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Functional connectivity mediates the relationship between self-efficacy and curiosity.

5 hours 42 min ago
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Functional connectivity mediates the relationship between self-efficacy and curiosity.

Neurosci Lett. 2019 Aug 20;:134442

Authors: Li Y, Huo T, Zhuang K, Song L, Wang X, Ren Z, Liu Q, Qiu J

Abstract
Curiosity is an important driving force for human development. This study employed resting-state functional magnetic resonance imaging (fMRI) data (n = 400) and a cross-validation-based predictive framework based on the functional connectivity between and within the default mode network (DMN), fronto-parietal task control network (FPN), and salience network (SN) to explore the relationship between these and curiosity. We found that the curiosity network consisting of functional connections in DMN, FPN, and SN can successfully predict curiosity, and the functional connections within the prefrontal cortex (PFC) and between its nodes and the angular gyrus (AG) made a greater contribution to prediction power. More important, although curiosity has long been considered the main intrinsic motivation of learning and self-efficacy (individual's confidence in his or her own ability) is the primary factor affecting learning motivation, few studies have explored the relationship between the two. Therefore, we speculated that the relationship between the curiosity brain network and curiosity might also be related to self-efficacy. In this study, the strength of the curiosity network was calculated as a mediation variable to explore the relationship between self-efficacy and curiosity. The results revealed that the strength of the curiosity brain network mediates the association between self-efficacy and curiosity score. Our findings suggest that self-efficacy plays an important role in shaping individuals' trait curiosity and extends understanding of the neural mechanism of curiosity.

PMID: 31442514 [PubMed - as supplied by publisher]

MAOA-VNTR genotype affects structural and functional connectivity in distributed brain networks.

5 hours 42 min ago
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MAOA-VNTR genotype affects structural and functional connectivity in distributed brain networks.

Hum Brain Mapp. 2019 Aug 23;:

Authors: Harneit A, Braun U, Geiger LS, Zang Z, Hakobjan M, van Donkelaar MMJ, Schweiger JI, Schwarz K, Gan G, Erk S, Heinz A, Romanczuk-Seiferth N, Witt S, Rietschel M, Walter H, Franke B, Meyer-Lindenberg A, Tost H

Abstract
Previous studies have linked the low expression variant of a variable number of tandem repeat polymorphism in the monoamine oxidase A gene (MAOA-L) to the risk for impulsivity and aggression, brain developmental abnormalities, altered cortico-limbic circuit function, and an exaggerated neural serotonergic tone. However, the neurobiological effects of this variant on human brain network architecture are incompletely understood. We studied healthy individuals and used multimodal neuroimaging (sample size range: 219-284 across modalities) and network-based statistics (NBS) to probe the specificity of MAOA-L-related connectomic alterations to cortical-limbic circuits and the emotion processing domain. We assessed the spatial distribution of affected links across several neuroimaging tasks and data modalities to identify potential alterations in network architecture. Our results revealed a distributed network of node links with a significantly increased connectivity in MAOA-L carriers compared to the carriers of the high expression (H) variant. The hyperconnectivity phenotype primarily consisted of between-lobe ("anisocoupled") network links and showed a pronounced involvement of frontal-temporal connections. Hyperconnectivity was observed across functional magnetic resonance imaging (fMRI) of implicit emotion processing (pFWE = .037), resting-state fMRI (pFWE = .022), and diffusion tensor imaging (pFWE = .044) data, while no effects were seen in fMRI data of another cognitive domain, that is, spatial working memory (pFWE = .540). These observations are in line with prior research on the MAOA-L variant and complement these existing data by novel insights into the specificity and spatial distribution of the neurogenetic effects. Our work highlights the value of multimodal network connectomic approaches for imaging genetics.

PMID: 31441562 [PubMed - as supplied by publisher]

The Metabolic Activity of Caudate and Prefrontal Cortex Negatively Correlates with the Severity of Idiopathic Parkinson's Disease.

5 hours 42 min ago
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The Metabolic Activity of Caudate and Prefrontal Cortex Negatively Correlates with the Severity of Idiopathic Parkinson's Disease.

