Altered connectivity in the right inferior frontal gyrus associated with self-control in adolescents exhibiting problematic smartphone use: A fMRI study

Brain alterations in individuals with exercise dependence: A multimodal neuroimaging investigation

Background

Exercise dependence (ED) is characterised by behavioural and psychological symptoms that resemble those of substance use disorders. However, it remains inconclusive whether ED is accompanied by similar brain alterations as seen in substance use disorders. Therefore, we investigated brain alterations in individuals with ED and inactive control participants.

Methods

In this cross-sectional neuroimaging investigation, 29 individuals with ED as assessed with the Exercise Dependence Scale (EDS) and 28 inactive control participants (max one hour exercising per week) underwent structural and functional resting-state magnetic resonance imaging (MRI). Group differences were explored using voxel-based morphometry and functional connectivity analyses. Analyses were restricted to the striatum, amygdala, and inferior frontal gyrus (IFG). Exploratory analyses tested whether relationships between brain structure and function were differently related to EDS subscales among groups.

Results

No structural differences were found between the two groups. However, right IFG and bilateral putamen volumes were differently related to the EDS subscales "time" and "tolerance", respectively, between the two groups. Resting-state functional connectivity was increased from right IFG to right superior parietal lobule in individuals with ED compared to inactive control participants. Furthermore, functional connectivity of the angular gyrus to the left IFG and bilateral caudate showed divergent relationships to the EDS subscale "tolerance" among groups.

Discussion

The findings suggest that ED may be accompanied by alterations in cognition-related brain structures, but also functional changes that may drive compulsive habitual behaviour. Further prospective studies are needed to disentangle beneficial and detrimental brain effects of ED.

Negative emotions mediate the association between the topology of the complex brain network and smartphone use disorder: A resting-state EEG study

Background

Increasing research has examined the factors related to smartphone use disorder. However, limited research has explored its neural basis.

Aims

We aimed to examine the relationship between the topology of the resting-state electroencephalography (rs-EEG) brain network and smartphone use disorder using minimum spanning tree analysis. Furthermore, we examined how negative emotions mediate this relationship.

Methods

This study included 113 young, healthy adults (mean age = 20.87 years, 46.9% males).

Results

The results showed that the alpha- and delta-band kappas and delta-band leaf fraction were positively correlated with smartphone use disorder. In contrast, the alpha-band diameter was negatively correlated with smartphone use disorder. Negative emotions fully mediated the relationship between alpha-band kappa and alpha-band diameter and smartphone use disorder. Furthermore, negative emotions partially mediated the relationship between delta-band kappa and smartphone use disorder. The findings suggest that excessive scale-free alpha- and delta-band brain networks contribute to the emergence of smartphone use disorder. In addition, the findings also demonstrate that negative emotions and smartphone use disorder share the same neural basis. Negative emotions play a mediating role in the association between topological deviations and smartphone use disorder.

Discussion

To the best of our knowledge, this is the first study to examine the neural basis of smartphone use disorder from the perspective of the topology of the rs-EEG brain network. Therefore, neuromodulation may be a potential intervention for smartphone use disorder.

Anxiety may alter the role of fronto-striatal circuitry in adolescent risky decision-making

BACKGROUND

Anxiety disorders often emerge in adolescence and are associated with risk aversion. Risk aversion conflicts with the typical adolescent approach-motivated phenotype and can interfere with learning and contribute to symptom maintenance.

METHODS

We investigated the neural and behavioral correlates of risk avoidance in a diverse sample of adolescents (N = 137; MAge = 11.3; 34.3 % white, 22.1 % Latino, 20 % Asian, 14.3 % Black, 9.3 % Mixed Race) as they completed a task involving risky decision-making and response inhibition during fMRI. Voluntary cautious choice was compared to successful response inhibition to isolate the neural systems underlying the decision to avoid a risk and identify their relation to risk-taking and anxiety in adolescents.

RESULTS

Anxious adolescents self-reported more avoidance but demonstrated normative risk-taking on the laboratory task. Interestingly, they responded quickly during response inhibition but took longer to decide in the face of risk. All youth showed widespread recruitment of decision-making and salience network regions when deciding to avoid risk. The neural mechanisms driving avoidance differed based on anxiety such that left inferior frontal gyrus (IFG) activation was linked to risk avoidance in adolescents with low anxiety and risk-taking in anxious adolescents, while striatal connectivity was linked to risk avoidance in anxious adolescents and risk-taking in those with low anxiety.

LIMITATIONS

This work is cross-sectional and therefore cannot speak to causality or directionality of effects.

CONCLUSIONS

These results suggest that the neural mechanisms contributing to adolescent risk-taking may function to promote avoidance in anxious youth, increasing vulnerability to maladaptive avoidance and further anxiety development.

