Most recent paper

Temporal Dynamics of Resting-state Functional Networks and Cognitive Functioning following Systemic Treatment for Breast Cancer

Wed, 06/15/2022 - 18:00

Brain Imaging Behav. 2022 Jun 15. doi: 10.1007/s11682-022-00651-8. Online ahead of print.

ABSTRACT

Many women with breast cancer suffer from a decline in memory and executive function, particularly after treatment with chemotherapy. Recent neuroimaging studies suggest that changes in network dynamics are fundamental in decline in these cognitive functions. This has, however, not yet been investigated in breast cancer patients. Using resting state functional magnetic resonance imaging, we prospectively investigated whether changes in dynamic functional connectivity were associated with changes in memory and executive function. We examined 34 breast cancer patients that received chemotherapy, 32 patients that did not receive chemotherapy, and 35 no-cancer controls. All participants were assessed prior to treatment and six months after completion of chemotherapy, or at similar intervals for the other groups. To assess memory and executive function, we used the Hopkins Verbal Learning Test - Immediate Recall and the Trail Making Test B, respectively. Using a sliding window approach, we then evaluated dynamic functional connectivity of resting state networks supporting memory and executive function, i.e. the default mode network and frontoparietal network, respectively. Next, we directly investigated the association between cognitive performance and dynamic functional connectivity. We found no group differences in cognitive performance or connectivity measures. The association between dynamic functional connectivity of the default mode network and memory differed significantly across groups. This was not the case for the frontoparietal network and executive function. This suggests that cancer and chemotherapy alter the role of dynamic functional connectivity in memory function. Further implications of these findings are discussed.

PMID:35705764 | DOI:10.1007/s11682-022-00651-8

A longitudinal study of functional connectome uniqueness and its association with psychological distress in adolescence

Tue, 06/14/2022 - 18:00

Neuroimage. 2022 Jun 11;258:119358. doi: 10.1016/j.neuroimage.2022.119358. Online ahead of print.

ABSTRACT

Each human brain has a unique functional synchronisation pattern (functional connectome) analogous to a fingerprint that underpins brain functions and related behaviours. Here we examine functional connectome (whole-brain and 13 networks) maturation by measuring its uniqueness in adolescents who underwent brain scans longitudinally from 12 years of age every four months. The uniqueness of a functional connectome is defined as its ratio of self-similarity (from the same subject at a different time point) to the maximal similarity-to-others (from a given subject and any others at a different time point). We found that the unique whole brain connectome exists in 12 years old adolescents, with 92% individuals having a whole brain uniqueness value greater than one. The cingulo-opercular network (CON; a long-acting 'brain control network' configuring information processing) demonstrated marginal uniqueness in early adolescence with 56% of individuals showing uniqueness greater than one (i.e., more similar to her/his own CON four months later than those from any other subjects) and this increased longitudinally. Notably, the low uniqueness of the CON correlates (β = -18.6, FDR-Q < < 0.001) with K10 levels at the subsequent time point. This association suggests that the individualisation of CON network is related to psychological distress levels. Our findings highlight the potential of longitudinal neuroimaging to capture mental health problems in young people who are undergoing profound neuroplasticity and environment sensitivity period.

PMID:35700948 | DOI:10.1016/j.neuroimage.2022.119358

Youth with Down syndrome display widespread increased functional connectivity during rest

Tue, 06/14/2022 - 18:00

Sci Rep. 2022 Jun 14;12(1):9836. doi: 10.1038/s41598-022-13437-1.

