School of Informatics, Computing, and Engineering (SICE)
Intelligent Systems Engineering Colloquium Series (ISE)
Speaker: Jaroslaw Harezlak, Associate Professor, Indiana University, School of Public Health
Where: Luddy Hall 1106
When: Friday, April 20, 2018 at 1:15 PM
Title: Brain Connectivity-Informed Regularization Methods for Regression
Abstract: One of the challenging problems in brain imaging research is a principled incorporation of information from different imaging modalities. Frequently, each modality is analyzed separately using, for instance, dimensionality reduction techniques, which result in a loss of mutual information. We propose a novel regularization method to estimate the association between the brain structure features and a scalar outcome within the linear regression framework. Our regularization technique provides a principled approach to use external information from the structural brain connectivity and inform the estimation of the regression coefficients. Our proposal extends the classical Tikhonov regularization framework by defining a penalty term based on the structural connectivity-derived Laplacian matrix. The approach is first illustrated using simulated data and compared with other penalized regression methods. We then apply our regularization method to study the associations between the alcoholism phenotypes and brain cortical thickness using a diffusion imaging derived measure of structural connectivity. Using the proposed methodology in 148 young male subjects with a risk for alcoholism, we found negative associations between cortical thickness and drinks per drinking day in bilateral caudal anterior cingulate cortex, left lateral OFC and left precentral gyrus.
Biography: Dr. Harezlak is an Associate Professor in the Department of Epidemiology and Biostatistics at the Indiana University School of Public Health-Bloomington, Indiana. After completing his doctoral studies at the Harvard University and 2 years of post-doctoral training at the Harvard School of Public Health, he joined Indiana University where he has been since. He has held a visiting appointment at Johns Hopkins University, Baltimore, MD and is an adjunct professor at the University of Wroclaw, Poland. His interests span a number of medical areas including mild traumatic brain injury, neurodegenerative diseases and physical activity as well as statistical areas including semiparametric regression, functional data analysis and brain imaging. Dr. Harezlak serves as an Associate Editor for PLoS One and Biostatistics and Epidemiology as well as a Guest Associate Editor for Statistics in Biosciences.