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Journal ArticleDOI

Nonlinear Dynamic Causal Models for fMRI

TL;DR: A nonlinear extension of DCM that models such processes (to second order) at the neuronal population level is presented and it is found that attention-induced increases in V5 responses could be best explained as a gating of the V1-->V5 connection by activity in posterior parietal cortex.
About: This article is published in NeuroImage.The article was published on 2008-08-15 and is currently open access. It has received 412 citations till now. The article focuses on the topics: Dynamic causal modelling.
Citations
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Journal ArticleDOI
TL;DR: The inception of this journal has been foreshadowed by an ever-increasing number of publications on functional connectivity, causal modeling, connectomics, and multivariate analyses of distributed patterns of brain responses.
Abstract: Over the past 20 years, neuroimaging has become a predominant technique in systems neuroscience. One might envisage that over the next 20 years the neuroimaging of distributed processing and connectivity will play a major role in disclosing the brain's functional architecture and operational principles. The inception of this journal has been foreshadowed by an ever-increasing number of publications on functional connectivity, causal modeling, connectomics, and multivariate analyses of distributed patterns of brain responses. I accepted the invitation to write this review with great pleasure and hope to celebrate and critique the achievements to date, while addressing the challenges ahead.

2,822 citations


Cites background from "Nonlinear Dynamic Causal Models for..."

  • ...These sorts of effects have motivated the development of nonlinear models of effective connectivity that consider explicitly interactions among synaptic inputs (e.g., Friston et al., 1995; Stephan et al., 2008)....

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Journal ArticleDOI
TL;DR: Analysis of signals in tactile afferent neurons and central processes in humans reveals how contact events are encoded and used to monitor and update task performance.
Abstract: During object manipulation tasks, the brain selects and implements action-phase controllers that use sensory predictions and afferent signals to tailor motor output to the physical properties of the objects involved. Analysis of signals in tactile afferent neurons and central processes in humans reveals how contact events are encoded and used to monitor and update task performance.

1,569 citations


Cites methods from "Nonlinear Dynamic Causal Models for..."

  • ...New analysis methods applicable to studies in humans might help, such as dynamic causal modellin...

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Journal ArticleDOI
TL;DR: The hierarchical Bayesian approach is considerably more robust than either of the other approaches in the presence of outliers and is expected to prove useful for a wide range of group studies, not only in the context of DCM, but also for other modelling endeavours, e.g. comparing different source reconstruction methods for EEG/MEG.

1,353 citations


Cites background or methods from "Nonlinear Dynamic Causal Models for..."

  • ...Given the probabilities r, the distribution of themultinomial variablemn describes the probability that model k generated the data of subject n: p mn jrð Þ = Y k rmnkk : ð4Þ For any given subject n, we can sample from this multinomial distribution to obtain a particular model k....

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  • ...Our goal is to invert this hierarchical model and estimate the posterior distribution over r....

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Journal ArticleDOI
TL;DR: It is argued that this neurobiological mechanism can explain failures of self-monitoring, leading to a mechanistic explanation for first-rank symptoms as pathognomonic features of schizophrenia, and may provide a basis for future diagnostic classifications with physiologically defined patient subgroups.
Abstract: Over the last 2 decades, a large number of neurophysiological and neuroimaging studies of patients with schizophrenia have furnished in vivo evidence for dysconnectivity, ie, abnormal functional integration of brain processes. While the evidence for dysconnectivity in schizophrenia is strong, its etiology, pathophysiological mechanisms, and significance for clinical symptoms are unclear. First, dysconnectivity could result from aberrant wiring of connections during development, from aberrant synaptic plasticity, or from both. Second, it is not clear how schizophrenic symptoms can be understood mechanistically as a consequence of dysconnectivity. Third, if dysconnectivity is the primary pathophysiology, and not just an epiphenomenon, then it should provide a mechanistic explanation for known empirical facts about schizophrenia. This article addresses these 3 issues in the framework of the dysconnection hypothesis. This theory postulates that the core pathology in schizophrenia resides in aberrant N-methyl-D-aspartate receptor (NMDAR)-mediated synaptic plasticity due to abnormal regulation of NMDARs by neuromodulatory transmitters like dopamine, serotonin, or acetylcholine. We argue that this neurobiological mechanism can explain failures of self-monitoring, leading to a mechanistic explanation for first-rank symptoms as pathognomonic features of schizophrenia, and may provide a basis for future diagnostic classifications with physiologically defined patient subgroups. Finally, we test the explanatory power of our theory against a list of empirical facts about schizophrenia.

1,073 citations

Journal ArticleDOI
TL;DR: Good practice recommendations for DCM are provided, in the form of ten simple rules, hopes that this article serves as a helpful tutorial for the growing community of DCM users.

758 citations


Cites background or methods from "Nonlinear Dynamic Causal Models for..."

  • ...For DCM, and other models of effective connectivity, a continuous acquisition scheme (with appropriate inter-slice gap) is advantageous, when compared to interleaved acquisition....

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  • ...Although inference can be about any aspect of model structure or any parameter in a DCM, the focus of DCM studies is typically on context-dependent changes in coupling....

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  • ...Otherwise nonlinear DCM can be used, in which the strength of any given connection is allowed to depend on activity in remote neuronal populations (Stephan et al., 2008)....

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  • ...Given the relative complexity of DCM, compared to conventional analysis techniques, a good knowledge of its theoretical foundations is needed to avoid pitfalls in its application and interpretation of results....

