New resting-state fMRI related studies at PubMed

Altered cortico-striatal functional connectivity in people with high levels of schizotypy: A longitudinal resting-state study

Sat, 03/06/2021 - 11:00

Asian J Psychiatr. 2021 Feb 28;58:102621. doi: 10.1016/j.ajp.2021.102621. Online ahead of print.


PURPOSE OF THE RESEARCH: Cortico-striatal functional connectivity has been implicated in the neuropathology of schizophrenia. However, the longitudinal relationship between the cortico-striatal connectivity and schizotypy remains unknown. We examined the resting-state fMRI connectivity in 27 individuals with a high level of schizotypy and 20 individuals with a low level of schizotypy at baseline and 18 months later. Correlations between changes in cortico-striatal connectivity and changes in schizotypy scores over time were examined.

PRINCIPAL RESULTS: We found both increased and decreased cortico-striatal connectivity in individuals with a high level of schizotypy at baseline. Over time, these individuals showed improvement in both the negative and positive schizotypal domains. Changes in striatal-insula connectivity were positively correlated with changes in positive schizotypy from baseline to follow-up.

MAJOR CONCLUSIONS: Our results suggested impaired cortico-striatal connectivity in individuals with a high level of schizotypy. The dysconnectivity mainly involves the dorsal striatum. The connectivity between the dorsal striatum and the insula may be a putative marker for temporal changes in positive schizotypy.

PMID:33676189 | DOI:10.1016/j.ajp.2021.102621

Consistency of functional connectivity across different movies

Sat, 03/06/2021 - 11:00

Neuroimage. 2021 Mar 3:117926. doi: 10.1016/j.neuroimage.2021.117926. Online ahead of print.


Movie fMRI has emerged as a powerful tool for investigating human brain function, and functional connectivity (FC) plays a predominant role in fMRI-based studies. Accordingly, movie-watching FC may have great potential for future studies on human brain function. Before wide application of movie-watching FC, however, it is essential to evaluate how much it is influenced by differences in movies. The main aim of this study was to investigate the consistency of movie-watching FC across different movies. For this purpose, we performed three sets of analyses on the four movie fMRI runs (with different movie stimuli) included in the HCP dataset. The first set was performed to evaluate the agreement of movie-watching FC in exact values using intra-class correlation (ICC), and the ICC of movie-watching FC across different movies (0.37 on average) was found to be comparable to that of resting-state FC across repeated scans. The second set was performed to evaluate the agreement of movie-watching FC in connectivity patterns, and the results indicate that individuals could be identified with relatively high accuracies (94%-99%) across different movies based on their FC matrices. The final set was performed to test the generalizability of predictive models based on movie-watching FC, as this generalizability is highly dependent on the consistency of the FC. The results indicate that predictive models trained based on FC extracted from one movie fMRI run can make good predictions on FC extracted from runs with different movie stimuli. Taken together, our findings indicate that movie-watching FC is highly consistent across different movies, and conclusions drawn based on movie-watching FC are generalizable.

PMID:33675997 | DOI:10.1016/j.neuroimage.2021.117926

Differences in basic psychological needs-related resting-state functional connectivity between individuals with high and low life satisfaction

Sat, 03/06/2021 - 11:00

Neurosci Lett. 2021 Mar 3:135798. doi: 10.1016/j.neulet.2021.135798. Online ahead of print.


Basic psychological needs including autonomy, competence, and relatedness can be affected by the level of life satisfaction. The current research aimed to elucidate differences in the association of these needs and functional connectivity of reward processing and emotion regulation between individuals with high and low life satisfaction. A total of 83 young adults were divided into the high life satisfaction (HLS) and low life satisfaction (LLS) groups and were scanned for 5-min resting-state fMRI. A seed-to-voxel analysis was performed using the seeds of the nucleus accumbens (NAcc), medial orbitofrontal cortex, subgenual anterior cingulate cortex (sgACC), insula, and amygdala. Analysis of covariance was conducted to test differences in the association of basic psychological needs and functional connectivity between the two groups. Connectivity strengths between the NAcc and right ventromedial prefrontal cortex and between the sgACC and left ventromedial prefrontal cortex were higher in the HLS group as the autonomy and relatedness scores increased, respectively, whereas in the LLS group as they decreased. Connectivity strengths between the NAcc and right midcingulate cortex and between the sgACC and left fusiform gyrus were higher in the HLS group as the competence and relatedness scores decreased, respectively, but in the LLS group as they increased. These findings suggest that individuals' perceived life satisfaction affects the relationship between the neural mechanism for reward processing and emotion regulation and basic psychological needs support. Psychological need satisfactions seem to have an emotional impact by acting as a contradictory brain mechanism between individuals with high and low life satisfaction.