ABSTRACT

Studies of resting-state functional connectivity in young people with Down syndrome (DS) have yielded conflicting results. Some studies have found increased connectivity while others have found a mix of increased and decreased connectivity. No studies have examined whole-brain connectivity at the voxel level in youth with DS during an eyes-open resting-state design. Additionally, no studies have examined the relationship between connectivity and network selectivity in youth with DS. Thus, the current study sought to fill this gap in the literature. Nineteen youth with DS (Mage = 16.5; range 7-23; 13 F) and 33 typically developing (TD) youth (Mage = 17.5; range 6-24; 18 F), matched on age and sex, completed a 5.25-min eyes-open resting-state fMRI scan. Whole-brain functional connectivity (average Pearson correlation of each voxel with every other voxel) was calculated for each individual and compared between groups. Network selectivity was then calculated and correlated with functional connectivity for the DS group. Results revealed that whole-brain functional connectivity was significantly higher in youth with DS compared to TD controls in widespread regions throughout the brain. Additionally, participants with DS had significantly reduced network selectivity compared to TD peers, and selectivity was significantly related to connectivity in all participants. Exploratory behavioral analyses revealed that regions showing increased connectivity in DS predicted Verbal IQ, suggesting differences in connectivity may be related to verbal abilities. These results indicate that network organization is disrupted in youth with DS such that disparate networks are overly connected and less selective, suggesting a potential target for clinical interventions.

PMID:35701489 | DOI:10.1038/s41598-022-13437-1

A longitudinal resource for studying connectome development and its psychiatric associations during childhood

Tue, 06/14/2022 - 18:00

Sci Data. 2022 Jun 14;9(1):300. doi: 10.1038/s41597-022-01329-y.

ABSTRACT

Most psychiatric disorders are chronic, associated with high levels of disability and distress, and present during pediatric development. Scientific innovation increasingly allows researchers to probe brain-behavior relationships in the developing human. As a result, ambitions to (1) establish normative pediatric brain development trajectories akin to growth curves, (2) characterize reliable metrics for distinguishing illness, and (3) develop clinically useful tools to assist in the diagnosis and management of mental health and learning disorders have gained significant momentum. To this end, the NKI-Rockland Sample initiative was created to probe lifespan development as a large-scale multimodal dataset. The NKI-Rockland Sample Longitudinal Discovery of Brain Development Trajectories substudy (N = 369) is a 24- to 30-month multi-cohort longitudinal pediatric investigation (ages 6.0-17.0 at enrollment) carried out in a community-ascertained sample. Data include psychiatric diagnostic, medical, behavioral, and cognitive phenotyping, as well as multimodal brain imaging (resting fMRI, diffusion MRI, morphometric MRI, arterial spin labeling), genetics, and actigraphy. Herein, we present the rationale, design, and implementation of the Longitudinal Discovery of Brain Development Trajectories protocol.

PMID:35701428 | DOI:10.1038/s41597-022-01329-y

Resting-state fMRI-based screening of deschloroclozapine in rhesus macaques predicts dosage-dependent behavioral effects

Tue, 06/14/2022 - 18:00

J Neurosci. 2022 Jun 13:JN-RM-0325-22. doi: 10.1523/JNEUROSCI.0325-22.2022. Online ahead of print.

ABSTRACT

Chemogenetic techniques such as Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) enable transient, reversible, and minimally invasive manipulation of neural activity in vivo. Their development in non-human primates is essential for uncovering neural circuits contributing to cognitive functions and their translation to humans. One key issue that has delayed the development of chemogenetic techniques in primates is the lack of an accessible drug-screening method. Here, we utilize resting-state functional MRI (rs-fMRI), a non-invasive neuroimaging tool, to assess the impact of deschloroclozapine (DCZ) on brain-wide resting-state functional connectivity in seven rhesus macaques (6 males and 1 female) without DREADDs. We found that systemic administration of 0.1 mg/kg DCZ did not alter the resting-state functional connectivity. Conversely, 0.3 mg/kg of DCZ was associated with a prominent increase in functional connectivity that was mainly confined to the connections of frontal regions. Additional behavioral tests confirmed a negligible impact of 0.1 mg/kg DCZ on socio-emotional behaviors as well as on reaction time in a probabilistic learning task. 0.3 mg/kg DCZ did, however, slow responses in the probabilistic learning task, suggesting attentional or motivational deficits associated with hyperconnectivity in fronto-temporo-parietal networks. Our study highlights both the excellent selectivity of DCZ as a DREADD actuator, and the side-effects of its excess dosage. The results demonstrate the translational value of rs-fMRI as a drug-screening tool to accelerate the development of chemogenetics in primates.SIGNIFICANCE STATEMENT:Chemogenetics such as Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) can afford control over neural activity with unprecedented spatiotemporal resolution. Accelerating the translation of chemogenetic neuromodulation from rodents to primates requires an approach to screen novel DREADD actuators in vivo Here, we assessed brain-wide activity in response to a DREADD actuator deschloroclozapine (DCZ) utilizing resting-state functional MRI (rs-fMRI) in macaque monkeys. We demonstrated that low-dose DCZ (0.1 mg/kg) did not change whole-brain functional connectivity or affective behaviors, while higher dose (0.3 mg/kg) altered frontal functional connectivity and slowed response in a learning task. Our study highlights the excellent selectivity of DCZ at proper dosing, and demonstrates the utility of rs-fMRI to screen novel chemogenetic actuators in primates.

