Emotions in reading: Dissociation of happiness and positivity.

The hierarchical emotion model proposed by Panksepp (1998) predicts that affective processing will rely on three functionally and neuroanatomically distinct levels, engaging subcortical networks (primary level), the limbic system (secondary level), and the neocortex (tertiary level). In the present fMRI study, we manipulated happiness and positivity, which are assumed to rely on secondary- and tertiary-level processes, respectively, to test these assumptions in a word recognition task. In accordance with the model predictions, evidence for a double dissociation was found in the brain activation patterns: Secondary-level processes engaged parts of the limbic system-specifically, the right hemispheric amygdala. Tertiary-level processes, in contrast, relied predominantly on frontal neocortical structures such as the left inferior frontal and medial frontal gyri. These results are interpreted as support for Panksepp's (1998) model and as an indicator of a semantic foundation of affective dimensions.