Dear all Hi Thank you so much for your time. I tried locating activation regions during a task by performing GLM analysis.The resulted beta maps consist of a large number of negative beta values and few positive ones(negative beta almost covers the whole brain when I view the beta maps uing mricroGL!!!).As far as I know positive beta value implies activation.What about negative beta? If I want to consider only the positive values should I manually zero the negative values? Thank you in advance. Best, Mahsa