Aging Dis. 2019 Aug;10(4):847-853

Authors: Chu JS, Liu TH, Wang KL, Han CL, Liu YP, Michitomo S, Zhang JG, Fang T, Meng FG

Abstract
Positron emission tomography (PET) scan with tracer [18F]-fluorodeoxy-glucose (18F-FDG) is widely used to measure the glucose metabolism in neurodegenerative disease such as Idiopathic Parkinson's disease (IPD). Previous studies using 18F-FDG PET mainly focused on the motor or non-motor symptoms but not the severity of IPD. In this study, we aimed to determine the metabolic patterns of 18F-FDG in different stages of IPD defined by Hoehn and Yahr rating scale (H-Y rating scale) and to identify regions in the brain that play critical roles in disease progression. Fifty IPD patients were included in this study. They were 29 men and 21 women (mean±SD, age 57.7±11.1 years, disease duration 4.0±3.8 years, H-Y 2.2±1.1). Twenty healthy individuals were included as normal controls. Following 18F-FDG PET scan, image analysis was performed using Statistical Parametric Mapping (SPM) and Resting-State fMRI Data Analysis Toolkit (REST). The metabolic feature of IPD and regions-of-interests (ROIs) were determined. Correlation analysis between ROIs and H-Y stage was performed. SPM analysis demonstrated a significant hypometabolic activity in bilateral putamen, caudate and anterior cingulate as well as left parietal lobe, prefrontal cortex in IPD patients. In contrast, hypermetabolism was observed in the cerebellum and vermis. There was a negative correlation (p=0.007, r=-0.412) between H-Y stage and caudate metabolic activity. Moreover, the prefrontal area also showed a negative correlation with H-Y (P=0.033, r=-0.334). Thus, the uptake of FDG in caudate and prefrontal cortex can potentially be used as a surrogate marker to evaluate the severity of IPD.

PMID: 31440389 [PubMed]

Effects of Estradiol Therapy on Resting-State Functional Connectivity of Transgender Women After Gender-Affirming Related Gonadectomy.

5 hours 42 min ago
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Effects of Estradiol Therapy on Resting-State Functional Connectivity of Transgender Women After Gender-Affirming Related Gonadectomy.

Front Neurosci. 2019;13:817

Authors: Schneider MA, Spritzer PM, Minuzzi L, Frey BN, Syan SK, Fighera TM, Schwarz K, Costa ÂB, da Silva DC, Garcia CCG, Fontanari AMV, Real AG, Anes M, Castan JU, Cunegatto FR, Lobato MIR

Abstract
An extreme incongruence between sex and gender identity leads individuals with gender dysphoria (GD) to seek cross-sex hormone therapy (CSHT), and gender-affirming surgery (GAS). Although few studies have investigated the effects of CSHT on the brain prior to GAS, no studies in the extant literature have evaluated its impact during hypogonadism in post-GAS individuals. Here, we aimed to evaluate the effects of estradiol on resting-state functional connectivity (rs-FC) of the sensorimotor cortex (SMC) and basal ganglia following surgical hypogonadism. Eighteen post-GAS (male-to-female) participants underwent functional magnetic resonance imaging (fMRI) and neuropsychiatric and hormonal assessment at two time points (t1, hormonal washout; t2, CSHT reintroduction). Based on the literature, the thalamus was selected as a seed, while the SMC and the dorsolateral striatum were targets for seed-based functional connectivity (sbFC). A second sbFC investigation consisted of a whole-brain voxel exploratory analysis again using the thalamus as a seed. A final complementary data-driven approach using multivoxel pattern analysis (MVPA) was conducted to identify a potential seed for further sbFC analyses. An increase in the rs-FC between the left thalamus and the left SCM/putamen followed CSHT. MVPA identified a cluster within the subcallosal cortex (SubCalC) representing the highest variation in peak activation between time points. Setting the SubCalC as a seed, whole-brain analysis showed a decoupling between the SubCalC and the medial frontal cortex during CSHT. These results indicate that CSHT with estradiol post-GAS, modulates rs-FC in regions engaged in cognitive, emotional, and sensorimotor processes.

PMID: 31440128 [PubMed]

Functional connectivity impairment of postcentral gyrus in relapsing-remitting multiple sclerosis with somatosensory disorder.

5 hours 42 min ago
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Functional connectivity impairment of postcentral gyrus in relapsing-remitting multiple sclerosis with somatosensory disorder.

Eur J Radiol. 2019 Sep;118:200-206

Authors: Fu J, Chen X, Gu Y, Xie M, Zheng Q, Wang J, Zeng C, Li Y

Abstract
PURPOSE: To characterize the spatial patterns of functional connectivity(FC) changes of whole brain in RRMS with somatosensory disorder(RRMS-SS) and to investigate the correlation between abnormal FC and clinical scores.
METHODS: Twenty-six RRMS-SS patients and 23 healthy controls(HC) underwent resting-state functional magnetic resonance imaging(RS-fMRI) scanning. The clinical scores were collected including Expanded Disability Status Scores(EDSS), Disease Duration and Somatosensory Evaluation by the Fugl-Meyer sensory score(FMSS). With the voxel-wise methods, RS-fMRI data were analyzed using REST software, to assess the FC of the postcentral gyrus(PoCG). Correlation between clinical variables and the strength of FC was analyzed.
RESULTS: Compared with HC, the left postcentral-based FC showed decreased FC of the right cerebellum_8, lingual lobe and Rolandic operculum gyrus, and increased FC of the left middle frontal lobe. The right postcentral-based FC revealed decreased FC with the right Heschl's gyrus lobule, and increased FC with bilateral middle frontal lobe (p <  0.001, AlphaSim corrected). Correlation analysis revealed that the FC of altered brain regions was associated with FMSS, EDSS and disease duration.
CONCLUSION: The functional connectivity of PoCG at RS-fMRI has multi-network changes in patients with RRMS-SS. This suggests a complex pattern of abnormal connections between the somatosensory network regions and the whole brain. Moreover, the correlation between the FC and the FMSS, such as the left middle frontal lobe and the right PoCG, indicate that these two brain regions play an important role in RRMS-SS.

