A regularized matrix factorization approach to induce structured sparse-low-rank solutions in the EEG inverse problem Articles uri icon

publication date

  • December 2014

volume

  • 2014

International Standard Serial Number (ISSN)

  • 1687-6172

Electronic International Standard Serial Number (EISSN)

  • 1687-6180

abstract

  • We consider the estimation of the Brain Electrical Sources (BES) matrix from noisy electroencephalographic (EEG) measurements, commonly named as the EEG inverse problem. We propose a new method to induce neurophysiological meaningful solutions, which takes into account the smoothness, structured sparsity, and low rank of the BES matrix. The method is based on the factorization of the BES matrix as a product of a sparse coding matrix and a dense latent source matrix. The structured sparse-low-rank structure is enforced by minimizing a regularized functional that includes the l 21-norm of the coding matrix and the squared Frobenius norm of the latent source matrix. We develop an alternating optimization algorithm to solve the resulting nonsmooth-nonconvex minimization problem. We analyze the convergence of the optimization procedure, and we compare, under different synthetic scenarios, the performance of our method with respect to the Group Lasso and Trace Norm regularizers when they are applied directly to the target matrix.

keywords

  • structured sparsity; low rank ; matrix factorization ; regularization ; nonsmooth-nonconvex optimization