Distinct dimensions of emotion in the human brain and their representation on the cortical surface

We experience a rich variety of emotions in daily life. While previous emotion studies focused on only a few predefined, restricted emotional states, a recent psychological study found a rich emotional representation in humans using a large set of diverse human-behavioural data. However, no representation of emotional states in the brain using emotion labels has been established on such a scale. To examine that, we used functional MRI to measure blood-oxygen-level-dependent (BOLD) responses when human subjects watched 3-h emotion-inducing movies labelled with 10,800 ratings regarding each of 80 emotion categories. By quantifying canonical correlations between BOLD responses and emotion ratings for the movie scenes, we found 25 significant dimensions of emotion representation in the brain. Then, we constructed a semantic space of the emotion representation and mapped the emotion categories on the cortical surface. We found that the emotion categories were smoothly represented from unimodal to transmodal regions on the cortical surface. This paper presents a cortical representation of a rich variety of emotion categories, which covers most of the emotional states suggested in traditional theories.