PMID: 31439243 [PubMed - in process]

Abnormal spontaneous neural activity in the medial prefrontal cortex and right superior temporal gyrus correlates with anhedonia severity in obsessive-compulsive disorder.

Fri, 08/23/2019 - 19:20
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Abnormal spontaneous neural activity in the medial prefrontal cortex and right superior temporal gyrus correlates with anhedonia severity in obsessive-compulsive disorder.

J Affect Disord. 2019 Aug 13;259:47-55

Authors: Xia J, Fan J, Du H, Liu W, Li S, Zhu J, Yi J, Tan C, Zhu X

Abstract
BACKGROUD: Converging evidence indicated the presence of clinically significant anhedonia in patients with obsessive-compulsive disorder (OCD). Studying anhedonia and its neural correlates in OCD may be beneficial in understanding the pathophysiology and treatment of OCD. However, the neural mechanisms that underlie anhedonia in OCD still remain unclear. The present study was designed to bridge this research gap by using resting-state functional magnetic resonance imaging (fMRI).
METHODS: 29 OCD patients with anhedonia (OCD-AH), 31 OCD patients with normal hedonia (OCD-NH), and 30 healthy controls (HC) received the fMRI scan. The low-frequency fluctuation (ALFF) approach was applied to compare spontaneous neural activity among the three groups. Relationships between the regional ALFFs and anhedonia levels were examined in OCD patients.
RESULT: OCD-AH and OCD-NH manifested overlapping but partially distinct brain alterations. Notably, compared to OCD-NH, the OCD-AH showed decreased ALFF in right superior temporal gyrus (STG) and increased ALFF in medial prefontal cortex (MPFC). Moreover, ALFF values in the right STG were negatively correlated with social anhedonia severity, and ALFFs in the MPFC were positively correlated with both physical and social anhedonia severity in patients with OCD.
LIMITATIONS: Relatively small sample size; ALFF could not provide more holistic information of brain network.
CONCLUSION: The present study revealed that abnormal spontaneous neural activity in MPFC is associated with both physical and social anhedonia, while altered intrinsic brain function in right STG is specifically associated with social anhedonia in OCD. These findings contribute to our understandings of the neurobiological mechanisms underlying anhedonia in OCD.

PMID: 31437701 [PubMed - as supplied by publisher]

Antidepressant and antisuicidal effects of ketamine on the functional connectivity of prefrontal cortex-related circuits in treatment-resistant depression: A double-blind, placebo-controlled, randomized, longitudinal resting fMRI study.

Fri, 08/23/2019 - 19:20
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Antidepressant and antisuicidal effects of ketamine on the functional connectivity of prefrontal cortex-related circuits in treatment-resistant depression: A double-blind, placebo-controlled, randomized, longitudinal resting fMRI study.

J Affect Disord. 2019 Aug 14;259:15-20

Authors: Chen MH, Lin WC, Tu PC, Li CT, Bai YM, Tsai SJ, Su TP

Abstract
BACKGROUND: Increasing evidence suggests that infusion of a subanesthetic dose of ketamine exerts antidepressant and antisuicidal effects in patients with treatment-resistant depression (TRD).
AIMS: In this investigation, we used the resting functional connectivity magnetic resonance imaging (fcMRI) to determine the effects of ketamine on the functional connectivity (FC) of prefrontal cortex (PFC)-related circuits in patients with TRD.
METHODS: Forty-eight patients with TRD were recruited and randomly divided into three groups on the basis of ketamine infusion dose: 0.5 mg/kg (standard dose), 0.2 mg/kg (low dose), or normal saline (a placebo infusion). Resting functional MRI data and clinical data were recorded at the baseline and on the third day after ketamine infusion treatment.
RESULTS: The standard-dose group showed a reduction in the FC of the left dorsal anterior cingulate cortex (dACC) and right dorsolateral (dl)PFC with the other frontal regions. The low-dose group demonstrated a more pervasive reduction of FC in the bilateral dACC with other frontal and parietal regions. A negative correlation was observed between the reduction in suicidal ideation and the reduction in the FC between the left dACC and right ACC regions in the standard-dose group, whereas a positive correlation was observed between the reduction in suicidal ideation and the increase in the FC between the right dlPFC and left superior parietal region in the low-dose group.
CONCLUSIONS: Our results support the hypothesis that PFC-related circuit modulation is crucial to the antidepressant and antisuicidal effects of the ketamine infusion treatment.

