New resting-state fMRI related studies at PubMed

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The Spontaneous Brain Activity of Disgust: Perspective from Resting State fMRI and Resting State EEG.

Fri, 01/22/2021 - 13:00
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The Spontaneous Brain Activity of Disgust: Perspective from Resting State fMRI and Resting State EEG.

Behav Brain Res. 2021 Jan 18;:113135

Authors: Li Z, Li Y, Li X, Zou F, Wang Y, Wu X, Luo Y, Zhang M

Abstract
In recent years, more and more studies on disgust have shown the association between disgust and various psychopathologies. Revealing the spontaneous brain activity patterns associated with disgust sensitivity from the perspective of individual differences will give us an insight into the neurologic nature of disgust and its psychopathological vulnerability. Here, we used two modal brain imaging techniques (resting fMRI and resting EEG) to reveal spontaneous brain activity patterns closely related to disgust sensitivity. The amplitude of low-frequency fluctuation results showed that disgust sensitivity is negatively correlated with the spontaneous activity of the right cerebellum crus II and positively correlated with the spontaneous activity of the right superior frontal cortex, which are inhibition-related brain regions. Furthermore, the microstate results of rest EEG indicated that the corrected duration, occurrence rate, and contribution of Class C, which is related to the anterior default mode network and is considered to be related to subjective representation of one' own body by combining interoceptive information with affective salience, were significantly positively correlated with the disgust sensitivity level. This data-driven approach provides the first evidence on the intrinsic brain features of disgust sensitivity based on two resting-state brain modalities. The results represent an initial effort to uncover the neurological basis of disgust sensitivity and its connection to psychopathology.

PMID: 33476686 [PubMed - as supplied by publisher]

Alterations in Resting-State Functional Brain Connectivity and Correlations with Vestibular/Ocular-Motor Screening Measures in Postconcussion Vestibular Dysfunction.

Fri, 01/22/2021 - 13:00
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Alterations in Resting-State Functional Brain Connectivity and Correlations with Vestibular/Ocular-Motor Screening Measures in Postconcussion Vestibular Dysfunction.

J Neuroimaging. 2021 Jan 21;:

Authors: Trofimova A, Smith JL, Ahluwalia V, Hurtado J, Gore RK, Allen JW

Abstract
BACKGROUND AND PURPOSE: Vestibular symptoms after concussion are common and associated with protracted recovery. The purpose of this study is to define resting-state functional MRI (rs-fMRI) brain connectivity alterations in patients with postconcussion vestibular dysfunction (PCVD) and correlations between rs-fMRI connectivity and symptoms provoked during Vestibular/Ocular-Motor Screening (VOMS) assessment.
METHODS: Prospective IRB approved study.
STUDY GROUP: 12 subjects with subacute PCVD (2-10 weeks); control group: 10 age-matched subjects without history of concussion or vestibular impairment. Both groups underwent clinical vestibular assessment. rs-fMRI was acquired on 3.0T Siemens Trio with a 12-channel head coil. rs-fMRI data analysis included independent component analysis-based functional connectivity group differences, graph theory analysis, and ROI-to-ROI connectivity correlation analysis with VOMS clinical derivatives. Group difference maps between resting-state networks were calculated using dual regression method and corrected for multiple comparisons. Correlation analysis between ROI-to-ROI rs-fMRI brain activation and VOMS assessment ratings was performed using Pearson correlation coefficient, with a significance threshold of P ≤ .05.
RESULTS: Compared to controls, PCVD group demonstrated significantly increased rs-fMRI connectivity between the default-mode network and right middle frontal gyrus and right postcentral gyrus; and between a vestibular-sensorimotor network and right prefrontal cortex. Significant positive correlations were found between clinical derivative VOMS scores and components of the vestibular, visual networks, and multisensory processing cortical representations.
CONCLUSION: Altered rs-fMRI brain connectivity with increased connectivity of visual input, multisensory processing, and spatial memory in PCVD is correlative with clinical derivative VOMS scores, suggesting maladaptive brain plasticity underlying vestibular symptomatology.

PMID: 33476477 [PubMed - as supplied by publisher]

Altered functional connectivity between hypothalamus and limbic system in fibromyalgia.

Fri, 01/22/2021 - 13:00
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Altered functional connectivity between hypothalamus and limbic system in fibromyalgia.

