Happy people are always similar: The evidence from brain morphological and functional inter-subject correlations

Approach bias modification reduces automatic gaming tendencies and enhances brain synchronization in internet gaming disorder

BACKGROUND

Automatic approaches to gaming-related cues are key factors in internet gaming disorder (IGD). Approach bias modification (ApBM) has been shown to reduce addictive behaviors, but its neurobiological effects remain poorly understood. This study examined changes in brain activities in the 'natural' state in IGD patients after ApBM.

METHODS

Fifty-five (of 61) IGD patients were randomly assigned to the approach-avoidance task (AAT, n = 30) and sham-AAT (n = 25) groups. Participants completed the pre-test, five real/sham ApBM sessions, and the post-test. In the pre-and post-tests, fMRI data were collected while viewing gaming and neutral videos. Inter-subject correlation (ISC) and functional connectivity (FC) analyses were conducted to explore the ApBM-related changes.

RESULTS

ANOVA of behavioral data revealed that ApBM significantly decreased the approach bias and addiction scores. The ISC analyses revealed increased synchronization in the paracentral lobule, precuneus, and insula regions in the ATT group after ApBM. Additionally, decreased FC was observed between the insula and superior frontal gyrus, precuneus, and orbitofrontal cortex in the AAT group.

CONCLUSIONS

Preliminary findings suggest that ApBM may be effective in reducing automatic approach tendencies toward gaming cues, highlighting its potential as an intervention strategy. However, it is important to note that the neurobiological evidence in this study only provides a possible association, and the results should be interpreted with caution. Future research is needed to further examine the clinical efficacy of ApBM in IGD, whether as a stand-alone treatment or as an adjunct to formal therapy.

Loss aversion and evidence accumulation in short-video addiction: A behavioral and neuroimaging investigation

Excessive use of short-video platforms not only impairs decision-making processes but also predisposes individuals to addictive behaviors. This study investigated the relationship between short-video addiction (SVA) symptoms and loss aversion (LA), delving into the underlying computational and neural mechanisms using the drift diffusion model (DDM) and the inter-subject representational similarity analysis (IS-RSA). Behavioral analyses revealed a significant negative correlation between SVA symptoms and the LA coefficient (lnλ). Additionally, the DDM-based drift rate (v) was found to mediate this relationship. Neuroimaging analyses further indicated that SVA symptoms were negatively associated with gain-related activity in the right precuneus, while positively correlating with loss-related activity in the right cerebellum and left postcentral gyrus. Notably, precuneus activation during gain processing mediated the relationship between SVA symptoms and both lnλ and drift rate. IS-RSA revealed that inter-subject variations in SVA symptoms were significantly associated with distinct activation patterns related to gain processing in the frontoparietal network (e.g., frontal pole, inferior frontal gyrus, and supramarginal gyrus) and motor network (e.g., precentral), as well as loss-related activation patterns in the motor networks (e.g., postcentral and pre-supplementary motor area). Similar patterns emerged when examining simultaneous gain and loss-related activation patterns. Mediation analyses further demonstrated that functional activation patterns in the motor network mediated the relationships between inter-subject variations in SVA symptoms and both loss-aversion and psychological processing patterns (e.g., decision threshold, drift rate, and non-decision time). These findings provide novel insights into the cognitive and neural mechanisms underlying the influence of SVA symptoms on loss aversion, and suggest the critical roles of evidence accumulation speed and specific brain activation patterns-particularly within the cognitive control and motor network-in shaping decision-making biases associated with addiction.

