New resting-state fMRI related studies at PubMed

Memory Suppression Ability can be Robustly Predicted by the Internetwork Communication of Frontoparietal Control Network

Thu, 03/04/2021 - 11:00

Cereb Cortex. 2021 Mar 1:bhab024. doi: 10.1093/cercor/bhab024. Online ahead of print.


Memory suppression (MS) is essential for mental well-being. However, no studies have explored how intrinsic resting-state functional connectivity (rs-FC) predicts this ability. Here, we adopted the connectome-based predictive modeling (CPM) based on the resting-state fMRI data to investigate whether and how rs-FC profiles in predefined brain networks (the frontoparietal control networks or FPCN) can predict MS in healthy individuals with 497 participants. The MS ability was assessed by MS-induced forgetting during the think/no-think paradigm. The results showed that FPCN network was especially informative for generating the prediction model for MS. Some regions of FPCN, such as middle frontal gyrus, superior frontal gyrus and inferior parietal lobe were critical in predicting MS. Moreover, functional interplay between FPCN and multiple networks, such as dorsal attention network (DAN), ventral attention network (VAN), default mode network (DMN), the limbic system and subcortical regions, enabled prediction of MS. Crucially, the predictive FPCN networks were stable and specific to MS. These results indicated that FPCN flexibility interacts with other networks to underpin the ability of MS. These would also be beneficial for understanding how compromises in these functional networks may have led to the intrusive thoughts and memories characterized in some mental disorders.

PMID:33662104 | DOI:10.1093/cercor/bhab024

Abnormalities of the default-mode network homogeneity and executive dysfunction in people with first-episode, treatment-naive left temporal lobe epilepsy

Thu, 03/04/2021 - 11:00

Eur Rev Med Pharmacol Sci. 2021 Feb;25(4):2039-2049. doi: 10.26355/eurrev_202102_25108.


OBJECTIVE: Converging evidence has demonstrated that there is aberrant connectivity of the default-mode network (DMN) in left temporal lobe epilepsy (lTLE) yet changes in the network homogeneity (NH) of the DMN in people with first-episode, treatment-naive lTLE remains unclear. In this study, we used an NH method to investigate the NH of the DMN in people with first-episode, treatment-naive, lTLE, at rest.

PATIENTS AND METHODS: We collected resting-state functional magnetic resonance imaging (rs-fMRI), and attention network test (ANT) data from 43 people with lTLE and 42well-matched, healthy control subjects. An NH approach was used to analyze the data.

RESULTS: People with lTLE have decreased NH in the right inferior temporal gyrus (ITG) and the left middle temporal lobe (MTG), and increased NH in the bilateral precuneus (PCu) and right inferior parietal lobe (IPL), as compared with the controls. We also found that people with lTLE had a longer executive control reaction time (RT). No significant correlations were found between abnormal NH values and clinical variables in the subjects.

CONCLUSIONS: These findings suggest that abnormal NH of the DMN exists in lTLE subjects and highlight the significance of the DMN in the pathophysiology of cognitive problems occurring in lTLE.

PMID:33660816 | DOI:10.26355/eurrev_202102_25108

Abnormal ventral attention network homogeneity in patients with right temporal lobe epilepsy

Thu, 03/04/2021 - 11:00

Eur Rev Med Pharmacol Sci. 2021 Feb;25(4):2031-2038. doi: 10.26355/eurrev_202102_25107.


OBJECTIVE: The attention network is the structural basis of cognitive function. As one of the two known attention networks, the ventral attention network (VAN) has a significant impact on the cognitive impairment of patients with epilepsy. Nevertheless, changes in network homogeneity (NH) are rarely reported in the VAN of right temporal lobe epilepsy (rTLE) patients. Therefore, we explored the NH of the VAN in rTLE patients in this study.

PATIENTS AND METHODS: Seventy rTLE patients and 69 healthy controls were recruited. All participants underwent resting-state functional magnetic resonance imaging (fMRI), which was the primary method of evaluation. The executive control reaction time (ECRT) was examined via the attentional network test. The Data Processing Assistant for Resting-State fMRI (DPARSF) was used to analyze NH. The independent component analysis (ICA) and correlation analysis were used in data analysis.