PMID:35701162 | DOI:10.1523/JNEUROSCI.0325-22.2022

The brain network underlying attentional blink predicts symptoms of attention deficit hyperactivity disorder in children

Tue, 06/14/2022 - 18:00

Cereb Cortex. 2022 Jun 14:bhac240. doi: 10.1093/cercor/bhac240. Online ahead of print.

ABSTRACT

Attention deficit hyperactivity disorder (ADHD) is a chronic neuropsychiatric disease that can markedly impair educational, social, and occupational function throughout life. Behavioral deficits may provide clues to the underlying neurological impairments. Children with ADHD exhibit a larger attentional blink (AB) deficit in rapid serial visual presentation (RSVP) tasks than typically developing children, so we examined whether brain connectivity in the neural network associated with AB can predict ADHD symptoms and thus serve as potential biomarkers of the underlying neuropathology. We first employed a connectome-based predictive model analysis of adult resting-state functional magnetic resonance imaging data to identify a distributed brain network for AB. The summed functional connectivity (FC) strength within the AB network reliably predicted individual differences in AB magnitude measured by a classical dual-target RSVP task. Furthermore, the summed FC strength within the AB network predicted individual differences in ADHD Rating Scale scores from an independent dataset of pediatric patients. Our findings suggest that the individual AB network could serve as an applicable neuroimaging-based biomarker of AB deficit and ADHD symptoms.

PMID:35699600 | DOI:10.1093/cercor/bhac240

Neural distinctiveness of fatigue and low sleep quality in multiple sclerosis

Tue, 06/14/2022 - 18:00

Eur J Neurol. 2022 Jun 14. doi: 10.1111/ene.15445. Online ahead of print.

ABSTRACT

BACKGROUND: Fatigue and low sleep quality in multiple sclerosis (MS) are closely related symptoms. Here, we investigated the associations between the brain's functional connectivity (FC) and fatigue and low sleep quality, to determine the degree of neural distinctiveness of these symptoms.

METHOD: One-hundred-four patients with relapsing-remitting MS (age: 38.9 ± 10.2 years, 66 females) completed the Modified Fatigue Impact Scale and the Pittsburgh Sleep Quality Index and underwent resting-state fMRI. FC was analyzed using independent-component analysis in sensorimotor, default-mode, fronto-parietal, and basal-ganglia networks. Multiple linear regression models allowed us to test the association between FC and fatigue and sleep quality while controlling for one another as well as for demographic, disease-related, and imaging variables.

RESULTS: Higher fatigue correlated with lower sleep quality (r = 0.54, p < 0.0001). Higher fatigue was associated with lower FC of the precentral gyrus in the sensorimotor network, the precuneus in the posterior default-mode network, and the superior frontal gyrus in the left fronto-parietal network, independently of sleep quality. Lower sleep quality was associated with lower FC of the left intraparietal sulcus in the left fronto-parietal network, independently of fatigue. We found specific associations between fatigue and the sensorimotor network's global FC, and between low sleep quality and the left fronto-parietal network's global FC.