PMID: 31437695 [PubMed - as supplied by publisher]

Experience-dependent neuroplasticity in trained musicians modulates the effects of chronic pain on insula-based networks - A resting-state fMRI study.

Fri, 08/23/2019 - 19:20
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Experience-dependent neuroplasticity in trained musicians modulates the effects of chronic pain on insula-based networks - A resting-state fMRI study.

Neuroimage. 2019 Aug 19;:116103

Authors: Zamorano AM, Montoya P, Cifre I, Vuust P, Riquelme I, Kleber B

Abstract
Recent resting-state fMRI studies associated extensive musical training with increased insula-based connectivity in large-scale networks involved in salience, emotion, and higher-order cognitive processes. Similar changes have also been found in chronic pain patients, suggesting that both types of experiences can have comparable effects on insula circuitries. Based on these observations, the current study asked the question whether, and if so in what way, different forms of experience-dependent neuroplasticity may interact. Here we assessed insula-based connectivity during fMRI resting-state between musicians and non-musicians both with and without chronic pain, and correlated the results with clinical pain duration and intensity. As expected, insula connectivity was increased in chronic pain non-musicians relative to healthy non-musicians (with cingulate cortex and supplementary motor area), yet no differences were found between chronic pain non-musicians and healthy musicians. In contrast, musicians with chronic pain showed decreased insula connectivity relative to both healthy musicians (with sensorimotor and memory regions) and chronic pain non-musicians (with the hippocampus, inferior temporal gyrus, and orbitofrontal cortex), as well as lower pain-related inferences with daily activities. Pain duration correlated positively with insula connectivity only in non-musicians, whereas pain intensity exhibited distinct relationships across groups. We conclude that although music-related sensorimotor training and chronic pain, taken in isolation, can lead to increased insula-based connectivity, their combination may lead to higher-order plasticity (metaplasticity) in chronic pain musicians, engaging brain mechanisms that can modulate the consequences of maladaptive experience-dependent neural reorganization (i.e., pain chronification).

PMID: 31437550 [PubMed - as supplied by publisher]

EPI distortion correction for concurrent human brain stimulation and imaging at 3T.

Fri, 08/23/2019 - 04:19

EPI distortion correction for concurrent human brain stimulation and imaging at 3T.

J Neurosci Methods. 2019 Aug 18;:108400

Authors: Oh H, Kim JH, Yau JM

Abstract
BACKGROUND: Transcranial magnetic stimulation (TMS) can be paired with functional magnetic resonance imaging (fMRI) in concurrent TMS-fMRI experiments. These multimodal experiments enable causal probing of network architecture in the human brain which can complement alternative network mapping approaches. Critically, merely introducing the TMS coil into the scanner environment can sometimes produce substantial magnetic field inhomogeneities and spatial distortions which limit the utility of concurrent TMS-fMRI.
METHOD AND RESULTS: We assessed the efficacy of point spread function corrected echo planar imaging (PSF-EPI) in correcting for the field inhomogeneities associated with a TMS coil at 3 T. In phantom and brain scans, we quantitatively compared the coil-induced distortion artifacts measured in EPI scans with and without PSF correction. We found that the application of PSF corrections to the EPI data significantly improved signal-to-noise and reduced distortions. In phantom scans with the PSF-EPI sequence, we also characterized the temporal profile of dynamic artifacts associated with TMS delivery and found that image quality remained high as long as the TMS pulse preceded the RF excitation pulses by at least 50 ms. Lastly, we validated the PSF-EPI sequence in human brain scans involving TMS and motor behavior as well as resting state fMRI scans.
CONCLUSIONS: Our collective results demonstrate the potential benefits of PSF-EPI for concurrent TMS-fMRI when coil-related artifacts are a concern. The ability to collect high quality resting state fMRI data in the same session as the concurrent TMS-fMRI experiment offers a unique opportunity to interrogate network architecture in the human brain.

PMID: 31434000 [PubMed - as supplied by publisher]

Altered amygdala resting-state functional connectivity following acupuncture stimulation at BaiHui (GV20) in first-episode drug-Naïve major depressive disorder.

Fri, 08/23/2019 - 04:19
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Altered amygdala resting-state functional connectivity following acupuncture stimulation at BaiHui (GV20) in first-episode drug-Naïve major depressive disorder.

