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Microstructural Changes in Motor Functional Conversion Disorder: Multimodal Imaging Approach on a Case.

Wed, 06/24/2020 - 23:19
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Microstructural Changes in Motor Functional Conversion Disorder: Multimodal Imaging Approach on a Case.

Brain Sci. 2020 Jun 18;10(6):

Authors: Longarzo M, Cavaliere C, Mele G, Tozza S, Tramontano L, Alfano V, Aiello M, Salvatore M, Grossi D

Abstract
BACKGROUND: Functional motor conversion disorders are characterized by neurological symptoms unrelated to brain structural lesions. The present study was conducted on a woman presenting motor symptoms causing motor dysfunction, using advanced multimodal neuroimaging techniques, electrophysiological and neuropsychological assessment.
METHODS: The patient underwent fluorodeoxyglucose-positron emission tomography-computed tomography (FDG-PET-CT) and functional magnetic resonance imaging (fMRI) with both task and resting-state paradigms and was compared with 11 healthy matched controls. To test differences in structural parameters, Bayesian comparison was performed. To test differences in functional parameters, a first- and second-level analysis was performed in task fMRI, while a seed-to-seed analysis to evaluate the connections between brain regions and identify intersubject variations was performed in resting-state fMRI.
RESULTS: FDG-PET showed two patterns of brain metabolism, involving the cortical and subcortical structures. Regarding the diffusion data, microstructural parameters were altered for U-shape fibers for the hand and feet regions. Resting-state analysis showed hypoconnectivity between the parahippocampal and superior temporal gyrus. Neurophysiological assessment showed no alterations. Finally, an initial cognitive impairment was observed, paralleled by an anxiety and mild depressive state.
CONCLUSIONS: While we confirmed no structural alterations sustaining this functional motor disorder, we report microstructural changes in sensory-motor integration for both the hand and feet regions that could functionally support clinical manifestations.

PMID: 32570773 [PubMed]

Controlled semantic summation correlates with intrinsic connectivity between default mode and control networks.

Tue, 06/23/2020 - 23:17
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Controlled semantic summation correlates with intrinsic connectivity between default mode and control networks.

Cortex. 2020 May 25;129:356-375

Authors: Evans M, Krieger-Redwood K, Gonzalez Alam TR, Smallwood J, Jefferies E

Abstract
The capacity to identify aspects of meaning that overlap across multiple concepts may relate to individual differences in the strength of intrinsic connectivity within and between distinct brain networks supporting semantic cognition. This study examined a semantic summation task, which tested the capacity to detect weak overlapping aspects of meaning, in 76 participants who were also scanned with resting-state fMRI. We examined associations between summation and the intrinsic connectivity of semantically-relevant default mode and control network regions. These networks are implicated in information integration and controlled retrieval respectively. We found higher intrinsic connectivity between default and control networks was associated with better performance in the summation task. The same pattern of coupling between semantic default mode and control networks was not associated with more efficient retrieval of individual weak as opposed to strong associations in an additional cohort of around 200 participants, suggesting this pattern is specific to the summation of multiple concepts, rather than semantic task difficulty. Finally, higher connectivity within the default mode network was associated with better performance when selecting a word that was strongly-related to a single probe item, supporting the role of this network in more automatic aspects of semantic retrieval.

PMID: 32569945 [PubMed - as supplied by publisher]

Scalable Bayesian matrix normal graphical models for brain functional networks.

Tue, 06/23/2020 - 23:17
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Scalable Bayesian matrix normal graphical models for brain functional networks.

Biometrics. 2020 Jun 22;:

Authors: Kundu S, Risk BB

Abstract
Recently, there has been an explosive growth in graphical modeling approaches for estimating brain functional networks. In a detailed study, we show that surprisingly, standard graphical modeling approaches for fMRI data may not yield accurate estimates of the brain network due to the inability to suitably account for temporal correlations. We propose a novel Bayesian matrix normal graphical model that jointly models the temporal covariance and the brain network under a separable structure for the covariance to obtain improved estimates. The approach is implemented via an efficient optimization algorithm that computes the maximum-a-posteriori network estimates having desirable theoretical properties and which is scalable to high dimensions. The proposed method leads to substantial gains in network estimation accuracy compared to standard brain network modeling approaches as illustrated via extensive simulations. We apply the method to resting state fMRI data from the Human Connectome Project (HCP) involving a large number of time scans and brain regions, to study the relationships between fluid intelligence and functional connectivity, where it is not computationally feasible to apply existing matrix normal graphical models. Our proposed approach led to the detection of differences in connectivity between high and low fluid intelligence groups, whereas these differences were less pronounced or absent using the graphical lasso. This article is protected by copyright. All rights reserved.

PMID: 32569385 [PubMed - as supplied by publisher]

Alterations in Functional Connectivity During Different Phases of the Triggered Migraine Attack.

Tue, 06/23/2020 - 23:17
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Alterations in Functional Connectivity During Different Phases of the Triggered Migraine Attack.