RESULTS: Compared to the control group, patients with right temporal lobe epilepsy showed a lower NH in the right superior temporal gyrus, and a longer ECRT. However, abnormal NH values had no significant association with the clinical measurements.

CONCLUSIONS: Patients with right temporal lobe epilepsy have abnormal NH values in the VAN, and the executive functions in rTLE patients are also altered. The altered NH values in VAN may help provide new insights into the pathophysiology of cognitive impairment in rTLE.

PMID:33660815 | DOI:10.26355/eurrev_202102_25107

Functional connectivity abnormalities of the long-axis hippocampal subregions in schizophrenia during episodic memory

Thu, 03/04/2021 - 11:00

NPJ Schizophr. 2021 Mar 3;7(1):19. doi: 10.1038/s41537-021-00147-2.


Past evidence suggests that hippocampal subregions, namely the anterior and posterior parts, may be engaged in distinct networks underlying the memory functions which may be altered in patients with schizophrenia. However, of the very few studies that have investigated the hippocampal longitudinal axis subdivisions functional connectivity in patients with schizophrenia, the majority was based on resting-state data, and yet, none aimed to examine these during an episodic memory task. A total of 41 patients with schizophrenia and 45 healthy controls were recruited for a magnetic resonance imaging protocol in which they performed an explicit memory task. Seed-based functional connectivity analysis was employed to assess connectivity abnormalities between hippocampal subregions and voxel-wise connectivity targets in patients with schizophrenia. We observed a significantly reduced connectivity between the posterior hippocampus and regions from the default mode network, but increased connectivity with the primary visual cortex, in patients with schizophrenia compared to healthy subjects. Increased connectivity between the anterior hippocampus and anterior temporal regions also characterized patients with schizophrenia. In the current study, we provided evidence and support for studying hippocampal subdivisions along the longitudinal axis in schizophrenia. Our results suggest that the abnormalities in hippocampal subregions functional connectivity reflect deficits in episodic memory that may be implicated in the pathophysiology of schizophrenia.

PMID:33658524 | DOI:10.1038/s41537-021-00147-2

Increased functional coupling between VTA and hippocampus during rest in first-episode psychosis

Thu, 03/04/2021 - 11:00

eNeuro. 2021 Mar 3:ENEURO.0375-20.2021. doi: 10.1523/ENEURO.0375-20.2021. Online ahead of print.


Animal models suggest that interactions between the hippocampus and ventral tegmental area (VTA) underlie the onset and etiology of psychosis. While a large body of research has separately characterized alterations in hippocampal and VTA function in psychosis, alterations across the VTA and hippocampus have not been characterized in first-episode psychosis (FEP). As the phase of psychosis most proximal to conversion, studies specifically focused on FEP are valuable to psychosis research. Here, we characterize alterations in VTA-hippocampal interactions across male and female human participants experiencing their first episode of psychosis using resting state functional magnetic resonance imaging. In comparison to age and sex matched healthy controls, FEP individuals had significantly greater VTA-hippocampal functional coupling, but significantly less VTA-striatal functional coupling. Further, increased VTA-hippocampal functional coupling in FEP correlated with individual differences in psychosis-related symptoms. Together these findings demonstrate alterations in mesolimbic-hippocampal circuits in FEP and extend prominent animal models of psychosis.Significance statementWe characterized differences in functional coupling between the VTA and hippocampus in FEP. We found enhanced functional coupling between the VTA and right hippocampus in FEP, which correlated with individual differences in psychosis symptoms. We broaden a growing literature characterizing mesolimbic-hippocampal interactions,showing a prominent role for this circuit in psychosis. Further, our findings connect well with animal models of psychosis which detail alterations in this circuit as a risk factor for developing psychosis. These findings support a model of increased functional interactions between the hippocampus and VTA with etiology of psychosis, and may predict individual differences in psychosis-related symptoms.

