TY - JOUR
T1 - Iterative approach of dual regression with a sparse prior enhances the performance of independent component analysis for group functional magnetic resonance imaging (fMRI) data
AU - Kim, Yong Hwan
AU - Kim, Junghoe
AU - Lee, Jong Hwan
N1 - Funding Information:
Sources of support: This work was supported by the WCU (World Class University) program through the National Research Foundation (NRF) of Korea funded by the Ministry of Education, Science and Technology ( R31-10008 ) and Basic Science Research Program, NRF grant of Korea ( 2012-0002342 ). These sponsors had no involvement in the study design, data collection, analysis/interpretation of data, writing of this manuscript, or decision to submit for publication.
PY - 2012/12
Y1 - 2012/12
N2 - This study proposes an iterative dual-regression (DR) approach with sparse prior regularization to better estimate an individual's neuronal activation using the results of an independent component analysis (ICA) method applied to a temporally concatenated group of functional magnetic resonance imaging (fMRI) data (i.e., Tc-GICA method). An ordinary DR approach estimates the spatial patterns (SPs) of neuronal activation and corresponding time courses (TCs) specific to each individual's fMRI data with two steps involving least-squares (LS) solutions. Our proposed approach employs iterative LS solutions to refine both the individual SPs and TCs with an additional a priori assumption of sparseness in the SPs (i.e., minimally overlapping SPs) based on L1-norm minimization. To quantitatively evaluate the performance of this approach, semi-artificial fMRI data were created from resting-state fMRI data with the following considerations: (1) an artificially designed spatial layout of neuronal activation patterns with varying overlap sizes across subjects and (2) a BOLD time series (TS) with variable parameters such as onset time, duration, and maximum BOLD levels. To systematically control the spatial layout variability of neuronal activation patterns across the "subjects" (n=12), the degree of spatial overlap across all subjects was varied from a minimum of 1voxel (i.e., 0.5-voxel cubic radius) to a maximum of 81voxels (i.e., 2.5-voxel radius) across the task-related SPs with a size of 100voxels for both the block-based and event-related task paradigms. In addition, several levels of maximum percentage BOLD intensity (i.e., 0.5, 1.0, 2.0, and 3.0%) were used for each degree of spatial overlap size. From the results, the estimated individual SPs of neuronal activation obtained from the proposed iterative DR approach with a sparse prior showed an enhanced true positive rate and reduced false positive rate compared to the ordinary DR approach. The estimated TCs of the task-related SPs from our proposed approach showed greater temporal correlation coefficients with a reference hemodynamic response function than those of the ordinary DR approach. Moreover, the efficacy of the proposed DR approach was also successfully demonstrated by the results of real fMRI data acquired from left-/right-hand clenching tasks in both block-based and event-related task paradigms.
AB - This study proposes an iterative dual-regression (DR) approach with sparse prior regularization to better estimate an individual's neuronal activation using the results of an independent component analysis (ICA) method applied to a temporally concatenated group of functional magnetic resonance imaging (fMRI) data (i.e., Tc-GICA method). An ordinary DR approach estimates the spatial patterns (SPs) of neuronal activation and corresponding time courses (TCs) specific to each individual's fMRI data with two steps involving least-squares (LS) solutions. Our proposed approach employs iterative LS solutions to refine both the individual SPs and TCs with an additional a priori assumption of sparseness in the SPs (i.e., minimally overlapping SPs) based on L1-norm minimization. To quantitatively evaluate the performance of this approach, semi-artificial fMRI data were created from resting-state fMRI data with the following considerations: (1) an artificially designed spatial layout of neuronal activation patterns with varying overlap sizes across subjects and (2) a BOLD time series (TS) with variable parameters such as onset time, duration, and maximum BOLD levels. To systematically control the spatial layout variability of neuronal activation patterns across the "subjects" (n=12), the degree of spatial overlap across all subjects was varied from a minimum of 1voxel (i.e., 0.5-voxel cubic radius) to a maximum of 81voxels (i.e., 2.5-voxel radius) across the task-related SPs with a size of 100voxels for both the block-based and event-related task paradigms. In addition, several levels of maximum percentage BOLD intensity (i.e., 0.5, 1.0, 2.0, and 3.0%) were used for each degree of spatial overlap size. From the results, the estimated individual SPs of neuronal activation obtained from the proposed iterative DR approach with a sparse prior showed an enhanced true positive rate and reduced false positive rate compared to the ordinary DR approach. The estimated TCs of the task-related SPs from our proposed approach showed greater temporal correlation coefficients with a reference hemodynamic response function than those of the ordinary DR approach. Moreover, the efficacy of the proposed DR approach was also successfully demonstrated by the results of real fMRI data acquired from left-/right-hand clenching tasks in both block-based and event-related task paradigms.
KW - Alternating least squares
KW - Back reconstruction
KW - Dual regression
KW - General linear model
KW - Group ICA
KW - Independent component analysis
KW - Iterative dual regression
KW - Non-Gaussianity
KW - Sparse prior
UR - http://www.scopus.com/inward/record.url?scp=84866991727&partnerID=8YFLogxK
U2 - 10.1016/j.neuroimage.2012.08.055
DO - 10.1016/j.neuroimage.2012.08.055
M3 - Article
C2 - 22939873
AN - SCOPUS:84866991727
VL - 63
SP - 1864
EP - 1889
JO - NeuroImage
JF - NeuroImage
SN - 1053-8119
IS - 4
ER -