Headache. 2020 Jun 22;:

Authors: Karsan N, Bose PR, O'Daly O, Zelaya FO, Goadsby PJ

Abstract
OBJECTIVE: To understand the changes in functional connectivity between brain areas of potential importance in migraine during different phases of the attack.
BACKGROUND: Migraine is a symptomatically heterogeneous disorder. Understanding the possible changes in brain function and, therefore, neurobiology during different phases of the migraine attack is important in developing disease biomarkers and advancing therapeutics.
DESIGN: Randomized, double-blind, placebo-controlled, multi-visit experimental study.
METHODS: Subjects aged 18-50 years with migraine with and without aura (≤22 headache days per month) were recruited from across the UK using advertising, from both population and hospital clinic samples (n = 53). Consented subjects had a 0.5 µg/kg/min nitroglycerin infusion or to placebo over 20 minutes during the period February 2015-July 2017. All subjects were exposed to a nitroglycerin infusion at least on 1 occasion at screening. For those subjects who consented to participate in imaging visits (n = 25), structural T1, T2 and FLAIR sequences and resting state blood oxygen level dependant contrast (rsBOLD) time series, using a multiecho EPI sequence, were conducted over 30-40 minutes at baseline and rsBOLD during premonitory symptoms and migraine headache on a 3T General Electric MR750 MRI scanner. For the placebo visit, the imaging was conducted at the same times following infusion in the absence of symptoms.
RESULTS: Montreal Neurological Institute (MNI) coordinates were used to characterize brain areas of connectivity change identified. Using repeated measures ANOVA models with time (visit number) and trigger substance (nitroglycerin/placebo) as factors, significant positive functional coupling was found between the thalami bilaterally and the right precuneus and cuneus regions during the nitroglycerin-triggered premonitory phase (T = 3.23, peak connectivity change at [-6, -68, 40] for left thalamus, P = .012 and [-4, -68, 40] for right thalamus, P = .019). The nitroglycerin-triggered premonitory phase was associated with a change in the direction of connectivity from positive to negative between the pons and the limbic lobe (T = 3.47, peak connectivity change at [2, 8, 50], P < .001). The headache phase of the nitroglycerin-triggered migraine attack was associated with ongoing negative functional coupling between the pons and the cingulate and frontal cortices, and positive functional coupling between the pons and the cerebellar tonsils and medulla (T = 3.47, peak connectivity change at [-8, -52, -58], P = .007).
CONCLUSIONS: Understanding the functional reorganization between subcortical and cortical brain areas in different phases of the migraine attack provides novel insights into the abnormal sensory processing and integration during migraine, as well as functional correlation with clinical symptoms displayed during each phase.

PMID: 32568433 [PubMed - as supplied by publisher]

Brain states govern the spatio-temporal dynamics of resting state functional connectivity.

Tue, 06/23/2020 - 23:17
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Brain states govern the spatio-temporal dynamics of resting state functional connectivity.

Elife. 2020 Jun 22;9:

Authors: Aedo-Jury F, Schwalm M, Hamzehpour L, Stroh A

Abstract
Previously, using simultaneous resting-state functional magnetic resonance imaging (fMRI) and photometry-based neuronal calcium recordings in the anesthetized rat, we identified blood oxygenation level-dependent (BOLD) responses directly related to slow calcium waves, revealing a cortex-wide and spatially organized correlate of locally recorded neuronal activity (Schwalm et al., 2017). Here, using the same techniques, we investigate two distinct cortical activity states: persistent activity, in which compartmentalized network dynamics were observed; and slow wave activity, dominated by a cortex-wide BOLD component, suggesting a strong functional coupling of inter-cortical activity. During slow wave activity we find a correlation between the occurring slow wave events and the strength of functional connectivity between different cortical areas. These findings suggest that down-up transitions of neuronal excitability can drive cortex-wide functional connectivity. This study provides further evidence that changes in functional connectivity are dependent on the brain's current state, directly linked to the generation of slow waves.

PMID: 32568067 [PubMed - as supplied by publisher]

Association between resting-state functional connectivity and reading in two writing systems in Japanese children with and without developmental dyslexia.

Tue, 06/23/2020 - 23:17
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Association between resting-state functional connectivity and reading in two writing systems in Japanese children with and without developmental dyslexia.

