Chronotopic encoding of emotional dimensions in the human brain assessed by FMRI

Abstract

Introduction

Affective experiences vary as function of context, motivations and the unfolding of events. This temporal fundamental aspect of emotional processes is often disrupted in psychiatric conditions.

Objectives

To investigate how the brain represents the association between affect and time, we combined fMRI and behavioral ratings during movie watching.

Methods

Participants watched ‘Forrest Gump’ in the fMRI scanner (n=14, 6F). Data were preprocessed (see 10.1101/2020.06.06.137851v1) and average brain activity from 1000 regions was extracted. Independent subjects (n=12, 5F) provided continuous ratings of the intensity of their affective state while watching the same movie. Using PCA, we derived the first 3 affective dimensions (polarity, complexity, intensity; 10.1038/s41467-019-13599-z) and computed their time-varying correlation in windows from 5-1000tps. We identified the window size with the maximum between-subjects accordance and computed the inter-subject functional connectivity (10.1038/ncomms12141). For each region, we obtained connectivity strength and its association in time with changes in affective dimensions (p_Bonf<0.05).

Results

Fluctuations in connectivity strength of the right rMFG, precuneus, pSTS/TPJ, dmPFC, aINS and left pMTG were associated to polarity. Also, connectivity of the right IPS/SPL, SFG, dpreCS, IFGpOrb, OFC, precuneus, vpreCS and pSTS/TPJ followed the timecourse of perceived intensity of affect.

Conclusions

Connectivity strength of default mode represents the pleasantness of the experience, whereas attention and control networks encode its intensity. Emotional descriptions converge in right temporoparietal and fronto-polar cortex, where the stream of affect is encoded in a chronotopic manner. These results expand our understanding of the neural correlates of emotional processing, a function severely affected by mental disorders.

Disclosure

No significant relationships.