PMID:33675884 | DOI:10.1016/j.neulet.2021.135798

Resting state functional connectivity in adolescent synthetic cannabinoid users with and without attention-deficit/hyperactivity disorder

Sat, 03/06/2021 - 11:00

Hum Psychopharmacol. 2021 Mar 6. doi: 10.1002/hup.2781. Online ahead of print.


OBJECTIVE: Synthetic cannabinoids (SCs) have become increasingly popular in recent years, especially among adolescents. The first aim of the current study was to examine resting-state functional connectivity (rsFC) in SC users compared to controls. Our second aim was to examine the influence of comorbid attention-deficit/hyperactivity disorder (ADHD) symptomatology on rsFC changes in SC users compared to controls.

METHODS: Resting-state functional magnetic resonance imaging (fMRI) analysis included 25 SC users (14 without ADHD and 11 with ADHD combined type) and 12 control subjects.

RESULTS: We found (i) higher rsFC between the default mode network (DMN) and salience network, dorsal attention network and cingulo-opercular network, and (ii) lower rsFC within the DMN and between the DMN and visual network in SC users compared to controls. There were no significant differences between SC users with ADHD and controls, nor were there any significant differences between SC users with and without ADHD.

CONCLUSIONS: We found the first evidence of abnormalities within and between resting state networks in adolescent SC users without ADHD. In contrast, SC users with ADHD showed no differences compared to controls. These results suggest that comorbidity of ADHD and substance dependence may show different rsFC alterations than substance use alone.

PMID:33675677 | DOI:10.1002/hup.2781

Brain Function in Children with Obstructive Sleep Apnea: A Resting-State fMRI Study

Sat, 03/06/2021 - 11:00

Sleep. 2021 Mar 1:zsab047. doi: 10.1093/sleep/zsab047. Online ahead of print.


OBJECTIVE: To explore the neural difference between children with obstructive sleep apnea (OSA) and healthy controls, together with the relation between this difference and cognitive dysfunction of children with OSA.

METHODS: Twenty children with OSA (7.2 ± 3.1 years, apnea hypopnea index (AHI): 16.5 ± 16.6 events/h) and 29 healthy controls (7.7 ± 2.8 years, AHI: 1.7 ± 1.2 events/h) were recruited and matched with age, gender, and handedness. All children underwent resting-state fMRI (rs-fMRI) and T1-wighted imaging. Some children were sedated for MRI scanning. We compared amplitude of low frequency fluctuation (ALFF) and regional homogeneity (ReHo) of children with OSA with those of healthy controls. During resting-state, the former reflects the intensity of the spontaneous neural activities, whereas the latter reflects temporal similarity of the spontaneous neural activities within a local brain region. Pearson correlation analysis was performed between these features of rs-fMRI and cognitive scores among children with OSA.

RESULTS: Compared with controls, children with OSA showed decreased ALFF in the left angular gyrus but increased ALFF in the right insula, and decreased ReHo in the left medial superior frontal gyrus, right lingual gyrus and left precuneus. Additionally, among children with OSA, the ReHo value in the right lingual gyrus was negatively correlated with FIQ and VIQ, whereas that in the left medial superior frontal gyrus was positively correlated with VIQ.

CONCLUSIONS: Children with OSA presented abnormal neural activities in some brain regions and impaired cognitive functions with the former possibly being the neural mechanism of the latter.

PMID:33675225 | DOI:10.1093/sleep/zsab047

A neuroimaging investigation into the role of peripheral metabolic biomarkers in the anticipation of reward in alcohol use

Fri, 03/05/2021 - 11:00

Drug Alcohol Depend. 2021 Feb 16;221:108638. doi: 10.1016/j.drugalcdep.2021.108638. Online ahead of print.