Brain Connect. 2020 Jun 21;:

Authors: Hashimoto T, Higuchi H, Uno A, Yokota S, Asano K, Taki Y, Kawashima R

Abstract
Reading acquisition is not equivalent across languages. Japanese is unique as it features two distinct writing systems that share the same sound and meaning: syllabic Hiragana and logographic Kanji scripts. Acquired reading difficulties in Hiragana and Kanji have been examined in older patients with brain lesions. However, the precise mechanisms underlying deficits in developmental dyslexia (DD) remain unclear. In this study, the neural signatures of Japanese children with DD were examined using resting-state functional magnetic resonance imaging. We examined 22 dyslexic and 46 typically developing (TD) children, aged 7-14 years. Reading performance in each writing system was correlated with neural connectivity in TD children. In contrast, in children with DD, weak associations between neural connectivity and reading performance were observed. In TD children, Hiragana-reading fluency was positively correlated with the left fusiform gyrus network. No significant correlations between Hiragana fluency and neural connectivity were observed in children with DD. Correspondingly, there were fewer correlations between Kanji accuracy and strength of reading-related connectivity in children with DD, while positive correlations with the bilateral fronto-parietal network and negative correlations with the left fusiform network were found in TD children. These data suggest that positive and negative coupling with neural connectivity is associated with developing Japanese reading skills. Furthermore, different neural connectivity correlations between Hiragana fluency and Kanji accuracy were detected in TD children but less in children with DD. Therefore, the two writing systems may exert differential effects and deficits on reading in healthy children and in children with DD, respectively.

PMID: 32567365 [PubMed - as supplied by publisher]

Connectivity dynamics from wakefulness to sleep.

Sun, 06/21/2020 - 23:14
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Connectivity dynamics from wakefulness to sleep.

Neuroimage. 2020 Jun 17;:117047

Authors: Damaraju E, Tagliazucchi E, Laufs H, Calhoun VD

Abstract
Interest in time-resolved connectivity in fMRI has grown rapidly in recent years. The most widely used technique for studying connectivity changes over time utilizes a sliding windows approach. There has been some debate about the utility of shorter versus longer windows, the use of fixed versus adaptive windows, as well as whether observed resting state dynamics during wakefulness may be predominantly due to changes in sleep state and subject head motion. In this work we use an independent component analysis (ICA)-based pipeline applied to concurrent EEG/fMRI data collected during wakefulness and various sleep stages and show: 1) connectivity states obtained from clustering sliding windowed correlations of resting state functional network time courses well classify the sleep states obtained from EEG data, 2) using shorter sliding windows instead of longer non-overlapping windows improves the ability to capture transition dynamics even at windows as short as 30 seconds, 3) motion appears to be mostly associated with one of the states rather than spread across all of them 4) a fixed tapered sliding window approach outperforms an adaptive dynamic conditional correlation approach, and 5) consistent with prior EEG/fMRI work, we identify evidence of multiple states within the wakeful condition which are able to be classified with high accuracy. Classification of wakeful only states suggest the presence of time-varying changes in connectivity in fMRI data beyond sleep state or motion. Results also inform about advantageous technical choices, and the identification of different clusters within wakefulness that are separable suggest further studies in this direction.

PMID: 32562782 [PubMed - as supplied by publisher]

Functional brain changes in the elderly for the perception of hand movements: a greater impairment occurs in proprioception than touch.

Sun, 06/21/2020 - 23:14
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Functional brain changes in the elderly for the perception of hand movements: a greater impairment occurs in proprioception than touch.

Neuroimage. 2020 Jun 17;:117056

Authors: Landelle C, Anton JL, Nazarian B, Sein J, Gharbi A, Felician O, Kavounoudias A

Abstract
Unlike age-related brain changes linked to motor activity, neural alterations related to self-motion perception remain unknown. Using fMRI data, we investigated age-related changes in the central processing of somatosensory information by inducing illusions of right-hand rotations with specific proprioceptive and tactile stimulation. Functional connectivity during resting-state (rs-FC) was also compared between younger and older participants. Results showed common sensorimotor activations in younger and older adults during proprioceptive and tactile illusions, but less deactivation in various right frontal regions and the precuneus were found in the elderly. Older participants exhibited a less-lateralized pattern of activity across the primary sensorimotor cortices (SM1) in the proprioceptive condition only. This alteration of the interhemispheric balance correlated with declining individual performance in illusion velocity perception from a proprioceptive, but not a tactile, origin. By combining task-related data, rs-FC and behavioral performance, this study provided consistent results showing that hand movement perception was altered in the elderly, with a more pronounced deterioration of the proprioceptive system, likely due to the breakdown of inhibitory processes with aging. Nevertheless, older people could benefit from an increase in internetwork connectivity to overcome this kinesthetic decline.

PMID: 32562781 [PubMed - as supplied by publisher]

Altered resting-state functional connectivity between subregions in the thalamus and cortex in migraine without aura.

Sun, 06/21/2020 - 23:14
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Altered resting-state functional connectivity between subregions in the thalamus and cortex in migraine without aura.