Brain Imaging Behav. 2019 Aug 20;:

Authors: Duan G, He Q, Pang Y, Chen W, Liao H, Liu H, Tan L, Liu Y, Tao J, Zhang J, Wei X, Sun P, Liu P, Deng D

Abstract
Amygdala is an important locus of dysfunction implicated in major depressive disorder(MDD). Aberrant amygdala networks(AN) had been reported in resting-state functional magnetic resonance imaging (rs-fMRI) study. The safety and efficacy of acupuncture treatment for MDD have been verified in previous clinical studies. This study is aimed to investigate whether acupuncture at GV20 could modulate the abnormal AN of patients with the first-episode, drug-naïve MDD by using rs-fMRI combined with functional connectivity (FC) method. Thirty MDD patient underwent 6-min rs-fMRI scans respectively before and after 20-min electro-acupuncture stimulate(EAS) at GV20. Twenty-nine healthy subjects underwent only a 6-min rs-fMRI scan. Based on the amygdala as the seed region, FC method was adopted to examine abnormal AN in patients by comparing with healthy subjects and to evaluate the influence of EAS on intrinsic connectivity within the AN in patients with MDD. Compared to healthy subjects, MDD patients had aberrant intrinsic AN which mainly showed increased FC between amygdala and hippocampus, precuneus, precentral gyrus and angular gyrus, as well as decreased FC between amygdala and orbital frontal cortex(OFC). Moreover, our results indicated that EAS at GV20 induced increased/decreased FC between amygdala and certain regions in MDD patients. In addition, the intrinsic amygdala FC within other certain brain regions in MDD patients were regulated by EAS at GV20. The abnormal AN of MDD patients could be modulated by EAS at GV20. Our findings may further provide the potential imaging evidence to support the modulatory mechanisms of acupuncture on MDD.

PMID: 31432318 [PubMed - as supplied by publisher]

"Resting-state fMRI in Parkinson's disease patients with cognitive impairment: A meta-analysis": Answer to Wang and colleagues.

Fri, 08/23/2019 - 04:19
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"Resting-state fMRI in Parkinson's disease patients with cognitive impairment: A meta-analysis": Answer to Wang and colleagues.

Parkinsonism Relat Disord. 2019 Jul 12;:

Authors: Wolters AF, van de Weijer SCF, Leentjens AFG, Duits AA, Jacobs HIL, Kuijf ML

PMID: 31431324 [PubMed - as supplied by publisher]

Identification of traits and functional connectivity-based neurotraits of chronic pain.

Wed, 08/21/2019 - 22:16
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Identification of traits and functional connectivity-based neurotraits of chronic pain.

PLoS Biol. 2019 Aug;17(8):e3000349

Authors: Vachon-Presseau E, Berger SE, Abdullah TB, Griffith JW, Schnitzer TJ, Apkarian AV

Abstract
Psychological and personality factors, socioeconomic status, and brain properties all contribute to chronic pain but have essentially been studied independently. Here, we administered a broad battery of questionnaires to patients with chronic back pain (CBP) and collected repeated sessions of resting-state functional magnetic resonance imaging (fMRI) brain scans. Clustering and network analyses applied on the questionnaire data revealed four orthogonal dimensions accounting for 56% of the variance and defining chronic pain traits. Two of these traits-Pain-trait and Emote-trait-were associated with back pain characteristics and could be related to distinct distributed functional networks in a cross-validation procedure, identifying neurotraits. These neurotraits showed good reliability across four fMRI sessions acquired over five weeks. Further, traits and neurotraits all related to the income, emphasizing the importance of socioeconomic status within the personality space of chronic pain. Our approach is a first step in providing metrics aimed at unifying the psychology and the neurophysiology of chronic pain applicable across diverse clinical conditions.

PMID: 31430270 [PubMed - in process]

Altered Spontaneous Brain Activity of Children with Unilateral Amblyopia: A Resting State fMRI Study.

Wed, 08/21/2019 - 22:16
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Altered Spontaneous Brain Activity of Children with Unilateral Amblyopia: A Resting State fMRI Study.