PMID:33658310 | DOI:10.1523/ENEURO.0375-20.2021

Alterations of brain network topology and structural-functional connectivity coupling in capsular versus pontine stroke

Wed, 03/03/2021 - 11:00

Eur J Neurol. 2021 Mar 3. doi: 10.1111/ene.14794. Online ahead of print.


BACKGROUND AND PURPOSE: This study was conducted to investigate whether capsular stroke (CS) and pontine stroke (PS) have different topological alterations of structural connectivity (SC), functional connectivity (FC) and the SC-FC coupling correlation with the movement assessment scores.

METHODS: Resting-state functional magnetic resonance imaging (rs-fMRI) and diffusion tensor imaging (DTI) were prospectively acquired in 46 CS, 36 PS, and 29 healthy controls (HCs). Graph theoretical network analyses of SC and FC were performed. Patients with lesions in left and right were analyzed respectively.

RESULTS: For the FC, the PS and CS both showed higher local efficiency (Eloc) than the HCs and the CS also showed higher clustering coefficient (Cp) than the HCs in the right-lesion analysis. For the SC, the PS and CS both displayed different normalized clustering coefficient (γ), small-worldness (σ), characteristic path length (Lp) with the HCs. Additionally, the CS showed higher normalized characteristic path length (λ) and lower Cp than the HCs and PS showed higher λ and lower global efficiency (Eg) than the HCs in the right-lesion analysis. Whereas, γ, σ, Cp, Lp were only significant between the PS and CS in the right-lesion analysis. Importantly, CS had a weaker coupling than the PS and the HCs in the right-lesion analysis. In addition, the patients had weaker structural-functional connectome correlation than controls.

CONCLUSIONS: CS and PS both showed FC and SC disruption and the CS had a weaker coupling than the PS in the right lesion analysis. This may provide useful information for individualized rehabilitative strategies.

PMID:33657258 | DOI:10.1111/ene.14794

Analysis of functional MRI signal complexity based on permutation fuzzy entropy in bipolar disorder

Wed, 03/03/2021 - 11:00

Neuroreport. 2021 Mar 1. doi: 10.1097/WNR.0000000000001617. Online ahead of print.


Bipolar disorder is a manifestation of an emotional disease and is associated with emotional and cognitive dysfunction. The entropy-based method has been widely used to study the complexity of resting-state functional MRI (rs-fMRI) signals in mental diseases; however, alterations in the brain rs-fMRI signal complexities in bipolar disorder patients remain unclear, and previously used entropy methods are sensitive to noise. Here, we performed a work using permutation fuzzy entropy (PFEN), which has better performance than previously used methods, to analyze the brain complexity of bipolar disorder patients. Based on PFEN research, we obtained brain entropy maps of 49 bipolar disorder patients and 49 normal control, extracted the regions of interest to analyze the complexity of abnormal brain regions and further analyzed the correlation between the PFEN values of abnormal brain regions and the clinical measurement scores. Compared with the values in the normal control group, we found that significantly increased PFEN values mainly appeared in the middle temporal gyrus, angular gyrus, superior occipital gyrus and medial superior frontal gyrus, and the decreased PFEN values were found in the inferior temporal gyrus in bipolar disorder patients. In addition, the PFEN values of the angular gyrus was significantly negatively correlated with clinical scores. These findings improve our understanding of the pathophysiology of bipolar disorder patients.

PMID:33657075 | DOI:10.1097/WNR.0000000000001617

Temporal dynamics alterations of spontaneous neuronal activity in anterior cingulate cortex predict suicidal risk in bipolar II patients

Wed, 03/03/2021 - 11:00

Brain Imaging Behav. 2021 Mar 3. doi: 10.1007/s11682-020-00448-7. Online ahead of print.