Mol Brain. 2021 Jan 20;14(1):17

Authors: Kong J, Huang Y, Liu J, Yu S, Ming C, Chen H, Wilson G, Harvey WF, Li W, Wang C

Abstract
The hypothalamus links the nervous system to the endocrine system and plays a crucial role in maintaining the human body's homeostasis. This study aims to investigate the resting state functional connectivity (rsFC) changes of the hypothalamus in fibromyalgia patients. 24 Fibromyalgia patients and 24 matched healthy controls (HCs) were recruited. Resting state fMRI data were collected from the fibromyalgia patients and HC's. Fibromyalgia patients went through a second scan after 12 weeks of Tai Chi mind-body intervention. Data analysis showed that fibromyalgia patients displayed less medial hypothalamus (MH) rsFC with the thalamus and amygdala when compared to the functional connectivity in the HCs. After the Tai Chi mind-body intervention, fibromyalgia patients showed increased MH rsFC with the thalamus and amygdala accompanied by clinical improvement. Effective connectivity analysis showed disrupted MH and thalamus interaction in the fibromyalgia patients, which was altered by mind-body exercise. Our findings suggest that fibromyalgia is associated with altered functional connectivity within the diencephalon and limbic system. Elucidating the roles of the diencephalon and limbic system in the pathophysiology and development of fibromyalgia may facilitate the development of a new biomarker and effective treatment methods for this prevalent disorder.Trial Registration ClinicalTrials.gov, NCT02407665. Registered: 3 April 2015, https://clinicaltrials.gov/ct2/show/NCT02407665?term=NCT02407665&draw=2&rank=1.

PMID: 33472674 [PubMed - in process]

Impact of Machine Learning Pipeline Choices in Autism Prediction From Functional Connectivity Data.

Fri, 01/22/2021 - 13:00
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Impact of Machine Learning Pipeline Choices in Autism Prediction From Functional Connectivity Data.

Int J Neural Syst. 2021 Jan 20;:2150009

Authors: Graña M, Silva M

Abstract
Autism Spectrum Disorder (ASD) is a largely prevalent neurodevelopmental condition with a big social and economical impact affecting the entire life of families. There is an intense search for biomarkers that can be assessed as early as possible in order to initiate treatment and preparation of the family to deal with the challenges imposed by the condition. Brain imaging biomarkers have special interest. Specifically, functional connectivity data extracted from resting state functional magnetic resonance imaging (rs-fMRI) should allow to detect brain connectivity alterations. Machine learning pipelines encompass the estimation of the functional connectivity matrix from brain parcellations, feature extraction, and building classification models for ASD prediction. The works reported in the literature are very heterogeneous from the computational and methodological point of view. In this paper, we carry out a comprehensive computational exploration of the impact of the choices involved while building these machine learning pipelines. Specifically, we consider six brain parcellation definitions, five methods for functional connectivity matrix construction, six feature extraction/selection approaches, and nine classifier building algorithms. We report the prediction performance sensitivity to each of these choices, as well as the best results that are comparable with the state of the art.

PMID: 33472548 [PubMed - as supplied by publisher]

Dynamic functional connectivity as a neural correlate of fatigue in multiple sclerosis.

Thu, 01/21/2021 - 11:40
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Dynamic functional connectivity as a neural correlate of fatigue in multiple sclerosis.

Neuroimage Clin. 2021 Jan 04;29:102556

Authors: Tijhuis FB, Broeders TAA, Santos FAN, Schoonheim MM, Killestein J, Leurs CE, van Geest Q, Steenwijk MD, Geurts JJG, Hulst HE, Douw L

Abstract
BACKGROUND: More than 80% of multiple sclerosis (MS) patients experience symptoms of fatigue. MS-related fatigue is only partly explained by structural (lesions and atrophy) and functional (brain activation and conventional static functional connectivity) brain properties.
OBJECTIVES: To investigate the relationship of dynamic functional connectivity (dFC) with fatigue in MS patients and to compare dFC with commonly used clinical and MRI parameters.
METHODS: In 35 relapsing-remitting MS patients (age: 42.83 years, female/male: 20/15, disease duration: 11 years) and 19 healthy controls (HCs) (age: 41.38 years, female/male: 11/8), fatigue was measured using the CIS-20r questionnaire at baseline and at 6-month follow-up. All subjects underwent structural and resting-state functional MRI at baseline. Global static functional connectivity (sFC) and dynamic functional connectivity (dFC) were calculated. dFC was assessed using a sliding-window approach by calculating the summed difference (diff) and coefficient of variation (cv) across windows. Moreover, regional connectivity between regions previously associated with fatigue in MS was estimated (i.e. basal ganglia and regions of the Default Mode Network (DMN): medial prefrontal, posterior cingulate and precuneal cortices). Hierarchical regression analyses were performed with forward selection to identify the most important correlates of fatigue at baseline. Results were not corrected for multiple testing due to the exploratory nature of the study.
RESULTS: Patients were more fatigued than HCs at baseline (p = 0.001) and follow-up (p = 0.002) and fatigue in patients was stable over time (p = 0.213). Patients had significantly higher baseline global dFC than HCs, but no difference in basal ganglia-DMN dFC. In the regression model for baseline fatigue in patients, basal ganglia-DMN dFC-cv (standardized β = -0.353) explained 12.5% additional variance on top of EDSS (p = 0.032). Post-hoc analysis revealed higher basal ganglia-DMN dFC-cv in non-fatigued patients compared to healthy controls (p = 0.013), whereas fatigued patients and healthy controls showed similar basal ganglia-DMN dFC.
CONCLUSIONS: Less dynamic connectivity between the basal ganglia and the cortex is associated with greater fatigue in MS patients, independent of disability status. Within patients, lower dynamics of these connections could relate to lower efficiency and increased fatigue. Increased dynamics in non-fatigued patients compared to healthy controls might represent a network organization that protects against fatigue or signal early network dysfunction.

