Brain topography, connectivity dynamics and coding mechanisms underlying the subjective experience of affective states

The present dissertation focuses on the behavioral and neural substratesof socio-affective abilities involved in the subjective emotionalexperience. Socio-affective abilities are the building blocks of the moregeneral domain of social cognition, which represents the cornerstone ofhuman interactions. In particular, understanding, predicting andresponding to others’ emotional signals are fundamental aspectsnecessary for the optimal functioning of human’s daily life. Emotions arepervasively present in dyadic interactions, give color to individualexperiences, and can rapidly change over time, as they are theconsequence of an active interplay between an individual and theenvironment. Despite their relevance, however, emotions are still anopen question for researchers.Indeed, which mechanisms link descriptions of affective states to brainactivity is still unclear, with evidence supporting either local ordistributed processing. Moreover, the majority of neuroimaging studiesso far did not take into account the dynamism of affective states and theirunfolding over time. For this reason, how the temporal characteristics ofemotions (e.g., duration, onset, resurgence) are represented in the brain,with the dynamics between specific regions related to differentemotional experiences is an open question.In light of all this, the studies reported in the present dissertation aimedto overcome previous limitations and answer these questions. In the firststudy we used brain hemodynamic activity evoked by an emotionallycharged movie and continuous ratings of the perceived emotionintensity to reveal the topographic organization of affective states. In thesecond study, we explored the dynamic interplay between differentbrain regions throughout a naturalistic situation. To do so, we relatedcontinuous ratings of the perceived intensity of various emotional statesto changes in functional connectivity among distinct brain regionsduring the watching of the same movie employed before.Our results showed that moment-by-moment ratings of perceivedemotions explain brain activity recorded in independent subjects. Mostimportantly, we demonstrated the existence of orthogonal and spatiallyoverlapping right temporo-parietal gradients encoding emotiondimensions, a mechanism that we named emotionotopy. We also unveiledthe central role of the right precentral sulcus during the subjectiveemotional experience, with changes in the functional connectivitydynamics of this region being modulated by three cardinal emotiondimensions.