Bipolar disorder type II (BD-II) is linked to an increased suicidal risk. Since a prior suicide attempt (SA) is the single most important risk factor for sequent suicide, the elucidation of involved neural substrates is critical for its prevention. Therefore, we examined the spontaneous brain activity and its temporal variabilities in suicide attempters with bipolar II during a major depressive episode. In this cross-sectional study, 101 patients with BD-II, including 44 suicidal attempters and 57 non-attempters, and 60 non-psychiatric controls underwent a resting-state functional magnetic resonance imaging (fMRI). Participants were assessed with Hamilton Rating Scale for Depression (HAMD) and Nurses, Global Assessment of Suicide Risk (NGASR). The dynamics of low-frequency fluctuation (dALFF) was measured using sliding-window analysis and its correlation with suicidal risk was conducted using Pearson correlation. Compared to non-attempters, suicidal attempters showed an increase in brain activity and temporal dynamics in the anterior cingulate cortex (ACC). In addition, the temporal variabilities of ACC activity positively correlated with suicidal risk (R = 0.45, p = 0.004), while static ACC activity failed to (R = 0.08, p > 0.05). Our findings showed that an aberrant static ALFF and temporal variability could affect suicidal behavior in BD-II patients. However, temporal variability of neuronal activity was more sensitive than static amplitude in reflecting diathesis for suicide in BD-II. Dynamics of brain activity could be considered in developing neuromarkers for suicide prevention.

PMID:33656698 | DOI:10.1007/s11682-020-00448-7

Altered Cerebro-Cerebellar Dynamic Functional Connectivity in Alcohol Use Disorder: a Resting-State fMRI Study

Wed, 03/03/2021 - 11:00

Cerebellum. 2021 Mar 3. doi: 10.1007/s12311-021-01241-y. Online ahead of print.


Alcohol use disorder (AUD) is widely associated with cerebellar dysfunction and altered cerebro-cerebellar functional connectivity (FC) that lead to cognitive impairments. Evidence for this association comes from resting-state functional magnetic resonance imaging (rsfMRI) studies that assess time-averaged measures of FC across the duration of a typical scan. This approach, however, precludes the assessment of potentially FC dynamics happening at faster timescales. In this study, using rsfMRI data, we aim at exploring cerebro-cerebellar FC dynamics in AUD patients (N = 18) and age- and sex-matched controls (N = 18). In particular, we quantified group-level differences in the temporal variability of FC between the posterior cerebellum and large-scale cognitive systems, and we investigated the role of the cerebellum in large-scale brain dynamics in terms of the temporal flexibility and integration of its regions. We found that, relative to controls, the AUD group exhibited significantly greater FC variability between the cerebellum and both the frontoparietal executive control (F1,31 = 7.01, p(FDR) = 0.028) and ventral attention (F1,31 = 7.35, p(FDR) = 0.028) networks. Moreover, the AUD group exhibited significantly less flexibility (F1,31 = 8.61, p(FDR) = 0.028) and greater integration (F1,31 = 9.11, p(FDR) = 0.028) in the cerebellum. Finally, in an exploratory analysis, we found distributed changes in the dynamics of canonical large-scale networks in AUD. Overall, this study brings evidence of AUD-related alterations in dynamic FC within major cerebro-cerebellar networks. This pattern has implications for explaining the development and maintenance of this disorder and improving our understating of the cerebellum's involvement in addiction.

PMID:33655376 | DOI:10.1007/s12311-021-01241-y

Towards robust and replicable sex differences in the intrinsic brain function of autism

Tue, 03/02/2021 - 11:00

Mol Autism. 2021 Mar 1;12(1):19. doi: 10.1186/s13229-021-00415-z.


BACKGROUND: Marked sex differences in autism prevalence accentuate the need to understand the role of biological sex-related factors in autism. Efforts to unravel sex differences in the brain organization of autism have, however, been challenged by the limited availability of female data.

METHODS: We addressed this gap by using a large sample of males and females with autism and neurotypical (NT) control individuals (ABIDE; Autism: 362 males, 82 females; NT: 409 males, 166 females; 7-18 years). Discovery analyses examined main effects of diagnosis, sex and their interaction across five resting-state fMRI (R-fMRI) metrics (voxel-level Z > 3.1, cluster-level P < 0.01, gaussian random field corrected). Secondary analyses assessed the robustness of the results to different pre-processing approaches and their replicability in two independent samples: the EU-AIMS Longitudinal European Autism Project (LEAP) and the Gender Explorations of Neurogenetics and Development to Advance Autism Research.

