Regional Homogeneity of Intrinsic Brain Activity in Happy and Unhappy Individuals

Abstract

BackgroundWhy are some people happier than others? This question has intrigued many researchers. However, limited work has addressed this question within a neuroscientific framework.MethodsThe present study investigated the neural correlates of trait happiness using the resting-state functional magnetic resonance imaging (rs-fMRI) approach. Specifically, regional homogeneity (ReHo) was examined on two groups of young adults: happy and unhappy individuals (N = 25 per group).ResultsDecreased ReHo in unhappy relative to happy individuals was observed within prefrontal cortex, medial temporal lobe, superior temporal lobe, and retrosplenial cortex. In contrast, increased ReHo in unhappy relative to happy individuals was observed within the dorsolateral prefrontal cortex, middle cingulate gyrus, putamen, and thalamus. In addition, the ReHo within the left thalamus was negatively correlated with Chinese Happiness Inventory (CHI) score within the happy group.LimitationsAs an exploratory study, we examined how general trait happiness is reflected in the regional homogeneity of intrinsic brain activity in a relatively small sample. Examining other types of happiness in a larger sample using a multitude of intrinsic brain activity indices are warranted for future work.ConclusionsThe local synchronization of BOLD signal is altered in unhappy individuals. The regions implicated in this alteration partly overlapped with previously identified default mode network, emotional circuitry, and rewarding system, suggesting that these systems may be involved in happiness.

A systematic review of the neural correlates of positive emotions

“…The authors concluded that systems concerned with default mode network (DMN), emotional circuitry, and the reward system may be involved in happiness. 37 In a subsequent study, Luo et al 39 showed that functional connectivity in the DMN was negatively associated with happiness and positively associated with the inclination to ruminate. These results highlight the importance of the DMN to work on the neural correlates of happiness, and suggest that rumination may play an important role in perception of happiness.…”

“…Negative and positive emotions were found to be associated with different cortical activation foci within a common neural network, probably discriminating different emotional feelings. [32][33][34][35][36][37] Compared with a control task, tasks designed to induce sad or happy mood produced similar activation of the amygdala-hippocampal area, with activation extending into the parahippocampal gyrus, as well as activation of the prefrontal, temporal, and anterior cingulate cortices and the precuneus. However, happiness produced stronger activation than sadness in the dorsolateral prefrontal cortex, the cingulate gyrus, the inferior temporal gyrus, and the cerebellum.…”

“…Furthermore, humans seem to be better at regulating positive emotions than negative emotions. 34 Luo et al 37 used resting-state fMRI (rs-fMRI) to investigate the neural correlates of trait happiness. They employed regional homogeneity (ReHo) as a measure of intrinsic brain activity in happy and unhappy individuals.…”

Different neural pathways linking personality traits and eudaimonic well-being: a resting-state functional magnetic resonance imaging study

“…Previous neuroimaging studies have begun to investigate the neural basis of EWB at the regional level and found that EWB is involved in multiple brain regions including the temporal, insular, prefrontal, and limbic cortices (Heller et al, 2013;Lewis, Kanai, Rees, & Bates, 2013;Luo, Huang, Yang, Li, Liu, & Wei, 2014;van Reekum et al, 2007). For example, structurally, higher EWB is associated with larger gray matter volume (GMV) in the insula (Lewis et al, 2013).…”

Alterations in regional homogeneity of resting-state brain activity in patients with major depressive disorder screening positive on the 32-item hypomania checklist (HCL-32)

“…ReHo abnormalities (either increase or decrease in ReHo value) are related to unbalanced local brain activity. In recent years, ReHo has been successfully used to investigate the brain function in healthy subjects (Kunisato et al, 2011;Luo et al, 2014) and clinical populations with psychiatric disorders Guo et al, 2011;Liang et al, 2013;Liu et al, 2012e;Zang et al, 2004). For MDD, extensively distributed abnormal brain activities have been observed during resting-state and some clinical symptoms have been related to specific abnormal patterns of brain activities (Yao et al, 2009).…”