Research On The Role Of Emotional Arousal In The Shared Neural Basis Of Positive And Negative Emotions

Emotions have long been a focus of interest in the fields of psychology and neuroscience,and previous studies have used functional Magnetic Resonance Imaging(f MRI)and emotional images to investigate the neural correlates of positive and negative affect.It is unclear whether co-activations indicate that positive and negative affect share common neural representations and what factor causes valence-unspecific emotions to show similar brain activation.Otherwise,given that arousal is a fundamental dimension of emotion,it is important for all emotional research to pay attention to the arousal that plays a key role in emotion processing and regulation.Psychiatric disorders such as posttraumatic stress disorder may also be triggered by confessional arousal.Investigation of the neural basis of arousal not only helps to explain the common neural representations of positive and negative affect,but also helps to better understand emotional processing and to develop new treatments for mental disorders.In this study,we used a naturalistic stimulus paradigm to induce different levels of emotional arousal in individuals and applied both multivariate pattern analysis and univariate analysis to answer two main questions:(1)whether arousal plays an important role in the shared neural representations of positive and negative affect and further(2)whether the neural signatures of subjective arousal can be determined.In the Study 1,during the arousal rating f MRI paradigm,participants(n = 60)were asked to rate their level of arousal experience following each video.(1)Univariate analysis revealed that cortical and subcortical regions were activated(i.e.,amygdala,insula,dorsomedial prefrontal cortex(dm PFC),dorsolateral prefrontal cortex(dl PFC),ventromedial prefrontal cortex(vm PFC))during both positive and negative conditions.(2)Whole-brain multivariate pattern analysis demonstrated positive and negative affect have similar neural responses in some regions(amygdala,hippocampus,anterior insula,some regions of prefrontal cortex).(3)Searchlight-based analysis and Region-of-Interest(ROI)analyses further revealed that positive and negative affect have a common neural representation in amygdala,insula,dl PFC,and dm PFC.Study 2 used three datasets,including the discovery cohort(study1,n = 60),validation cohort(n = 30),and generalization cohort(from previous studies,n = 49).Using multivariate pattern analysis,we developed subjective arousal-predictive model with high sensitivity and robustness and identified the important regions for decoding arousal in the brain,including amygdala,insula,parahippocampal,dl PFC,dm PFC.We also found that these regions show overlapping activity in the shared neural representation of positive and negative affect,and that models predicting positive and negative affect were able to predict arousal in the validation dataset.It has been shown that valence is closely linked to arousal at the neural level.In conclusion,our studies systematically verified the role of emotional arousal in the common neural basis of positive and negative emotions using two f MRI studies and identified the neural signatures of arousal in the brain.We emphasized the crucial role of arousal in emotional studies and neural signatures of subjective arousal could be used to evaluate the treatment of psychiatric disorders related to arousal.