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Genetic and Environmental Influence on the Human Functional Connectome.

Tue, 11/12/2019 - 21:22

Genetic and Environmental Influence on the Human Functional Connectome.

Cereb Cortex. 2019 Nov 11;:

Authors: Reineberg AE, Hatoum AS, Hewitt JK, Banich MT, Friedman NP

Abstract
Detailed mapping of genetic and environmental influences on the functional connectome is a crucial step toward developing intermediate phenotypes between genes and clinical diagnoses or cognitive abilities. We analyzed resting-state functional magnetic resonance imaging data from two adult twin samples (Nos = 446 and 371) to quantify genetic and environmental influence on all pairwise functional connections between 264 brain regions (~35 000 functional connections). Nonshared environmental influence was high across the whole connectome. Approximately 14-22% of connections had nominally significant genetic influence in each sample, 4.6% were significant in both samples, and 1-2% had heritability estimates greater than 30%. Evidence of shared environmental influence was weak. Genetic influences on connections were distinct from genetic influences on a global summary measure of the connectome, network-based estimates of connectivity, and movement during the resting-state scan, as revealed by a novel connectome-wide bivariate genetic modeling procedure. The brain's genetic organization is diverse and not as one would expect based solely on structure evident in nongenetically informative data or lower resolution data. As follow-up, we make novel classifications of functional connections and examine highly localized connections with particularly strong genetic influence. This high-resolution genetic taxonomy of brain connectivity will be useful in understanding genetic influences on brain disorders.

PMID: 31711120 [PubMed - as supplied by publisher]

The effect of chronic neuroglycopenia on resting state networks in GLUT1 syndrome across the lifespan.

Tue, 11/12/2019 - 21:22

The effect of chronic neuroglycopenia on resting state networks in GLUT1 syndrome across the lifespan.

Hum Brain Mapp. 2019 Nov 11;:

Authors: Vaudano AE, Olivotto S, Ruggieri A, Gessaroli G, Talami F, Parmeggiani A, De Giorgis V, Veggiotti P, Meletti S

Abstract
Glucose transporter type I deficiency syndrome (GLUT1DS) is an encephalopathic disorder due to a chronic insufficient transport of glucose into the brain. PET studies in GLUT1DS documented a widespread cortico-thalamic hypometabolism and a signal increase in the basal ganglia, regardless of age and clinical phenotype. Herein, we captured the pattern of functional connectivity of distinct striatal, cortical, and cerebellar regions in GLUT1DS (10 children, eight adults) and in healthy controls (HC, 19 children, 17 adults) during rest. Additionally, we explored for regional connectivity differences in GLUT1 children versus adults and according to the clinical presentation. Compared to HC, GLUT1DS exhibited increase connectivity within the basal ganglia circuitries and between the striatal regions with the frontal cortex and cerebellum. The excessive connectivity was predominant in patients with movement disorders and in children compared to adults, suggesting a correlation with the clinical phenotype and age at fMRI study. Our findings highlight the primary role of the striatum in the GLUT1DS pathophysiology and confirm the dependency of symptoms to the patients' chronological age. Despite the reduced chronic glucose uptake, GLUT1DS exhibit increased connectivity changes in regions highly sensible to glycopenia. Our results may portrait the effect of neuroprotective brain strategy to overcome the chronic poor energy supply during vulnerable ages.

PMID: 31710770 [PubMed - as supplied by publisher]

Interindividual Covariations of Brain Functional and Structural Connectivities Are Decomposed Blindly to Subnetworks: A Fusion-Based Approach.

Tue, 11/12/2019 - 21:22

Interindividual Covariations of Brain Functional and Structural Connectivities Are Decomposed Blindly to Subnetworks: A Fusion-Based Approach.

