New resting-state fMRI related studies at PubMed

Altered neural networks and cognition in a hereditary colon cancer

Mon, 10/25/2021 - 10:00

IBRO Neurosci Rep. 2021 Oct 2;11:137-143. doi: 10.1016/j.ibneur.2021.09.007. eCollection 2021 Dec.

ABSTRACT

Familial Adenomatous Polyposis (FAP) is an autosomal dominant disorder caused by mutation of the APC gene presenting with numerous colorectal adenomatous polyps and a near 100% risk of colon cancer. Preliminary research findings from our group indicate that FAP patients experience significant deficits across many cognitive domains. In the current study, fMRI brain metrics in a FAP population and matched controls were used to further the mechanistic understanding of reported cognitive deficits. This research identified and characterized any possible differences in resting brain networks and associations between neural network changes and cognition from 34 participants (18 FAP patients, 16 healthy controls). Functional connectivity analysis was performed using FSL with independent component analysis (ICA) to identify functional networks. Significant differences between cases and controls were observed in 8 well-established resting state networks. With the addition of an aggregate cognitive measure as a covariate, these differences were virtually non-existent, indicating a strong correlation between cognition and brain activity at the network level. The data indicate robust and pervasive effects on functional neural network activity among FAP patients and these effects are likely involved in cognitive deficits associated with this disease.

PMID:34693396 | PMC:PMC8517154 | DOI:10.1016/j.ibneur.2021.09.007

Identification and Therapeutic Outcome Prediction of Cervical Spondylotic Myelopathy Based on the Functional Connectivity From Resting-State Functional MRI Data: A Preliminary Machine Learning Study

Mon, 10/25/2021 - 10:00

Front Neurol. 2021 Oct 8;12:711880. doi: 10.3389/fneur.2021.711880. eCollection 2021.

ABSTRACT

Currently, strategies to diagnose patients and predict neurological recovery in cervical spondylotic myelopathy (CSM) using MR images of the cervical spine are urgently required. In light of this, this study aimed at exploring potential preoperative brain biomarkers that can be used to diagnose and predict neurological recovery in CSM patients using functional connectivity (FC) analysis of a resting-state functional MRI (rs-fMRI) data. Two independent datasets, including total of 53 patients with CSM and 47 age- and sex-matched healthy controls (HCs), underwent the preoperative rs-fMRI procedure. The FC was calculated from the automated anatomical labeling (AAL) template and used as features for machine learning analysis. After that, three analyses were used, namely, the classification of CSM patients from healthy adults using the support vector machine (SVM) within and across datasets, the prediction of preoperative neurological function in CSM patients via support vector regression (SVR) within and across datasets, and the prediction of neurological recovery in CSM patients via SVR within and across datasets. The results showed that CSM patients could be successfully identified from HCs with high classification accuracies (84.2% for dataset 1, 95.2% for dataset 2, and 73.0% for cross-site validation). Furthermore, the rs-FC combined with SVR could successfully predict the neurological recovery in CSM patients. Additionally, our results from cross-site validation analyses exhibited good reproducibility and generalization across the two datasets. Therefore, our findings provide preliminary evidence toward the development of novel strategies to predict neurological recovery in CSM patients using rs-fMRI and machine learning technique.

PMID:34690912 | PMC:PMC8531403 | DOI:10.3389/fneur.2021.711880

White-Matter Hyperintensity Load and Differences in Resting-State Network Connectivity Based on Mild Cognitive Impairment Subtype

Mon, 10/25/2021 - 10:00

Front Aging Neurosci. 2021 Oct 7;13:737359. doi: 10.3389/fnagi.2021.737359. eCollection 2021.

ABSTRACT

"Mild cognitive impairment" (MCI) is a diagnosis characterised by deficits in episodic memory (aMCI) or in other non-memory domains (naMCI). Although the definition of subtypes is helpful in clinical classification, it provides little insight on the variability of neurofunctional mechanisms (i.e., resting-state brain networks) at the basis of symptoms. In particular, it is unknown whether the presence of a high load of white-matter hyperintensities (WMHs) has a comparable effect on these functional networks in aMCI and naMCI patients. This question was addressed in a cohort of 123 MCI patients who had completed an MRI protocol inclusive of T1-weighted, fluid-attenuated inversion recovery (FLAIR) and resting-state fMRI sequences. T1-weighted and FLAIR images were processed with the Lesion Segmentation Toolbox to quantify whole-brain WMH volumes. The CONN toolbox was used to preprocess all fMRI images and to run an independent component analysis for the identification of four large-scale haemodynamic networks of cognitive relevance (i.e., default-mode, salience, left frontoparietal, and right frontoparietal networks) and one control network (i.e., visual network). Patients were classified based on MCI subtype (i.e., aMCI vs. naMCI) and WMH burden (i.e., low vs. high). Maps of large-scale networks were then modelled as a function of the MCI subtype-by-WMH burden interaction. Beyond the main effects of MCI subtype and WMH burden, a significant interaction was found in the salience and left frontoparietal networks. Having a low WMH burden was significantly more associated with stronger salience-network connectivity in aMCI (than in naMCI) in the right insula, and with stronger left frontoparietal-network connectivity in the right frontoinsular cortex. Vice versa, having a low WMH burden was significantly more associated with left-frontoparietal network connectivity in naMCI (than in aMCI) in the left mediotemporal lobe. The association between WMH burden and strength of connectivity of resting-state functional networks differs between aMCI and naMCI patients. Although exploratory in nature, these findings indicate that clinical profiles reflect mechanistic interactions that may play a central role in the definition of diagnostic and prognostic statuses.