CONCLUSION: Despite the high correlation between fatigue and low sleep quality in the clinical picture, our findings clearly indicate that, on the neural level, fatigue and low sleep quality in MS are associated with decreased FC in distinct functional brain networks.

PMID:35699354 | DOI:10.1111/ene.15445

Decreased Connectivity in Precuneus of the Ventral Attentional Network in First-Episode, Treatment-Naïve Patients With Major Depressive Disorder: A Network Homogeneity and Independent Component Analysis

Mon, 06/13/2022 - 18:00

Front Psychiatry. 2022 May 27;13:925253. doi: 10.3389/fpsyt.2022.925253. eCollection 2022.

ABSTRACT

BACKGROUND AND OBJECTIVE: The ventral attentional network (VAN) can provide quantitative information on cognitive problems in patients with major depressive disorder (MDD). Nevertheless, little is known about network homogeneity (NH) changes in the VAN of these patients. The aim of this study was to examine the NH values in the VAN by independent component analysis (ICA) and compare the NH values between MDD patients and the normal controls (NCs).

METHODS: Attentional network test and resting-state functional magnetic resonance imaging (rs-fMRI) data were collected from 73 patients, and 70 NCs matched by gender, age, and education years. ICA and NH were employed to evaluate the data. Moreover, the NH values were compared, and Spearman's rank correlation analysis was used to assess the correlations with the executive control reaction time (ECRT).

RESULTS: Our results showed that the first-episode, treatment-naive MDD patients had decreased NH in the right precuneus (PCu) and abnormal ECRT compared with NCs. However, no significant correlation was found between the NH values and measured clinical variables.

CONCLUSION: Our results highlight the potential importance of VAN in the pathophysiology of cognitive problems in MDD, thus offering new directions for future research on MDD.

PMID:35693966 | PMC:PMC9184427 | DOI:10.3389/fpsyt.2022.925253

Reorganized Brain Functional Network Topology in Presbycusis

Mon, 06/13/2022 - 18:00

Front Aging Neurosci. 2022 May 26;14:905487. doi: 10.3389/fnagi.2022.905487. eCollection 2022.

ABSTRACT

PURPOSE: Presbycusis is characterized by bilateral sensorineural hearing loss at high frequencies and is often accompanied by cognitive decline. This study aimed to identify the topological reorganization of brain functional network in presbycusis with/without cognitive decline by using graph theory analysis approaches based on resting-state functional magnetic resonance imaging (rs-fMRI).

METHODS: Resting-state fMRI scans were obtained from 30 presbycusis patients with cognitive decline, 30 presbycusis patients without cognitive decline, and 50 age-, sex-, and education-matched healthy controls. Graph theory was applied to analyze the topological properties of brain functional networks including global and nodal metrics, modularity, and rich-club organization.

RESULTS: At the global level, the brain functional networks of all participants were found to possess small-world properties. Also, significant group differences in global network metrics were observed among the three groups such as clustering coefficient, characteristic path length, normalized characteristic path length, and small-worldness. At the nodal level, several nodes with abnormal betweenness centrality, degree centrality, nodal efficiency, and nodal local efficiency were detected in presbycusis patients with/without cognitive decline. Changes in intra-modular connections in frontal lobe module and inter-modular connections in prefrontal subcortical lobe module were found in presbycusis patients exposed to modularity analysis. Rich-club nodes were reorganized in presbycusis patients, while the connections among them had no significant group differences.

CONCLUSION: Presbycusis patients exhibited topological reorganization of the whole-brain functional network, and presbycusis patients with cognitive decline showed more obvious changes in these topological properties than those without cognitive decline. Abnormal changes of these properties in presbycusis patients may compensate for cognitive impairment by mobilizing additional neural resources.

PMID:35693344 | PMC:PMC9177949 | DOI:10.3389/fnagi.2022.905487

Amygdalar Functional Connectivity Differences Associated With Reduced Pain Intensity in Pediatric Peripheral Neuropathic Pain

Mon, 06/13/2022 - 18:00

Front Pain Res (Lausanne). 2022 May 27;3:918766. doi: 10.3389/fpain.2022.918766. eCollection 2022.