J Magn Reson Imaging. 2019 Nov 11;:

Authors: Keyvanfard F, Nasiraei-Moghaddam A, Hagmann P

Abstract
BACKGROUND: Studying brain interindividual variations has recently gained interest to understand different human behaviors. It is particularly important to investigate how a variety of functional differences can be associated with a few differences in brain structure. It would be more meaningful if such an investigation is performed jointly at the network level to connect structural building blocks to functional variations modules.
PURPOSE: To decompose the interindividual variations of brain in the form of mutual functional and structural subnetworks based on a data-driven approach.
STUDY TYPE: Retrospective.
POPULATION: In all, 92 healthy subjects.
FIELD STRENGTH/SEQUENCE: 3T Siemens/MPRAGE, diffusion spectrum imaging (DSI) acquisition protocol, gradient echo sequence.
ASSESSMENT: The proposed approach was quantitatively assessed by examining the consistency of the networks against the number of subjects. Distribution of the obtained components across brain regions was studied and their relevance was qualitatively evaluated by comparison to variations that had been independently reported previously.
STATISTICAL TESTS: Permutation test, two-sample t-test, Pearson correlation coefficient.
RESULTS: Ten pairs of components including functional and structural subnetworks were obtained. Assessing the reproducibility of the proposed method with respect to the sample size indicated reliable detection of connections (above 70%) for all components by reducing the number of subjects to 70. Specifically, one of the functional subnetworks can be used to distinguish left-handed from right-handed people (P = 2.6 × 10-8 ) as the basic interindividual variation. This functional subnetwork has a main overlap (40.18%) with the somatomotor system and the Broca part was captured in its corresponding structural subnetwork.
DATA CONCLUSION: These results show that the proposed method can reveal intersubject variations systematically through a mathematical algorithm of joint independent component analysis. They confirm that intersubject variations can be expressed in the form of building blocks. In contrast to the functional subnetworks that were discoverable independently, their structural counterparts were found and interpreted only in conjunction with the functional subnetworks.
LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019.

PMID: 31710412 [PubMed - as supplied by publisher]

Primary Open Angle Glaucoma Is Associated With Functional Brain Network Reorganization.

Tue, 11/12/2019 - 21:22
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Primary Open Angle Glaucoma Is Associated With Functional Brain Network Reorganization.

Front Neurol. 2019;10:1134

Authors: Minosse S, Garaci F, Martucci A, Lanzafame S, Di Giuliano F, Picchi E, Cesareo M, Mancino R, Guerrisi M, Pistolese CA, Floris R, Nucci C, Toschi N

Abstract
Background: Resting-state functional magnetic resonance imaging (rs-fMRI) is commonly employed to study changes in functional brain connectivity. The recent hypothesis of a brain involvement in primary open angle Glaucoma has sprung interest for neuroimaging studies in this classically ophthalmological pathology. Object: We explored a putative reorganization of functional brain networks in Glaucomatous patients, and evaluated the potential of functional network disruption indices as biomarkers of disease severity in terms of their relationship to clinical variables as well as select retinal layer thicknesses. Methods: Nineteen Glaucoma patients and 16 healthy control subjects (age: 50-76, mean 61.0 ± 8.2 years) underwent rs-fMRI examination at 3T. After preprocessing, rs-fMRI time series were parcellated into 116 regions using the Automated Anatomical Labeling atlas and adjacency matrices were computed based on partial correlations. Graph-theoretical measures of integration, segregation and centrality as well as group-wise and subject-wise disruption index estimates (which use regression of graph-theoretical metrics across subjects to quantify overall network changes) were then generated for all subjects. All subjects also underwent Optical Coherence Tomography (OCT) and visual field index (VFI) quantification. We then examined associations between brain network measures and VFI, as well as thickness of retinal nerve fiber layer (RNFL) and macular ganglion cell layer (MaculaGCL). Results: In Glaucoma, group-wise disruption indices were negative for all graph theoretical metrics. Also, we found statistically significant group-wise differences in subject-wise disruption indexes in all local metrics. Two brain regions serving as hubs in healthy controls were not present in the Glaucoma group. Instead, three hub regions were present in Glaucoma patients but not in controls. We found significant associations between all disruption indices and VFI, RNFL as well as MaculaGCL. The disruption index based on the clustering coefficient yielded the best discriminative power for differentiating Glaucoma patients from healthy controls [Area Under the ROC curve (AUC) 0.91, sensitivity, 100%; specificity, 78.95%]. Conclusions: Our findings support a possible relationship between functional brain changes and disease severity in Glaucoma, as well as alternative explanations for motor and cognitive symptoms in Glaucoma, possibly pointing toward an inclusion of this pathology in the heterogeneous group of disconnection syndromes.