PMID:34690743 | PMC:PMC8529279 | DOI:10.3389/fnagi.2021.737359

Physically Active Lifestyle Is Associated With Attenuation of Hippocampal Dysfunction in Cognitively Intact Older Adults

Mon, 10/25/2021 - 10:00

Front Aging Neurosci. 2021 Oct 6;13:720990. doi: 10.3389/fnagi.2021.720990. eCollection 2021.

ABSTRACT

Alterations in hippocampal function have been shown in older adults, which are expressed as changes in hippocampal activity and connectivity. While hippocampal activation during memory demands has been demonstrated to decrease with age, some older individuals present increased activity, or hyperactivity, of the hippocampus which is associated with increased neuropathology and poor memory function. In addition, lower functional coherence between the hippocampus and core hubs of the default mode network (DMN), namely, the posteromedial and medial prefrontal cortices, as well as increased local intrahippocampal connectivity, were also demonstrated in cognitively intact older adults. Aerobic exercise has been shown to elicit neuroprotective effects on hippocampal structure and vasculature in aging, and improvements in cardiorespiratory fitness have been suggested to mediate these exercise-related effects. However, how these lifestyle factors relate to hippocampal function is not clear. Fifty-two cognitively intact older adults (aged 65-80 years) have been recruited and divided into physically active (n = 29) or non-active (n = 23) groups based on their aerobic activity lifestyle habits. Participants underwent resting-state and task-based fMRI experiments which included an associative memory encoding paradigm followed by a post-scan memory recognition test. In addition, 44 participants also performed cardiopulmonary exercise tests to evaluate cardiorespiratory fitness by measuring peak oxygen consumption (Vo2peak). While both groups demonstrated increased anterior hippocampal activation during memory encoding, a physically active lifestyle was associated with significantly lower activity level and higher memory performance in the recognition task. In addition, the physically active group also demonstrated higher functional connectivity of the anterior and posterior hippocampi with the core hubs of the DMN and lower local intra-hippocampal connectivity within and between hemispheres. Vo2peak was negatively associated with the hippocampal activation level and demonstrated a positive correlation with hippocampal-DMN connectivity. According to these findings, an aerobically active lifestyle may be associated with attenuation of hippocampal dysfunction in cognitively intact older adults.

PMID:34690738 | PMC:PMC8527880 | DOI:10.3389/fnagi.2021.720990

Abnormal Low-Frequency Oscillations Reflect Abnormal Eye Movement and Stereovision in Patients With Comitant Exotropia

Mon, 10/25/2021 - 10:00

Front Hum Neurosci. 2021 Oct 8;15:754234. doi: 10.3389/fnhum.2021.754234. eCollection 2021.

ABSTRACT

Background: Patients with comitant exotropia (CE) are accompanied by abnormal eye movements and stereovision. However, the neurophysiological mechanism of impaired eye movements and stereovision in patient with CE is still unclear. Purpose: The purpose of this study is to investigate spontaneous neural activity changes in patients with CE using the amplitude of low-frequency fluctuation (ALFF) method and the machine learning method. Materials and Methods: A total of 21 patients with CE and 21 healthy controls (HCs) underwent resting-state magnetic resonance imaging scans. The ALFF and fractional amplitude of low-frequency fluctuation (fALFF) values were chosen as classification features using a machine learning method. Results: Compared with the HC group, patients with CE had significantly decreased ALFF values in the right angular (ANG)/middle occipital gyrus (MOG)/middle temporal gyrus (MTG) and bilateral supplementary motor area (SMA)/precentral gyrus (PreCG). Meanwhile, patients with CE showed significantly increased fALFF values in the left putamen (PUT) and decreased fALFF values in the right ANG/MOG. Moreover, patients with CE showed a decreased functional connectivity (FC) between the right ANG/MOG/MTG and the bilateral calcarine (CAL)/lingual (LING) and increased FC between the left PUT and the bilateral cerebellum 8/9 (CER 8/9). The support vector machine (SVM) classification reaches a total accuracy of 93 and 90% and the area under the curve (AUC) of 0.93 and 0.90 based on ALFF and fALFF values, respectively. Conclusion: Our result highlights that patients with CE had abnormal brain neural activities including MOG and supplementary motor area/PreCG, which might reflect the neural mechanism of eye movements and stereovision dysfunction in patients with CE. Moreover, ALFF and fALFF could be sensitive biomarkers for distinguishing patients with CE from HCs.

