Nonlinear regression of functional MRI data: An item recognition task study

A classical item-recognition task was used to examine human verbal working memory in an event-related functional MRI (fMRI) study. A highly flexible e xperimental design incorporated a broad variation of memory load and delay time. This design allows for only three or four repetitions per stimulus co ndition. In a first step, linear regression analysis was applied to locate functional activation in the fMRI data. As a second step, the time course o f the hemodynamic response (HR) was analyzed using nonlinear regression, wh ich served to quantify the dependency between HR shape properties and stimu lation conditions in several regions-of-interest. On the basis of this stud y, a closer description of the frontoparietal network involved in verbal wo rking memory was possible, (C) 2000 Academic Press.