Eur J Neurol. 2020 Jun 19;:

Authors: Qin Z, Su J, He XW, Zhu Q, Cui Y, Zhang J, Wang M, Gao T, Tang W, Hu Y, Liu YS, Qiao Y, Liu JR, Li J, Du X

Abstract
BACKGROUND: Migraine is a complex and disabling neurological disorder, and the exact neurological mechanisms remain unclear. Thalamus is considered the hub of the central processing and integration of nociceptive information, as well as the modulation of these processes.
METHOD: Forty-eight migraineurs without aura (MWoAs) during the interictal phase and 48 age- and sex-matched healthy controls (HCs) underwent resting-state fMRI scans. We utilized masked independent component analysis (mICA) and seed-based functional connectivity (FC) to investigate whether MWoA exhibited abnormal FC between subregions in the thalamus and the cortex regions.
RESULTS: MWoAs showed significantly weaker FC between the anterior dorsal nucleus (ADN) and left precuneus. Additionally, MWoAs exhibited significantly reduced FC between the ventral posterior nucleus (VPN) and left precuneus, right inferior parietal lobule, and right middle frontal gyrus; furthermore, the FC Z scores between VPN and right inferior parietal lobule were negatively correlated with pain intensity in MWoAs. The disease duration of patients was negatively correlated with the FC Z scores between the VPN and right inferior parietal lobule.
CONCLUSION: These altered thalamocortical connectivity patterns may contribute to multisensory integration abnormalities, deficits in pain attention, cognitive evaluation, and pain modulation. Pain sensitivity and disease duration are closely tied to abnormal FC between VPN and right inferior parietal lobule. Remarkably, recurrent headache attacks might contribute to this maladaptive functional plasticity closely related to pain intensity.

PMID: 32562320 [PubMed - as supplied by publisher]

The correlation between family relationships and brain activity within the reward circuit in adolescents with Internet gaming disorder.

Sun, 06/21/2020 - 23:14
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The correlation between family relationships and brain activity within the reward circuit in adolescents with Internet gaming disorder.

Sci Rep. 2020 Jun 19;10(1):9951

Authors: Hwang H, Hong J, Kim SM, Han DH

Abstract
Disrupted reward circuits and diminished behavioural control have been suggested as the pathophysiologies of Internet gaming disorder (IGD). Family functioning is thought to play an important role in reward-related control. We hypothesized that adolescents with IGD show disrupted patterns of family relationships, which are associated with brain activity within the reward circuit. 42 adolescents with IGD without comorbidities and 41 healthy controls were assessed for family function and psychological states using the Korean Wechsler Intelligence Scale for Children (K-WISC), Korean version of DuPaul's attention deficit hyperactivity disorder (ADHD) Rating Scale (K-ARS), Young Internet Addiction Scale (YIAS), Children's Depression Inventory (CDI), Beck Anxiety Inventory (BAI), and the relationship domain of the Family Environmental Scale (FES-R). Brain activity was assessed via resting-state fMRI. Adolescents with IGD showed increased K-ARS, BAI, and YIAS scores, but decreased FES-R and FES-cohesion subscale scores; YIAS scores were negatively correlated with FES-R scores. Brain connectivity from the cingulate to the striatum was decreased, positively correlated with FES-R scores, and negatively correlated with IGD severity. Adolescents with IGD showed disrupted family relationships, which was associated with the severity of the disorder, and dis-connectivity within the reward circuit.

PMID: 32561779 [PubMed - as supplied by publisher]

Connectome-based models can predict early symptom improvement in major depressive disorder.

Sun, 06/21/2020 - 23:14
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Connectome-based models can predict early symptom improvement in major depressive disorder.

J Affect Disord. 2020 Aug 01;273:442-452

Authors: Ju Y, Horien C, Chen W, Guo W, Lu X, Sun J, Dong Q, Liu B, Liu J, Yan D, Wang M, Zhang L, Guo H, Zhao F, Zhang Y, Shen X, Constable RT, Li L

Abstract
BACKGROUND: Major depressive disorder (MDD) is a debilitating mental illness with more than 50% of patients not achieving an adequate response using first-line treatments. Reliable models that predict antidepressant treatment outcome are needed to guide clinical decision making. We aimed to build predictive models of treatment improvement for MDD patients using machine learning approaches based on fMRI resting-state functional connectivity patterns.
METHODS: Resting-state fMRI data were acquired from 192 untreated MDD patients at recruitment, and their severity of depression was assessed by Hamilton Rating Scale for Depression (HAMD) at baseline. Patients were given medication after the initial MR scan and their symptoms were monitored through HAMD for a period of six months. Connectome-based predictive modeling (CPM) algorithms were implemented to predict the improvement in HAMD score at one month from resting-state connectivity at baseline. Additionally, by selectively combining the features from all leave-one-out iterations in the model building stage, we created a consensus model that could be generalized to predict improvement in HAMD score in samples of non-overlapping subjects at different time points.
RESULTS: Using baseline functional connectivity, CPM successfully predicted symptom improvement of depression at one month. In addition, a consensus 'MDD improvement model' could predict symptom improvement for novel individuals at the two-week, one-month, two-month and three-month time points after antidepressant treatment.
CONCLUSIONS: Individual pre-treatment functional brain networks contain meaningful information that can be gleaned to build predictors of treatment outcome. The identified MDD improvement networks could be an appropriate biomarker for predicting individual therapeutic response of antidepressant treatment. Replication and validation using other large datasets will be a key next step before these models can be used in clinical practice.