PMID:34690728 | PMC:PMC8531266 | DOI:10.3389/fnhum.2021.754234

Dynamic Network Connectivity Reveals Markers of Response to Deep Brain Stimulation in Parkinson's Disease

Mon, 10/25/2021 - 10:00

Front Hum Neurosci. 2021 Oct 6;15:729677. doi: 10.3389/fnhum.2021.729677. eCollection 2021.

ABSTRACT

Background: Neuronal loss in Parkinson's Disease (PD) leads to widespread neural network dysfunction. While graph theory allows for analysis of whole brain networks, patterns of functional connectivity (FC) associated with motor response to deep brain stimulation of the subthalamic nucleus (STN-DBS) have yet to be explored. Objective/Hypothesis: To investigate the distributed network properties associated with STN-DBS in patients with advanced PD. Methods: Eighteen patients underwent 3-Tesla resting state functional MRI (rs-fMRI) prior to STN-DBS. Improvement in UPDRS-III scores following STN-DBS were assessed 1 year after implantation. Independent component analysis (ICA) was applied to extract spatially independent components (ICs) from the rs-fMRI. FC between ICs was calculated across the entire time series and for dynamic brain states. Graph theory analysis was performed to investigate whole brain network topography in static and dynamic states. Results: Dynamic analysis identified two unique brain states: a relative hypoconnected state and a relative hyperconnected state. Time spent in a state, dwell time, and number of transitions were not correlated with DBS response. There were no significant FC findings, but graph theory analysis demonstrated significant relationships with STN-DBS response only during the hypoconnected state - STN-DBS was negatively correlated with network assortativity. Conclusion: Given the widespread effects of dopamine depletion in PD, analysis of whole brain networks is critical to our understanding of the pathophysiology of this disease. Only by leveraging graph theoretical analysis of dynamic FC were we able to isolate a hypoconnected brain state that contained distinct network properties associated with the clinical effects of STN-DBS.

PMID:34690721 | PMC:PMC8526554 | DOI:10.3389/fnhum.2021.729677

Brain Structural and Functional Connectivity: A Review of Combined Works of Diffusion Magnetic Resonance Imaging and Electro-Encephalography

Mon, 10/25/2021 - 10:00

Front Hum Neurosci. 2021 Oct 7;15:721206. doi: 10.3389/fnhum.2021.721206. eCollection 2021.

ABSTRACT

Implications of structural connections within and between brain regions for their functional counterpart are timely points of discussion. White matter microstructural organization and functional activity can be assessed in unison. At first glance, however, the corresponding findings appear variable, both in the healthy brain and in numerous neuro-pathologies. To identify consistent associations between structural and functional connectivity and possible impacts for the clinic, we reviewed the literature of combined recordings of electro-encephalography (EEG) and diffusion-based magnetic resonance imaging (MRI). It appears that the strength of event-related EEG activity increases with increased integrity of structural connectivity, while latency drops. This agrees with a simple mechanistic perspective: the nature of microstructural white matter influences the transfer of activity. The EEG, however, is often assessed for its spectral content. Spectral power shows associations with structural connectivity that can be negative or positive often dependent on the frequencies under study. Functional connectivity shows even more variations, which are difficult to rank. This might be caused by the diversity of paradigms being investigated, from sleep and resting state to cognitive and motor tasks, from healthy participants to patients. More challenging, though, is the potential dependency of findings on the kind of analysis applied. While this does not diminish the principal capacity of EEG and diffusion-based MRI co-registration, it highlights the urgency to standardize especially EEG analysis.

PMID:34690718 | PMC:PMC8529047 | DOI:10.3389/fnhum.2021.721206

Neuroplasticity and Motor Rehabilitation in Multiple Sclerosis: A Systematic Review on MRI Markers of Functional and Structural Changes

Mon, 10/25/2021 - 10:00

Front Neurosci. 2021 Oct 6;15:707675. doi: 10.3389/fnins.2021.707675. eCollection 2021.

