The Brain Mechanism Of Romantic Love

Romantic love is generally considered to be one of the most profound and meaningful emotions in human emotions,and plays an important role in human reproduction,development,survival and evolution.Previous studies have shown that romantic love affects our emotions,behaviors and cognition.Previous resting-state and task-related functional magnetic resonance imaging(fMRI)studies show that romantic love is closely related to brain functional changes in reward and motivation systems.Previous studies on the neural mechanisms of romantic love are almost limited to reward and motivation systems,but in theory,romantic love may also relate to social cognitive systems(such as self-representation systems that include others into the self).Therefore,in this study,college students are recruited as the participants,task-related and resting-state fMRI are used as the research method and we aimed to explore whether the neural mechanism of romantic love is associated with other brain networks in addition to reward and motivation system,through changes of the brain activation level and brain network indicators of individuals in love.Study 1: We used the task of seeing photos to further explore the brain mechanism of romantic love by investigating differences in brain activation indicators under different conditions.Forty-eight college students in love(sixteen male)from Southwest University participate in the study.Participants are required to provide four photos as experimental materials: self,mother,heterosexual friend,and partner.Then they need to recall the most impressive thing that happened with the person in the photo while looking at the photo(lasting 30s),and then count down numbers(lasting 40s).The results of whole brain activation analysis found that(1)compared with looking at their own photos,looking at the photo of their partner activated the left superior medial frontal gyrus(involving reward);while the right angular gyrus(involving self-concept and self-representation),right inferior temporal gyrus and right middle temporal gyrus(involving emotion-social processing)deactivated.(2)Compared with looking at the photo of their own mother,there is no positive activation area when looking at the photo of their partner,but negative activation occurs in the right rolandic operculum,right insula,and right putamen,indicating that part of the difference in the activation of romantic love and affection brain is from the reward.Study 2: We used the resting-state fMRI technique and graph theory analysis method to explore the brain mechanism of romantic love by investigating differences in brain network between individuals in love and single individuals.A total of 66 students from Southwest University were randomly recruited,of which 34 were in the love group(16 females and 18 males),32 in the single group(14 females and 18 males).The graph theory analysis results found that compared with single group,the brain network of love group:(1)the small-world character is lower;(2)the meaning clustering coefficient is lower;(3)the degree of modularity is lower(the average network module of the love group is five,and six in the single group);(4)the degree of some brain regions changed: decreased degree in angular gyrus,and increased degree in fusiform gyrus and orbitofrontal cortex;(5)partial correlation analysis shows that the Passionate Love Scale(PLS)score has a negative correlation with local efficiency of the left medial orbitofrontal cortex,a negative correlation with degree of the left angular gyrus,a positive correlation with clustering coefficient and local efficiency of the left fusiform gyrus and a trending positive correlation with aforementioned indicators of the right fusiform gyrus.This study shows that the resting-state brain network of individual in love has changed: the separation degree of whole brain network decreased,but the processing of reward(orbitofrontal cortex)and selfrepresentation(angular and fusiform gyrus)enhanced.This study draws the following conclusions:In addition to the reward and motivation systems(orbitofrontal cortex etc.),Romantic love also involves social cognition self-representation system(medial superior frontal gyrus,angular gyrus,fusiform gyrus etc.).Our study enriches and expands the related research of romantic love,and deepens our understanding about the brain mechanism of romantic love.