PMID: 33472144 [PubMed - as supplied by publisher]

Altered Brain Network Centrality in Patients with Diabetic Optic Neuropathy: A Resting-State FMRI Study.

Thu, 01/21/2021 - 11:40
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Altered Brain Network Centrality in Patients with Diabetic Optic Neuropathy: A Resting-State FMRI Study.

Endocr Pract. 2020 Dec;26(12):1399-1405

Authors: Xu QH, Li QY, Yu K, Ge QM, Shi WQ, Li B, Liang RB, Lin Q, Zhang YQ, Shao Y

Abstract
OBJECTIVE: Recent studies have suggested that diabetic optic neuropathy (DON) independently increases the incidence of brain diseases like cerebral infarction and hemorrhage. In this study, voxel-level degree centrality (DC) was used to study potential changes in functional network brain activity in DON patients.
METHODS: The study included 14 DON patients and 14 healthy controls (HCs) matched by age, sex, and weight. All subjects underwent resting functional magnetic resonance imaging. Receiver operating characteristic curves and Pearson correlation analysis were performed.
RESULTS: The DC values of the left frontal mid-orb and right middle frontal gyrus/right frontal sup were significantly lower in DON patients compared to HCs. The DC value of the left temporal lobe was also significantly higher than in HCs.
CONCLUSION: Three different brain regions show DC changes in DON patients, suggesting common optic neuropathy in the context of diabetes and providing new ideas for treating optic nerve disease in patients with long-term diabetes.
ABBREVIATIONS: AUC = area under the curve; BCVA = best corrected visual acuity; DC = degree centrality; DON = diabetic optic neuropathy; fMRI = functional magnetic resonance imaging; HC = healthy control; LFMO = left frontal mid orb; LTL = left temporal lobe; RFS = right frontal sup; RMFG = right middle frontal gyrus; ROC = receiver operating characteristic.

PMID: 33471731 [PubMed - as supplied by publisher]

Intrinsic dialogues between the two hemispheres in middle-aged male alcoholics: a resting-state functional MRI study.

Thu, 01/21/2021 - 11:40
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Intrinsic dialogues between the two hemispheres in middle-aged male alcoholics: a resting-state functional MRI study.

Neuroreport. 2021 Jan 18;:

Authors: Dai X, Zhang J, Gao L, Yu J, Li Y, Du B, Huang X, Zhang H

Abstract
BACKGROUND: The purpose of this study was to investigate the interhemispheric intrinsic connectivity measured by resting-state functional MRI (R-fMRI) in middle-aged male alcoholics.
METHODS: Thirty male alcoholics (47.33 ± 8.30 years) and 30 healthy males (47.20 ± 6.17 years) were recruited and obtained R-fMRI data. Inter- and intrahemispheric coordination was performed by using voxel-mirrored homotopic connectivity (VMHC) and seed-based functional connectivity analysis.
RESULTS: We found significantly decreased VMHC in a set of regions in male alcoholics patients, including lateral temporal, inferior frontal gyrus, insular/insulae operculum, precuneus/posterior cingulate gyrus, and pars triangularis (P < 0.05, corrected). Subsequent seed-based functional connectivity analysis demonstrated disrupted functional connectivity between the regions of local homotopic connectivity deficits and other areas of the brain, particularly the areas subserving the default, salience, primary somatomotor, and language systems.
CONCLUSIONS: Middle-aged male alcoholic subjects demonstrated prominent reductions in inter- and intrahemispheric functional coherence. These abnormal changes may reflect degeneration of system/network integration, particularly the domains subserving default, linguistic processing, and salience integration.

PMID: 33470766 [PubMed - as supplied by publisher]

Aberrant intrinsic connectivity in women victims of sexual assault.

Thu, 01/21/2021 - 11:40
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Aberrant intrinsic connectivity in women victims of sexual assault.