ABSTRACT

Background: Motor rehabilitation is routinely used in clinical practice as an effective method to reduce progressive disability gain in multiple sclerosis (MS), but rehabilitation approaches are typically unstandardized, and only few studies have investigated the impact of rehabilitation on brain neuroplasticity. Objective: To summarize and critically analyze studies applying MRI markers of functional connectivity and structural changes to assess the effect of motor rehabilitation on brain neuroplasticity in MS. Methods: Literature search was performed using PubMed and EMBASE, selecting studies having as a subject motor rehabilitation and advanced MRI techniques investigating neuroplasticity in adult patients affected by MS. Results: Seventeen out of 798 papers were selected, of which 5 applied structural MRI (4 diffusion tensor imaging, 1 volumetric measurements), 7 applied functional fMRI (5 task-related fMRI, 2 resting-state fMRI) whereas the remaining 5 applied both structural and functional imaging. Discussion: The considerable data heterogeneity and the small sample sizes characterizing the studies limit interpretation and generalization of the results. Overall, motor rehabilitation promotes clinical improvement, paralleled by positive adaptive brain changes, whose features and extent depend upon different variables, including the type of rehabilitation approach. MRI markers of functional and structural connectivity should be implemented in studies testing the efficacy of motor rehabilitation. They allow for a better understanding of neuroplastic mechanisms underlying rehabilitation-mediated clinical achievements, facilitating the identification of rehabilitation strategies tailored to patients' needs and abilities.

PMID:34690670 | PMC:PMC8526725 | DOI:10.3389/fnins.2021.707675

Alterations of Regional Homogeneity in Children With Congenital Sensorineural Hearing Loss: A Resting-State fMRI Study

Mon, 10/25/2021 - 10:00

Front Neurosci. 2021 Oct 6;15:678910. doi: 10.3389/fnins.2021.678910. eCollection 2021.

ABSTRACT

Background: Brain functional alterations have been observed in children with congenital sensorineural hearing loss (CSNHL). The purpose of this study was to assess the alterations of regional homogeneity in children with CSNHL. Methods: Forty-five children with CSNHL and 20 healthy controls were enrolled into this study. Brain resting-state functional MRI (rs-fMRI) for regional homogeneity including the Kendall coefficient consistency (KCC-ReHo) and the coherence-based parameter (Cohe-ReHo) was analyzed and compared between the two groups, i.e., the CSNHL group and the healthy control group. Results: Compared to the healthy controls, children with CSNHL showed increased Cohe-ReHo values in left calcarine and decreased values in bilateral ventrolateral prefrontal cortex (VLPFC) and right dorsolateral prefrontal cortex (DLPFC). Children with CSNHL also had increased KCC-ReHo values in the left calcarine, cuneus, precentral gyrus, and right superior parietal lobule (SPL) and decreased values in the left VLPFC and right DLPFC. Correlations were detected between the ReHo values and age of the children with CSNHL. There were positive correlations between ReHo values in the pre-cuneus/pre-frontal cortex and age (p < 0.05). There were negative correlations between ReHo values in bilateral temporal lobes, fusiform gyrus, parahippocampal gyrus and precentral gyrus, and age (p < 0.05). Conclusion: Children with CSNHL had RoHo alterations in the auditory, visual, motor, and other related brain cortices as compared to the healthy controls with normal hearing. There were significant correlations between ReHo values and age in brain regions involved in information integration and processing. Our study showed promising data using rs-fMRI ReHo parameters to assess brain functional alterations in children with CSNHL.

PMID:34690668 | PMC:PMC8526795 | DOI:10.3389/fnins.2021.678910

Comparison of Quantitative Electroencephalography between Tic Disorder and Attention-Deficit/Hyperactivity Disorder in Children

Mon, 10/25/2021 - 10:00

Clin Psychopharmacol Neurosci. 2021 Nov 30;19(4):739-750. doi: 10.9758/cpn.2021.19.4.739.

ABSTRACT

OBJECTIVE: Attention-deficit/hyperactivity disorder (ADHD) and tic disorder (TD) are among the most common comorbid psychopathologies and have a shared genetic basis. The psychopathological and neurophysiological aspects of the mechanism underlying the comorbidity of both disorders have been investigated, but the pathophysiological aspects remain unclear. Therefore, this study aimed to compare the neurophysiological characteristics of ADHD with those of TD using resting-state electroencephalography and exact low-resolution brain electromagnetic tomography (eLORETA) analysis.

METHODS: We performed eLORETA analysis based on the resting-state scalp-recorded electrical potential distribution in 34 children with ADHD and 21 age-matched children with TD. Between-group differences in electroencephalography (EEG) current source density in delta, theta, alpha, beta, and gamma bands were investigated in each cortical region.