BACKGROUND: The relationship between alcohol use and metabolism has focused on the effects of alcohol use on metabolic factors. Metabolic factors, such as triglycerides, cholesterol, and glucose, have been shown to be associated with increased risk for heavy alcohol consumption and alcohol use disorder (AUD). It's been suggested that changes in metabolic factors may play a role in reward seeking behaviors and pathways. Studies on feeding behavior and obesity revealed the role of triglycerides in neural response to food cues in neurocircuitry regulating reward and feeding behaviors. This study aimed to explore the relationship of peripheral metabolism, alcohol use, and reward processing in individuals that use alcohol.

METHODS: Ninety participants from a previously collected dataset were included in the analysis. Participants were treatment seeking, detoxified individuals with AUD and healthy individuals without AUD, with the following metabolic biomarkers: triglyceride, glucose, high- and low-density cholesterol, and HbA1c levels. Participants completed a neuroimaging version of the Monetary Incentive Delay task (MID).

RESULTS: Correlations on peripheral metabolic biomarkers, alcohol use, and neural activity during reward anticipation and outcome during the MID task were not significant. Mediation models revealed triglycerides and high-density cholesterol had significant effects on left anterior insula during anticipation of potential monetary loss and this effect was not mediated by alcohol use.

CONCLUSION: Limbic recruitment by anticipation of monetary rewards revealed an independent relationship with peripheral metabolism and was not affected by individual differences in alcohol use, despite the effects of alcohol use on metabolic markers and reward processing neural circuitry.

PMID:33667782 | DOI:10.1016/j.drugalcdep.2021.108638

A Structure-Function Substrate of Memory for Spatial Configurations in Medial and Lateral Temporal Cortices

Fri, 03/05/2021 - 11:00

Cereb Cortex. 2021 Feb 27:bhab001. doi: 10.1093/cercor/bhab001. Online ahead of print.


Prior research has shown a role of the medial temporal lobe, particularly the hippocampal-parahippocampal complex, in spatial cognition. Here, we developed a new paradigm, the conformational shift spatial task (CSST), which examines the ability to encode and retrieve spatial relations between unrelated items. This task is short, uses symbolic cues, incorporates two difficulty levels, and can be administered inside the scanner. A cohort of 48 healthy young adults underwent the CSST, together with a set of behavioral measures and multimodal magnetic resonance imaging (MRI). Inter-individual differences in CSST performance correlated with scores on an established spatial memory paradigm, but neither with episodic memory nor mnemonic discrimination, supporting specificity. Analyzing high-resolution structural MRI data, individuals with better spatial memory showed thicker medial and lateral temporal cortices. Functional relevance of these findings was supported by task-based functional MRI analysis in the same participants and ad hoc meta-analysis. Exploratory resting-state functional MRI analyses centered on clusters of morphological effects revealed additional modulation of intrinsic network integration, particularly between lateral and medial temporal structures. Our work presents a novel spatial memory paradigm and supports an integrated structure-function substrate in the human temporal lobe. Task paradigms are programmed in python and made open access.

PMID:33667310 | DOI:10.1093/cercor/bhab001

A comprehensive data-driven analysis framework for detecting impairments in brain function networks with resting state fMRI in HIV-infected individuals on cART

Fri, 03/05/2021 - 11:00

J Neurovirol. 2021 Mar 5. doi: 10.1007/s13365-021-00943-7. Online ahead of print.


Central nervous system (CNS) sequelae continue to be common in HIV-infected individuals despite combination antiretroviral therapy (cART). These sequelae include HIV-associated neurocognitive disorder (HAND) and virologic persistence in the CNS. Resting state functional magnetic resonance imaging (rsfMRI) is a widely used tool to examine the integrity of brain function and pathology. In this study, we examined 16 HIV-positive (HIV+) subjects and 12 age, sex, and race matched HIV seronegative controls (HIV-) whole-brain high-resolution rsfMRI along with a battery of neurocognitive tests. A comprehensive data-driven analysis of rsfMRI revealed impaired functional connectivity, with very large effect sizes in executive function, language, and multisensory processing networks in HIV+ subjects. These results indicate the potential of high-resolution rsfMRI in combination with advanced data analysis techniques to yield biomarkers of neural impairment in HIV.

