RESUMO
The medial prefrontal cortex (mPFC) has been implicated in the pathophysiology of social impairments including social fear. However, the precise subcortical partners that mediate mPFC dysfunction on social fear behaviour have not been identified. Employing a social fear conditioning paradigm, we induced robust social fear in mice and found that the lateral habenula (LHb) neurons and LHb-projecting mPFC neurons are synchronously activated during social fear expression. Moreover, optogenetic inhibition of the mPFC-LHb projection significantly reduced social fear responses. Importantly, consistent with animal studies, we observed an elevated prefrontal-habenular functional connectivity in subclinical individuals with higher social anxiety characterized by heightened social fear. These results unravel a crucial role of the prefrontal-habenular circuitry in social fear regulation and suggest that this pathway could serve as a potential target for the treatment of social fear symptom often observed in many psychiatric disorders.
RESUMO
As a critical node connecting the forebrain with the midbrain, the lateral habenula (LHb) processes negative feedback in response to aversive events and plays an essential role in value-based decision-making. Compulsive drug use, a hallmark of substance use disorder, is attributed to maladaptive decision-making regarding aversive drug-use-related events and has been associated with dysregulation of various frontal-midbrain circuits. To understand the contributions of frontal-habenula-midbrain circuits in the development of drug dependence, we employed a rat model of methamphetamine self-administration (SA) in the presence of concomitant footshock, which has been proposed to model compulsive drug-taking in humans. In this longitudinal study, functional MRI data were collected at pretraining baseline, after 20 d of long-access SA phase, and after 5 d of concomitant footshock coupled with SA (punishment phase). Individual differences in response to punishment were quantified by a "compulsivity index (CI)," defined as drug infusions at the end of punishment phase, normalized by those at the end of SA phase. Functional connectivity of LHb with the frontal cortices and substantia nigra (SN) after the punishment phase was positively correlated with the CI in rats that maintained drug SA despite receiving increasing-intensity footshock. In contrast, functional connectivity of the same circuits was negatively correlated with CI in rats that significantly reduced SA. These findings suggest that individual differences in compulsive drug-taking are reflected by alterations within frontal-LHb-SN circuits after experiencing the negative consequences from SA, suggesting these circuits may serve as unique biomarkers and potential therapeutic targets for individualized treatment of addiction.
Assuntos
Habenula , Metanfetamina , Transtornos Relacionados ao Uso de Substâncias , Humanos , Ratos , Animais , Habenula/fisiologia , Estudos Longitudinais , Comportamento Compulsivo , Lobo Frontal/diagnóstico por imagemRESUMO
Creativity, a high-order cognitive ability, has received wide attention from researchers and educators who are dedicated to promoting its development throughout one's lifespan. Currently, creativity is commonly assessed with divergent thinking tasks, such as the Alternative Uses Task. Recent advancements in neuroimaging techniques have enabled the identification of brain markers for high-order cognitive abilities. One such brain structure of interest in this regard is the hippocampus, which has been found to play an important role in generating creative thoughts in adulthood. However, such role of the hippocampus in childhood is not clear. Thus, this study aimed to investigate the associations between creativity, as measured by divergent thinking, and both the volume of the hippocampus and its resting-state functional connectivity in 116 children aged 8-12 years. The results indicate significant relations between divergent thinking and the volume of the hippocampal head and the hippocampal tail, as well as the volume of a subfield comprising cornu ammonis 2-4 and dentate gyrus within the hippocampal body. Additionally, divergent thinking was significantly related to the differences between the anterior and the posterior hippocampus in their functional connectivity to other brain regions during rest. These results suggest that these two subregions may collaborate with different brain regions to support diverse cognitive processes involved in the generation of creative thoughts. In summary, these findings indicate that divergent thinking is significantly related to the structural and functional characteristics of the hippocampus, offering potential insights into the brain markers for creativity during the developmental stage.