RESULTS: Compared with the TD group, the ADHD group showed significantly increased theta activity in the frontal region (superior frontal gyrus, t = 3.37, p < 0.05; medial frontal gyrus, t = 3.35, p < 0.05). In contrast, children with TD showed decreased posterior alpha activity than those with ADHD (precuneus, t = -3.40, p < 0.05; posterior cingulate gyrus, t = -3.38, p < 0.05). These findings were only significant when the eyes were closed.

CONCLUSION: Increased theta activity in the frontal region is a neurophysiological marker that can distinguish ADHD from TD. Also, reduced posterior alpha activity might represent aberrant inhibitory control. Further research needs to confirm these characteristics by simultaneously measuring EEG-functional magnetic resonance imaging.

PMID:34690129 | DOI:10.9758/cpn.2021.19.4.739

Can resting-state fMRI help localize the seizure onset zone in focal epilepsies?

Mon, 10/25/2021 - 10:00

Clin Neurophysiol. 2021 Oct 8:S1388-2457(21)00742-2. doi: 10.1016/j.clinph.2021.09.009. Online ahead of print.

NO ABSTRACT

PMID:34690066 | DOI:10.1016/j.clinph.2021.09.009

Resting-state functional magnetic resonance imaging analysis of modified electroconvulsive therapy in the treatment of major depressive disorder

Mon, 10/25/2021 - 10:00

Zhonghua Yi Xue Za Zhi. 2021 Oct 26;101(39):3221-3226. doi: 10.3780/cma.j.cn112137-20210402-00807.

ABSTRACT

Objective: To explore the effect of modified electroconvulsive therapy (MECT) on resting-state functional connectivity (RSFC) in patients with major depressive disorder (MDD). Methods: Patients with MDD from Anhui Mental Health Center from October 2017 to May 2019 were included. Using bilateral nucleus accumbens (NAcc) as seed points, changes of RSFC were investigated before and after MECT through resting-state functional magnetic imaging (fMRI). Antidepressant effects were measured by 17 items of Hamilton Depressive Rating Scale (HDRS-17). Correlation analysis was performed between changed HRSD-17 scores and changes of functional connectivity. Results: A total of 40 MDD patients (10 males and 30 females), aged (38±11) years, who received MECT were included in the study. After MECT, patients showed increased RSFC in the right NAcc (rNAcc) and superior frontal gyrus (P<0.001), right supramarginal gyrus (P<0.001), right angular gyrus (rAG) (P= 0.017), right inferior parietal lobule (P= 0.017), left superior frontal gyrus (LSFG) (P<0.001), left middle temporal gyrus (P=0.017) and left angular gyrus (LAG) (P=0.012), respectively. The RSFC changes of rNAcc-LSFG (r=-0.454, P = 0.003), rNAcc-rAG (r=-0.437, P=0.005) and rNAcc-lAG (r=-0.383, P=0.015) were negatively correlated with the changes of HRSD-17 scores. Conclusions: MECT may alleviate major depression by regulating the functional connectivity between the rNAcc and bilateral angular gyrus and left superior frontal gyrus.

PMID:34689534 | DOI:10.3780/cma.j.cn112137-20210402-00807

Resting-State fMRI Functional Connectivity Strength Predicts Local Activity Change in the Dorsal Cingulate Cortex: A Multi-Target Focused rTMS Study

Sun, 10/24/2021 - 10:00

Cereb Cortex. 2021 Oct 23:bhab380. doi: 10.1093/cercor/bhab380. Online ahead of print.

ABSTRACT

Previous resting state functional magnetic resonance imaging (RS-fMRI) studies suggested that repetitive transcranial magnetic stimulation (rTMS) can modulate local activity in distant areas via functional connectivity (FC). A brain region has more than one connection with the superficial cortical areas. The current study proposed a multi-target focused rTMS protocol for indirectly stimulating a deep region, and to investigate 1) whether FC strength between stimulation targets (right middle frontal gyrus [rMFG] and right inferior parietal lobule [rIPL]) and effective region (dorsal anterior cingulate cortex [dACC]) can predict local activity changes of dACC and 2) whether multiple stimulation targets can focus on the dACC via FC. A total of 24 healthy participants received rTMS with two stimulation targets, both showing strong FC with the dACC. There were four rTMS conditions (>1 week apart, 10 Hz, 1800 pulses for each): rMFG-target, rIPL-target, Double-targets (900 pulses for each target), and Sham. The results failed to validate the multi-target focused rTMS hypothesis. But rMFG-target significantly decreased the local activity in the dACC. In addition, stronger dACC-rMFG FC was associated with a greater local activity change in the dACC. Future studies should use stronger FC to focus stimulation effects on the deep region.