PMID: 32560939 [PubMed - as supplied by publisher]

Short-term nicotine deprivation alters dorsal anterior cingulate glutamate concentration and concomitant cingulate-cortical functional connectivity.

Sat, 06/20/2020 - 23:13
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Short-term nicotine deprivation alters dorsal anterior cingulate glutamate concentration and concomitant cingulate-cortical functional connectivity.

Neuropsychopharmacology. 2020 Jun 19;:

Authors: Abulseoud OA, Ross TJ, Nam HW, Caparelli EC, Tennekoon M, Schleyer B, Castillo J, Fedota J, Gu H, Yang Y, Stein E

Abstract
Most cigarette smokers who wish to quit too often relapse within the first few days of abstinence, primarily due to the aversive aspects of the nicotine withdrawal syndrome (NWS), which remains poorly understood. Considerable research has suggested that the dorsal anterior cingulate cortex (dACC) plays a key role in nicotine dependence, with its functional connections between other brain regions altered as a function of trait addiction and state withdrawal. The flow of information between dACC and fronto-striatal regions is secured through different pathways, the vast majority of which are glutamatergic. As such, we investigated dACC activity using resting state functional connectivity (rsFC) with functional magnetic resonance imaging (fMRI) and glutamate (Glu) concentration with magnetic resonance spectroscopy (MRS). We also investigated the changes in adenosine levels in plasma during withdrawal as a surrogate for brain adenosine, which plays a role in fine-tuning synaptic glutamate transmission. Using a double-blind, placebo-controlled, randomized crossover design, nontreatment seeking smoking participants (N = 30) completed two imaging sessions, one while nicotine sated and another after 36 h nicotine abstinence. We observed reduced dACC Glu (P = 0.029) along with a significant reduction in plasma adenosine (P = 0.03) and adenosine monophosphate (AMP; P < 0.0001) concentrations during nicotine withdrawal in comparison with nicotine sated state. This withdrawal state manipulation also led to an increase in rsFC strength (P < 0.05) between dACC and several frontal cortical regions, including left superior frontal gyrus (LSFG), and right middle frontal gyrus (RMFG). Moreover, the state-trait changes in dACC Glu and rsFC strength between the dACC and both SFG and MFG were positively correlated (P = 0.012, and P = 0.007, respectively). Finally, the change in circuit strength between dACC and LSFG was negatively correlated with the change in withdrawal symptom manifestations as measured by the Wisconsin Smoking Withdrawal Scale (P = 0.04) and Tobacco Craving Questionnaire (P = 0.014). These multimodal imaging-behavioral findings reveal the complex cascade of changes induced by acute nicotine deprivation and call for further investigation into the potential utility of adenosine- and glutamate-signaling as novel therapeutic targets to treat the NWS.

PMID: 32559759 [PubMed - as supplied by publisher]

A computational model-based analysis of basal ganglia pathway changes in Parkinson's disease inferred from resting-state fMRI.

Sat, 06/20/2020 - 23:13
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A computational model-based analysis of basal ganglia pathway changes in Parkinson's disease inferred from resting-state fMRI.

Eur J Neurosci. 2020 Jun 19;:

Authors: Maith O, Villagrasa Escudero F, Dinkelbach HÜ, Baladron J, Horn A, Irmen F, Kühn AA, Hamker FH

Abstract
Previous computational model-based approaches for understanding the dynamic changes related to Parkinson's disease made particular assumptions about Parkinson's disease related activity changes or specified dopamine-dependent activation or learning rules. Inspired by recent model-based analysis of resting-state fMRI, we have taken a data-driven approach. We fit the free parameters of a spiking neuro-computational model to match correlations of blood-oxygen-level-dependent signals between different basal ganglia nuclei and obtain subject-specific neurocomputational models of two subject groups: Parkinson patients and matched controls. When comparing mean firing rates at rest and connectivity strengths between the control and Parkinsonian model groups, several significant differences were found that are consistent with previous experimental observations. We discuss the implications of our approach and compare its results also with the popular "rate model" of the basal ganglia. Our study suggests that a model-based analysis of imaging data from healthy and Parkinsonian subjects is a promising approach for the future to better understand Parkinson related changes in the basal ganglia and corresponding treatments.

PMID: 32558966 [PubMed - as supplied by publisher]

Altered functional connectivity of brain regions based on a meta-analysis in patients with T2DM: A resting-state fMRI study.

Sat, 06/20/2020 - 23:13
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Altered functional connectivity of brain regions based on a meta-analysis in patients with T2DM: A resting-state fMRI study.

