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Principal Investigator  
Principal Investigator's Name: Yogasudha Veturi
Institution: Pennsylvania State University
Department: Biobehavioral Health / Statistics
Country:
Proposed Analysis: We propose to understand between-sex genetic heterogeneity in the stress-cognitive decline relationship using Bayesian multivariate random effect interaction models implemented on cortisol levels and cognitive assessments. We will also identify areas of the brain associated with sex-specific neurodegeneration using extensions of same interaction models implemented on voxel-level functional neuroimaging data. Our past work has suggested genetic heterogeneity between sexes for obesity-related risk factors for cognitive decline (e.g., systolic blood pressure and waist-hip-ratio). Several small effect causal loci can cumulatively influence sex differences among individuals with cognitive decline. We developed methods that can incorporate genotype-by-sex random-effect interactions (GBS-REI) in a hierarchical Bayesian framework. These methods can decompose conditional SNP effects into three components: (i) shared across sexes, (ii) male-specific and (iii) female-specific deviations from the shared component and offer opportunities to study sex-specific genetic architectures of stress and cognitive decline. Our models can estimate average correlation of marker effects between sexes, proportion of non-zero effects as well as offer SNP-specific correlation of effects. Importantly, these can yield unbiased estimates of between-sex effect correlation. This is in stark contrast to obtaining a simple correlation of effects from sex-stratified models, which is heavily biased towards zero. To our knowledge, no other existing models can offer such a rich variety of genetic summaries for male, female and shared SNP effects. We also developed powerful region-based score tests that can test for the statistical significance of the between-sex correlation of effects on a gene-by-gene or pathway-by-pathway basis. These methods can be used to understand between-sex genetic heterogeneity in the stress-cognitive decline relationship as well as understand the regions of the brain driving the genetic heterogeneity.
Additional Investigators  
Investigator's Name: Hyebin Song
Proposed Analysis: We are developing hierarchical statistical models that can integrate longitudinal fMRI data with multi-omic data to predict risk of AD.
Investigator's Name: Varun Kartikey
Proposed Analysis: Performing QC on the fMRI and genomic ADNI data to set the stage for implementing novel statistical methods.