Brain Imaging Behav. 2021 Jan 19;:

Authors: Quidé Y, Zine A, Descriaud C, Saint-Martin P, Andersson F, El-Hage W

Abstract
This study aims to determine if resting-state functional connectivity may represent a marker for the progression of posttraumatic stress disorder (PTSD) in women victims of sexual assault. Participants were 25 adult women recruited three weeks following exposure to sexual assault (T1) and 19 age-matched healthy, non trauma-exposed controls (HC). Among the victims, 10 participants met (PTSD) and 15 did not meet (trauma-exposed controls, TEC) DSM-IV criteria for PTSD six months post-trauma (T2). At both visits, patterns of intrinsic connectivity, a measure of network centrality at each voxel of the brain, were derived from resting-state functional magnetic resonance imaging. Compared to both the HC and TEC groups, victims who developed PTSD at T2 showed higher centrality in the right middle/superior occipital gyrus at T1, while reduced centrality of the posterior cingulate cortex (PCC)/precuneus at T1 was found for the TEC group, compared to the HC group only. There were no differences in intrinsic connectivity at T1 between the TEC and PTSD groups. There were no significant between-group differences in intrinsic connectivity at T2, and no significant group-by-time interaction. This study indicates that increased occipital centrality three weeks post-trauma exposure may represent a marker of the later development of PTSD. On the other hand, reduced centrality of the PCC/precuneus may represent a marker of resilience to trauma exposure.

PMID: 33469788 [PubMed - as supplied by publisher]

Organisational and neuromodulatory underpinnings of structural-functional connectivity decoupling in patients with Parkinson's disease.

Thu, 01/21/2021 - 11:40
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Organisational and neuromodulatory underpinnings of structural-functional connectivity decoupling in patients with Parkinson's disease.

Commun Biol. 2021 Jan 19;4(1):86

Authors: Zarkali A, McColgan P, Leyland LA, Lees AJ, Rees G, Weil RS

Abstract
Parkinson's dementia is characterised by changes in perception and thought, and preceded by visual dysfunction, making this a useful surrogate for dementia risk. Structural and functional connectivity changes are seen in humans with Parkinson's disease, but the organisational principles are not known. We used resting-state fMRI and diffusion-weighted imaging to examine changes in structural-functional connectivity coupling in patients with Parkinson's disease, and those at risk of dementia. We identified two organisational gradients to structural-functional connectivity decoupling: anterior-to-posterior and unimodal-to-transmodal, with stronger structural-functional connectivity coupling in anterior, unimodal areas and weakened towards posterior, transmodal regions. Next, we related spatial patterns of decoupling to expression of neurotransmitter receptors. We found that dopaminergic and serotonergic transmission relates to decoupling in Parkinson's overall, but instead, serotonergic, cholinergic and noradrenergic transmission relates to decoupling in patients with visual dysfunction. Our findings provide a framework to explain the specific disorders of consciousness in Parkinson's dementia, and the neurotransmitter systems that underlie these.

PMID: 33469150 [PubMed - in process]

Crosstalk between Depression and Dementia with Resting-State fMRI Studies and Its Relationship with Cognitive Functioning.

Thu, 01/21/2021 - 11:40
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Crosstalk between Depression and Dementia with Resting-State fMRI Studies and Its Relationship with Cognitive Functioning.

Biomedicines. 2021 Jan 16;9(1):

Authors: Kim J, Kim YK

Abstract
Alzheimer's disease (AD) is the most common type of dementia, and depression is a risk factor for developing AD. Epidemiological studies provide a clinical correlation between late-life depression (LLD) and AD. Depression patients generally remit with no residual symptoms, but LLD patients demonstrate residual cognitive impairment. Due to the lack of effective treatments, understanding how risk factors affect the course of AD is essential to manage AD. Advances in neuroimaging, including resting-state functional MRI (fMRI), have been used to address neural systems that contribute to clinical symptoms and functional changes across various psychiatric disorders. Resting-state fMRI studies have contributed to understanding each of the two diseases, but the link between LLD and AD has not been fully elucidated. This review focuses on three crucial and well-established networks in AD and LLD and discusses the impacts on cognitive decline, clinical symptoms, and prognosis. Three networks are the (1) default mode network, (2) executive control network, and (3) salience network. The multiple properties emphasized here, relevant for the hypothesis of the linkage between LLD and AD, will be further developed by ongoing future studies.

PMID: 33467174 [PubMed]

Identifying Diurnal Variability of Brain Connectivity Patterns Using Graph Theory.

Thu, 01/21/2021 - 11:40
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Identifying Diurnal Variability of Brain Connectivity Patterns Using Graph Theory.