Assuntos
Encéfalo , Imageamento por Ressonância Magnética , Criança , Humanos , Imageamento por Ressonância Magnética/métodos , Encéfalo/diagnóstico por imagem , Criatividade , Cognição , Mapeamento Encefálico/métodos , Hipocampo/diagnóstico por imagemRESUMO
Negative emotional state has been found to correlate with poor cognitive performance in cannabis-dependent (CD) individuals, but not healthy controls (HCs). To examine the neural substrates underlying such unusual emotion-cognition coupling, we analyzed the behavioral and resting state fMRI data from the Human Connectome Project and found opposite brain-behavior associations in the CD and HC groups: (i) although the cognitive performance was positively correlated with the within-network functional connectivity strength and segregation (i.e. clustering coefficient and local efficiency) of the cognitive network in HCs, these correlations were inversed in CDs; (ii) although the cognitive performance was positively correlated with the within-network Granger effective connectivity strength and integration (i.e. characteristic path length) of the cognitive network in CDs, such associations were not significant in HCs. In addition, we also found that the effective connectivity strength within cognition network mediated the behavioral coupling between emotional state and cognitive performance. These results indicate a disorganization of the cognition network in CDs, and may help improve our understanding of substance use disorder.
Assuntos
Conectoma , Abuso de Maconha , Humanos , Abuso de Maconha/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Cognição , Conectoma/métodos , Emoções , Imageamento por Ressonância Magnética/métodosRESUMO
Working memory (WM) is essential for cognition, but the underlying neural mechanisms remain elusive. From a hierarchical processing perspective, this paper proposed and tested a hypothesis that a domain-general network at the top of the WM hierarchy can interact with distinct domain-preferential intermediate circuits to support WM. Employing a novel N-back task, we first identified the posterior superior temporal gyrus (pSTG), middle temporal area (MT), and postcentral gyrus (PoCG) as intermediate regions for biological motion and shape motion processing, respectively. Using further psychophysiological interaction analyses, we delineated a frontal-parietal network (FPN) as the domain-general network. These results were further verified and extended by a delayed match to sample (DMS) task. Although the WM load-dependent and stimulus-free activations during the DMS delay phase confirm the role of FPN as a domain-general network to maintain information, the stimulus-dependent activations within this network during the DMS encoding phase suggest its involvement in the final stage of the hierarchical processing chains. In contrast, the load-dependent activations of intermediate regions in the N-back task highlight their further roles beyond perception in WM tasks. These results provide empirical evidence for a hierarchical processing model of WM and may have significant implications for WM training.
Assuntos
Cognição , Memória de Curto Prazo , Lobo Frontal/diagnóstico por imagem , Cognição/fisiologia , Humanos , Masculino , Feminino , Adulto , Imageamento por Ressonância MagnéticaRESUMO
Excessive use of the internet, which is a typical scenario of self-control failure, could lead to potential consequences such as anxiety, depression, and diminished academic performance. However, the underlying neuropsychological mechanisms remain poorly understood. This study aims to investigate the structural basis of self-control and internet addiction. In a cohort of 96 internet gamers, we examined the relationships among grey matter volume and white matter integrity within the frontostriatal circuits and internet addiction severity, as well as self-control measures. The results showed a significant and negative correlation between dACC grey matter volume and internet addiction severity (p < 0.001), but not with self-control. Subsequent tractography from the dACC to the bilateral ventral striatum (VS) was conducted. The fractional anisotropy (FA) and radial diffusivity of dACC-right VS pathway was negatively (p = 0.011) and positively (p = 0.020) correlated with internet addiction severity, respectively, and the FA was also positively correlated with self-control (p = 0.036). These associations were not observed for the dACC-left VS pathway. Further mediation analysis demonstrated a significant complete mediation effect of self-control on the relationship between FA of the dACC-right VS pathway and internet addiction severity. Our findings suggest that the dACC-right VS pathway is a critical neural substrate for both internet addiction and self-control. Deficits in this pathway may lead to impaired self-regulation over internet usage, exacerbating the severity of internet addiction.
