmetric effective connectivity, such that the regions in the SN and DAN exerted an inhibitory influence on the cDN regions; whereas the cDN exerted an excitatory influence on the SN and DAN regions...
November 17, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/29158202/dynamic-effective-connectivity-in-resting-state-fmri
#2
REVIEW
Hae-Jeong Park, Karl Friston, Chongwon Pae, Bumhee Park, Adeel Razi
Context-sensitive and activity-dependent fluctuations in connectivity underlie functional integration in the brain and have been studied widely in terms of synaptic plasticity, learning and condition-specific (e.g., attentional) modulations of synaptic efficacy. This dynamic aspect of brain connectivity has recently attracted a lot of attention in the resting state fMRI community. To explain dynamic functional connectivity in terms of directed effective connectivity among brain regions, we introduce a novel method to identify dynamic effective connectivity using spectral dynamic causal modelling (spDCM)...
November 17, 2017: NeuroImage
https://www.readbyqxmd.com/read/29116142/working-memory-attention-and-salience-in-active-inference
#3
Thomas Parr, Karl J Friston
The psychological concepts of working memory and attention are widely used in the cognitive and neuroscientific literatures. Perhaps because of the interdisciplinary appeal of these concepts, the same terms are often used to mean very different things. Drawing on recent advances in theoretical neurobiology, this paper tries to highlight the correspondence between these established psychological constructs and the formal processes implicit in mathematical descriptions of brain function. Here, we consider attention and salience from the perspective offered by active inference...
November 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29111773/factors-to-consider-when-reviewing-and-reconciling-research-findings-methodological-statistical-and-theoretical
#4
Sally J Robinson
Neuroscience is a rapidly evolving interdisciplinary field that is changing the way research is conducted and theories are developed. However, variability between studies and apparently discrepant findings may contribute to difficulties identifying commonalities that can help inform and enhance clinical practice. This article presents a framework to consider when reviewing neuropsychological studies, such that apparent discrepancies in findings may be considered in unison to provide informed theoretical understanding...
November 7, 2017: Applied Neuropsychology. Child
https://www.readbyqxmd.com/read/29111409/mulan-evaluation-and-ensemble-statistical-inference-for-functional-connectivity
#5
Huifang E Wang, Karl J Friston, Christian G Bénar, Marmaduke M Woodman, Patrick Chauvel, Viktor Jirsa, Christophe Bernard
Many analysis methods exist to extract graphs of functional connectivity from neuronal networks. Confidence in the results is limited because, (i) different methods give different results, (ii) parameter setting directly influences the final result, and (iii) systematic evaluation of the results is not always performed. Here, we introduce MULAN (MULtiple method ANalysis), which assumes an ensemble based approach combining multiple analysis methods and fuzzy logic to extract graphs with the most probable structure...
October 27, 2017: NeuroImage
https://www.readbyqxmd.com/read/29093675/a-factor-graph-description-of-deep-temporal-active-inference
#6
Bert de Vries, Karl J Friston
Active inference is a corollary of the Free Energy Principle that prescribes how self-organizing biological agents interact with their environment. The study of active inference processes relies on the definition of a generative probabilistic model and a description of how a free energy functional is minimized by neuronal message passing under that model. This paper presents a tutorial introduction to specifying active inference processes by Forney-style factor graphs (FFG). The FFG framework provides both an insightful representation of the probabilistic model and a biologically plausible inference scheme that, in principle, can be automatically executed in a computer simulation...
2017: Frontiers in Computational Neuroscience
https://www.readbyqxmd.com/read/29091338/analysis-of-family-wise-error-rates-in-statistical-parametric-mapping-using-random-field-theory
#7
Guillaume Flandin, Karl J Friston
This technical report revisits the analysis of family-wise error rates in statistical parametric mapping-using random field theory-reported in (Eklund et al. []: arXiv 1511.01863). Contrary to the understandable spin that these sorts of analyses attract, a review of their results suggests that they endorse the use of parametric assumptions-and random field theory-in the analysis of functional neuroimaging data. We briefly rehearse the advantages parametric analyses offer over nonparametric alternatives and then unpack the implications of (Eklund et al...
November 1, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/29038652/hierarchical-recursive-organization-and-the-free-energy-principle-from-biological-self-organization-to-the-psychoanalytic-mind
#8
Patrick Connolly, Vasi van Deventer
The present paper argues that a systems theory epistemology (and particularly the notion of hierarchical recursive organization) provides the critical theoretical context within which the significance of Friston's (2010a) Free Energy Principle (FEP) for both evolution and psychoanalysis is best understood. Within this perspective, the FEP occupies a particular level of the hierarchical organization of the organism, which is the level of biological self-organization. This form of biological self-organization is in turn understood as foundational and pervasive to the higher levels of organization of the human organism that are of interest to both neuroscience as well as psychoanalysis...
