Journal of Biometrics & Biostatistics

Sam Efromovich

Publications

• Research Article
  Statistical Analysis of Large Cross-Covariance and Cross-Correlation Matrices Produced by fMRI Images
  Author(s): Sam Efromovich and Ekaterina SmirnovaSam Efromovich and Ekaterina Smirnova
  
  The paper describes the theory, methods and application of statistical analysis of large-p-small-n cross-correlation matrices arising in fMRI studies of neuroplasticity, which is the ability of the brain to recognize neural pathways based on new experience and change in learning. Traditionally these studies are based on averaging images over large areas in right and left hemispheres and then finding a single cross-correlation function. It is proposed to conduct such an analysis based on a voxel-to-voxel level which immediately yields large cross-correlation matrices. Furthermore, the matrices have an interesting property to have both sparse and dense rows and columns. Main steps in solving the problem are: (i) treat observations, available for a single voxel, as a nonparametric regression; (ii) use a wavelet transform and then work with empirical wavelet coefficients; (iii) develop th.. Read More»
  DOI: 10.4172/2155-6180.1000193

  Abstract PDF