Brain Sci. 2021 Jan 16;11(1):

Authors: Farahani FV, Fafrowicz M, Karwowski W, Bohaterewicz B, Sobczak AM, Ceglarek A, Zyrkowska A, Ostrogorska M, Sikora-Wachowicz B, Lewandowska K, Oginska H, Beres A, Hubalewska-Mazgaj M, Marek T

Abstract
Significant differences exist in human brain functions affected by time of day and by people's diurnal preferences (chronotypes) that are rarely considered in brain studies. In the current study, using network neuroscience and resting-state functional MRI (rs-fMRI) data, we examined the effect of both time of day and the individual's chronotype on whole-brain network organization. In this regard, 62 participants (39 women; mean age: 23.97 ± 3.26 years; half morning- versus half evening-type) were scanned about 1 and 10 h after wake-up time for morning and evening sessions, respectively. We found evidence for a time-of-day effect on connectivity profiles but not for the effect of chronotype. Compared with the morning session, we found relatively higher small-worldness (an index that represents more efficient network organization) in the evening session, which suggests the dominance of sleep inertia over the circadian and homeostatic processes in the first hours after waking. Furthermore, local graph measures were changed, predominantly across the left hemisphere, in areas such as the precentral gyrus, putamen, inferior frontal gyrus (orbital part), inferior temporal gyrus, as well as the bilateral cerebellum. These findings show the variability of the functional neural network architecture during the day and improve our understanding of the role of time of day in resting-state functional networks.

PMID: 33467070 [PubMed]

The benefit of high-performance gradients on echo planar imaging for BOLD-based resting-state functional MRI.

Thu, 01/21/2021 - 11:40
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The benefit of high-performance gradients on echo planar imaging for BOLD-based resting-state functional MRI.

Phys Med Biol. 2020 11 27;65(23):235024

Authors: Kang D, Jo HJ, In MH, Yarach U, Meyer NK, Bardwell Speltz LJ, Gray EM, Trzasko JD, Huston Iii J, Bernstein MA, Shu Y

Abstract
Improved gradient performance in an MRI system reduces distortion in echo planar imaging (EPI), which has been a key imaging method for functional studies. A lightweight, low-cryogen compact 3T MRI scanner (C3T) is capable of achieving 80 mT m-1 gradient amplitude with 700 T m-1 s-1 slew rate, in comparison with a conventional whole-body 3T MRI scanner (WB3T, 50 mT m-1 with 200 T m-1 s-1). We investigated benefits of the high-performance gradients in a high-spatial-resolution (1.5 mm isotropic) functional MRI study. Reduced echo spacing in the EPI pulse sequence inherently leads to less severe geometric distortion, which provided higher accuracy than with WB3T for registration between EPI and anatomical images. The cortical coverage of C3T datasets was improved by more accurate signal depiction (i.e. less dropout or pile-up). Resting-state functional analysis results showed that greater magnitude and extent in functional connectivity (FC) for the C3T than the WB3T when the selected seed region is susceptible to distortions, while the FC matrix for well-known brain networks showed little difference between the two scanners. This shows that the improved quality in EPI is particularly valuable for studying certain brain regions typically obscured by severe distortion.

PMID: 33245051 [PubMed - indexed for MEDLINE]

Epilepsy enhance global efficiency of language networks in right temporal lobe gliomas.

Wed, 01/20/2021 - 16:40
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Epilepsy enhance global efficiency of language networks in right temporal lobe gliomas.

CNS Neurosci Ther. 2021 Jan 19;:

Authors: Fang S, Wang Y, Jiang T

Abstract
AIMS: We analyzed the resting state functional magnetic resonance images to investigate the alterations of neural networks in patients with glioma-related epilepsy (GRE).
METHODS: Fifty-six patients with right temporal lower-grade glioma were divided into GRE (n = 28) and non-GRE groups. Twenty-eight healthy subjects were recruited after matching age, sex, and education level. Sensorimotor, visual, language, and left executive control networks were applied to generate functional connectivity matrices, and their topological properties were investigated.
RESULTS: No significant alterations in functional connectivity were found. The least significant discovery test revealed differences only in the language network. The shortest path length, clustering coefficient, local efficiency, and vulnerability were greater in the non-GRE group than in the other groups. The nodal efficiencies of two nodes (mirror areas to Broca and Wernicke) were weaker in the non-GRE group than in the other groups. The node of degree centrality (Broca), nodal local efficiency (Wernicke), and nodal clustering coefficient (temporal polar) were greater in the non-GRE group than in the healthy group.
CONCLUSION: Different tumor locations alter different neural networks. Temporal lobe gliomas in the right hemisphere altered the language network. Glioma itself and GRE altered the network in opposing ways in patients with right temporal glioma.

PMID: 33464718 [PubMed - as supplied by publisher]

Do intrinsic brain functional networks predict working memory from childhood to adulthood?

Wed, 01/20/2021 - 16:40
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Do intrinsic brain functional networks predict working memory from childhood to adulthood?

