Comparing three models of arousal in the human brain.

The bipolar valence-arousal model is assumed by many to be an underlying structure of conscious experience of core affect and emotion. In this work, we compare three versions of the bipolar valence-arousal model at the neural domain, using functional magnetic resonance imaging (fMRI). Specifically, we systematically contrast three models of arousal: model 1-'arousal as a separate quale from valence', model 2-'arousal as intensity of bipolar valence' and model 3-'arousal as a linear combination of unipolar pleasant and unpleasant'. Using parametric modulation analysis, we estimated the ability of each model to predict activation in arousal-related brain regions, in response to affective stimuli. The results suggest that arousal is not separable from valence in its ability to predict arousal-related neural activity. The relevance of the results to the theory of conscious affect is discussed.

Dissociating affective and semantic valence.

We examined the possible dissociation between two modes of valence: affective valence (valence of e emotional response) and semantic valence (stored knowledge about valence of an object or event). In Experiment 1, 50 participants viewed affective pictures that were repeatedly presented while their facial electromyography (EMG) activation and heart rate response were continuously recorded. Half of the participants provided self-report ratings about the valence of their feelings and half about the valence of the stimulus. Next, all participants performed an affective Simon task. In Experiment 2, 30 new participants performed the affective Simon task with the repeated exposure embedded within the task. The results showed that measures related to affective valence (feelings-focused self-reports, heart rate, and facial EMG activations) attenuated with repeated exposure to pleasant and unpleasant pictures, whereas measures related to semantic valence (knowledge-focused self-reports and congruency effect of affective Simon task) did not. These findings strongly suggest that affective and semantic valence represent two distinct psychological constructs. (PsycINFO Database Record