Neural patterns associated with mixed valence feelings differ in consistency and predictability throughout the brain

Mixed valence feelings, defined by the simultaneous presence of positive and negative affect, remain understudied in neuroscience. We used functional magnetic resonance imaging to investigate subjects watching an animated short film known to induce mixed feelings. These same subjects were asked to identify the time periods during which they had experienced positive, negative, and mixed feelings. Using Hidden-Markov models, we found that activity in the insula, amygdala, nucleus accumbens, and anterior cingulate allowed us to predict the onset of new feeling states as determined by individual self-report. Further analyses found spatiotemporally unique and consistent neural patterns in the insular cortex for univalent states, but not for mixed valence states. However, ventromedial prefrontal cortex and anterior cingulate exhibited unique neural consistency for both univalent and mixed valence states. This study is the first to reveal direct evidence for a neurally consistent representation of mixed feelings in the central nervous system.