Assuntos
Imagem de Tensor de Difusão , Substância Cinzenta , Transtorno de Adição à Internet , Autocontrole , Substância Branca , Humanos , Substância Branca/diagnóstico por imagem , Substância Branca/patologia , Masculino , Transtorno de Adição à Internet/diagnóstico por imagem , Transtorno de Adição à Internet/fisiopatologia , Feminino , Imagem de Tensor de Difusão/métodos , Adulto , Adulto Jovem , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/patologia , Estriado Ventral/diagnóstico por imagem , Estriado Ventral/fisiopatologia , Estriado Ventral/patologia , Índice de Gravidade de Doença , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiopatologia , Corpo Estriado/diagnóstico por imagem , Corpo Estriado/patologia , Corpo Estriado/fisiopatologia , Internet , Lobo Frontal/diagnóstico por imagem , Lobo Frontal/patologia , Lobo Frontal/fisiopatologiaRESUMO
BACKGROUND AND AIMS: The pathophysiology of achalasia, which involves central nuclei abnormalities, remains unknown. We investigated the resting-state functional MRI (rs-fMRI) features of patients with achalasia. METHODS: We applied resting-state functional MRI (rs-fMRI) to investigate the brain features in patients with achalasia (n = 27), compared to healthy controls (n = 29). Focusing on three regions of interest (ROIs): the dorsal motor nucleus of the vagus (DMV), the nucleus ambiguus (NA), and the nucleus of the solitary tract (NTS), we analyzed variations in resting-state functional connectivity (rs-FC), fractional amplitude of low-frequency fluctuations (fALFF), and regional homogeneity (ReHo). RESULTS: Achalasia patients demonstrated stronger functional connectivity between the NA and the right precentral gyrus, left postcentral gyrus, and left insula. No significant changes were found in the DMV or NTS. The fMRI analysis showed higher rs-FC values for NA-DMV and NA-NTS connections in achalasia patients. Achalasia patients exhibited decreased fALFF values in the NA, DMV, and NTS regions, as well as increased ReHo values in the NA and DMV regions. A positive correlation was observed between fALFF values in all six ROIs and the width of the barium meal. The NTS fALFF value and NA ReHo value displayed a positive correlation with integrated relaxation pressure (IRP), while the ReHo value in the right precentral gyrus showed an inverse correlation with the height of the barium meal. CONCLUSIONS: Abnormal rs-FC and regional brain activity was found in patients with achalasia. Our study provides new insights into the pathophysiology of achalasia and highlights the potential of rs-fMRI in improving the diagnosis and treatment of this condition.
Assuntos
Mapeamento Encefálico , Acalasia Esofágica , Humanos , Acalasia Esofágica/diagnóstico por imagem , Bário , Encéfalo/diagnóstico por imagem , Núcleo Solitário , Imageamento por Ressonância MagnéticaRESUMO
Self-control is important for long-term success and could be a protective factor against maladaptive behaviours such as excessive gaming activity or Internet gaming disorder (IGD). However, the neurobiological basis of self-control and its relationship to IGD remain elusive. Using resting-state fMRI data from 89 participants aged from 18 to 26, we found that self-control and the number of IGD symptoms (IGD-S) were positively and negatively correlated with functional connectivity between right ventral striatum (rVS) and dorsal anterior cingulate cortex (dACC), respectively. A mediation analysis indicated that self-control influenced IGD-S partially through the rVS-dACC connectivity. In addition, step-wise regression analyses revealed that the rVS connectivity in a reward-anticipation limbic pathway contributed to IGD-S but not self-control, independent of the dACC pathway. These results suggest that the cingulate-ventral striatal functional connectivity may serve as an important neurobiological underpinning of self-control to regulate maladaptive behaviours such as these manifesting IGD through striatal circuitry balance.
Assuntos
Comportamento Aditivo , Estriado Ventral , Jogos de Vídeo , Humanos , Comportamento Aditivo/diagnóstico por imagem , Encéfalo , Mapeamento Encefálico/métodos , Giro do Cíngulo/diagnóstico por imagem , Internet , Transtorno de Adição à Internet , Imageamento por Ressonância Magnética , Vias Neurais/diagnóstico por imagem , Estriado Ventral/diagnóstico por imagemRESUMO
Substance use disorders (SUDs) impose severe negative impacts upon individuals, their families, and society. Clinical studies demonstrate that some chronic stimulant users are able to curtail their drug use when faced with adverse consequences while others continue to compulsively use drugs. The mechanisms underlying this dichotomy are poorly understood, which hampers the development of effective individualized treatments of a disorder that currently has no Food and Drug Administration-approved pharmacological treatments. In the present study, using a rat model of methamphetamine self-administration (SA) in the presence of concomitant foot shocks, thought to parallel compulsive drug taking by humans, we found that SA behavior correlated with alterations in the balance between an increased orbitofrontal cortex-dorsomedial striatal "go" circuit and a decreased prelimbic cortex-ventrolateral striatal "stop" circuit. Critically, this correlation was seen only in rats who continued to self-administer at a relatively high rate despite receiving foot shocks of increasing intensity. While the stop circuit functional connectivity became negative after repeated SA in all rats, "shock-resistant" rats showed strengthening of this negative connectivity after shock exposure. In contrast, "shock-sensitive" rats showed a return toward their baseline levels after shock exposure. These results may help guide novel noninvasive brain stimulation therapies aimed at restoring the physiological balance between stop and go circuits in SUDs.