Hum Brain Mapp. 2020 Nov;41(16):4574-4586

Authors: Zhang H, Hao S, Lee A, Eickhoff SB, Pecheva D, Cai S, Meaney M, Chong YS, Broekman BFP, Fortier MV, Qiu A

Abstract
Working memory (WM) is defined as the ability to maintain a representation online to guide goal-directed behavior. Its capacity in early childhood predicts academic achievements in late childhood and its deficits are found in various neurodevelopmental disorders. We employed resting-state fMRI (rs-fMRI) of 468 participants aged from 4 to 55 years and connectome-based predictive modeling (CPM) to explore the potential predictive power of intrinsic functional networks to WM in preschoolers, early and late school-age children, adolescents, and adults. We defined intrinsic functional networks among brain regions identified by activation likelihood estimation (ALE) meta-analysis on existing WM functional studies (ALE-based intrinsic functional networks) and intrinsic functional networks generated based on the whole brain (whole-brain intrinsic functional networks). We employed the CPM on these networks to predict WM in each age group. The CPM using the ALE-based and whole-brain intrinsic functional networks predicted WM of individual adults, while the prediction power of the ALE-based intrinsic functional networks was superior to that of the whole-brain intrinsic functional networks. Nevertheless, the CPM using the whole-brain but not the ALE-based intrinsic functional networks predicted WM in adolescents. And, the CPM using neither the ALE-based nor whole-brain networks predicted WM in any of the children groups. Our findings showed the trend of the prediction power of the intrinsic functional networks to cognition in individuals from early childhood to adulthood.

PMID: 33463860 [PubMed - in process]

DREZotomy in the management of post brachial plexus root avulsion neuropathic pain: fMRI correlates for pain relief.

Wed, 01/20/2021 - 16:40
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DREZotomy in the management of post brachial plexus root avulsion neuropathic pain: fMRI correlates for pain relief.

Br J Neurosurg. 2021 Jan 19;:1-10

Authors: Baruah S, Bhat DI, Devi BI, Uppar AM, Bharti K, Ramalingaiah AH

Abstract
BACKGROUND: Deafferentiation pain following brachial plexus root avulsion has been documented to be severe enough to affect activities of daily living in patients. Microsurgical DREZotomy is known to alleviate the symptoms by decreasing the afferent signals transmitted from the spinal cord to sensory cortex.
OBJECTIVES: To document and analyse the effectiveness of DREZotomy and to evaluate the role of 'sensory cortex' in the cause and relief of dysesthetic pain, using fMRI.
MATERIALS AND METHODS: This was a prospective study conducted between 2010 and 2016 and included all patients who underwent DREZotomy for dysesthetic pain following traumatic brachial plexus injury (TBPI). Patients were evaluated both preoperatively and postoperatively with Visual Analogue Scale(VAS), Hospital Anxiety and Depression score (HADS) and SF36 questionnaire and effectiveness of surgery was assessed. Functional magnetic resonance imaging (fMRI) of the brain in resting state was performed before and after surgery and was also compared with controls. Patients underwent standard microsurgical DREZotomy from C5 to D1. Postoperative assessment was done at 6 weeks and 6 months following surgery.
RESULTS: Our series had 18 patients aged between 22 and 63 years. RTA was the most common cause of injury. There was significant decrease in pain at 6 months follow up compared to pre-operative values as assessed by VAS, HADS, SF36 questionnaire. fMRI analysis revealed cluster activations in the sensory, motor cortex and in the right cingulate gyrus in the preoperative group which was higher than in normal controls. In the postoperative group, the size of the resting state activation was significantly reduced.
CONCLUSION: DREZotomy is an effective procedure for TBPI patients. We hypothesize that these fMRI findings reflect the cortical reorganization that occurs not only after injury but also following successful surgery which explains the cause and relief of dyesthetic pain.

PMID: 33463389 [PubMed - as supplied by publisher]

Excitatory-inhibitory balance within EEG microstates and resting-state fMRI networks: assessed via simultaneous trimodal PET-MR-EEG imaging.

Wed, 01/20/2021 - 16:40
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Excitatory-inhibitory balance within EEG microstates and resting-state fMRI networks: assessed via simultaneous trimodal PET-MR-EEG imaging.

Transl Psychiatry. 2021 Jan 18;11(1):60

Authors: Rajkumar R, Régio Brambilla C, Veselinović T, Bierbrier J, Wyss C, Ramkiran S, Orth L, Lang M, Rota Kops E, Mauler J, Scheins J, Neumaier B, Ermert J, Herzog H, Langen KJ, Binkofski FC, Lerche C, Shah NJ, Neuner I