2017: Frontiers in Psychology
https://www.readbyqxmd.com/read/29029962/answering-schr%C3%A3-dinger-s-question-a-free-energy-formulation
#9
REVIEW
Maxwell James Désormeau Ramstead, Paul Benjamin Badcock, Karl John Friston
The free-energy principle (FEP) is a formal model of neuronal processes that is widely recognised in neuroscience as a unifying theory of the brain and biobehaviour. More recently, however, it has been extended beyond the brain to explain the dynamics of living systems, and their unique capacity to avoid decay. The aim of this review is to synthesise these advances with a meta-theoretical ontology of biological systems called variational neuroethology, which integrates the FEP with Tinbergen's four research questions to explain biological systems across spatial and temporal scales...
September 20, 2017: Physics of Life Reviews
https://www.readbyqxmd.com/read/29024792/effective-connectivity-inferred-from-fmri-transition-dynamics-during-movie-viewing-points-to-a-balanced-reconfiguration-of-cortical-interactions
#10
REVIEW
Matthieu Gilson, Gustavo Deco, Karl Friston, Patric Hagmann, Dante Mantini, Viviana Betti, Gian Luca Romani, Maurizio Corbetta
Our behavior entails a flexible and context-sensitive interplay between brain areas to integrate information according to goal-directed requirements. However, the neural mechanisms governing the entrainment of functionally specialized brain areas remain poorly understood. In particular, the question arises whether observed changes in the regional activity for different cognitive conditions are explained by modifications of the inputs to the brain or its connectivity? We observe that transitions of fMRI activity between areas convey information about the tasks performed by 19 subjects, watching a movie versus a black screen (rest)...
October 9, 2017: NeuroImage
https://www.readbyqxmd.com/read/29018337/editorial-self-organization-in-the-nervous-system
#11
EDITORIAL
Yan M Yufik, Biswa Sengupta, Karl Friston
No abstract text is available yet for this article.
2017: Frontiers in Systems Neuroscience
https://www.readbyqxmd.com/read/28981514/a-unifying-bayesian-account-of-contextual-effects-in-value-based-choice
#12
Francesco Rigoli, Christoph Mathys, Karl J Friston, Raymond J Dolan
Empirical evidence suggests the incentive value of an option is affected by other options available during choice and by options presented in the past. These contextual effects are hard to reconcile with classical theories and have inspired accounts where contextual influences play a crucial role. However, each account only addresses one or the other of the empirical findings and a unifying perspective has been elusive. Here, we offer a unifying theory of context effects on incentive value attribution and choice based on normative Bayesian principles...
October 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28851996/uncovering-the-underlying-mechanisms-and-whole-brain-dynamics-of-deep-brain-stimulation-for-parkinson-s-disease
#13
Victor M Saenger, Joshua Kahan, Tom Foltynie, Karl Friston, Tipu Z Aziz, Alexander L Green, Tim J van Hartevelt, Joana Cabral, Angus B A Stevner, Henrique M Fernandes, Laura Mancini, John Thornton, Tarek Yousry, Patricia Limousin, Ludvic Zrinzo, Marwan Hariz, Paulo Marques, Nuno Sousa, Morten L Kringelbach, Gustavo Deco
Deep brain stimulation (DBS) for Parkinson's disease is a highly effective treatment in controlling otherwise debilitating symptoms. Yet the underlying brain mechanisms are currently not well understood. Whole-brain computational modeling was used to disclose the effects of DBS during resting-state functional Magnetic Resonance Imaging in ten patients with Parkinson's disease. Specifically, we explored the local and global impact that DBS has in creating asynchronous, stable or critical oscillatory conditions using a supercritical bifurcation model...