PMID:33666883 | DOI:10.1007/s13365-021-00943-7

Myocardial Deformation Assessed by MR Feature Tracking in Groups of Patients With Ischemic Heart Disease

Fri, 03/05/2021 - 11:00

J Magn Reson Imaging. 2021 Mar 4. doi: 10.1002/jmri.27588. Online ahead of print.


BACKGROUND: Global myocardial strain assessments have been shown to provide useful measures of contractility in many diseases, but whether feature tracking (FT)-derived strain at rest can differentiate ischemic myocardium from infarcted and remote myocardium in patients with coronary artery disease (CAD) remains unclear.

PURPOSE: To evaluate the performance of magnetic resonance imaging FT-derived strain in the detection of regional myocardial deformation in ischemic, infarcted, and apparent normal myocardium in CAD.

STUDY TYPE: Retrospective POPULATION: A total of 109 patients with CAD.

FIELD STRENGTH/SEQUENCES: Steady-state free-precession rest cine, T1-weighted saturation-recovery fast gradient echo stress/rest perfusion, and two-dimensional phase-sensitive inversion recovery breath-hold late gadolinium enhancement (LGE) tests were performed at 3.0 T.

ASSESSMENT: Based on perfusion and LGE images, left ventricular (LV) myocardial segments of CAD patients were categorized into ischemic, infarcted, and negative groups. The FT longitudinal (LS) and circumferential strain (CS) of normal subjects and the three CAD groups were calculated. Z-scores of each segment of CAD patients were calculated.

STATISTIC TESTS: χ2 testing, analysis of variance (ANOVA), and Kruskal-Wallis tests. Z-scores were used to compare the strain between CAD groups.

RESULTS: There were significant differences in global LS (GLS) and CS (GCS) between healthy controls (GLS: -19.0% ± 1.4%, GCS, -20.9% ± 1.8%), ischemia (GLS: -17.4% ± 2.1%, GCS, -19.6% ± 1.9%), infarction (GLS: -16.4% ± 1.9%, GCS, -17.8% ± 1.9%), and negative patients (GLS: -17.7% ± 1.4%, GCS, -20.9% ± 2.4%) (all P < 0.05). There were significant differences in regional LS and CS between ischemic (LS, -16.1% ± 5.0%, CS, -18.7% ± 5.0%), infarcted (LS, -14.8% ± 5.2%, CS, -15.3% ± 4.8%), and negative segments (LS, -17.6% ± 5.2%, CS, -19.8% ± 4.8%) (all P < 0.05). The differences in the z-scores of regional LS and CS between the ischemic, infarcted, and negative segments were also significant (all P < 0.05).

DATA CONCLUSION: FT-derived rest strain indices of the LV myocardium of CAD patients were higher compared to healthy controls and varied between ischemic, infarcted, and negative segments.


PMID:33665932 | DOI:10.1002/jmri.27588

Auditory Stimulation Modulates Resting-State Functional Connectivity in Unresponsive Wakefulness Syndrome Patients

Fri, 03/05/2021 - 11:00

Front Neurosci. 2021 Feb 16;15:554194. doi: 10.3389/fnins.2021.554194. eCollection 2021.


Passive listening to music is associated with several psychological and physical benefits in both, healthy and diseased populations. In this fMRI study, we examined whether preferred music has effects on the functional connectivity within resting-state networks related to consciousness. Thirteen patients in unresponsive wakefulness syndrome (UWS) and 18 healthy controls (HC) were enrolled. Both groups were exposed to different auditory stimulation (scanner noise, preferred music, and aversive auditory stimulation). Functional connectivity was analyzed using a seed-based approach. In HC, no differences were found between the three conditions, indicating that their networks are already working at high level. UWS patients showed impaired functional connectivity within all resting-state networks. In addition, functional connectivity of the auditory network was modulated by preferred music and aversive auditory stimulation. Hence, both conditions have the potential to modulate brain activity of UWS patients.

PMID:33664643 | PMC:PMC7921457 | DOI:10.3389/fnins.2021.554194

Understanding Vulnerability and Adaptation in Early Brain Development using Network Neuroscience

Fri, 03/05/2021 - 11:00

Trends Neurosci. 2021 Mar 1:S0166-2236(21)00021-7. doi: 10.1016/j.tins.2021.01.008. Online ahead of print.


