RT Journal Article T1 Regularized bagged canonical component analysis for multiclass learning in brain imaging A1 Sevilla Salcedo, Carlos A1 Gómez Verdejo, Vanessa A1 Tohka, Jussi A2 Alzheimer’s Disease Neuroimaging Initiative (ADNI), AB A fundamental problem of supervised learning algorithms for brain imaging applications is that the number of features far exceeds the number of subjects. In this paper, we propose a combined feature selection and extraction approach for multiclass problems. This method starts with a bagging procedure which calculates the sign consistency of the multivariate analysis (MVA) projection matrix feature-wise to determine the relevance of each feature. This relevance measure provides a parsimonious matrix, which is combined with a hypothesis test to automatically determine the number of selected features. Then, a novel MVA regularized with the sign and magnitude consistency of the features is used to generate a reduced set of summary components providing a compact data description. We evaluated the proposed method with two multiclass brain imaging problems: 1) the classification of the elderly subjects in four classes (cognitively normal, stable mild cognitive impairment (MCI), MCI converting to AD in 3 years, and Alzheimer’s disease) based on structural brain imaging data from the ADNI cohort; 2) the classification of children in 3 classes (typically developing, and 2 types of Attention Deficit/Hyperactivity Disorder (ADHD)) based on functional connectivity. Experimental results confirmed that each brain image (defined by 29.852 features in the ADNI database and 61.425 in the ADHD) could be represented with only 30 − 45% of the original features. Furthermore, this information could be redefined into two or three summary components, providing not only a gain of interpretability but also classification rate improvements when compared to state-of-art reference methods. PB Springer Nature SN 1539-2791 YR 2020 FD 2020-10 LK https://hdl.handle.net/10016/33848 UL https://hdl.handle.net/10016/33848 LA eng NO Alzheimer’s Disease Neuroimaging Initiative (ADNI) is a Group/Institutional Author. Data used in preparation of this article were obtained from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database (adni.loni.usc.edu). As such, the investigators within the ADNI contributed to the design and implementation of ADNI and/or provided data but did not participate in analysis or writing of this report. NO C. Sevilla-Salcedo and V. Gomez-Verdejo's work has been partly funded by the Spanish MINECO grant TEC2014-52289-R and TEC2017-83838-R as well as KERMES, which is a NoE on kernel methods for structured data, funded by the Spanish Ministry of Economy and Competitiveness, TEC2016-81900-REDT ru. Jussi Tohka's work is supported by the Academy of Finland (grant 316258). DS e-Archivo RD 27 jul. 2024