PMID:34689201 | DOI:10.1093/cercor/bhab380

Default-mode and fronto-parietal network connectivity during rest distinguishes asymptomatic patients with bipolar disorder and major depressive disorder

Sun, 10/24/2021 - 10:00

Transl Psychiatry. 2021 Oct 23;11(1):547. doi: 10.1038/s41398-021-01660-9.

ABSTRACT

Bipolar disorder (BD) is commonly misdiagnosed as major depressive disorder (MDD). This is understandable, as depression often precedes mania and is otherwise indistinguishable in both. It is therefore imperative to identify neural mechanisms that can differentiate the two disorders. Interrogating resting brain neural activity may reveal core distinguishing abnormalities. We adopted an a priori approach, examining three key networks documented in previous mood disorder literature subserving executive function, salience and rumination that may differentiate euthymic BD and MDD patients. Thirty-eight patients with BD, 39 patients with MDD matched for depression severity, and 39 age-gender matched healthy controls, completed resting-state fMRI scans. Seed-based and data-driven Independent Component analyses (ICA) were implemented to examine group differences in resting-state connectivity (pFDR < 0.05). Seed analysis masks were target regions identified from the fronto-parietal (FPN), salience (SN) and default-mode (DMN) networks. Seed-based analyses identified significantly greater connectivity between the subgenual cingulate cortex (DMN) and right dorsolateral prefrontal cortex (FPN) in BD relative to MDD and controls. The ICA analyses also found greater connectivity between the DMN and inferior frontal gyrus, an FPN region in BD relative to MDD. There were also significant group differences across the three networks in both clinical groups relative to controls. Altered DMN-FPN functional connectivity is thought to underlie deficits in the processing, management and regulation of affective stimuli. Our results suggest that connectivity between these networks could potentially distinguish the two disorders and could be a possible trait mechanism in BD persisting even in the absence of symptoms.

PMID:34689161 | DOI:10.1038/s41398-021-01660-9

Body-mind relaxation meditation modulates the thalamocortical functional connectivity in major depressive disorder: a preliminary resting-state fMRI study

Sun, 10/24/2021 - 10:00

Transl Psychiatry. 2021 Oct 23;11(1):546. doi: 10.1038/s41398-021-01637-8.

ABSTRACT

Mindfulness-based interventions such as meditation have increasingly been utilized for the treatment of psychological disorders and have been shown to be effective in the treatment of depression and relapse prevention. However, it remains largely unclear the neural mechanism of the therapeutic effects of meditation among depressed individuals. In this study, we investigated how body-mind relaxation meditation (BMRM) can modulate the thalamocortical functional connectivity (FC) in major depressive disorder patients and healthy controls. In the present study, we recruited 21 medication-naive adolescents with major depressive disorder (MDDs) and 24 matched healthy controls (HCs). We designed an audio recording to induce body-mind relaxation meditation. Resting-state fMRI (rs-fMRI) scans were collected before and after the BMRM intervention in both groups. The thalamus subregions were defined according to the Human Brainnetome Atlas, and functional connectivity (FC) was measured and compared to find brain regions that were affected by the BMRM intervention. Before the BMRM intervention, MDDs showed reduced FC of the bilateral precuneus/post cingulate cortex with the left posterior parietal thalamus and left caudal temporal thalamus, as well as an increased FC of the left occipital thalamus with the left medial frontal cortex. Moreover, aberrant FCs in MDDs at baseline were normalized following the BMRM intervention. After the BMRM intervention, both MDDs and HCs showed decreased FC between the left rostral temporal thalamus and the left inferior occipital. Given the small sample used in this study, future studies are warranted to evaluate the generalizability of these findings. Our findings suggest that BMRM is associated with changes in thalamocortical functional connectivity in MDDs. BMRM may act by strengthening connections between the thalamus and the default mode network, which are involved in a variety of high-level functioning, such as attention and self-related processes.

PMID:34689151 | DOI:10.1038/s41398-021-01637-8

Aberrant large-scale brain modules in deficit and non-deficit schizophrenia

Sun, 10/24/2021 - 10:00

Prog Neuropsychopharmacol Biol Psychiatry. 2021 Oct 21:110461. doi: 10.1016/j.pnpbp.2021.110461. Online ahead of print.

ABSTRACT

OBJECTIVE: Schizophrenia is a heterogenous psychiatric disease, and deficit schizophrenia (DS) is a clinical subgroup with primary and enduring negative symptoms. Although previous neuroimaging studies have identified functional connectome alterations in schizophrenia, the modular organizations in DS and nondeficit schizophrenia (NDS) remains poorly understood. Therefore, this study aimed to investigate the modular-level alterations in DS patients compared with the NDS and healthy control (HC) groups.