Early adversity influences brain development and emerging behavioral phenotypes relevant for psychiatric disorders. Understanding the effects of adversity before and after conception on brain development has implications for contextualizing current public health crises and pervasive health inequities. The use of functional magnetic resonance imaging (fMRI) to study the brain at rest has shifted understanding of brain functioning and organization in the earliest periods of life. Here we review applications of this technique to examine effects of early life stress (ELS) on neurodevelopment in infancy, and highlight targets for future research. Building on the foundation of existing work in this area will require tackling significant challenges, including greater inclusion of often marginalized segments of society, and conducting larger, properly powered studies.

PMID:33663814 | DOI:10.1016/j.tins.2021.01.008

Anhedonia correlates with functional connectivity of the nucleus accumbens subregions in patients with major depressive disorder

Thu, 03/04/2021 - 11:00

Neuroimage Clin. 2021 Feb 23;30:102599. doi: 10.1016/j.nicl.2021.102599. Online ahead of print.


BACKGROUND: The nucleus accumbens (NAc) is an important region in reward circuit that has been linked with anhedonia, which is a characteristic symptom of major depressive disorder (MDD). However, the relationship between the functional connectivity of the NAc subregions and anhedonia in MDD patients remains unclear.

METHODS: We acquired resting-state functional magnetic resonance imaging (fMRI) scans from fifty-one subjects (23 MDD patients and 28 healthy controls). We assessed subjects' trait anhedonia with the Temporal Experience of Pleasure Scale (TEPS). Seed-based resting-state functional connectivity (rsFC) was conducted for each of the NAc subregions (bilateral core-like and shell-like subdivisions) separately to identify regions whose rsFCs with the NAc subregions were altered in the MDD patients and regions whose rsFCs with the NAc subregions showed different correlates with anhedonia between the MDD patients and the healthy controls.

RESULTS: Compared with the health controls, the MDD patients showed decreased rsFCs of the right NAc core-like subdivision with the left mid-anterior orbital prefrontal cortex and the right inferior parietal lobe as well as decreased rsFC of the left NAc core-like subdivision with the right middle frontal gyrus. Moreover, the severity of anhedonia by the group interaction was significant for the rsFC of the right NAc shell-like subdivision with the subgenual/pregenual anterior cingulate cortex and the rsFC of the right NAc core-like subdivision with the precuneus.

CONCLUSIONS: We found that the neural correlates of anhedonia indicated by the rsFCs of the NAc subregions were modulated by depression. The modulation effect was regionally-dependent. These findings enrich our understanding of the neural basis of anhedonia in MDD.

PMID:33662708 | DOI:10.1016/j.nicl.2021.102599

The neurobiology of prefrontal transcranial direct current stimulation (tDCS) in promoting brain plasticity: a systematic review and meta-analyses of human and rodent studies

Thu, 03/04/2021 - 11:00

Neurosci Biobehav Rev. 2021 Mar 1:S0149-7634(21)00095-6. doi: 10.1016/j.neubiorev.2021.02.035. Online ahead of print.


The neurobiological mechanisms underlying prefrontal transcranial direct current stimulation (tDCS) remain elusive. Randomized, sham-controlled trials in humans and rodents applying in vivo prefrontal tDCS were included to explore whether prefrontal tDCS modulates resting-state and event-related functional connectivity, neural oscillation and synaptic plasticity. Fifty studies were included in the systematic review and 32 in the meta-analyses. Neuroimaging meta-analysis indicated anodal prefrontal tDCS significantly enhanced bilateral median cingulate activity [familywise error (FWE)-corrected p < .005]; meta-regression revealed a positive relationship between changes in median cingulate activity after tDCS and current density (FWE-corrected p < .005) as well as electric current strength (FWE-corrected p < .05). Meta-analyses of electroencephalography and magnetoencephalography data revealed nonsignificant changes (ps >.1) in both resting-state and event-related oscillatory power across all frequency bands. Applying anodal tDCS over the rodent hippocampus/prefrontal cortex enhanced long-term potentiation and brain brain-derived neurotrophic factor expression in the stimulated brain regions (ps <.005). Evidence supporting prefrontal tDCS administration is preliminary; more methodologically consistent studies evaluating its effects on cognitive function that include brain activity measurements are needed.

PMID:33662444 | DOI:10.1016/j.neubiorev.2021.02.035

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