PMID: 31708862 [PubMed]

Stereoscopic Rendering via Goggles Elicits Higher Functional Connectivity During Virtual Reality Gaming.

Tue, 11/12/2019 - 21:22
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Stereoscopic Rendering via Goggles Elicits Higher Functional Connectivity During Virtual Reality Gaming.

Front Hum Neurosci. 2019;13:365

Authors: Forlim CG, Bittner L, Mostajeran F, Steinicke F, Gallinat J, Kühn S

Abstract
Virtual reality (VR) simulates real-world scenarios by creating a sense of presence in its users. Such immersive scenarios lead to behavior that is more similar to that displayed in real world settings, which may facilitate the transfer of knowledge and skills acquired in VR to similar real world situations. VR has already been used in education, psychotherapy, rehabilitation and it comes as an appealing choice for training intervention purposes. The aim of the present study was to investigate to what extent VR technology for games presented via goggles can be used in a magnetic resonance imaging scanner (MRI), addressing the question of whether brain connectivity differs between VR stimulation via goggles and a presentation from a screen via mirror projection. Moreover, we wanted to investigate whether stereoscopic goggle stimulation, where both eyes receive different visual input, would elicit stronger brain connectivity than a stimulation in which both eyes receive the same visual input (monoscopic). To our knowledge, there is no previous research using games and functional connectivity (FC) in MRI to address this question. Multiple analyses approaches were taken so that different aspects of brain connectivity could be covered: fractional low-frequency fluctuation, independent component analysis (ICA), seed-based FC (SeedFC) and graph analysis. In goggle presentation (mono and stereoscopic) as contrasted to screen, we found differences in brain activation in left cerebellum and postcentral gyrus as well as differences in connectivity in the visual cortex and frontal inferior cortex [when focusing on the visual and default mode network (DMN)]. When considering connectivity in specific areas of interest, we found higher connectivity between bilateral superior frontal cortex and the temporal lobe, as well as bilateral inferior parietal cortex with right calcarine and right lingual cortex. Furthermore, we found superior frontal cortex and insula/putamen to be more strongly connected in goggle stereoscopic vs. goggle monoscopic, in line with our hypothesis. We assume that the condition that elicits higher brain connectivity values should be most suited for long-term brain training interventions given that, extended training under these conditions could permanently improve brain connectivity on a functional as well as on a structural level.

PMID: 31708759 [PubMed]

Computer-Based Cognitive Training Improves Brain Functional Connectivity in the Attentional Networks: A Study With Primary School-Aged Children.

Tue, 11/12/2019 - 21:22
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Computer-Based Cognitive Training Improves Brain Functional Connectivity in the Attentional Networks: A Study With Primary School-Aged Children.

Front Behav Neurosci. 2019;13:247

Authors: Sánchez-Pérez N, Inuggi A, Castillo A, Campoy G, García-Santos JM, González-Salinas C, Fuentes LJ

Abstract
We have shown that a computer-based program that trains schoolchildren in cognitive tasks that mainly tap working memory (WM), implemented by teachers and integrated into school routine, improved cognitive and academic skills compared with an active control group. Concretely, improvements were observed in inhibition skills, non-verbal IQ, mathematics and reading skills. Here, we focus on a subsample from the overarching study who volunteered to be scanned using a resting state fMRI protocol before and 6-month after training. This sample reproduced the aforementioned behavioral effects, and brain functional connectivity changes were observed within the attentional networks (ATN), linked to improvements in inhibitory control. Findings showed stronger relationships between inhibitory control scores and functional connectivity in a right middle frontal gyrus (MFG) cluster in trained children compared to children from the control group. Seed-based analyses revealed that connectivity between the r-MFG and homolateral parietal and superior temporal areas were more strongly related to inhibitory control in trained children compared to the control group. These findings highlight the relevance of computer-based cognitive training, integrated in real-life school environments, in boosting cognitive/academic performance and brain functional connectivity.