RESULTS: Discovery analyses in ABIDE revealed significant main effects of diagnosis and sex across the intrinsic functional connectivity of the posterior cingulate cortex, regional homogeneity and voxel-mirrored homotopic connectivity (VMHC) in several cortical regions, largely converging in the default network midline. Sex-by-diagnosis interactions were confined to the dorsolateral occipital cortex, with reduced VMHC in females with autism. All findings were robust to different pre-processing steps. Replicability in independent samples varied by R-fMRI measures and effects with the targeted sex-by-diagnosis interaction being replicated in the larger of the two replication samples-EU-AIMS LEAP.

LIMITATIONS: Given the lack of a priori harmonization among the discovery and replication datasets available to date, sample-related variation remained and may have affected replicability.

CONCLUSIONS: Atypical cross-hemispheric interactions are neurobiologically relevant to autism. They likely result from the combination of sex-dependent and sex-independent factors with a differential effect across functional cortical networks. Systematic assessments of the factors contributing to replicability are needed and necessitate coordinated large-scale data collection across studies.

PMID:33648569 | DOI:10.1186/s13229-021-00415-z

Dynamic functional connectome predicts individual working memory performance across diagnostic categories

Mon, 03/01/2021 - 11:00

Neuroimage Clin. 2021 Feb 23;30:102593. doi: 10.1016/j.nicl.2021.102593. Online ahead of print.


Working memory impairment is a common feature of psychiatric disorders. Although its neural mechanisms have been extensively examined in healthy subjects or individuals with a certain clinical condition, studies investigating neural predictors of working memory in a transdiagnostic sample are scarce. The objective of this study was to create a transdiagnostic predictive working memory model from whole-brain functional connectivity using connectome-based predictive modeling (CPM), a recently developed machine learning approach. Resting-state functional MRI data from 242 subjects across 4 diagnostic categories (healthy controls and individuals with schizophrenia, bipolar disorder, and attention deficit/hyperactivity) were used to construct dynamic and static functional connectomes. Spatial working memory was assessed by the spatial capacity task. CPM was conducted to predict individual working memory from dynamic and static functional connectivity patterns. Results showed that dynamic connectivity-based CPM models successfully predicted overall working memory capacity and accuracy as well as mean reaction time, yet their static counterparts fell short in the prediction. At the neural level, we found that dynamic connectivity of the frontoparietal and somato-motor networks were negatively correlated with working memory capacity and accuracy, and those of the default mode and visual networks were positively associated with mean reaction time. Moreover, different feature selection thresholds, parcellation strategies and model validation methods as well as diagnostic categories did not significantly influence the prediction results. Our findings not only are coherent with prior reports that dynamic functional connectivity encodes more behavioral information than static connectivity, but also help advance the translation of cognitive "connectome fingerprinting" into real-world application.

PMID:33647810 | DOI:10.1016/j.nicl.2021.102593

Functional connectivity density alterations in middle-age retinal detachment patients

Mon, 03/01/2021 - 11:00

Brain Behav. 2021 Mar 1:e01783. doi: 10.1002/brb3.1783. Online ahead of print.


OBJECTIVE: Middle-age patients with retinal detachment (RD) exhibit a loss of visual information, and previous studies of functional magnetic resonance imaging (fMRI) have demonstrated abnormal spontaneous activity in the RD brain. Therefore, this study assessed changes in local functional connectivity density (lFCD) and long-range functional connectivity density (longFCD) in middle-age RD patients during resting-state FC.

METHODS: In total, 32 middle-age patients with RD (18 men and 14 women), and 32 age-, sex-, and education-matched normal controls (NCs) (18 men and 14 women) were recruited and underwent functional magnetic resonance examination in the resting state. Two-sample t test was performed to compare lFCD and longFCD between groups. Receiver operating characteristic (ROC) curves were generated to distinguish middle-age RD patients from NCs.