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  • ...For example, one can replace both sensory and cognitive sub-networks with inputs representing the sensory stimuli (Heim et al., 2009; Smith et al., 2006) and the cognitive process (den Ouden et al., submitted for publication; Stephan et al., 2008), respectively....

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References
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Journal ArticleDOI

16,176 citations


"Nonlinear Dynamic Causal Models for..." refers background in this paper

  • ...F is a lower bound on the log model evidence such that F ¼ ln p yjmð Þ−KL q θð Þ;p θjy;mð Þ½ ð8Þ Here, KL denotes the Kulback–Leibler divergence (Kullback and Leibler 1951) between an approximating posterior density q(θ) and the true posterior, p(θ|y,m)....

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  • ...Here, KL denotes the Kulback–Leibler divergence (Kullback and Leibler 1951) between an approximating posterior density q(θ) and the true posterior, p(θ|y,m)....

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Journal ArticleDOI
TL;DR: The evidence for this hypothesis, and the origins of the different kinetic phases of synaptic enhancement, as well as the interpretation of statistical changes in transmitter release and roles played by other factors such as alterations in presynaptic Ca(2+) influx or postsynaptic levels of [Ca(2+)]i are discussed.
Abstract: ▪ Abstract Synaptic transmission is a dynamic process. Postsynaptic responses wax and wane as presynaptic activity evolves. This prominent characteristic of chemical synaptic transmission is a crucial determinant of the response properties of synapses and, in turn, of the stimulus properties selected by neural networks and of the patterns of activity generated by those networks. This review focuses on synaptic changes that result from prior activity in the synapse under study, and is restricted to short-term effects that last for at most a few minutes. Forms of synaptic enhancement, such as facilitation, augmentation, and post-tetanic potentiation, are usually attributed to effects of a residual elevation in presynaptic [Ca2+]i, acting on one or more molecular targets that appear to be distinct from the secretory trigger responsible for fast exocytosis and phasic release of transmitter to single action potentials. We discuss the evidence for this hypothesis, and the origins of the different kinetic phases...

4,687 citations


"Nonlinear Dynamic Causal Models for..." refers background in this paper

  • ...All these processes are driven by the history of prior synaptic activity and are thus nonlinear (Zucker and Regehr 2002)....

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  • ...NMDA-controlled rapid trafficking of AMPA receptors (Malinow and Malenka 2002), synaptic depression/facilitation (Zucker and Regehr 2002) or “early LTP” (Frey and Morris 1998)(1)....

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  • ...…for a range of processes which alter synaptic strengths with time constants in the range of milliseconds to minutes; e.g. NMDA-controlled rapid trafficking of AMPA receptors (Malinow and Malenka 2002), synaptic depression/facilitation (Zucker and Regehr 2002) or “early LTP” (Frey and Morris 1998)1....

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Journal ArticleDOI
TL;DR: As with previous analyses of effective connectivity, the focus is on experimentally induced changes in coupling, but unlike previous approaches in neuroimaging, the causal model ascribes responses to designed deterministic inputs, as opposed to treating inputs as unknown and stochastic.

4,182 citations

Journal ArticleDOI
TL;DR: Interactions among extrastriate, inferotemporal, and posterior parietal regions during visual processing, under different attentional and perceptual conditions, are focused on.

2,917 citations


"Nonlinear Dynamic Causal Models for..." refers background or methods in this paper

  • ...…have been proposed for inferring effective connectivity from neuroimaging data, including regressionbased models like psycho-physiological interactions (PPI; Friston et al., 1997), structural equation modelling (SEM; r Neuroimaging, Institute of are, London WC1N 3BG, UK. han). rights reserved....

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  • ...A few previous studies of effective connectivity have modelled changes in connection strength as a function of activity in a different region (Friston et al., 1995; Büchel and Friston, 1997: Friston et al., 1997; Friston and Büchel, 2000)....

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  • ...In the past, a variety of models have been proposed for inferring effective connectivity from neuroimaging data, including regressionbased models like psycho-physiological interactions (PPI; Friston et al., 1997), structural equation modelling (SEM;...

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Journal ArticleDOI
TL;DR: The growing literature that supports a critical role for AMPA receptors trafficking in LTP and LTD is reviewed, focusing on the roles proposed for specific AMPA receptor subunits and their interacting proteins.
Abstract: Activity-dependent changes in synaptic function are believed to underlie the formation of memories. Two prominent examples are long-term potentiation (LTP) and long-term depression (LTD), whose mechanisms have been the subject of considerable scrutiny over the past few decades. Here we review the growing literature that supports a critical role for AMPA receptor trafficking in LTP and LTD, focusing on the roles proposed for specific AMPA receptor subunits and their interacting proteins. While much work remains to understand the molecular basis for synaptic plasticity, recent results on AMPA receptor trafficking provide a clear conceptual framework for future studies.

2,587 citations


"Nonlinear Dynamic Causal Models for..." refers background in this paper

  • ...NMDA-controlled rapid trafficking of AMPA receptors (Malinow and Malenka 2002), synaptic depression/facilitation (Zucker and Regehr 2002) or “early LTP” (Frey and Morris 1998)(1)....

    [...]

  • ...…for a range of processes which alter synaptic strengths with time constants in the range of milliseconds to minutes; e.g. NMDA-controlled rapid trafficking of AMPA receptors (Malinow and Malenka 2002), synaptic depression/facilitation (Zucker and Regehr 2002) or “early LTP” (Frey and Morris 1998)1....

    [...]