  It is now recognized that important information can be extracted from the
brain spontaneous activity, as exposed by recent analysis using a repertoire of
computational methods. In this context a novel method, based on a blind
deconvolution technique, is used in this paper to analyze potential changes due
to chronic pain in the brain pain matrix's effective connectivity. The approach
is able to deconvolve the hemodynamic response function to spontaneous neural
events, i.e., in the absence of explicit onset timings, and to evaluate
information transfer between two regions as a joint probability of the
occurrence of such spontaneous events. The method revealed that the chronic
pain patients exhibit important changes in the Insula's effective connectivity
which can be relevant to understand the overall impact of chronic pain on brain
function.