PMID: 31708757 [PubMed]

The Relationship Between Local Field Potentials and the Blood-Oxygenation-Level Dependent MRI Signal Can Be Non-linear.

Tue, 11/12/2019 - 21:22
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The Relationship Between Local Field Potentials and the Blood-Oxygenation-Level Dependent MRI Signal Can Be Non-linear.

Front Neurosci. 2019;13:1126

Authors: Zhang X, Pan WJ, Keilholz S

Abstract
Functional magnetic resonance imaging (fMRI) is currently one of the most important neuroimaging methods in neuroscience. The image contrast in fMRI relies on the blood-oxygenation-level dependent (BOLD) signal, which indirectly reflects neural activity through neurovascular coupling. Because the mechanism that links the BOLD signal to neural activities involves multiple complicated processes, where neural activity, regional metabolism, hemodynamics, and the BOLD signal are all inter-connected, understanding the quantitative relationship between the BOLD signal and the underlying neural activities is crucial for interpreting fMRI data. Simultaneous local field potential (LFP) and fMRI recordings provide a method to study neurovascular coupling. There were a few studies that have shown non-linearities in stimulus related responses, but whether there is any non-linearity in LFP-BOLD relationship at rest has not been specifically quantified. In this study, we analyzed the simultaneous LFP and resting state-fMRI data acquired from rodents, and found that the relationship between LFP and BOLD is non-linear under isoflurane (ISO) anesthesia, but linear under dexmedetomidine (DMED) anesthesia. Subsequent analysis suggests that such non-linearity may come from the non-Gaussian distribution of LFP power and switching from LFP power to LFP amplitude can alleviate the problem to a degree. We also confirmed that, despite the non-linearity in the mean LFP-BOLD curve, the Pearson correlation between the two signals is relatively unaffected.

PMID: 31708727 [PubMed]

Cerebellar Functional Anatomy: a Didactic Summary Based on Human fMRI Evidence.

Tue, 11/12/2019 - 00:19
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Cerebellar Functional Anatomy: a Didactic Summary Based on Human fMRI Evidence.

Cerebellum. 2019 Nov 09;:

Authors: Guell X, Schmahmann J

Abstract
The cerebellum is relevant for virtually all aspects of behavior in health and disease. Cerebellar findings are common across all kinds of neuroimaging studies of brain function and dysfunction. A large and expanding body of literature mapping motor and non-motor functions in the healthy human cerebellar cortex using fMRI has served as a tool for interpreting these findings. For example, results of cerebellar atrophy in Alzheimer's disease in caudal aspects of Crus I/II and medial lobule IX can be interpreted by consulting a large number of task, resting-state, and gradient-based reports that describe the functional characteristics of these specific aspects of the cerebellar cortex. Here, we provide a concise summary that outlines organizational principles observed consistently across these studies of normal cerebellar organization. This basic framework may be useful for investigators performing or reading experiments that require a functional interpretation of human cerebellar topography.

PMID: 31707620 [PubMed - as supplied by publisher]

Altered spontaneous brain activity in obsessive-compulsive personality disorder.

Tue, 11/12/2019 - 00:19
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Altered spontaneous brain activity in obsessive-compulsive personality disorder.

Compr Psychiatry. 2019 Nov 05;96:152144

Authors: Lei H, Huang L, Li J, Liu W, Fan J, Zhang X, Xia J, Zhao K, Zhu X, Rao H