Assuntos
Comportamento Compulsivo/fisiopatologia , Punição/psicologia , Transtornos Relacionados ao Uso de Substâncias/psicologia , Animais , Estimulantes do Sistema Nervoso Central/farmacologia , Conectoma/métodos , Corpo Estriado/fisiopatologia , Modelos Animais de Doenças , Eletrochoque/métodos , Masculino , Metanfetamina/farmacologia , Córtex Pré-Frontal/fisiopatologia , Ratos , Ratos Sprague-Dawley , Autoadministração , Transtornos Relacionados ao Uso de Substâncias/fisiopatologiaRESUMO
Cutting-edge recommendation algorithms have been widely used by media platforms to suggest users with personalized content. While such user-specific recommendations may satisfy users' needs to obtain intended information, some users may develop a problematic use pattern manifested by addiction-like undesired behaviors. Using a popular video sharing and recommending platform (TikTok) as an example, the present study first characterized use-related undesired behaviors with a questionnaire, then investigated how personally recommended videos modulated brain activity with an fMRI experiment. We found more undesired symptoms were related to lower self-control ability among young adults, and about 5.9% of TikTok users may have significant problematic use. The fMRI results showed higher brain activations in sub-components of the default mode network (DMN), ventral tegmental area, and discrete regions including lateral prefrontal, anterior thalamus, and cerebellum when viewing personalized videos in contrast to non-personalized ones. Psychophysiological interaction analyses revealed stronger coupling between activated DMN subregions and neural pathways underlying auditory and visual processing, as well as the frontoparietal network. This study highlights the functional heterogeneity of DMN in viewing personalized videos and may shed light on the neural underpinnings of how recommendation algorithms are able to keep the user's attention to suggested contents.
Assuntos
Córtex Cerebral/fisiologia , Rede de Modo Padrão/fisiologia , Transtorno de Adição à Internet/fisiopatologia , Autocontrole , Mídias Sociais , Área Tegmentar Ventral/fisiologia , Gravação em Vídeo , Adulto , Córtex Cerebral/diagnóstico por imagem , Rede de Modo Padrão/diagnóstico por imagem , Feminino , Humanos , Transtorno de Adição à Internet/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Área Tegmentar Ventral/diagnóstico por imagem , Adulto JovemRESUMO
With the emergence of AI-powered recommender systems and their extensive use in the video streaming service, questions and concerns also arise. Why can recommended video content continuously capture users' attention? What is the impact of long-term exposure to personalized video content on one's behaviors and brain functions? To address these questions, we designed an fMRI experiment presenting participants with personally recommended videos and generally recommended ones. To examine how large-scale networks were modulated by personalized video content, graph theory analysis was applied to investigate the interaction between seven networks, including the ventral and dorsal attention networks (VAN, DAN), frontal-parietal network (FPN), salience network (SN), and three subnetworks of default mode network (dorsal medial prefrontal (dMPFC), Core, and medial temporal lobe (MTL)). Our results showed that viewing nonpersonalized video content mainly enhanced the connectivity in the DAN-FPN-Core pathway, whereas viewing personalized ones increased not only the connectivity in this pathway but also the DAN-VAN-dMPFC pathway. In addition, both personalized and nonpersonalized short videos decreased the couplings between SN and VAN as well as between two DMN subsystems, Core and MTL. Collectively, these findings uncovered distinct patterns of network interactions in response to short videos and provided insights into potential neural mechanisms by which human behaviors are biased by personally recommended content.
