Brain Effective Connectivity Pattern Modulation by Repeating Blocks of an fMRI Task
Purpose: Effective connectivity is an active time-variable type of association between brain regions. The change of links’ strength in effective connectivity networks has been studied before but as far as we know, the change in the structure of the network has not yet been tested. Procedures: We si...
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Tehran University of Medical Sciences
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doaj-269c20b9cefa4c2abbbabf12f995753c2020-11-25T04:07:47ZengTehran University of Medical SciencesFrontiers in Biomedical Technologies2345-58372016-12-0133-4Brain Effective Connectivity Pattern Modulation by Repeating Blocks of an fMRI TaskArash Zare Sadeghi0Amirhomayoun Jafari1Seyed AmirHosein Batouli2Mohammad Ali Oghabian3Skull Base Research Center, Iran University of Medical Sciences, Tehran, Iran. AND Neuroimaging and Analysis Group (NIAG), Imaging center, Imam Khomeini hospital complex, Tehran University of Medical Sciences, Tehran, IranMedical Physics and Biomedical Engineering Department, School of Medicine, Tehran University of Medical Sciences, Tehran IranNeuroimaging and Analysis Group, Imam Khomeini Hospital Complex, Tehran University of Medical sciences, Tehran, IranNeuroimaging and Analysis Group, Imam Khomeini Hospital Complex, Tehran University of Medical sciences, Tehran, Iran. AND Medical Physics and Biomedical Engineering Department, School of Medicine, Tehran University of Medical Sciences, Tehran Iran Purpose: Effective connectivity is an active time-variable type of association between brain regions. The change of links’ strength in effective connectivity networks has been studied before but as far as we know, the change in the structure of the network has not yet been tested. Procedures: We simulated a time-variable data including three regions and one input to validate our method. In addition, we used a real fMRI data in order to evaluate the time-variability of brain effective connectivity between four brain regions using Dynamic Causal Modeling. The model space contained 38 models, all including the four regions of ventromedial prefrontal cortex, dor-solateral prefrontal cortex, amygdala, and ventral striatum. In both data, a proper moving window algorithm was used to find the changes over time. Results: The results of simulated data matched the simulated pattern change over time. The results of real data initially showed time-dependent changes in the strength of some of the connections between brain regions. The most valid changes happened in the input and non-linear modulatory links. The input links’ strength increased and the nonlinear links’ strength decreased exponentially. These results show that the pattern of effective connectivity network changes and so reporting a single network for the whole data acquisition period is not meaningful. Conclusion: In this study, we have used a method to find the time-dependent pattern changes during an fMRI task. We have shown the links’ strength change over time and accordingly the structure of the network changes. https://fbt.tums.ac.ir/index.php/fbt/article/view/81Dynamic Causal ModelingfMRISliding WindowTime Variability |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Arash Zare Sadeghi Amirhomayoun Jafari Seyed AmirHosein Batouli Mohammad Ali Oghabian |
spellingShingle |
Arash Zare Sadeghi Amirhomayoun Jafari Seyed AmirHosein Batouli Mohammad Ali Oghabian Brain Effective Connectivity Pattern Modulation by Repeating Blocks of an fMRI Task Frontiers in Biomedical Technologies Dynamic Causal Modeling fMRI Sliding Window Time Variability |
author_facet |
Arash Zare Sadeghi Amirhomayoun Jafari Seyed AmirHosein Batouli Mohammad Ali Oghabian |
author_sort |
Arash Zare Sadeghi |
title |
Brain Effective Connectivity Pattern Modulation by Repeating Blocks of an fMRI Task |
title_short |
Brain Effective Connectivity Pattern Modulation by Repeating Blocks of an fMRI Task |
title_full |
Brain Effective Connectivity Pattern Modulation by Repeating Blocks of an fMRI Task |
title_fullStr |
Brain Effective Connectivity Pattern Modulation by Repeating Blocks of an fMRI Task |
title_full_unstemmed |
Brain Effective Connectivity Pattern Modulation by Repeating Blocks of an fMRI Task |
title_sort |
brain effective connectivity pattern modulation by repeating blocks of an fmri task |
publisher |
Tehran University of Medical Sciences |
series |
Frontiers in Biomedical Technologies |
issn |
2345-5837 |
publishDate |
2016-12-01 |
description |
Purpose: Effective connectivity is an active time-variable type of association between brain regions. The change of links’ strength in effective connectivity networks has been studied before but as far as we know, the change in the structure of the network has not yet been tested.
Procedures: We simulated a time-variable data including three regions and one input to validate our method. In addition, we used a real fMRI data in order to evaluate the time-variability of brain effective connectivity between four brain regions using Dynamic Causal Modeling. The model space contained 38 models, all including the four regions of ventromedial prefrontal cortex, dor-solateral prefrontal cortex, amygdala, and ventral striatum. In both data, a proper moving window algorithm was used to find the changes over time.
Results: The results of simulated data matched the simulated pattern change over time. The results of real data initially showed time-dependent changes in the strength of some of the connections between brain regions. The most valid changes happened in the input and non-linear modulatory links. The input links’ strength increased and the nonlinear links’ strength decreased exponentially. These results show that the pattern of effective connectivity network changes and so reporting a single network for the whole data acquisition period is not meaningful.
Conclusion: In this study, we have used a method to find the time-dependent pattern changes during an fMRI task. We have shown the links’ strength change over time and accordingly the structure of the network changes.
|
topic |
Dynamic Causal Modeling fMRI Sliding Window Time Variability |
url |
https://fbt.tums.ac.ir/index.php/fbt/article/view/81 |
work_keys_str_mv |
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