A nonlinear measure of fmri functional connectivity based on resting bold event triggered averages (rbeta)

D. FRAIMAN, E. R. TAGLIAZUCCHI, P. BALENZUELA, M. A. MUÑOZ, P. MONTOYA, D. R. CHIALVO

Congreso; Neuroscience 2011; 2011

Spontaneous fluctuations in BOLD fMRI signals organize into rich spatial patterns which are closely related to those seen in response to task performance/stimulation. In this work we propose a method based on the analysis of spontaneous resting BOLD event triggered averages ("rBETA"). The rBETA method evaluates the average BOLD time course at a region of interest after spontaneous activations in a seed region, thus it is a nonlinear measure of functional connectivity between brain regions. To validate the approach we recover the connectivity patterns observed during a simple motor task, from subsequent resting state measurements. In addition, we show how the rBETA method is able to detect, during the resting state, specific connectivity alterations described previously in chronic back pain patients during painful thermal stimulation. The results show that the rBETA is a reliable tool, allowing for a straightforward computation and interpretation of the strength of fMRI brain pair-wise interactions in health and disease.