Abstract
The symbiosis of neuronal activities and glucose energy metabolism is reflected in the generation of functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) signals. However, their association with the balance between neuronal excitation and inhibition (E/I-B), which is closely related to the activities of glutamate and γ-aminobutyric acid (GABA) and the receptor availability (RA) of GABAA and mGluR5, remains unexplored. This research investigates these associations during the resting state (RS) condition using simultaneously recorded PET/MR/EEG (trimodal) data. The trimodal data were acquired from three studies using different radio-tracers such as, [11C]ABP688 (ABP) (N = 9), [11C]Flumazenil (FMZ) (N = 10) and 2-[18F]fluoro-2-deoxy-D-glucose (FDG) (N = 10) targeted to study the mGluR5, GABAA receptors and glucose metabolism respectively. Glucose metabolism and neuroreceptor binding availability (non-displaceable binding potential (BPND)) of GABAA and mGluR5 were found to be significantly higher and closely linked within core resting-state networks (RSNs). The neuronal generators of EEG microstates and the fMRI measures were most tightly associated with the BPND of GABAA relative to mGluR5 BPND and the glucose metabolism, emphasising a predominance of inhibitory processes within in the core RSNs at rest. Changes in the neuroreceptors leading to an altered coupling with glucose metabolism may render the RSNs vulnerable to psychiatric conditions. The paradigm employed here will likely help identify the precise neurobiological mechanisms behind these alterations in fMRI functional connectivity and EEG oscillations, potentially benefitting individualised healthcare treatment measures.

PMID: 33462192 [PubMed - in process]

Neurovascular coupling alterations in type 2 diabetes: a 5-year longitudinal MRI study.

Wed, 01/20/2021 - 16:40
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Neurovascular coupling alterations in type 2 diabetes: a 5-year longitudinal MRI study.

BMJ Open Diabetes Res Care. 2021 Jan;9(1):

Authors: Zhang Y, Zhang X, Ma G, Qin W, Yang J, Lin J, Zhang Q

Abstract
INTRODUCTION: Respective alterations in resting-state brain neural activity and cerebral blood flow (CBF) in type 2 diabetes mellitus (T2DM) have been reported. However, their coupling alteration in T2DM remains largely unknown.
RESEARCH DESIGN AND METHODS: Twenty-seven patients with T2DM aged 40-67 years and 36 well-matched healthy controls (HCs) underwent resting-state functional MRI (rs-fMRI) and arterial spin labeling (ASL) scans at two time points with a 5-year interval. Regional homogeneity (ReHo) and CBF were calculated from rs-fMRI and ASL, respectively. The standardized ReHo:CBF ratio (mReHo:mCBF ratio), the spontaneous neuronal activity per unit CBF supply, was compared between the two time points. Relationships between the mReHo:mCBF ratio and memory performance were analyzed.
RESULTS: Over 5 years, decreased mReHo:mCBF ratios in patients with T2DM were mainly distributed in four regions, among which the left insula exhibited more severely decreased mReHo:mCBF ratio in patients with T2DM than in HCs, while the left postcentral gyrus, the right Rolandic operculum, and the right precentral gyrus showed no significant intergroup difference. Correlations between the mReHo:mCBF ratio and memory performance were also found in patients with T2DM.
CONCLUSIONS: This study suggests that T2DM may accelerate neurovascular coupling impairment in specific brain regions (the left insula), contributing to memory decline. This study implies that the mReHo:mCBF ratio is a potential imaging marker for detecting neurovascular changes.

PMID: 33462074 [PubMed - in process]

Longitudinal changes in blood-based biomarkers in chronic moderate to severe traumatic brain injury: preliminary findings.

Wed, 01/20/2021 - 16:40
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Longitudinal changes in blood-based biomarkers in chronic moderate to severe traumatic brain injury: preliminary findings.

Brain Inj. 2021 Jan 18;:1-7

Authors: Schnakers C, Divine J, Johnson MA, Lutkenhoff E, Monti MM, Keil KM, Guthrie J, Pouratian N, Patterson D, Jensen G, Morales VC, Weaver KF, Rosario ER

Abstract
Objectives: This longitudinal study aims at 1) providing preliminary evidence of changes in blood-based biomarkers across time in chronic TBI and 2) relating these changes to outcome measures and cerebral structure and activity. Methods: Eight patients with moderate-to-severe TBI (7 males, 35 ± 7.6 years old, 5 severe TBI, 17.52 ± 3.84 months post-injury) were evaluated at monthly intervals across 6 time-points using: a) Blood-based biomarkers (GFAP, NSE, S100A12, SDBP145, UCH-L1, T-tau, P-tau, P-tau/T-tau ratio); b) Magnetic Resonance Imaging to evaluate changes in brain structure; c) Resting-state electroencephalograms to evaluate changes in brain function; and d) Outcome measures to assess cognition, emotion, and functional recovery (MOCA, RBANS, BDI-II, and DRS). Results: Changes in P-tau levels were found across time [p = .007]. P-tau was positively related to functional [p < .001] and cognitive [p = .006] outcomes, and negatively related to the severity of depression, 6 months later [R = -0.901; p =.006]. P-tau and P-tau/T-tau ratio were also positively correlated to shape change in subcortical areas such as brainstem [T(7) = 4.71, p = .008] and putamen [T(7) = 3.25, p = .012]. Conclusions: Our study provides preliminary findings that suggest a positive relationship between P-tau and the recovery of patients with chronic TBI.