ABSTRACT

BACKGROUND: There is evidence of altered corticolimbic circuitry in adults with chronic pain, but relatively little is known of functional brain mechanisms in adolescents with neuropathic pain (NeuP). Pediatric NeuP is etiologically and phenotypically different from NeuP in adults, highlighting the need for pediatric-focused research. The amygdala is a key limbic region with important roles in the emotional-affective dimension of pain and in pain modulation.

OBJECTIVE: To investigate amygdalar resting state functional connectivity (rsFC) in adolescents with NeuP.

METHODS: This cross-sectional observational cohort study compared resting state functional MRI scans in adolescents aged 11-18 years with clinical features of chronic peripheral NeuP (n = 17), recruited from a tertiary clinic, relative to healthy adolescents (n = 17). We performed seed-to-voxel whole-brain rsFC analysis of the bilateral amygdalae. Next, we performed post hoc exploratory correlations with clinical variables to further explain rsFC differences.

RESULTS: Adolescents with NeuP had stronger negative rsFC between right amygdala and right dorsolateral prefrontal cortex (dlPFC) and stronger positive rsFC between right amygdala and left angular gyrus (AG), compared to controls (P FDR <0.025). Furthermore, lower pain intensity correlated with stronger negative amygdala-dlPFC rsFC in males (r = 0.67, P = 0.034, n = 10), and with stronger positive amygdala-AG rsFC in females (r = -0.90, P = 0.006, n = 7). These amygdalar rsFC differences may thus be pain inhibitory.

CONCLUSIONS: Consistent with the considerable affective and cognitive factors reported in a larger cohort, there are rsFC differences in limbic pain modulatory circuits in adolescents with NeuP. Findings also highlight the need for assessing sex-dependent brain mechanisms in future studies, where possible.

PMID:35692562 | PMC:PMC9184677 | DOI:10.3389/fpain.2022.918766

Task- and resting-state fMRI studies in multiple sclerosis: From regions to systems and time-varying analysis. Current status and future perspective

Sun, 06/12/2022 - 18:00

Neuroimage Clin. 2022 Jun 6;35:103076. doi: 10.1016/j.nicl.2022.103076. Online ahead of print.

ABSTRACT

Multiple sclerosis (MS) is a neurological disorder affecting the central nervous system and features extensive functional brain changes that are poorly understood but relate strongly to clinical impairments. Functional magnetic resonance imaging (fMRI) is a non-invasive, powerful technique able to map activity of brain regions and to assess how such regions interact for an efficient brain network. FMRI has been widely applied to study functional brain changes in MS, allowing to investigate functional plasticity consequent to disease-related structural injury. The first studies in MS using active fMRI tasks mainly aimed to study such plastic changes by identifying abnormal activity in salient brain regions (or systems) involved by the task. In later studies the focus shifted towards resting state (RS) functional connectivity (FC) studies, which aimed to map large-scale functional networks of the brain and to establish how MS pathology impairs functional integration, eventually leading to the hypothesized network collapse as patients clinically progress. This review provides a summary of the main findings from studies using task-based and RS fMRI and illustrates how functional brain alterations relate to clinical disability and cognitive deficits in this condition. We also give an overview of longitudinal studies that used task-based and RS fMRI to monitor disease evolution and effects of motor and cognitive rehabilitation. In addition, we discuss the results of studies using newer technologies involving time-varying FC to investigate abnormal dynamism and flexibility of network configurations in MS. Finally, we show some preliminary results from two recent topics (i.e., multimodal MRI analysis and artificial intelligence) that are receiving increasing attention. Together, these functional studies could provide new (conceptual) insights into disease stage-specific mechanisms underlying progression in MS, with recommendations for future research.

PMID:35691253 | DOI:10.1016/j.nicl.2022.103076

Adaptation of prelimbic cortex mediated by IL-6/STAT3/Acp5 pathway contributes to the comorbidity of neuropathic pain and depression in rats

Sat, 06/11/2022 - 18:00

J Neuroinflammation. 2022 Jun 11;19(1):144. doi: 10.1186/s12974-022-02503-0.