Neural Plast. 2019;2019:3681430

Authors: Dai P, Zhang J, Wu J, Chen Z, Zou B, Wu Y, Wei X, Xiao M

Abstract
Objective: This study is aimed at investigating differences in local brain activity and functional connectivity (FC) between children with unilateral amblyopia and healthy controls (HCs) by using resting state functional magnetic resonance imaging (rs-fMRI).
Methods: Local activity and FC analysis methods were used to explore the altered spontaneous brain activity of children with unilateral amblyopia. Local brain function analysis methods included the amplitude of low-frequency fluctuation (ALFF). FC analysis methods consisted of the FC between the primary visual cortex (PVC-FC) and other brain regions and the FC network between regions of interest (ROIs-FC) selected by independent component analysis.
Results: The ALFF in the bilateral frontal, temporal, and occipital lobes in the amblyopia group was lower than that in the HCs. The weakened PVC-FC was mainly concentrated in the frontal lobe and the angular gyrus. The ROIs-FC between the default mode network, salience network, and primary visual cortex network (PVCN) were significantly reduced, whereas the ROIs-FC between the PVCN and the high-level visual cortex network were significantly increased in amblyopia.
Conclusions: Unilateral amblyopia may reduce local brain activity and FC in the dorsal and ventral visual pathways and affect the top-down attentional control. Amblyopia may also alter FC between brain functional networks. These findings may help understand the pathological mechanisms of children with amblyopia.

PMID: 31428144 [PubMed - in process]

Prediction of neurocognition in youth from resting state fMRI.

Wed, 08/21/2019 - 22:16
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Prediction of neurocognition in youth from resting state fMRI.

Mol Psychiatry. 2019 Aug 19;:

Authors: Sripada C, Rutherford S, Angstadt M, Thompson WK, Luciana M, Weigard A, Hyde LH, Heitzeg M

Abstract
Difficulties with higher-order cognitive functions in youth are a potentially important vulnerability factor for the emergence of problematic behaviors and a range of psychopathologies. This study examined 2013 9-10 year olds in the first data release from the Adolescent Brain Cognitive Development 21-site consortium study in order to identify resting state functional connectivity patterns that predict individual-differences in three domains of higher-order cognitive functions: General Ability, Speed/Flexibility, and Learning/Memory. For General Ability scores in particular, we observed consistent cross-site generalizability, with statistically significant predictions in 14 out of 15 held-out sites. These results survived several tests for robustness including replication in split-half analysis and in a low head motion subsample. We additionally found that connectivity patterns involving task control networks and default mode network were prominently implicated in predicting differences in General Ability across participants. These findings demonstrate that resting state connectivity can be leveraged to produce generalizable markers of neurocognitive functioning. Additionally, they highlight the importance of task control-default mode network interconnections as a major locus of individual differences in cognitive functioning in early adolescence.

PMID: 31427753 [PubMed - as supplied by publisher]

Characterization of Cerebellar Atrophy and Resting State Functional Connectivity Patterns in Sporadic Adult-Onset Ataxia of Unknown Etiology (SAOA).

Tue, 08/20/2019 - 19:13
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Characterization of Cerebellar Atrophy and Resting State Functional Connectivity Patterns in Sporadic Adult-Onset Ataxia of Unknown Etiology (SAOA).

Cerebellum. 2019 Aug 17;:

Authors: Jiang X, Faber J, Giordano I, Machts J, Kindler C, Dudesek A, Speck O, Kamm C, Düzel E, Jessen F, Spottke A, Vielhaber S, Boecker H, Klockgether T, Scheef L

Abstract
Sporadic adult-onset ataxia of unknown etiology (SAOA) is a non-genetic neurodegenerative disorder of the cerebellum of unknown cause which manifests with progressive ataxia without severe autonomic failure. Although SAOA is associated with cerebellar degeneration, little is known about the specific cerebellar atrophy pattern in SAOA. Thirty-seven SAOA patients and 49 healthy controls (HCs) were included at two centers. We investigated the structural and functional characteristics of SAOA brains using voxel-based morphometry (VBM) and resting-state functional imaging (rs-fMRI). In order to examine the functional consequence of structural cerebellar alterations, the amplitude of low-frequency fluctuation (ALFF) and degree centrality (DC) were analyzed, and then assessed their relation with disease severity, disease duration, and age of onset within these regions. Group differences were investigated using two-sample t tests, controlling for age, gender, site, and the total intracranial volume. The VBM analysis revealed a significant, mostly bilateral reduction of local gray matter (GM) volume in lobules I-V, V, VI, IX, X, and vermis VIII a/b in SAOA patients, compared with HCs. The GM volume loss in these regions was significantly associated with disease severity, disease duration, and age of onset. The disease-related atrophy regions did not show any functional alternations compared with HCs but were functionally characterized by high ALFF and poor DC compared with intact cerebellar regions. Our data revealed volume reduction in SAOA in cerebellar regions that are known to be involved in motor and somatosensory processing, corresponding with the clinical phenotype of SAOA. Our data suggest that the atrophy occurs in those cerebellar regions which are characterized by high ALFF and poor DC. Further studies have to show if these findings are specific for SAOA, and if they can be used to predict disease progression.

PMID: 31422550 [PubMed - as supplied by publisher]

Transcranial direct current stimulation facilitates response inhibition through dynamic modulation of the fronto-basal ganglia network.