Brain Behav. 2020 Jun 18;:e01725

Authors: Zhang D, Gao J, Yan X, Tang M, Zhe X, Cheng M, Chen W, Zhang X

Abstract
OBJECTIVE: To explore the neural mechanisms of brain impairment in type 2 diabetes mellitus (T2DM), abnormal changes to the functional connections between brain regions in the resting state were investigated based on a meta-analysis.
METHODS: Resting-state functional magnetic resonance imaging (fMRI) and neuropsychological assessment were performed on 38 patients with T2DM and 33 healthy controls (HCs). Functional connectivity between regions based on a meta-analysis and other voxels in the brain was calculated and compared between the two groups using a two-sample t test. A correlation analysis was conducted between clinical/cognitive variables and functional connection values from the regions with significant differences in the above comparison.
RESULTS: Patients in the T2DM group showed a significantly decreased functional connection between the right posterior cerebellum and the right middle/inferior occipital gyrus, left middle temporal gyrus, left superior frontal gyrus, left middle frontal gyrus, left insula, left precuneus, and right paracentral lobule/left precuneus when compared with HC group. The functional connection values between the right insula and left medial frontal gyrus, left supplementary motor area, and between the left lingual gyrus and right middle/inferior occipital gyrus in patients with T2DM were significantly decreased. Moreover, the functional connection values between the right posterior cerebellum and left middle frontal gyrus, and between the right posterior cerebellum and left precuneus were negatively correlated with HbA1c in the T2DM group (r = -.356, p = .03; r = -.334, p = .043).
CONCLUSIONS: Our study showed a wide range of cerebellar-cerebral circuit abnormalities in patients with T2DM, which provides a new direction to investigate the neuropathological mechanisms of T2DM from the perspective of the cerebellum.

PMID: 32558376 [PubMed - as supplied by publisher]

Structural and Functional Thalamic Changes in Parkinson's Disease With Mild Cognitive Impairment.

Sat, 06/20/2020 - 23:13
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Structural and Functional Thalamic Changes in Parkinson's Disease With Mild Cognitive Impairment.

J Magn Reson Imaging. 2020 Jun 17;:

Authors: Li MG, He JF, Liu XY, Wang ZF, Lou X, Ma L

Abstract
BACKGROUND: The thalamus is a key node of deep gray matter and previous studies have demonstrated that it is involved in the modulation of cognition.
PURPOSE: To investigate the volume changes of the thalamus and its subregions and altered thalamus functional connectivity patterns in Parkinson's disease (PD) patients with and without mild cognitive impairment (MCI).
STUDY TYPE: Prospective.
POPULATION: Thirty-three patients with MCI (PD-MCI), 36 PD patients having no cognitive impairment (PD-NCI), 21 healthy controls (HCs).
SEQUENCE: 3.0T MRI scanner; 3D T1 -weighted fast spoiled gradient recalled echo (3D T1 -FSPGR); resting-state fMRI ASSESSMENT: Voxel-based morphometry (VBM) was performed to calculate the volume of the thalamus and its subregions. The left and right total thalamus were considered seeds and seed-based functional connectivity (FC) was analyzed. Additionally, correlations between volumes and cognitive performance and between FC values and cognitive performance were examined separately.
STATISTICAL TEST: Analysis of covariance (ANCOVA); two-sample t-tests; partial correlation analysis.
RESULTS: The volumes of the total thalamus (PD-MCI vs. PD-NCI vs. HCs: 18.39 ± 1.67 vs. 19.63 ± 1.79 vs. 19.47 ± 1.35) and its subregions were significantly reduced in PD-MCI as compared to PD-NCI (total thalamus: P = 0.002) and HCs (total thalamus: P = 0.012). Compared with PD-NCI, PD-MCI showed increased FC between the thalamus and bilateral middle cingulate cortex and left posterior cingulate cortex, and decreased FC between thalamus and the left superior occipital gyrus, left cuneus, left precuneus, and left middle occipital gyrus. Volumes of thalamus and the subregions, as well as the FC of thalamus with the identified regions, were significantly correlated (P < 0.05, FDR-corrected) with neuropsychological scores in PD patients.
DATA CONCLUSION: We noted volume loss and altered FC of thalamus in PD-MCI patients, and these changes were correlated with global cognitive performance.
LEVEL OF EVIDENCE: 2 TECHNICAL EFFICIENCY: Stage 2.

PMID: 32557988 [PubMed - as supplied by publisher]

Neuronavigation based 10 sessions of repetitive transcranial magnetic stimulation therapy in chronic migraine: an exploratory study.

Sat, 06/20/2020 - 23:13
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Neuronavigation based 10 sessions of repetitive transcranial magnetic stimulation therapy in chronic migraine: an exploratory study.