ABSTRACT

BACKGROUND: The adaption of brain region is fundamental to the development and maintenance of nervous system disorders. The prelimbic cortex (PrL) participates in the affective components of the pain sensation. However, whether and how the adaptation of PrL contributes to the comorbidity of neuropathic pain and depression are unknown.

METHODS: Using resting-state functional magnetic resonance imaging (rs-fMRI), genetic knockdown or overexpression, we systematically investigated the activity of PrL region in the pathogenesis of neuropathic pain/depression comorbid using the combined approaches of immunohistochemistry, electrophysiology, and behavior.

RESULTS: The activity of PrL and the excitability of pyramidal neurons were decreased, and the osteoclastic tartrate-resistant acid phosphatase 5 (Acp5) expression in PrL neurons was upregulated following the acquisition of spared nerve injury (SNI)-induced comorbidity. Genetic knockdown of Acp5 in pyramidal neurons, but not parvalbumin (PV) neurons or somatostatin (SST) neurons, attenuated the decrease of spike number, depression-like behavior and mechanical allodynia in comorbidity rats. Overexpression of Acp5 in PrL pyramidal neurons decreased the spike number and induced the comorbid-like behavior in naïve rats. Moreover, the expression of interleukin-6 (IL-6), phosphorylated STAT3 (p-STAT3) and acetylated histone H3 (Ac-H3) were significantly increased following the acquisition of comorbidity in rats. Increased binding of STAT3 to the Acp5 gene promoter and the interaction between STAT3 and p300 enhanced acetylation of histone H3 and facilitated the transcription of Acp5 in PrL in the modeled rodents. Inhibition of IL-6/STAT3 pathway prevented the Acp5 upregulation and attenuated the comorbid-like behaviors in rats.

CONCLUSIONS: These data suggest that the adaptation of PrL mediated by IL-6/STAT3/Acp5 pathway contributed to the comorbidity of neuropathic pain/depression induced by SNI.

PMID:35690777 | DOI:10.1186/s12974-022-02503-0

Uncovering individual differences in fine-scale dynamics of functional connectivity

Sat, 06/11/2022 - 18:00

Cereb Cortex. 2022 Jun 12:bhac214. doi: 10.1093/cercor/bhac214. Online ahead of print.

ABSTRACT

Functional connectivity (FC) profiles contain subject-specific features that are conserved across time and have potential to capture brain-behavior relationships. Most prior work has focused on spatial features (nodes and systems) of these FC fingerprints, computed over entire imaging sessions. We propose a method for temporally filtering FC, which allows selecting specific moments in time while also maintaining the spatial pattern of node-based activity. To this end, we leverage a recently proposed decomposition of FC into edge time series (eTS). We systematically analyze functional magnetic resonance imaging frames to define features that enhance identifiability across multiple fingerprinting metrics, similarity metrics, and data sets. Results show that these metrics characteristically vary with eTS cofluctuation amplitude, similarity of frames within a run, transition velocity, and expression of functional systems. We further show that data-driven optimization of features that maximize fingerprinting metrics isolates multiple spatial patterns of system expression at specific moments in time. Selecting just 10% of the data can yield stronger fingerprints than are obtained from the full data set. Our findings support the idea that FC fingerprints are differentially expressed across time and suggest that multiple distinct fingerprints can be identified when spatial and temporal characteristics are considered simultaneously.

PMID:35690591 | DOI:10.1093/cercor/bhac214

Functional Connectome-Based Predictive Modeling in Autism

Sat, 06/11/2022 - 18:00

Biol Psychiatry. 2022 Apr 25:S0006-3223(22)01202-1. doi: 10.1016/j.biopsych.2022.04.008. Online ahead of print.