The Effects of Digital Addiction on Brain Function and Structure of Children and Adolescents: A Scoping Review

The escalating prevalence of studies investigating digital addiction (DA) and its detrimental impact on the human brain's structure and functionality has been noticeable in recent years. Yet, an overwhelming majority of these reviews have been predominantly geared towards samples comprising college students or adults and have only inspected a single variant of DA, such as internet gaming disorder, internet addiction disorder, problematic smartphone use, tablet overuse, and so forth. Reviews focusing on young children and adolescents (ages 0-18), or those which amalgamate various types of DA, are decidedly scarce. Given this context, summarizing the effects of DA on brain structure and functionality during the vital developmental stage (0-18 years) is of immense significance. A scoping review, complying with the PRISMA extension for such reviews, was conducted to amalgamate findings from 28 studies spanning a decade (2013-2023) and to examine the influence of assorted forms of DA on the brains of children and adolescents (0-18 years). The synthesized evidence indicated two primary results: (1) DA exerts harmful effects on the structure and functionality of the brains of children and adolescents, and (2) the prefrontal lobe is the region most consistently reported as impacted across all research. Furthermore, this review discerned a notable void of studies investigating the neural indices of digital addiction, along with a shortage of studies focusing on young children (0-6 years old) and longitudinal evidence. This research could provide the necessary theoretical basis for the thwarting and intervention of digital addiction, a measure indispensable for ensuring healthy brain development in children and adolescents.

Dissociating the Link of Neural Correlates of Inhibition to the Degree of Substance Use and Substance-Related Problems: A Preregistered, Multimodal, Combined Cross-sectional and Longitudinal Study

BACKGROUND

Frontal hypoactivation during inhibition is a promising phenotype for substance use disorders (SUDs), but studies comparing individuals with SUDs with unaffected individuals have reported inconsistent results. This may result from distinctive associations of neural correlates of inhibition with the degree of substance use and the severity of substance-related problems-two correlated but distinct facets of SUDs-reflecting a potentially disregarded confounding effect. This preregistered study tested whether frontal hypoactivation during inhibition is specifically linked to substance-related problems in SUDs beyond the degree of substance use.

METHODS

A stop signal task during functional magnetic resonance imaging, trait self-control, substance use, and substance-related problems in the past 12 months were assessed in 121 (poly)substance users. One hundred seven participants completed a 1-year follow-up. We examined the association between multimodal indicators of inhibition (neural activation in regions of interest, inhibitory performance, trait self-control) and substance-related problems while controlling for the degree of substance use.

RESULTS

Right inferior frontal gyrus hypoactivation explained variance in substance-related problems beyond the degree of substance use, while hyperactivation in the same region explained variance in the degree of substance use beyond the effects of substance-related problems, both cross-sectionally (problems: Bonferroni-Holm-corrected p = .048; use: p < .01) and prospectively (problems at trend level: p = .096; use: p = .01). Trait and behavioral inhibition were unrelated to problems beyond the effects of substance use (ps > .05).

CONCLUSIONS

We demonstrated that frontal hypoactivation during inhibition specifically relates to substance-related problems. Interestingly, increased activity may even represent a resilience factor in substance use without SUDs. Future studies should distinguish between processes linked to the degree of substance use and substance-related problems to advance understanding of why some substance users develop SUDs and others do not.

Right inferior frontal gyrus theta-burst stimulation reduces smoking behaviors and strengthens fronto-striatal-limbic resting-state functional connectivity: a randomized crossover trial

Introduction

Functional and anatomical irregularities in the right inferior frontal gyrus (rIFG), a ventrolateral prefrontal region that mediates top-down inhibitory control over prepotent behavioral responding, are implicated in the ongoing maintenance of nicotine dependence (ND). However, there is little research on the effects of neuromodulation of the rIFG on smoking behavior, inhibitory control, and resting-state functional connectivity (rsFC) among individuals with ND.

Methods

In this double-blind, crossover, theta-burst stimulation (TBS) study, adults with ND (N = 31; female: n = 15) completed a baseline session and were then randomized to two counterbalanced sessions of functionally neuronavigated TBS to the rIFG: continuous TBS (cTBS) on 1 day and intermittent TBS (iTBS) on another. Differences in cigarette cravings, smoking, and fronto-striatal-limbic rsFC were assessed.