Tue, 08/20/2019 - 19:13
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Transcranial direct current stimulation facilitates response inhibition through dynamic modulation of the fronto-basal ganglia network.

Brain Stimul. 2019 Aug 07;:

Authors: Sandrini M, Xu B, Volochayev R, Awosika O, Wang WT, Butman JA, Cohen LG

Abstract
BACKGROUND: Response inhibition refers to the ability to stop an on-going action quickly when it is no longer appropriate. Previous studies showed that transcranial direct current stimulation (tDCS) applied with the anode over the right inferior frontal cortex (rIFC), a critical node of the fronto-basal ganglia inhibitory network, improved response inhibition. However, the tDCS effects on brain activity and network connectivity underlying this behavioral improvement are not known.
OBJECTIVE: This study aimed to address the effects of tDCS applied with the anode over the rIFC on brain activity and network functional connectivity underlying the behavioral change in response inhibition.
METHODS: Thirty participants performed a stop-signal task in a typical laboratory setting as a baseline during the first study visit (i.e., Session 1). In the second visit (at least 24 h after Session 1), all participants underwent resting-state functional magnetic resonance imaging (rsfMRI) scans before and after 1.5 mA tDCS (Anodal or Sham). Immediately following the post-tDCS rsfMRI, participants performed the same stop-signal task as in Session 1 during an event-related fMRI (efMRI) scan in a 3T scanner. Changes in task performance, i.e., the stop-signal response time (SSRT), a measure of response inhibition efficiency, was determined relative to the participants' own baseline performance in Session 1.
RESULTS: Consistent with previous findings, Anodal tDCS facilitated the SSRT. efMRI results showed that Anodal tDCS strengthened the functional connectivity between right pre-supplementary motor area (rPreSMA) and subthalamic nuclei during Stop responses. rsfMRI revealed changes in intrinsic connectivity between rIFC and caudate, and between rIFC, rPreSMA, right inferior parietal cortex (rIPC), and right dorsolateral prefrontal cortex (rDLPFC) after Anodal tDCS. In addition, corresponding to the regions of rsfMRI connectivity change, the efMRI BOLD signal in the rDLPFC and rIPC during Go responses accounted for 74% of the variance in SSRT after anodal tDCS, indicating an effect of tDCS on the Go-Stop process.
CONCLUSION: These results indicate that tDCS with the anode over the rIFC facilitates response inhibition by modulating neural activity and functional connectivity in the fronto-basal ganglia as well as rDLPFC and rIPC as an integral part of the response inhibition network.

PMID: 31422052 [PubMed - as supplied by publisher]

Graph theory and network topological metrics may be the potential biomarker in Parkinson's disease.

Tue, 08/20/2019 - 19:13
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Graph theory and network topological metrics may be the potential biomarker in Parkinson's disease.

J Clin Neurosci. 2019 Aug 13;:

Authors: Huang LC, Wu PA, Lin SZ, Pang CY, Chen SY

Abstract
This study used Voxel-based morphometry (VBM) and resting-state functional magnetic resonance imaging (rs-fMRI) to investigate changes in brain structure and networks functional connectivity, respectively. We tried to identify the potential biomarkers in Parkinson's disease (PD) progression. We recruited nine idiopathic PD patients and seven healthy control participants (HC group) who were age-matched to undergo T1-weighted images and rs-fMRI on 1.5 T. Brain structure differences were analyzed by VBM. Topological properties of networks functional connectivity were analyzed by graph theory. Thirty-two nodes of 8 networks and 133 nodes of interest then were identified with graph theory approaches. VBM examinations showed significant decreases of brain gray matter regions including the left temporal lobe, left middle temporal, middle temporal gyrus, parietal lobe, postcentral gyrus, left inferior parietal gyrus, medial frontal gyrus and supplement motor area in PD patients compared to the HC group. The 32 ROI of networks topological metrics measurement in PD demonstrated increases of global efficiency, cost, and degree in frontoparietal PPC (R) network, but decreases of local efficiency, clustering coefficient, and average path length in salience ACC, dorsal attention FEF (L), and salience aInsula (R) networks, respectively. All 165 ROI connectomes showed eight connections intensity changes, that decrease in OP r to frontoparietal PPC, putamen r to cereb11, and SFG l to Ver8 in PD. These results suggest that the graph theory and the network topological metrics measurement may be the potential biomarkers in PD to evaluate the disease progress and to monitor the therapeutic results.

PMID: 31420273 [PubMed - as supplied by publisher]

Memory and motor control in patients with psychogenic nonepileptic seizures.

Sat, 08/17/2019 - 19:09
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Memory and motor control in patients with psychogenic nonepileptic seizures.