RESULTS: Compared with NCs, middle-age RD patients demonstrated increased lFCD values in the right inferior temporal gyrus, and increased longFCD values in the bilateral inferior frontal gyri, left superior and middle frontal gyrus, bilateral inferior temporal gyri, and left cerebellum posterior lobe. Middle-age RD patient exhibited decreased lFCD values in the left cuneus, right lingual gyrus, and left middle frontal gyrus. They also had lower longFCD values in the left lingual gyrus and left inferior occipital gyrus. ROC curve analysis showed excellent accuracy of the specific areas under the curve.

CONCLUSION: Our results reveal that middle-age RD patients exhibited variations of binarized lFCD and longFCD in specific brain areas, which provides insight into the pathological mechanism of RD patients with acute visual loss.

PMID:33645927 | DOI:10.1002/brb3.1783

Disrupted Neural Activity in Individuals With Iridocyclitis Using Regional Homogeneity: A Resting-State Functional Magnetic Resonance Imaging Study

Mon, 03/01/2021 - 11:00

Front Neurol. 2021 Feb 12;12:609929. doi: 10.3389/fneur.2021.609929. eCollection 2021.


Objective: This study used the regional homogeneity (ReHo) technique to explore whether spontaneous brain activity is altered in patients with iridocyclitis. Methods: Twenty-six patients with iridocyclitis (14 men and 12 women) and 26 healthy volunteers (15 men and 11 women) matched for sex and age were enrolled in this study. The ReHo technique was used to comprehensively assess changes in whole-brain synchronous neuronal activity. The diagnostic ability of the ReHo method was evaluated by means of receive operating characteristic (ROC) curve analysis. Moreover, associations of average ReHo values in different brain areas and clinical characteristics were analyzed using correlation analysis. Result: Compared with healthy volunteers, reduced ReHo values were observed in patients with iridocyclitis in the following brain regions: the right inferior occipital gyrus, bilateral calcarine, right middle temporal gyrus, right postcentral gyrus, left superior occipital gyrus, and left precuneus. In contrast, ReHo values were significantly enhanced in the right cerebellum, left putamen, left supplementary motor area, and left inferior frontal gyrus in patients with iridocyclitis, compared with healthy volunteers (false discovery rate correction, P < 0.05). Conclusion: Patients with iridocyclitis exhibited disturbed synchronous neural activities in specific brain areas, including the visual, motor, and somatosensory regions, as well as the default mode network. These findings offer a novel image-guided research strategy that might aid in exploration of neuropathological or compensatory mechanisms in patients with iridocyclitis.

PMID:33643195 | PMC:PMC7907498 | DOI:10.3389/fneur.2021.609929

Abnormal Default-Mode Network Homogeneity in Patients With Mild Cognitive Impairment in Chinese Communities

Mon, 03/01/2021 - 11:00

Front Neurol. 2021 Feb 11;11:569806. doi: 10.3389/fneur.2020.569806. eCollection 2020.


Background and Objective: Current evidence suggests that abnormalities within the default-mode network (DMN) play a key role in the broad-scale cognitive problems that characterize mild cognitive impairment (MCI). However, little is known about the alterations of DMN network homogeneity (NH) in MCI. Methods: Resting-state functional magnetic resonance imaging scans (rs-fMRI) were collected from 38 MCI patients and 69 healthy controls matched for age, gender, and education. NH approach was employed to analyze the imaging dataset. Cognitive performance was measured with the Chinese version of Alzheimer's disease assessment scale-Cognitive subscale (ADAS-Cog). Results: Two groups have no significant differences between demographic factors. And mean ADAS-Cog score in MCI was 12.02. MCI patients had significantly lower NH values than controls in the right anterior cingulate cortex and significantly higher NH values in the ventral medial prefrontal cortex(vmPFC) than those in healthy controls. No significant correlations were found between abnormal NH values and ADAS-Cog in the patients. Conclusions: These findings provide further evidence that abnormal NH of the DMN exists in MCI, and highlight the significance of DMN in the pathophysiology of cognitive problems occurring in MCI.

PMID:33643176 | PMC:PMC7905225 | DOI:10.3389/fneur.2020.569806