Neurol Sci. 2020 Jun 15;:

Authors: Kumar A, Mattoo B, Bhatia R, Kumaran S, Bhatia R

Abstract
INTRODUCTION: Chronic migraine is a disease of altered cortical excitability. Repetitive transcranial magnetic stimulation provides a novel non-invasive method to target the nociceptive circuits in the cortex. Motor cortex is one such potential target. In this study, we targeted the left motor cortex using fMRI-guided neuronavigation.
MATERIALS AND METHODS: Twenty right-handed patients were randomized into real and sham rTMS group. Baseline subjective pain assessments were done using visual analog scale (VAS) and questionnaires: State-Trait Anxiety Inventory, Becks Depression Inventory, and Migraine Disability Assessment (MIDAS) questionnaire. Objectively, pain was assessed by means of thermal pain thresholds using quantitative sensory testing. For corticomotor excitability parameters, resting motor thresholds and motor-evoked potentials were mapped. For rTMS total, 600 pulses in 10 trains at 10 Hz with an intertrain interval of 60 s were delivered in each session. Ten such sessions were given 5 days per week over 2 consecutive weeks. The duration of each session was 10 min. Real rTMS was administered at 70% of Resting MT. All the tests were repeated post-intervention and after 1 month of follow-up. There are no studies reporting the use of fMRI-based TMS for targeting the motor cortex in CM patients.
RESULTS: We observed a significant reduction in the mean VAS rating, headache frequency, and MIDAS questionnaire in real rTMS group which was maintained after 1 month of follow-up.
CONCLUSION: Ten sessions of fMRI-based rTMS over the left motor cortex may provide long-term pain relief in CM, but further studies are warranted to confirm our preliminary findings.

PMID: 32556749 [PubMed - as supplied by publisher]

Altered Resting-State Functional Connectivity Between Awake and Isoflurane Anesthetized Marmosets.

Sat, 06/20/2020 - 23:13
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Altered Resting-State Functional Connectivity Between Awake and Isoflurane Anesthetized Marmosets.

Cereb Cortex. 2020 Jun 18;:

Authors: Hori Y, Schaeffer DJ, Gilbert KM, Hayrynen LK, Cléry JC, Gati JS, Menon RS, Everling S

Abstract
The common marmoset (Callithrix jacchus) is a New World primate that is becoming increasingly popular as a preclinical model. To assess functional connectivity (FC) across the marmoset brain, resting-state functional MRI (RS-fMRI) is often performed under isoflurane anesthesia to avoid the effects of motion, physiological stress, and training requirements. In marmosets, however, it remains unclear how isoflurane anesthesia affects patterns of FC. Here, we investigated the effects of isoflurane on FC when delivered with either medical air or 100% pure oxygen, two canonical methods of inhalant isoflurane anesthesia delivery. The results demonstrated that when delivered with either medical air or 100% oxygen, isoflurane globally decreased FC across resting-state networks that were identified in awake marmosets. Generally, although isoflurane globally decreased FC in resting-state networks, the spatial structure of the networks was preserved. Outside of the context of RS networks, we indexed pair-wise functional connectivity between regions across the brain and found that isoflurane substantially altered interhemispheric and thalamic FC. Taken together, these findings indicate that RS-fMRI under isoflurane anesthesia is useful to evaluate the global structure of functional networks, but may obfuscate important nodes of some network components when compared to data acquired in fully awake marmosets.

PMID: 32556184 [PubMed - as supplied by publisher]

Longitudinal changes of brain microstructure and function in nonconcussed female rugby players.

Sat, 06/20/2020 - 23:13
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Longitudinal changes of brain microstructure and function in nonconcussed female rugby players.

Neurology. 2020 Jun 17;:

Authors: Manning KY, Brooks JS, Dickey JP, Harriss A, Fischer L, Jevremovic T, Blackney K, Barreira C, Brown A, Bartha R, Doherty T, Fraser D, Holmes J, Dekaban GA, Menon RS

Abstract
OBJECTIVE: To longitudinally assess brain microstructure and function in female varsity athletes participating in contact and noncontact sports.
METHODS: Concussion-free female rugby players (n = 73) were compared to age-matched (ages 18-23) female swimmers and rowers (n = 31) during the in- and off-season. Diffusion and resting-state fMRI (rs-fMRI) measures were the primary outcomes. The Sports Concussion Assessment Tool and head impact accelerometers were used to monitor symptoms and impacts, respectively.
RESULTS: We found cross-sectional (contact vs noncontact) and longitudinal (in- vs off-season) changes in white matter diffusion measures and rs-fMRI network connectivity in concussion-free contact athletes relative to noncontact athletes. In particular, mean, axial, and radial diffusivities were increased with decreased fractional anisotropy in multiple white matter tracts of contact athletes accompanied with default mode and visual network hyperconnectivity (p < 0.001). Longitudinal diffusion changes in the brainstem between the in- and off-season were observed for concussion-free contact athletes only, with progressive changes observed in a subset of athletes over multiple seasons. Axial diffusivity was significantly lower in the genu and splenium of the corpus callosum in those contact athletes with a history of concussion.
CONCLUSIONS: Together, these findings demonstrate longitudinal changes in the microstructure and function of the brain in otherwise healthy, asymptomatic athletes participating in contact sport. Further research to understand the long-term brain health and biological implications of these changes is required, in particular to what extent these changes reflect compensatory, reparative, or degenerative processes.