Epilepsy Behav. 2019 Aug 13;98(Pt A):279-284

Authors: Dienstag A, Ben-Naim S, Gilad M, Ekstein D, Arzy S, Eitan R

Abstract
Psychogenic nonepileptic seizures (PNES) are of the most elusive phenomena in epileptology. Patients with PNES present episodes resembling epileptic seizures in their semiology yet lacking the underlying epileptic brain activity. These episodes are assumed to be related to psychological distress from past trauma, yet the underlying mechanism of this manifestation is still unknown. Using resting-state functional magnetic resonance imaging (fMRI), we investigated functional connectivity changes within and between large-scale brain networks in 9 patients with PNES, compared with a group of 13 age- and gender-matched healthy controls. Functional magnetic resonance imaging analyses identified functional connectivity disturbances between the medial temporal lobe (MTL) and the sensorimotor cortex and between the MTL and ventral attention networks in patients with PNES. Within network connectivity reduction was found within the visual network. Our findings suggest that PNES relate to changes in connectivity in between areas that are involved in memory processing and motor activity and attention control. These results may shed new light on the way by which traumatic memories may relate to PNES.

PMID: 31419649 [PubMed - as supplied by publisher]

Degrees of lateralisation in semantic cognition: Evidence from intrinsic connectivity.

Sat, 08/17/2019 - 19:09
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Degrees of lateralisation in semantic cognition: Evidence from intrinsic connectivity.

Neuroimage. 2019 Aug 13;:116089

Authors: Gonzalez Alam TR, Karapanagiotidis T, Smallwood J, Jefferies E

Abstract
The semantic network is thought to include multiple components, including heteromodal conceptual representations and semantic control processes that shape retrieval to suit the circumstances. Much of this network is strongly left-lateralised; however, work to date has not considered whether separable components of semantic cognition have different degrees of lateralisation. This study examined intrinsic connectivity of four regions implicated in heteromodal semantic cognition, identified using large scale meta-analyses: two sites which have been argued to act as heteromodal semantic hubs in anterior temporal lobe (ATL) and angular gyrus (AG); and two sites implicated in semantic control in inferior frontal (IFG) and posterior middle temporal gyri (pMTG). We compared the intrinsic connectivity of these sites in left hemisphere (LH) and right hemisphere (RH), and linked individual differences in the strength of within- and between-hemisphere connectivity from left-lateralised seeds to performance on semantic tasks, in a sample of 196 healthy volunteers. ATL showed more symmetrical patterns of intrinsic connectivity than the other three sites. The connectivity between IFG and pMTG was stronger in the LH than the RH, suggesting that the semantic control network is strongly left-lateralised. The degree of hemispheric lateralization also predicted behaviour: participants with stronger intrinsic connectivity within the LH had better semantic performance, while those with stronger intrinsic connectivity between left pMTG and homotopes of semantic regions in the RH performed more poorly on judgements of weak associations, which require greater control. Stronger connectivity between left AG and visual cortex was also linked to poorer perceptual performance. Overall, our results show that hemispheric lateralisation is particularly important for the semantic control network, and that this lateralisation has contrasting functional consequences for the retrieval of dominant and subordinate aspects of knowledge.

PMID: 31419614 [PubMed - as supplied by publisher]

A deconvolution algorithm for multi-echo functional MRI: Multi-echo Sparse Paradigm Free Mapping.

Sat, 08/17/2019 - 19:09
Related Articles

A deconvolution algorithm for multi-echo functional MRI: Multi-echo Sparse Paradigm Free Mapping.

Neuroimage. 2019 Aug 13;:116081

Authors: Caballero-Gaudes C, Moia S, Panwar P, Bandettini PA, Gonzalez-Castillo J

Abstract
This work introduces a novel algorithm for deconvolution of the BOLD signal in multi-echo fMRI data: Multi-echo Sparse Paradigm Free Mapping (ME-SPFM). Assuming a linear dependence of the BOLD percent signal change on the echo time (TE) and using sparsity-promoting regularized least squares estimation, ME-SPFM yields voxelwise time-varying estimates of the changes in the apparent transverse relaxation (ΔR2∗) without prior knowledge of the timings of individual BOLD events. Our results in multi-echo fMRI data collected during a multi-task event-related paradigm at 3 Tesla demonstrate that the maps of R2∗ changes obtained with ME-SPFM at the times of the stimulus trials show high spatial and temporal concordance with the activation maps and BOLD signals obtained with standard model-based analysis. This method yields estimates of ΔR2∗ having physiologically plausible values. Owing to its ability to blindly detect events, ME-SPFM also enables us to map ΔR2∗ associated with spontaneous, transient BOLD responses occurring between trials. This framework is a step towards deciphering the dynamic nature of brain activity in naturalistic paradigms, resting-state or experimental paradigms with unknown timing of the BOLD events.

PMID: 31419613 [PubMed - as supplied by publisher]