Assuntos
Córtex Cerebral/fisiologia , Comportamento de Escolha/fisiologia , Conectoma , Rede Nervosa/fisiologia , Mídias Sociais , Adulto , Córtex Cerebral/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Rede Nervosa/diagnóstico por imagem , Gravação em Vídeo , Adulto JovemRESUMO
Cognitive, functional, and structural brain factors involving frontal executive and striatal reward networks have been implicated in Internet gaming disorder (IGD). However, frontostriatal network connectivity and its association with addiction severity are poorly understood in IGD. Resting-state fMRI data from 337 subjects (130 with IGD, 207 with recreational game use [RGU]) were collected. Striatal-cortical communications were measured with resting-state functional connectivity (FC) using coherent spontaneous fluctuations in the blood-oxygenation-level-dependent fMRI signal. Correlations were calculated between FC measures and IGD-related assessments (addiction severity and craving scores). Decreased FC was predominantly observed in IGD subjects, with IGD subjects showing decreased FC between the putamen and superior frontal gyrus (SFG), middle frontal gyrus (MFG), and inferior frontal gyrus (IFG) and the ventral striatum and IFG, superior temporal gyrus, and MFG. Disorder severity and craving scores were negatively correlated with FC between striatal and frontal brain regions. Associations between diminished FC in corticostriatal circuitry and clinical features (IGD craving, severity) suggest potential therapeutic targets for neuromodulation treatments. The extent to which frontostriatal circuits involving executive control over reward processes may be altered to treat IGD warrants additional study.
Assuntos
Transtorno de Adição à Internet/fisiopatologia , Vias Neurais/fisiopatologia , Jogos de Vídeo/psicologia , Adulto , Mapeamento Encefálico , Fissura , Função Executiva , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Córtex Pré-Frontal/fisiopatologia , Putamen/fisiopatologia , Recompensa , Estriado Ventral/fisiopatologia , Adulto JovemRESUMO
Abacus-based mental calculation (AMC) involves temporary storage and manipulation of an imaginary abacus closely related to the function of visuospatial working memory (VSWM). The present study thus investigated the effects of AMC training on VSWM and its neural correlates. A total of 144 human subjects (67 boys) were assigned to AMC or control groups at their entry to primary school. The AMC group received 2 h AMC training per week for 5 school years, whereas the control group spent the time in activities, such as conventional calculation and reading. Raven's Intelligence Test was administered both before and after training. Two arithmetic tests and a VSWM task were conducted after training. Among these participants, fMRI data were collected from 64 children for the VSWM task. Behavioral results indicated that the AMC group outperformed controls on both arithmetic and VSWM tasks, but not on Raven's Intelligence Test. While the two groups activated similar regions during the VSWM task, the AMC group showed greater activation than the controls in frontal, parietal, and occipital areas. Interestingly, the activation of right middle frontal gyrus mediated the relation between the arithmetic ability and the VSWM performance in the AMC group, suggesting that the frontal region may be the neural substrate underlying the transfer effect from AMC training to VSWM. Although the transfer effects seem quite limited considering the length and intensity of the training, these findings suggest that long-term AMC training not only improves arithmetic ability but also has a potential positive effect on VSWM.SIGNIFICANCE STATEMENT Plasticity of working memory is one of the most rapidly expanding research fields in the developmental and cognitive sciences. Previous studies suggest that abacus-based mental calculation (AMC) relies on a visuospatial imaginary strategy, which is closely related to visuospatial working memory (VSWM). However, the impacts of AMC training on VSWM and the underlying neural basis remain unclear. Here, we found that AMC training enhanced VSWM in children, which was accompanied by altered activation in frontal, parietal, and occipital areas. Moreover, we observed that activation in right middle frontal gyrus played a significant mediation role in the transfer of AMC training to VSWM. These findings provide a new perspective to VSWM training and also advance our understanding of related brain plasticity.
