Figure 1.

Relationships among experiments, tasks, cognitive components, and brain regions. Underpinning our approach is the premise that performing any given task often engages not one but several cognitive components that are in turn supported by multiple brain regions (Walton and Paul 1901; Posner et al. 1988; Mesulam 1990; Poldrack 2006). Different tasks might engage common and distinct cognitive components. Furthermore, different components may activate common and distinct brain regions. Here, we demonstrated that the framework can be instantiated with a formal mathematical model (Rosen-Zvi et al. 2010), whose parameters can be estimated. The estimated model parameters are the probability that a task would recruit a cognitive component for an activation focus (i.e., Pr(component | task)) and the probability a cognitive component would activate a brain voxel for an activation focus (i.e., Pr(voxel | component)). The model parameters enabled us to derive quantitative maps of functional specialization and flexibility across the cerebral cortex. Here, the term “cognitive component” is operationally defined as latent variables within the mathematical model (Supplementary Fig. 1).