An optimized-sequence event-related morphological paradigm reveals Bayesian evidence of brain activation during Spanish verb-tense operations

A Bayesian-inference group analysis, done on functional magnetic resonance images corresponding to healthy Mexican Spanish-speaking subjects to whom an optimized-sequence rapid-presentation event-related morphological paradigm was applied, revealed statistically the activation of key brain regions (e.g. the inferior frontal gyrus including areas such as Brodmann 44 and 45, left hemisphere, for verbal inflections, the anterior region of the opercular and right superior temporal gyrus for infinitives, etc.). The sequence of stimuli that allowed us to statistically reveal loci of Spanish verbal computational operations such us rapid verbal inflections was optimized by using a statistical efficiency metrics based on the covariance of the set of regressor coefficients with respect to the matrix of such regressors (basis functions in correspondence to the occurrence of stimuli). This way, by launching a Gaussian- based random search we ended up with one of the best combinatory sequences for presentation of the stimuli.