Abstract
BACKGROUND: Obsessive-compulsive personality disorder (OCPD) is one of the most prevalent personality disorders in general population. However, neural mechanisms underlying OCPD remain elusive. The aim of this study is to use functional magnetic resonance imaging (fMRI) to examine whether OCPD patients will exhibit altered spontaneous brain activity as compared to healthy controls (HC).
METHODS: Resting-state fMRI data were acquired in 37 OCPD patients and 37 matched HC. Amplitudes of low-frequency fluctuation (ALFF) were calculated and compared between the two groups. Correlation analysis was performed between regional ALFF values and OCPD severity scores.
RESULTS: Significant group differences in regional ALFF were found in multiple brain regions. Compared to HCs, OCPD subjects had increased ALFF in bilateral caudate, left precuneus, left insula, and left medial superior frontal gyrus, and decreased ALFF in the right fusiform gyrus and left lingual gyrus. The ALFF values in the left precuneus correlated with OCPD severity scores.
LIMITATIONS: We excluded patients with comorbidity and did not conduct cognitive function assessments. Our findings are also limited to cross-sectional analysis.
CONCLUSIONS: OCPD patients exhibit altered spontaneous neural activity as compared to healthy controls in multiple brain regions, which may reflect different characteristic symptoms of OCPD pathophysiology, including cognitive inflexibility, excessive self-control, lower empathy, and visual attention bias.

PMID: 31707312 [PubMed - as supplied by publisher]

Functional reorganization during the recovery of contralesional target selection deficits after prefrontal cortex lesions in macaque monkeys.

Tue, 11/12/2019 - 00:19
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Functional reorganization during the recovery of contralesional target selection deficits after prefrontal cortex lesions in macaque monkeys.

Neuroimage. 2019 Nov 07;:116339

Authors: Adam R, Johnston K, Menon RS, Everling S

Abstract
Visual extinction has been characterized by the failure to respond to a visual stimulus in the contralesional hemifield when presented simultaneously with an ipsilesional stimulus (Corbetta and Shulman, 2011). Unilateral damage to the macaque frontoparietal cortex commonly leads to deficits in contralesional target selection that resemble visual extinction. Recently, we showed that macaque monkeys with unilateral lesions in the caudal prefrontal cortex (PFC) exhibited contralesional target selection deficits that recovered over 2-4 months (Adam et al., 2019). Here, we investigated the longitudinal changes in functional connectivity (FC) of the frontoparietal network after a small or large right caudal PFC lesion in four macaque monkeys. We collected ultra-high field resting-state fMRI at 7-T before the lesion and at weeks 1-16 post-lesion and compared the functional data with behavioural performance on a free-choice saccade task. We found that the pattern of frontoparietal network FC changes depended on lesion size, such that the recovery of contralesional extinction was associated with an initial increase in network FC that returned to baseline in the two small lesion monkeys, whereas FC continued to increase throughout recovery in the two monkeys with a larger lesion. We also found that the FC between contralesional dorsolateral PFC and ipsilesional parietal cortex correlated with behavioural recovery and that the contralesional dorsolateral PFC showed increasing degree centrality with the frontoparietal network. These findings suggest that both the contralesional and ipsilesional hemispheres play an important role in the recovery of function. Importantly, optimal compensation after large PFC lesions may require greater recruitment of distant and intact areas of the frontoparietal network, whereas recovery from smaller lesions was supported by a normalization of the functional network.

PMID: 31707193 [PubMed - as supplied by publisher]

Protocol for a systematically-developed, phase I/II, single-blind randomized controlled trial of treadmill walking exercise training effects on cognition and brain function in persons with multiple sclerosis.

Tue, 11/12/2019 - 00:19
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Protocol for a systematically-developed, phase I/II, single-blind randomized controlled trial of treadmill walking exercise training effects on cognition and brain function in persons with multiple sclerosis.

Contemp Clin Trials. 2019 Nov 05;:105878

Authors: Sandroff BM, Diggs MD, Bamman MM, Cutter GR, Baird JF, Jones CD, Rinker JR, Wylie GR, DeLuca J, Motl RW