ABSTRACT

Autism is a heterogeneous neurodevelopmental condition, and functional magnetic resonance imaging-based studies have helped advance our understanding of its effects on brain network activity. We review how predictive modeling, using measures of functional connectivity and symptoms, has helped reveal key insights into this condition. We discuss how different prediction frameworks can further our understanding of the brain-based features that underlie complex autism symptomatology and consider how predictive models may be used in clinical settings. Throughout, we highlight aspects of study interpretation, such as data decay and sampling biases, that require consideration within the context of this condition. We close by suggesting exciting future directions for predictive modeling in autism.

PMID:35690495 | DOI:10.1016/j.biopsych.2022.04.008

Arousal impacts distributed hubs modulating the integration of brain functional connectivity

Sat, 06/11/2022 - 18:00

Neuroimage. 2022 Jun 8:119364. doi: 10.1016/j.neuroimage.2022.119364. Online ahead of print.

ABSTRACT

Even when subjects are at rest, it is thought that brain activity is organized into distinct brain states during which reproducible patterns are observable. Yet, it is unclear how to define or distinguish different brain states. A potential source of brain state variation is arousal, which may play a role in modulating functional interactions between brain regions. Here, we use simultaneous resting state functional magnetic resonance imaging (fMRI) and pupillometry to study the impact of arousal levels indexed by pupil area on the integration of large-scale brain networks. We employ a novel sparse dictionary learning-based method to identify hub regions participating in between-network integration stratified by arousal, by measuring k-hubness, the number (k) of functionally overlapping networks in each brain region. We show evidence of a brain-wide decrease in between-network integration and inter-subject variability at low relative to high arousal, with differences emerging across regions of the frontoparietal, default mode, motor, limbic, and cerebellum networks. State-dependent changes in k-hubness relate to the actual patterns of network integration within these hubs, suggesting a brain state transition from high to low arousal characterized by global synchronization and reduced network overlaps. We demonstrate that arousal is not limited to specific brain areas known to be directly associated with arousal regulation, but instead has a brain-wide impact that involves high-level between-network communications. Lastly, we show a systematic change in pairwise fMRI signal correlation structures in the arousal state-stratified data, and demonstrate that the choice of global signal regression could result in different conclusions in conventional graph theoretical analysis and in the analysis of k-hubness when studying arousal modulations. Together, our results suggest the presence of global and local effects of pupil-linked arousal modulations on resting state brain functional connectivity.

PMID:35690257 | DOI:10.1016/j.neuroimage.2022.119364

Local inefficiency of the default mode network in young men with narcissistic personality disorder

Sat, 06/11/2022 - 18:00

Neurosci Lett. 2022 Jun 8:136720. doi: 10.1016/j.neulet.2022.136720. Online ahead of print.

ABSTRACT

Neuroimaging studies have shown structural deficits in the default mode network (DMN) in patients with narcissistic personality disorder (NPD); however, the functional basis of the DMN in NPD remains unclear. This study aimed to explore the functional basis of the DMN in NPD from the perspective of the connectome. Nineteen young male patients with NPD (mean age, 18.47±0.77 years; range, 18-20 years) and 19 young male healthy control (HC) participants (mean age, 19.05±1.31 years; range, 18-22 years) were recruited for resting-state functional magnetic resonance imaging examinations. The DMN architecture was depicted by 20 DMN subregions. Graph theory approaches were applied to investigate the functional topology within the DMN in NPD, and Pearson correlations between network parameters and psychological scores were assessed. The NPD group demonstrated topological anomalies in the DMN indicated by a decrease in the clustering coefficient and local efficiency compared with the HC group. Additionally, the NPD group showed increased nodal clustering and efficiency in the right posterior cingulate cortex. In the NPD group, local efficiency within the DMN was found to be positively correlated with the Narcissistic Personality Inventory score and negatively correlated the Hiding the Self score. The NPD group showed abnormal topology within the DMN, indicating that the functional segregation of the DMN is disturbed in NPD. The destroyed topology of the DMN may represent a functional basis of the pathogenesis of NPD in young adult males and may be related to the increased vulnerability in NPD, including hiding the self.

PMID:35690230 | DOI:10.1016/j.neulet.2022.136720