METHODS: A previously collected dataset was re-analyzed, in which 74 chronic male schizophrenia patients (33 DS and 41 NDS) and 40 HC underwent resting-state functional magnetic resonance imaging with eyes closed in a Siemens 3 T scanner (scanning duration = 8 min). Modular- (intramodule and intermodule connectivity) and nodal- [normalized within-module degree (Zi) and participation coefficient (PCi)] level graph theory properties were computed and compared among the three groups. Receiver operating characteristic curve (ROC) analyses were performed to examine the classification ability of these measures, and partial correlations were conducted between network measures and symptom severity. Validation analyses on head motion, network sparsity, and parcellation scheme were also performed.

RESULTS: Both schizophrenia subgroups showed decreased intramodule connectivity in salience network (SN), somatosensory-motor network (SMN), and visual network (VN), and increased intermodule connectivity in SMN-default mode network (DMN) and SMN-frontoparietal network (FPN). Compared with NDS patients, DS patients showed weaker intramodule connectivity in SN and stronger intermodule connectivity in SMN-FPN and SMN-VN. At the nodal level, the schizophrenia-related alterations were distributed in SN, SMN, VN, and DMN, and 7 DS-specific nodal alterations were identified. Intramodule connectivity of SN, intermodule connectivity of SMN-VN, and Zi of left precuneus successfully distinguished the three groups. Partial correlational analyses revealed that these measures were related to negative symptoms, general psychiatric symptoms, and neurocognitive function.

CONCLUSION: Our findings suggest that functional connectomes, especially SN, SMN, and VN, may capture the distinct and common disruptions of DS and NDS. These findings may help to understand the neuropathology of negative symptoms of schizophrenia and inform targets for treating different schizophrenia subtypes.

PMID:34688810 | DOI:10.1016/j.pnpbp.2021.110461

Thalamocortical dysconnectivity in lifelong premature ejaculation: a functional MRI study

Sun, 10/24/2021 - 10:00

Urology. 2021 Oct 21:S0090-4295(21)00983-3. doi: 10.1016/j.urology.2021.10.010. Online ahead of print.

ABSTRACT

OBJECTIVES: To detect seed-based functional connectivity (FC) between various cortical sub-regions and the thalamus in lifelong premature ejaculation (LPE) patients and explore whether specific thalamocortical networks are significantly altered in PE patients compared to healthy controls (HCs) Methods: Fifty non-medicated LPE patients and 40 age-matched HCs underwent a resting-state functional MRI. FC was adopted to identify specific thalamocortical connectivity between the thalamus and six cortical regions of interest (i.e. the motor cortex/supplementary motor, the prefrontal cortex, the temporal lobe, the posterior parietal cortex, the somatosensory cortex and the occipital lobe). In LPE patients, regression analysis was subsequently conducted to assess relationships of thalamocortical connectivity with the Premature Ejaculation Diagnostic Tool (PEDT) score and the Intravaginal Ejaculatory Latency Time (IELT).

RESULTS: LPE patients had significantly decreased FC between the motor cortex and bilateral ventral thalamus, between the prefrontal cortex and left dorsomedial thalamus, as well as between the temporal cortex and bilateral ventromedial thalamus. In LPE patients, PEDT score was significantly positively associated with the thalamus-posterior parietal cortex FC, and negatively associated with the thalamus-temporal cortex FC, while IELT was positively associated with the thalamus-temporal cortex and thalamus-motor cortex FC.

CONCLUSION: These results enrich the imaging evidence for the understanding of the neurobiological mechanisms and/or consequences of LPE.

PMID:34688769 | DOI:10.1016/j.urology.2021.10.010

Alterations in large-scale functional networks in adult posttraumatic stress disorder: A systematic review and meta-analysis of resting-state functional connectivity studies

Sun, 10/24/2021 - 10:00

Neurosci Biobehav Rev. 2021 Oct 21:S0149-7634(21)00460-7. doi: 10.1016/j.neubiorev.2021.10.017. Online ahead of print.