August 29, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28836726/dynamic-causal-modeling-in-ptsd-and-its-dissociative-subtype-bottom-up-versus-top-down-processing-within-fear-and-emotion-regulation-circuitry
#14
Andrew A Nicholson, Karl J Friston, Peter Zeidman, Sherain Harricharan, Margaret C McKinnon, Maria Densmore, Richard W J Neufeld, Jean Théberge, Frank Corrigan, Rakesh Jetly, David Spiegel, Ruth A Lanius
OBJECTIVE: Posttraumatic stress disorder (PTSD) is associated with decreased top-down emotion modulation from medial prefrontal cortex (mPFC) regions, a pathophysiology accompanied by hyperarousal and hyperactivation of the amygdala. By contrast, PTSD patients with the dissociative subtype (PTSD + DS) often exhibit increased mPFC top-down modulation and decreased amygdala activation associated with emotional detachment and hypoarousal. Crucially, PTSD and PTSD + DS display distinct functional connectivity within the PFC, amygdala complexes, and the periaqueductal gray (PAG), a region related to defensive responses/emotional coping...
August 24, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28807873/neurophysiologically-informed-markers-of-individual-variability-and-pharmacological-manipulation-of-human-cortical-gamma
#15
A D Shaw, R J Moran, S D Muthukumaraswamy, J Brealy, D E Linden, K J Friston, K D Singh
The ability to quantify synaptic function at the level of cortical microcircuits from non-invasive data would be enormously useful in the study of neuronal processing in humans and the pathophysiology that attends many neuropsychiatric disorders. Here, we provide proof of principle that one can estimate inter-and intra-laminar interactions among specific neuronal populations using induced gamma responses in the visual cortex of human subjects - using dynamic causal modelling based upon the canonical microcircuit (CMC; a simplistic model of a cortical column)...
November 1, 2017: NeuroImage
https://www.readbyqxmd.com/read/28782543/the-active-construction-of-the-visual-world
#16
REVIEW
Thomas Parr, Karl J Friston
What we see is fundamentally dependent on where we look. Despite this seemingly obvious statement, many accounts of the neurobiology underpinning visual perception fail to consider the active nature of how we sample our sensory world. This review offers an overview of the neurobiology of visual perception, which begins with the control of saccadic eye movements. Starting from here, we can follow the anatomy backwards, to try to understand the functional architecture of neuronal networks that support the interrogation of a visual scene...
September 2017: Neuropsychologia
https://www.readbyqxmd.com/read/28777724/active-inference-curiosity-and-insight
#17
Karl J Friston, Marco Lin, Christopher D Frith, Giovanni Pezzulo, J Allan Hobson, Sasha Ondobaka
This article offers a formal account of curiosity and insight in terms of active (Bayesian) inference. It deals with the dual problem of inferring states of the world and learning its statistical structure. In contrast to current trends in machine learning (e.g., deep learning), we focus on how people attain insight and understanding using just a handful of observations, which are solicited through curious behavior. We use simulations of abstract rule learning and approximate Bayesian inference to show that minimizing (expected) variational free energy leads to active sampling of novel contingencies...
October 2017: Neural Computation
https://www.readbyqxmd.com/read/28720781/distinct-top-down-and-bottom-up-brain-connectivity-during-visual-perception-and-imagery
#18
N Dijkstra, P Zeidman, S Ondobaka, M A J van Gerven, K Friston
Research suggests that perception and imagination engage neuronal representations in the same visual areas. However, the underlying mechanisms that differentiate sensory perception from imagination remain unclear. Here, we examine the directed coupling (effective connectivity) between fronto-parietal and visual areas during perception and imagery. We found an increase in bottom-up coupling during perception relative to baseline and an increase in top-down coupling during both perception and imagery, with a much stronger increase during imagery...
July 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28702345/hierarchical-disruption-in-the-bayesian-brain-focal-epilepsy-and-brain-networks
#19
Amir Omidvarnia, Mangor Pedersen, Richard E Rosch, Karl J Friston, Graeme D Jackson
In this opinion paper, we describe a combined view of functional and effective brain connectivity along with the free-energy principle for investigating persistent disruptions in brain networks of patients with focal epilepsy. These changes are likely reflected in effective connectivity along the cortical hierarchy and construct the basis of increased local functional connectivity in focal epilepsy. We propose a testable framework based on dynamic causal modelling and functional connectivity analysis with the capacity of explaining commonly observed connectivity changes during interictal periods...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28637913/predicting-green-really-radical-plant-predictive-processing
#20
Paco Calvo, Karl Friston
In this article we account for the way plants respond to salient features of their environment under the free-energy principle for biological systems. Biological self-organization amounts to the minimization of surprise over time. We posit that any self-organizing system must embody a generative model whose predictions ensure that (expected) free energy is minimized through action. Plants respond in a fast, and yet coordinated manner, to environmental contingencies. They pro-actively sample their local environment to elicit information with an adaptive value...
June 2017: Journal of the Royal Society, Interface
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