PMID: 32554762 [PubMed - as supplied by publisher]

Pre-trained MRI-based Alzheimer's disease classification models to classify memory clinic patients.

Sat, 06/20/2020 - 23:13
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Pre-trained MRI-based Alzheimer's disease classification models to classify memory clinic patients.

Neuroimage Clin. 2020 Jun 04;27:102303

Authors: de Vos F, Schouten TM, Koini M, Bouts MJRJ, Feis RA, Lechner A, Schmidt R, van Buchem MA, Verhey FRJ, Olde Rikkert MGM, Scheltens P, de Rooij M, van der Grond J, Rombouts SARB

Abstract
Anatomical magnetic resonance imaging (MRI), diffusion MRI and resting state functional MRI (rs-fMRI) have been used for Alzheimer's disease (AD) classification. These scans are typically used to build models for discriminating AD patients from control subjects, but it is not clear if these models can also discriminate AD in diverse clinical populations as found in memory clinics. To study this, we trained MRI-based AD classification models on a single centre data set consisting of AD patients (N = 76) and controls (N = 173), and used these models to assign AD scores to subjective memory complainers (N = 67), mild cognitive impairment (MCI) patients (N = 61), and AD patients (N = 61) from a multi-centre memory clinic data set. The anatomical MRI scans were used to calculate grey matter density, subcortical volumes and cortical thickness, the diffusion MRI scans were used to calculate fractional anisotropy, mean, axial and radial diffusivity, and the rs-fMRI scans were used to calculate functional connectivity between resting state networks and amplitude of low frequency fluctuations. Within the multi-centre memory clinic data set we removed scan site differences prior to applying the models. For all models, on average, the AD patients were assigned the highest AD scores, followed by MCI patients, and later followed by SMC subjects. The anatomical MRI models performed best, and the best performing anatomical MRI measure was grey matter density, separating SMC subjects from MCI patients with an AUC of 0.69, MCI patients from AD patients with an AUC of 0.70, and SMC patients from AD patients with an AUC of 0.86. The diffusion MRI models did not generalise well to the memory clinic data, possibly because of large scan site differences. The functional connectivity model separated SMC subjects and MCI patients relatively good (AUC = 0.66). The multimodal MRI model did not improve upon the anatomical MRI model. In conclusion, we showed that the grey matter density model generalises best to memory clinic subjects. When also considering the fact that grey matter density generally performs well in AD classification studies, this feature is probably the best MRI-based feature for AD diagnosis in clinical practice.

PMID: 32554321 [PubMed - as supplied by publisher]

Mind-Wandering in Adolescents Predicts Worse Affect and Is Linked to Aberrant Default Mode Network-Salience Network Connectivity.

Sat, 06/20/2020 - 23:13
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Mind-Wandering in Adolescents Predicts Worse Affect and Is Linked to Aberrant Default Mode Network-Salience Network Connectivity.

J Am Acad Child Adolesc Psychiatry. 2020 Jun 12;:

Authors: Webb CA, Israel ES, Belleau E, Appleman L, Forbes EE, Pizzagalli DA

Abstract
OBJECTIVE: Understanding the fluctuating emotional and cognitive states of adolescents with depressive symptoms requires fine-grained and naturalistic measurements. This study used ecological momentary assessment (EMA) to investigate the affective correlates and consequences of mind-wandering in adolescents with anhedonia (AH) and typically developing (TD) controls. In addition, we examined the association between mind-wandering and resting state functional connectivity between the medial prefrontal cortex (mPFC), a core hub of the Default Mode Network (DMN) linked to internally-oriented mentation, and networks linked to attentional control (Dorsal Attention Network; DAN) and affect/salience detection (Salience Network; SN).
METHOD: Sixty-five adolescents, ages 12-18 years (TD=36; AH=29) completed a resting state fMRI scan and subsequently used a smartphone application for EMA data collection (2-3 times/day for 5 days). Each survey (N=678) prompted adolescents to report on their current positive and negative affect (PA and NA), cognition and activity.
RESULTS: The frequency of mind-wandering was higher for AH (70.0% of EMA samples) relative to TD (59.2%) participants, and the AH participants were more likely to mind-wander to unpleasant content. Mind-wandering was associated with higher concurrent NA, even when controlling for plausible confounds (eg, current activity, social companion, rumination). Time-lagged analyses revealed a bidirectional association between mind-wandering and PA. Greater levels of mind-wandering within the AH group were associated with stronger mPFC-SN/DAN connectivity.
CONCLUSION: Rates of mind-wandering were high, especially among adolescents with anhedonia, and predicted worse affect. The relation between mind-wandering and enhanced mPFC-SN coupling may reflect heightened bottom-up influence of affective and sensory salience on DMN-mediated internally-oriented thought.

PMID: 32553785 [PubMed - as supplied by publisher]