ABSTRACT

Posttraumatic stress disorder (PTSD) is associated with dysfunction in large-scale brain functional networks, as revealed by resting-state functional connectivity studies. However, it remains unclear which networks have been most consistently affected and, more importantly, what role disease and trauma may play in the disrupted functional networks. We performed a systematic review of studies exploring network alterations using seed-based functional connectivity analysis, comparing individuals with PTSD to controls in general as well as trauma-exposed or nonexposed controls specifically, and quantitative meta-analysis was conducted when the number of studies was appropriately high. We found that hypoconnectivity within the default-mode network (DMN) as well as between the affective network (AN) and DMN were specifically associated with traumatic experience. Additionally, hyperconnectivity between the AN and somatomotor network (SMN) and between the DMN and SMN were specifically related to PTSD. Our results emphasize the effect of trauma itself on alterations in intrinsic brain networks and highlight disease-associated network alterations, which may help us better understand the neural mechanisms of trauma and PTSD.

PMID:34688728 | DOI:10.1016/j.neubiorev.2021.10.017

Functional abnormality in the sensorimotor system attributed to NRXN1 variants in boys with attention deficit hyperactivity disorder

Sat, 10/23/2021 - 10:00

Brain Imaging Behav. 2021 Oct 23. doi: 10.1007/s11682-021-00579-5. Online ahead of print.

ABSTRACT

Impaired sensorimotor circuits have been suggested in Attention-deficit/hyperactivity disorder (ADHD). NRXN1, highly expressed in cortex and cerebellum, was one of the candidate risk genes for ADHD, while its effects on sensorimotor circuits are unclear. In this content, we aimed to investigate the differential brain effects as functions of the cumulative genetic effects of NRXN1 variants in ADHD and healthy controls (HCs), identifying a potential pathway mapping from NRXN1, sensorimotor circuits, to ADHD. Magnetic resonance imaging, blood samples and clinical assessments were acquired from 53 male ADHD and 46 sex-matched HCs simultaneously. The effects of the cumulative genetic effects of NRXN1 variants valued by poly-variant risk score (PRS), on brain function was measured by resting-state functional connectivity (rs-FC) of cerebrocerebellar circuits. Mediation analyses were conducted to evaluate the association between NRXN1, functional abnormality, and ADHD diagnosis, as well as ADHD symptoms. The results were validated by bootstrapping and 10,000 times permutation tests. The rs-FC analyses demonstrated significant mediation models for ADHD diagnosis, and emphasized the involvement of cerebellum, middle cingulate gyrus and temporal gyrus, which are crucial parts of sensorimotor circuits. The current study suggested NRXN1 conferred risk for ADHD by regulating the function of sensorimotor circuits.

PMID:34687402 | DOI:10.1007/s11682-021-00579-5

Diagnostic Efficacy of Voxel-Mirrored Homotopic Connectivity in Vascular Dementia as Compared to Alzheimer's Related Neurodegenerative Diseases-A Resting State fMRI Study

Sat, 10/23/2021 - 10:00

Life (Basel). 2021 Oct 19;11(10):1108. doi: 10.3390/life11101108.

ABSTRACT

Previous studies have demonstrated that functional connectivity (FC) of different brain regions in resting state function MRI were abnormal in patients suffering from mild cognitive impairment (MCI) and Alzheimer's disease (AD) when comparing to healthy controls (HC) using seed based, independent component analysis (ICA) or small world network techniques. A new technique called voxel-mirrored homotopic connectivity (VMHC) was used in the current study to evaluate the value of interhemispheric functional connectivity (IFC) as a diagnostic tool to differentiate vascular dementia (VD) from other Alzheimer's related neurodegenerative diseases. Eighty-three participants were recruited from the university hospital memory clinic. A multidisciplinary panel formed by a neuroradiologist and two geriatricians classified the participants into VD (13), AD (16), MCI (29), and HC (25) based on clinical history, Montreal Cognitive Assessment Hong Kong version (HK‑MoCA) neuropsychological score, structural MRI, MR perfusion, and 18-F Flutametamol (amyloid) PET-CT findings of individual subjects. We adopted the calculation method used by Kelly et al. (2011) and Zuo et al. (2010) in obtaining VMHC maps. Specific patterns of VMHC maps were obtained for VD, AD, and MCI to HC comparison. VD showed significant reduction in VMHC in frontal orbital gyrus and gyrus rectus. Increased VMHC was observed in default mode network (DMN), executive control network (ECN), and the remaining salient network (SN) regions. AD showed a reduction of IFC in all DMN, ECN, and SN regions; whereas MCI showed VMHC reduction in vSN, and increased VMHC in DMN and ECN. When combining VMHC values of relevant brain regions, the accuracy was improved to 87%, 92%, and 83% for VD, AD, and MCI from HC, respectively, in receiver operating characteristic (ROC) analysis. Through studying the VMHC maps and using VMHC values in relevant brain regions, VMHC can be considered as a reliable diagnostic tool for VD, AD, and MCI from HC.

PMID:34685479 | PMC:PMC8538280 | DOI:10.3390/life11101108

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