Assuntos
Encéfalo/fisiologia , Aprendizagem/fisiologia , Memória de Curto Prazo/fisiologia , Plasticidade Neuronal/fisiologia , Ensino , Criança , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Matemática , Materiais de EnsinoRESUMO
Executive function (EF) refers as to a set of high-level cognitive abilities that are critical to many aspects of daily life. Despite its importance in human daily life, the neural networks responsible for the development of EF in childhood are not well understood. The present study thus aimed to examine the development of task-dependent brain network organization and its relationship to age-related improvements in EF. To address this issue, we recruited eighty-eight Chinese children ranging in age from 7 to 12 years old, and collected their functional magnetic resonance imaging (fMRI) data when they performed an EF task. By utilizing graph theory, we found that the task-dependent brain network modules became increasingly segregated with age. Specifically, the intra-module connections within the default-mode network (DMN), frontal-parietal network (FPN) and sensorimotor network (SMN) increased significantly with age. In contrast, the inter-module connections of the visual network to both the FPN/SMN decreased significantly with age. Most importantly, modular segregation of the FPN significantly mediated the relationship between age and EF performance. These findings add to our growing understanding of how development changes in task-dependent brain network organization support vast behavioral improvements in EF observed during childhood.
Assuntos
Encéfalo/diagnóstico por imagem , Desenvolvimento Infantil/fisiologia , Rede de Modo Padrão/diagnóstico por imagem , Função Executiva/fisiologia , Encéfalo/crescimento & desenvolvimento , Encéfalo/fisiologia , Criança , Rede de Modo Padrão/crescimento & desenvolvimento , Rede de Modo Padrão/fisiologia , Feminino , Lobo Frontal/diagnóstico por imagem , Lobo Frontal/crescimento & desenvolvimento , Lobo Frontal/fisiologia , Neuroimagem Funcional , Humanos , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/diagnóstico por imagem , Vias Neurais/crescimento & desenvolvimento , Vias Neurais/fisiologia , Lobo Parietal/diagnóstico por imagem , Lobo Parietal/crescimento & desenvolvimento , Lobo Parietal/fisiologia , Tempo de Reação , Córtex Sensório-Motor/diagnóstico por imagem , Córtex Sensório-Motor/crescimento & desenvolvimento , Córtex Sensório-Motor/fisiologiaRESUMO
Coordinated activity within and differential activity between large-scale neuronal networks such as the default mode network (DMN) and the control network (CN) is a critical feature of brain organization. The CN usually exhibits activations in response to cognitive tasks while the DMN shows deactivations; in addition, activity between the two networks is anti-correlated at rest. To address this issue, we used functional MRI to measure whole-brain BOLD signal during resting-state and task-evoked conditions, and MR spectroscopy (MRS) to quantify GABA and glutamate concentrations, in nodes within the DMN and CN (MPFC and DLPFC, respectively) in 19 healthy individuals at 3 Tesla. We found that GABA concentrations in the MPFC were significantly associated with DMN deactivation during a working memory task and with anti-correlation between DMN and CN at rest and during task performance, while GABA concentrations in the DLPFC weakly modulated DMN-CN anti-correlation in the opposite direction. Highlighting specificity, glutamate played a less significant role related to brain activity. These findings indicate that GABA in the MPFC is potentially involved in orchestrating between-network brain activity at rest and during task performance.
Assuntos
Encéfalo/fisiologia , Vias Neurais/fisiologia , Ácido gama-Aminobutírico/fisiologia , Adulto , Encéfalo/metabolismo , Mapeamento Encefálico , Feminino , Ácido Glutâmico/metabolismo , Ácido Glutâmico/fisiologia , Humanos , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Masculino , Memória de Curto Prazo/fisiologia , Vias Neurais/metabolismo , Adulto Jovem , Ácido gama-Aminobutírico/metabolismoRESUMO
Deactivation of the default mode network (DMN) is one of the most reliable observations from neuroimaging and has significant implications in development, aging, and various neuropsychiatric disorders. However, the neural mechanism underlying DMN deactivation remains elusive. As the coordination of regional neurochemical substrates and interregional neural interactions are both essential in support of brain functions, a quantitative description of how they impact DMN deactivation may provide new insights into the mechanism. Using an n-back working memory task fMRI and magnetic resonance spectroscopy, we probed the pairwise relationship between task-induced deactivation, interregional functional connectivity and regional excitation-inhibition balance (evaluated by glutamate/GABA ratio) in the posterior cingulate cortex/precuneus (PCC/PCu). Task-induced PCC/PCu deactivation correlated with its excitation-inhibition balance and interregional functional connectivity, where participants with lower glutamate/GABA ratio, stronger intra-DMN connections and stronger antagonistic DMN-SN (salience network)/ECN (executive control network) inter-network connections had greater PCC/PCu deactivation. Mediation analyses revealed that the DMN-SN functional interactions partially mediated the relationship between task-induced deactivation and the excitation-inhibition balance at the PCC/PCu. The triple-relationship discovered in the present study has the potential to bridge DMN-deactivation related findings from various neuroimaging modalities and may provide new insights into the neural mechanism of DMN deactivation. Moreover, this finding may have significant implications for neuropsychiatric disorders related to the DMN dysfunction and suggests an integrated application of pharmacological and neuromodulation-based strategies for rescuing DMN deactivation deficits.
