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A Sensitivity Analysis of fMRI Balloon Model.

Zayane C, Laleg-Kirati TM - Comput Math Methods Med (2015)

Bottom Line: By identifiability, we mean the ability to estimate accurately the model parameters given the input and the output measurement.Previous studies of the Balloon model have somehow added knowledge either by choosing prior distributions for the parameters, freezing some of them, or looking for the solution as a projection on a natural basis of some vector space.In these studies, the identification was generally assessed using event-related paradigms.

View Article: PubMed Central - PubMed

Affiliation: Computer, Electrical and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.

ABSTRACT
Functional magnetic resonance imaging (fMRI) allows the mapping of the brain activation through measurements of the Blood Oxygenation Level Dependent (BOLD) contrast. The characterization of the pathway from the input stimulus to the output BOLD signal requires the selection of an adequate hemodynamic model and the satisfaction of some specific conditions while conducting the experiment and calibrating the model. This paper, focuses on the identifiability of the Balloon hemodynamic model. By identifiability, we mean the ability to estimate accurately the model parameters given the input and the output measurement. Previous studies of the Balloon model have somehow added knowledge either by choosing prior distributions for the parameters, freezing some of them, or looking for the solution as a projection on a natural basis of some vector space. In these studies, the identification was generally assessed using event-related paradigms. This paper justifies the reasons behind the need of adding knowledge, choosing certain paradigms, and completing the few existing identifiability studies through a global sensitivity analysis of the Balloon model in the case of blocked design experiment.

No MeSH data available.


Related in: MedlinePlus

Norm of the BOLD relative error in percent (100 · ‖Δy‖/‖y‖) as a function of variation in parameters; the error value is limited to 40% for most of the parameters. It goes to more than 50% for Θ6 to view the maximum.
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fig3: Norm of the BOLD relative error in percent (100 · ‖Δy‖/‖y‖) as a function of variation in parameters; the error value is limited to 40% for most of the parameters. It goes to more than 50% for Θ6 to view the maximum.

Mentions: Each subplot of Figure 3 (except the first one which is the nominal BOLD) corresponds to the relative error in percent of the BOLD signal when one of the parameters takes values in a grid around the nominal value (shown in Table 1).


A Sensitivity Analysis of fMRI Balloon Model.

Zayane C, Laleg-Kirati TM - Comput Math Methods Med (2015)

Norm of the BOLD relative error in percent (100 · ‖Δy‖/‖y‖) as a function of variation in parameters; the error value is limited to 40% for most of the parameters. It goes to more than 50% for Θ6 to view the maximum.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4442414&req=5

fig3: Norm of the BOLD relative error in percent (100 · ‖Δy‖/‖y‖) as a function of variation in parameters; the error value is limited to 40% for most of the parameters. It goes to more than 50% for Θ6 to view the maximum.
Mentions: Each subplot of Figure 3 (except the first one which is the nominal BOLD) corresponds to the relative error in percent of the BOLD signal when one of the parameters takes values in a grid around the nominal value (shown in Table 1).

Bottom Line: By identifiability, we mean the ability to estimate accurately the model parameters given the input and the output measurement.Previous studies of the Balloon model have somehow added knowledge either by choosing prior distributions for the parameters, freezing some of them, or looking for the solution as a projection on a natural basis of some vector space.In these studies, the identification was generally assessed using event-related paradigms.

View Article: PubMed Central - PubMed

Affiliation: Computer, Electrical and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.

ABSTRACT
Functional magnetic resonance imaging (fMRI) allows the mapping of the brain activation through measurements of the Blood Oxygenation Level Dependent (BOLD) contrast. The characterization of the pathway from the input stimulus to the output BOLD signal requires the selection of an adequate hemodynamic model and the satisfaction of some specific conditions while conducting the experiment and calibrating the model. This paper, focuses on the identifiability of the Balloon hemodynamic model. By identifiability, we mean the ability to estimate accurately the model parameters given the input and the output measurement. Previous studies of the Balloon model have somehow added knowledge either by choosing prior distributions for the parameters, freezing some of them, or looking for the solution as a projection on a natural basis of some vector space. In these studies, the identification was generally assessed using event-related paradigms. This paper justifies the reasons behind the need of adding knowledge, choosing certain paradigms, and completing the few existing identifiability studies through a global sensitivity analysis of the Balloon model in the case of blocked design experiment.

No MeSH data available.


Related in: MedlinePlus