Results

Relative to baseline, cTBS significantly reduced appetitive and withdrawal cravings immediately after treatment. The effects of cTBS on withdrawal craving persisted for 24 h, as well as produced a reduction in smoking. Furthermore, cTBS significantly strengthened rsFC between the rIFG pars opercularis and subcallosal cingulate (fronto-striatal circuit), and between the rIFG pars opercularis and the right posterior parahippocampal gyrus (fronto-limbic circuit). At post-24 h, cTBS-induced increase in fronto-striatal rsFC was significantly associated with less appetitive craving, while the increase in fronto-limbic rsFC was significantly associated with less withdrawal craving and smoking.

Discussion

These findings warrant further investigation into the potential value of rIFG cTBS to attenuate smoking behavior among individuals with ND.

Neuroimaging the effects of smartphone (over-)use on brain function and structure-a review on the current state of MRI-based findings and a roadmap for future research

The smartphone represents a transformative device that dramatically changed our daily lives, including how we communicate, work, entertain ourselves, and navigate through unknown territory. Given its ubiquitous availability and impact on nearly every aspect of our lives, debates on the potential impact of smartphone (over-)use on the brain and whether smartphone use can be "addictive" have increased over the last years. Several studies have used magnetic resonance imaging to characterize associations between individual differences in excessive smartphone use and variations in brain structure or function. Therefore, it is an opportune time to summarize and critically reflect on the available studies. Following this overview, we present a roadmap for future research to improve our understanding of how excessive smartphone use can affect the brain, mental health, and cognitive and affective functions.

Problematic smartphone use is associated with differences in static and dynamic brain functional connectivity in young adults

Introduction

This study aimed to investigate the possible associations between problematic smartphone use and brain functions in terms of both static and dynamic functional connectivity patterns.

Materials and methods

Resting-state functional magnetic resonance imaging data were scanned from 53 young healthy adults, all of whom completed the Short Version of the Smartphone Addiction Scale (SAS-SV) to assess their problematic smartphone use severity. Both static and dynamic functional brain network measures were evaluated for each participant. The brain network measures were correlated the SAS-SV scores, and compared between participants with and without a problematic smartphone use after adjusting for sex, age, education, and head motion.

Results

Two participants were excluded because of excessive head motion, and 56.9% (29/51) of the final analyzed participants were found to have a problematic smartphone use (SAS-SV scores ≥ 31 for males and ≥ 33 for females, as proposed in prior research). At the global network level, the SAS-SV score was found to be significantly positively correlated with the global efficiency and local efficiency of static brain networks, and negatively correlated with the temporal variability using the dynamic brain network model. Large-scale subnetwork analyses indicated that a higher SAS-SV score was significantly associated with higher strengths of static functional connectivity within the frontoparietal and cinguloopercular subnetworks, as well as a lower temporal variability of dynamic functional connectivity patterns within the attention subnetwork. However, no significant differences were found when directly comparing between the groups of participants with and without a problematic smartphone use.

Conclusion

Our results suggested that problematic smartphone use is associated with differences in both the static and dynamic brain network organizations in young adults. These findings may help to identify at-risk population for smartphone addiction and guide targeted interventions for further research. Nevertheless, it might be necessary to confirm our findings in a larger sample, and to investigate if a more applicable SAS-SV cutoff point is required for defining problematic smartphone use in young Chinese adults nowadays.

University freshmen's excessive smartphone use and psychological safety during the COVID-19 pandemic

Although excessive smartphone use has been confirmed as being associated with specific representations of mental health (e. g., anxiety, depression, wellbeing, etc.) throughout the COVID-19 pandemic, the relationship between excessive smartphone use and cognitive representations of mental health (i.e., psychological safety) is not yet fully understood. This study aimed to identify the association between excessive smartphone use and psychological safety among university freshmen during the COVID-19 pandemic; in addition, we examined the mediation effects of hardiness and interpersonal distress in this relationship. In this study, 1,224 university freshmen were selected at random from several universities in Guizhou Province of China. The Psychological Safety Scale was used to evaluate the mental health of university freshmen; the Mobile Phone Dependence Scale was used to evaluate excessive smartphone use; the Hardiness Questionnaire was used to evaluate hardiness; and the Interpersonal Relation Synthetic Diagnose Test was used to evaluate interpersonal distress. The findings showed that: (1) the greater the degree of excessive smartphone use, the more serious respondents' interpersonal distress and the lower their hardiness; (2) excessive smartphone use was not only directly related to the psychological safety of university freshmen but also indirectly related to their psychological safety through the independent mediation of hardiness and interpersonal distress, as well as through the chain mediation of hardiness and interpersonal distress. In general, excessive smartphone use in university freshmen could lead to a decline in their psychological safety. Also, hardiness and interpersonal distress play a complex role in this relationship. During the COVID-19 pandemic, interventions on the mental health of college freshmen should not only provide guidance on how to use their smartphone responsibly but also to provide them with support and guidance for the enhancement of their hardiness and improvement of their interpersonal relationships.