Assuntos
Mapeamento Encefálico/métodos , Encéfalo/fisiologia , Rede Nervosa/fisiologia , Adolescente , Adulto , Função Executiva/fisiologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Masculino , Memória de Curto Prazo/fisiologia , Pessoa de Meia-Idade , Adulto JovemRESUMO
While chronic cocaine use is associated with abnormalities in both brain structure and function within and interactions between regions, previous studies have been limited to interrogating structure and function independently, and the detected neural differences have not been applied to independent samples to assess the clinical relevance of results. We investigated consequences of structural differences on resting-state functional connectivity in cocaine addiction and tested whether resting-state functional connectivity of the identified circuits predict relapse in an independent cohort. Subjects included 64 non-treatment-seeking cocaine users (NTSCUs) and 67 healthy control subjects and an independent treatment-completed cohort (n = 45) of cocaine-dependent individuals scanned at the end of a 30-day residential treatment programme. Differences in cortical thickness and related resting-state functional connectivity between NTSCUs and healthy control subjects were identified. Survival analysis, applying cortical thickness of the identified regions, resting-state functional connectivity of the identified circuits and clinical characteristics to the treatment cohort, was used to predict relapse. Lower cortical thickness in bilateral insula and higher thickness in bilateral temporal pole were found in NTSCUs versus healthy control subjects. Whole brain resting-state functional connectivity analyses with these four different anatomical regions as seeds revealed eight weaker circuits including within the salience network (insula seeds) and between temporal pole and elements of the default mode network in NTSCUs. Applying these circuits and clinical characteristics to the independent cocaine-dependent treatment cohort, functional connectivity between right temporal pole and medial prefrontal cortex, combined with years of education, predicted relapse status at 150 days with 88% accuracy. Deficits in the salience network suggest an impaired ability to process physiologically salient events, while abnormalities in a temporal pole-medial prefrontal cortex circuit might speak to the social-emotional functional alterations in cocaine addiction. The involvement of the temporal pole-medial prefrontal cortex circuit in a model highly predictive of relapse highlights the importance of social-emotional functions in cocaine dependence, and provides a potential underlying neural target for therapeutic interventions, and for identifying those at high risk of relapse.
Assuntos
Córtex Cerebral/fisiopatologia , Transtornos Relacionados ao Uso de Cocaína/fisiopatologia , Córtex Pré-Frontal/fisiopatologia , Lobo Temporal/fisiopatologia , Adulto , Estudos de Casos e Controles , Córtex Cerebral/patologia , Transtornos Relacionados ao Uso de Cocaína/patologia , Estudos de Coortes , Feminino , Neuroimagem Funcional , Humanos , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/patologia , Vias Neurais/fisiopatologia , Córtex Pré-Frontal/patologia , Recidiva , Lobo Temporal/patologia , Resultado do TratamentoRESUMO
Deactivation of the human brain's default mode network (DMN) is regarded as suppression of endogenous activity to support exogenous task-related processes. This phenomenon has important functional relevance and insufficient DMN deactivation has been implicated in several neuropsychiatric disorders. However, the neurochemical mechanism of the DMN's deactivation remains largely unknown. In the present study, we test the hypothesis that the major excitatory and inhibitory neurotransmitters, glutamate and GABA, respectively, are associated with DMN deactivation. We used magnetic resonance spectroscopy to measure neurotransmitter concentrations in the posterior cingulate cortex/precuneus (PCC/PCu), a key component of the DMN, and functional magnetic resonance imaging to evaluate DMN deactivation induced by an n-back working memory task. Our results demonstrate significant associations of glutamate and GABA with DMN deactivation. Specifically, high regional GABA concentration in the PCC/PCu area is associated with enhanced deactivation induced by the task in the same region, whereas high glutamate concentration is associated with reduced deactivation. Furthermore, the association between GABA and DMN deactivation increases with the cognitive loads. These neurochemical characteristics of DMN deactivation may provide novel insights toward better understanding of the DMN's functions under normal physiological conditions and dysfunctions in neuropsychiatric disorders.
