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See detailConnectivity changes underlying spectral EEG changes during propofol-induced loss of consciousness.
Boly, Mélanie ULg; Moran, Rosalyn; Murphy, Michael et al

in The Journal of neuroscience : the official journal of the Society for Neuroscience (2012), 32(20), 7082-90

The mechanisms underlying anesthesia-induced loss of consciousness remain a matter of debate. Recent electrophysiological reports suggest that while initial propofol infusion provokes an increase in fast ... [more ▼]

The mechanisms underlying anesthesia-induced loss of consciousness remain a matter of debate. Recent electrophysiological reports suggest that while initial propofol infusion provokes an increase in fast rhythms (from beta to gamma range), slow activity (from delta to alpha range) rises selectively during loss of consciousness. Dynamic causal modeling was used to investigate the neural mechanisms mediating these changes in spectral power in humans. We analyzed source-reconstructed data from frontal and parietal cortices during normal wakefulness, propofol-induced mild sedation, and loss of consciousness. Bayesian model selection revealed that the best model for explaining spectral changes across the three states involved changes in corticothalamic interactions. Compared with wakefulness, mild sedation was accounted for by an increase in thalamic excitability, which did not further increase during loss of consciousness. In contrast, loss of consciousness per se was accompanied by a decrease in backward corticocortical connectivity from frontal to parietal cortices, while thalamocortical connectivity remained unchanged. These results emphasize the importance of recurrent corticocortical communication in the maintenance of consciousness and suggest a direct effect of propofol on cortical dynamics. [less ▲]

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See detailPreserved feedforward but impaired top-down processes in the vegetative state.
Boly, Mélanie ULg; Garrido, Marta Isabel; Gosseries, Olivia ULg et al

in Science (2011), 332(6031), 858-62

Frontoparietal cortex is involved in the explicit processing (awareness) of stimuli. Frontoparietal activation has also been found in studies of subliminal stimulus processing. We hypothesized that an ... [more ▼]

Frontoparietal cortex is involved in the explicit processing (awareness) of stimuli. Frontoparietal activation has also been found in studies of subliminal stimulus processing. We hypothesized that an impairment of top-down processes, involved in recurrent neuronal message-passing and the generation of long-latency electrophysiological responses, might provide a more reliable correlate of consciousness in severely brain-damaged patients, than frontoparietal responses. We measured effective connectivity during a mismatch negativity paradigm and found that the only significant difference between patients in a vegetative state and controls was an impairment of backward connectivity from frontal to temporal cortices. This result emphasizes the importance of top-down projections in recurrent processing that involve high-order associative cortices for conscious perception. [less ▲]

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See detailResponse to comment on "preserved feedforward but impaired top-down processes in the vegetative state".
Boly, Mélanie ULg; Garrido, Marta Isabel; Gosseries, Olivia ULg et al

in Science (2011), 334(6060), 1203

King et al. raise some technical issues about our recent study showing impaired top-down processes in the vegetative state. We welcome the opportunity to provide more details about our methods and results ... [more ▼]

King et al. raise some technical issues about our recent study showing impaired top-down processes in the vegetative state. We welcome the opportunity to provide more details about our methods and results and to resolve their concerns. We substantiate our interpretation of the results and provide a point-by-point response to the issues raised. [less ▲]

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See detailBayesian inversion for induced responses
Mattout, Jérémie; Phillips, Christophe ULg; Daunizeau, Jean et al

in Friston, Karl; Ashburner, John; Kiebel, Stefan (Eds.) et al Statistical Parametric Mapping: the analysis of functional brain images (2007)

The book Statistical Parametric Mapping: The Analysis of Functional Brain Images (2007) provides the background and methodology for the analysis of all types of brain imaging data, from functional ... [more ▼]