PMID: 33461331 [PubMed - as supplied by publisher]

Corticocortical and Thalamocortical Changes in Functional Connectivity and White Matter Structural Integrity after Reward-Guided Learning of Visuospatial Discriminations in Rhesus Monkeys.

Wed, 01/20/2021 - 16:40
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Corticocortical and Thalamocortical Changes in Functional Connectivity and White Matter Structural Integrity after Reward-Guided Learning of Visuospatial Discriminations in Rhesus Monkeys.

J Neurosci. 2020 10 07;40(41):7887-7901

Authors: Pelekanos V, Premereur E, Mitchell DJ, Chakraborty S, Mason S, Lee ACH, Mitchell AS

Abstract
The frontal cortex and temporal lobes together regulate complex learning and memory capabilities. Here, we collected resting-state functional and diffusion-weighted MRI data before and after male rhesus macaque monkeys received extensive training to learn novel visuospatial discriminations (reward-guided learning). We found functional connectivity changes in orbitofrontal, ventromedial prefrontal, inferotemporal, entorhinal, retrosplenial, and anterior cingulate cortices, the subicular complex, and the dorsal, medial thalamus. These corticocortical and thalamocortical changes in functional connectivity were accompanied by related white matter structural alterations in the uncinate fasciculus, fornix, and ventral prefrontal tract: tracts that connect (sub)cortical networks and are implicated in learning and memory processes in monkeys and humans. After the well-trained monkeys received fornix transection, they were impaired in learning new visuospatial discriminations. In addition, the functional connectivity profile that was observed after the training was altered. These changes were accompanied by white matter changes in the ventral prefrontal tract, although the integrity of the uncinate fasciculus remained unchanged. Our experiments highlight the importance of different communication relayed among corticocortical and thalamocortical circuitry for the ability to learn new visuospatial associations (learning-to-learn) and to make reward-guided decisions.SIGNIFICANCE STATEMENT Frontal neural networks and the temporal lobes contribute to reward-guided learning in mammals. Here, we provide novel insight by showing that specific corticocortical and thalamocortical functional connectivity is altered after rhesus monkeys received extensive training to learn novel visuospatial discriminations. Contiguous white matter fiber pathways linking these gray matter structures, namely, the uncinate fasciculus, fornix, and ventral prefrontal tract, showed structural changes after completing training in the visuospatial task. Additionally, different patterns of functional and structural connectivity are reported after removal of subcortical connections within the extended hippocampal system, via fornix transection. These results highlight the importance of both corticocortical and thalamocortical interactions in reward-guided learning in the normal brain and identify brain structures important for memory capabilities after injury.

PMID: 32900835 [PubMed - indexed for MEDLINE]

Effects of TPH2 gene variation and childhood trauma on the clinical and circuit-level phenotype of functional movement disorders.

Wed, 01/20/2021 - 16:40
Related Articles

Effects of TPH2 gene variation and childhood trauma on the clinical and circuit-level phenotype of functional movement disorders.

J Neurol Neurosurg Psychiatry. 2020 08;91(8):814-821

Authors: Spagnolo PA, Norato G, Maurer CW, Goldman D, Hodgkinson C, Horovitz S, Hallett M

Abstract
BACKGROUND: Functional movement disorders (FMDs), part of the wide spectrum of functional neurological disorders (conversion disorders), are common and often associated with a poor prognosis. Nevertheless, little is known about their neurobiological underpinnings, particularly with regard to the contribution of genetic factors. Because FMD and stress-related disorders share a common core of biobehavioural manifestations, we investigated whether variants in stress-related genes also contributed, directly and interactively with childhood trauma, to the clinical and circuit-level phenotypes of FMD.
METHODS: Sixty-nine patients with a 'clinically defined' diagnosis of FMD were genotyped for 18 single-nucleotide polymorphisms (SNPs) from 14 candidate genes. FMD clinical characteristics, psychiatric comorbidity and symptomatology, and childhood trauma exposure were assessed. Resting-state functional connectivity data were obtained in a subgroup of 38 patients with FMD and 38 age-matched and sex-matched healthy controls. Amygdala-frontal connectivity was analysed using a whole-brain seed-based approach.
RESULTS: Among the SNPs analysed, a tryptophan hydroxylase 2 (TPH2) gene polymorphism-G703T-significantly predicted clinical and neurocircuitry manifestations of FMD. Relative to GG homozygotes, T carriers were characterised by earlier FMD age of onset and decreased connectivity between the right amygdala and the middle frontal gyrus. Furthermore, the TPH2 genotype showed a significant interaction with childhood trauma in predicting worse symptom severity.
CONCLUSIONS: This is, to our knowledge, the first study showing that the TPH2 genotype may modulate FMD both directly and interactively with childhood trauma. Because both this polymorphism and early-life stress alter serotonin levels, our findings support a potential molecular mechanism modulating FMD phenotype.

PMID: 32576619 [PubMed - indexed for MEDLINE]

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