Assuntos
Encéfalo/metabolismo , Ácido Glutâmico/metabolismo , Memória de Curto Prazo/fisiologia , Modelos Neurológicos , Descanso/fisiologia , Ácido gama-Aminobutírico/metabolismo , Adulto , Análise de Variância , Encéfalo/irrigação sanguínea , Mapeamento Encefálico , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Masculino , Vias Neurais , Oxigênio/sangue , Valor Preditivo dos TestesRESUMO
Mindfulness has garnered attention for its potential in alleviating cigarette cravings; however, the neural mechanisms underlying its efficacy remain inadequately understood. This study (N=46, all men) aims to examine the impact of a mindfulness strategy on regulating cue-induced craving and associated brain activity. Twenty-three smokers, consuming over 10 cigarettes daily for at least 2 yearsï¼ were compared to twenty-three non-smokers. During a regulation of craving task, participants were asked to practice mindfulness during smoking cue-exposure or passively view smoking cues while fMRI scans were completed. A 2 (condition: mindfulness-cigarette and look-cigarette) × 2 (phase: early, late of whole smoking cue-exposure period) repeated measures ANOVA showed a significant interaction of the craving scores between condition and phase, indicating that the mindfulness strategy dampened late-phase craving. Additionally, within the smoker group, the fMRI analyses revealed a significant main effect of mindfulness condition and its interaction with time in several brain networks involving reward, emotion, and interoception. Specifically, the bilateral insula, ventral striatum, and amygdala showed lower activation in the mindfulness condition, whereas the activation of right orbitofrontal cortex mirrored the strategy-time interaction effect of the craving change. This study illuminates the dynamic interplay between mindfulness, smoking cue-induced craving, and neural activity, offering insights into how mindfulness may effectively regulate cigarette cravings.
Assuntos
Fissura , Sinais (Psicologia) , Imageamento por Ressonância Magnética , Atenção Plena , Fumantes , Humanos , Fissura/fisiologia , Masculino , Atenção Plena/métodos , Adulto , Fumantes/psicologia , Adulto Jovem , Tonsila do Cerebelo/fisiopatologia , Estriado Ventral/fisiopatologia , Estriado Ventral/diagnóstico por imagem , Recompensa , Córtex Pré-Frontal/fisiopatologia , Córtex Pré-Frontal/diagnóstico por imagem , Interocepção/fisiologia , Emoções/fisiologia , Córtex Insular/fisiopatologia , Encéfalo/fisiopatologia , Encéfalo/diagnóstico por imagem , Fumar Cigarros/psicologia , Fumar Cigarros/terapiaRESUMO
The pervasive nature of short-form video platforms has seamlessly integrated into daily routines, yet it is important to recognize their potential adverse effects on both physical and mental health. Prior research has identified a detrimental impact of excessive short-form video consumption on attentional behavior, but the underlying neural mechanisms remain unexplored. In the current study, we aimed to investigate the effect of short-form video use on attentional functions, measured through the attention network test (ANT). A total of 48 participants, consisting of 35 females and 13 males, with a mean age of 21.8 years, were recruited. The mobile phone short video addiction tendency questionnaire (MPSVATQ) and self-control scale (SCS) were conducted to assess the short video usage behavior and self-control ability. Electroencephalogram (EEG) data were recorded during the completion of the ANT task. The correlation analysis showed a significant negative relationship between MPSVATQ and theta power index reflecting the executive control in the prefrontal region (r = -0.395, p = 0.007), this result was not observed by using theta power index of the resting-state EEG data. Furthermore, a significant negative correlation was identified between MPSVATQ and SCS outcomes (r = -0.320, p = 0.026). These results suggest that an increased tendency toward mobile phone short video addiction could negatively impact self-control and diminish executive control within the realm of attentional functions. This study sheds light on the adverse consequences stemming from short video consumption and underscores the importance of developing interventions to mitigate short video addiction.