Semiparametric
Detection of Significant
Activation for Brain fMRI Chunming Zhang Statistics Department University of Wisconsin, Madison Abstract
Functional magnetic resonance
imaging (fMRI) aims to locate activated regions in human brains when
specific tasks are performed. The conventional tool for analyzing fMRI
data applies some variant of the linear model, which is restrictive in
modeling assumptions. To yield more accurate prediction of the
time-course behavior of neuronal responses, the semi-parametric
inference for the underlying hemodynamic response function is developed
to identification of significantly activated voxels. Under mild
regularity conditions, we demonstrate that a class of the proposed
semi-parametric test statistics, based on the local-linear estimation
technique, follow Chi-Squared distributions under the null hypotheses
for a number of useful hypotheses. Furthermore, a new false discovery
rate approach which incorporates spatial information of voxel-wise
p-values is devised for detecting the regions of activation. Simulation
evaluations and real fMRI data application endorse that the
semiparametric inference procedure delivers more efficient detection of
activated brain areas than popular imaging analysis tools.
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