Neuroanatomical and functional substrates of the short video addiction and its association with brain transcriptomic and cellular architecture

Short video addiction (SVA) has emerged as a growing behavioral and social issue, driven by the widespread use of digital platforms that provide highly engaging, personalized, and brief video content. We investigated the neuroanatomical and functional substrates of SVA symptoms, alongside brain transcriptomic and cellular characteristics, using Inter-Subject Representational Similarity Analysis (IS-RSA) and transcriptomic approaches. Behaviorally, we found that dispositional envy was associated with SVA. Structurally, SVA was positively correlated with increased morphological volumes in the orbitofrontal cortex (OFC) and bilateral cerebellum. Functionally, the dorsolateral prefrontal cortex (DLPFC), posterior cingulate cortex (PCC), cerebellum, and temporal pole (TP) exhibited heightened spontaneous activity, which was positively correlated with SVA severity. Transcriptomic and cellular analyses also showed specific genes linked to gray matter volume (GMV) associated with SVA, with predominant expression in excitatory and inhibitory neurons. These genes showed distinct spatiotemporal expression patterns in the cerebellum during adolescence. This study offers a comprehensive framework integrating structural, functional, and neurochemical evidence to highlight the neural-transcriptomic underpinnings of SVA symptoms in a non-clinical population.

Dissociable ventral and dorsal sensorimotor functional circuits linking the hypomanic personality traits to aggression via behavioral inhibition system

Hypomanic personality traits (HPT) are susceptibility markers for psychiatric disorders, particularly bipolar disorder, and are strongly associated with aggressive behaviors. However, the neuropsychological mechanisms underlying this association remain unclear. This study utilized psychometric network analysis and Inter-Subject Representation Similarity Analysis (IS-RSA) to explore the neuropsychological circuits that link HPT to aggression in a large non-clinical population. Psychometric network analysis (n = 716) identified two key nodes: the Behavioral Inhibition System (BIS) and mood volatility, a core dimension of HPT. We observed a positive correlation between mood volatility and aggression, with BIS serving as a mediating factor. Task-based functional imaging (n = 53) further revealed a double dissociation between the dorsal (dSMC) and ventral (vSMC) sensorimotor cortices to HPT, specifically during the processing of reward magnitude and delay in a delayed reward paradigm. Functional patterns within these regions mediated the relationship between individual differences in mood volatility and aggression, with BIS acting as a mediator through parallel pathways. Resting-state functional imaging (n = 505) replicated this functional segregation and revealed distinct integrative patterns: the dSMC was functionally connected to the frontoparietal network (FPN) and the vSMC to the sensorimotor network (SMN). These circuits collectively mediated the associations among mood volatility, aggression, and BIS. These findings highlight the critical role of sensorimotor circuits and BIS in understanding the neuropsychological pathways linking HPT-related mood volatility to aggression.

Microstructural and functional substrates underlying dispositional greed and its link with trait but not state impulsivity

The interplay between personality traits and impulsivity has long been a central theme in psychology and psychiatry. However, the potential association between Greed Personality Traits (GPT) and impulsivity, encompassing both trait and state impulsivity and future time perspective, remains largely unexplored. To address these issues, we employed questionnaires and an inter-temporal choice task to estimate corresponding trait/state impulsivity and collected multi-modal neuroimaging data (resting-state functional imaging: n = 430; diffusion-weighted imaging: n = 426; task-related functional imaging: n = 53) to investigate the underlying microstructural and functional substrates. Behavioral analyses revealed that GPT mediated the association between time perspective (e.g., present fatalism) and trait impulsivity (e.g., motor impulsivity). Functional imaging analyses further identified that brain activation strengths and patterns related to delay length, particularly in the dorsomedial prefrontal cortex, superior parietal lobule, and cerebellum, were associated with GPT. Moreover, individuals with similar levels of greed exhibited analogous spontaneous brain activity patterns, predominantly in the Default Mode Network (DMN), Fronto-Parietal Network (FPN), and Visual Network (VIS). Diffusion imaging analysis observed specific microstructural characteristics in the spinocerebellar/pontocerebellar fasciculus, internal/external capsule, and corona radiata that support the formation of GPT. Furthermore, the corresponding neural activation pattern, spontaneous neural activity pattern, and analogous functional couplings among the aforementioned brain regions mediated the relationships between time perspective and GPT and between GPT and motor impulsivity. These findings provide novel insights into the possible pathway such as time perspective → dispositional greed → impulsivity and uncover their underlying microstructural and functional substrates.