The book Statistical Parametric Mapping: The Analysis of Functional Brain Images (2007) provides the background and methodology for the analysis of all types of brain imaging data, from functional magnetic resonance imaging to magnetoencephalography. Critically, "Statistical Parametric Mapping" provides a widely accepted conceptual framework which allows treatment of all these different modalities. The book takes the reader from the basic concepts underlying the analysis of neuroimaging data to cutting edge approaches that would be difficult to find in any other source. The material is presented in an incremental way so that the reader can understand the precedents for each new development. This book will be particularly useful to neuroscientists engaged in any form of brain mapping; who have to contend with the real-world problems of data analysis and understanding the techniques they are using. It is primarily a scientific treatment and a didactic introduction to the analysis of brain imaging data. It can be used as both a textbook for students and scientists starting to use the techniques, as well as a reference for practicing neuroscientists. [less ▲]

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See detailBayesian inversion of EEG models
Mattout, Jérémie; Phillips, Christophe ULg; Daunizeau, Jean et al

in Friston, Karl; Ashburner, John; Kiebel, Stefan (Eds.) et al Statistical Parametric Mapping: the analysis of functional brain images (2007)

The book Statistical Parametric Mapping: The Analysis of Functional Brain Images (2007) provides the background and methodology for the analysis of all types of brain imaging data, from functional ... [more ▼]

The book Statistical Parametric Mapping: The Analysis of Functional Brain Images (2007) provides the background and methodology for the analysis of all types of brain imaging data, from functional magnetic resonance imaging to magnetoencephalography. Critically, "Statistical Parametric Mapping" provides a widely accepted conceptual framework which allows treatment of all these different modalities. The book takes the reader from the basic concepts underlying the analysis of neuroimaging data to cutting edge approaches that would be difficult to find in any other source. The material is presented in an incremental way so that the reader can understand the precedents for each new development. This book will be particularly useful to neuroscientists engaged in any form of brain mapping; who have to contend with the real-world problems of data analysis and understanding the techniques they are using. It is primarily a scientific treatment and a didactic introduction to the analysis of brain imaging data. It can be used as both a textbook for students and scientists starting to use the techniques, as well as a reference for practicing neuroscientists. [less ▲]

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See detailForward models for EEG
Phillips, Christophe ULg; Mattout, Jérémie; Friston, Karl

in Friston, Karl; Ashburner, John; Kiebel, Stefan (Eds.) et al Statistical Parametric Mapping: the analysis of functional brain images (2007)

The book Statistical Parametric Mapping: The Analysis of Functional Brain Images (2007) provides the background and methodology for the analysis of all types of brain imaging data, from functional ... [more ▼]

The book Statistical Parametric Mapping: The Analysis of Functional Brain Images (2007) provides the background and methodology for the analysis of all types of brain imaging data, from functional magnetic resonance imaging to magnetoencephalography. Critically, "Statistical Parametric Mapping" provides a widely accepted conceptual framework which allows treatment of all these different modalities. The book takes the reader from the basic concepts underlying the analysis of neuroimaging data to cutting edge approaches that would be difficult to find in any other source. The material is presented in an incremental way so that the reader can understand the precedents for each new development. This book will be particularly useful to neuroscientists engaged in any form of brain mapping; who have to contend with the real-world problems of data analysis and understanding the techniques they are using. It is primarily a scientific treatment and a didactic introduction to the analysis of brain imaging data. It can be used as both a textbook for students and scientists starting to use the techniques, as well as a reference for practicing neuroscientists. [less ▲]

Detailed reference viewed: 11 (0 ULg)
See detailStatistical Parametric Mapping
Ashburner, John; Barnes, Gareth; Chen, Chun-Chuan et al

Software (1994)

Statistical Parametric Mapping refers to the construction and assessment of spatially extended statistical processes used to test hypotheses about functional imaging data. These ideas have been ... [more ▼]

Statistical Parametric Mapping refers to the construction and assessment of spatially extended statistical processes used to test hypotheses about functional imaging data. These ideas have been instantiated in software that is called SPM. The SPM software package has been designed for the analysis of brain imaging data sequences. The sequences can be a series of images from different cohorts, or time-series from the same subject. The current release is designed for the analysis of fMRI, PET, SPECT, EEG and MEG. [less ▲]

Detailed reference viewed: 138 (1 ULg)