Abstract
Slowed cognitive processing speed (CPS) is a common and debilitating consequence of multiple sclerosis (MS) that is notoriously difficult to treat. As such, we undertook a systematic line of research that indicated that supervised, progressive treadmill walking exercise (TMWX) training might improve CPS and brain functioning among fully-ambulatory persons with MS. The current study will be the first adequately-powered, single-blind randomized controlled trial (RCT) that examines the efficacy of 12-weeks of TMWX training compared with an active control condition on CPS, thalamocortical brain connectivity (based on resting-state fMRI), and exploratory functional outcomes in 88 fully-ambulatory persons with MS who present with slowed CPS. The intervention condition involves supervised, progressive TMWX training 3 times/week over 12-weeks; this initially involves 15-min of light-to-moderate intensity TMWX that progresses up to 40-min of vigorous intensity TMWX. The active control condition involves supervised, minimal intensity, stretching-and-resistance exercise that will be delivered on the same frequency as the intervention condition. The primary study outcomes involve Symbol Digit Modalities Test performance (i.e., CPS) and fMRI-based measures of thalamocortical resting-state functional connectivity. Exploratory study outcomes involve measures of community participation, activities of daily living, quality of life, and functional mobility. All study outcomes will be administered before and after the 12-week study period by treatment-blinded assessors. If successful, the current study will provide the first Class I evidence for the effects of TMWX training as an approach for improving CPS and its neural correlate, and possibly mitigating the impact of slowed CPS on functional outcomes in MS.

PMID: 31704437 [PubMed - as supplied by publisher]

Functional Territories of Human Dentate Nucleus.

Sun, 11/10/2019 - 03:17
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Functional Territories of Human Dentate Nucleus.

Cereb Cortex. 2019 Nov 07;:

Authors: Guell X, D'Mello AM, Hubbard NA, Romeo RR, Gabrieli JDE, Whitfield-Gabrieli S, Schmahmann JD, Anteraper SA

Abstract
Anatomical connections link the cerebellar cortex with multiple sensory, motor, association, and paralimbic cerebral areas. The majority of fibers that exit cerebellar cortex synapse in dentate nuclei (DN) before reaching extracerebellar structures such as cerebral cortex, but the functional neuroanatomy of human DN remains largely unmapped. Neuroimaging research has redefined broad categories of functional division in the human brain showing that primary processing, attentional (task positive) processing, and default-mode (task negative) processing are three central poles of neural macroscale functional organization. This broad spectrum of human neural processing categories is represented not only in the cerebral cortex, but also in the thalamus, striatum, and cerebellar cortex. Whether functional organization in DN obeys a similar set of macroscale divisions, and whether DN are yet another compartment of representation of a broad spectrum of human neural processing categories, remains unknown. Here, we show for the first time that human DN are optimally divided into three functional territories as indexed by high spatio-temporal resolution resting-state MRI in 77 healthy humans, and that these three distinct territories contribute uniquely to default-mode, salience-motor, and visual cerebral cortical networks. Our findings provide a systems neuroscience substrate for cerebellar output to influence multiple broad categories of neural control.

PMID: 31701117 [PubMed - as supplied by publisher]

Static magnetic field stimulation of the supplementary motor area modulates resting-state activity and motor behavior.

Sun, 11/10/2019 - 03:17
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Static magnetic field stimulation of the supplementary motor area modulates resting-state activity and motor behavior.

Commun Biol. 2019;2:397

Authors: Pineda-Pardo JA, Obeso I, Guida P, Dileone M, Strange BA, Obeso JA, Oliviero A, Foffani G

Abstract
Focal application of a strong static magnetic field over the human scalp induces measurable local changes in brain function. Whether it also induces distant effects across the brain and how these local and distant effects collectively affect motor behavior remains unclear. Here we applied transcranial static magnetic field stimulation (tSMS) over the supplementary motor area (SMA) in healthy subjects. At a behavioral level, tSMS increased the time to initiate movement while decreasing errors in choice reaction-time tasks. At a functional level, tSMS increased SMA resting-state fMRI activity and bilateral functional connectivity between the SMA and both the paracentral lobule and the lateral frontotemporal cortex, including the inferior frontal gyrus. These results suggest that tSMS over the SMA can induce behavioral aftereffects associated with modulation of both local and distant functionally-connected cortical circuits involved in the control of speed-accuracy tradeoffs, thus offering a promising protocol for cognitive and clinical research.

PMID: 31701026 [PubMed]

Distinct individual differences in default mode network connectivity relate to off-task thought and text memory during reading.

Sun, 11/10/2019 - 03:17
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Distinct individual differences in default mode network connectivity relate to off-task thought and text memory during reading.

Sci Rep. 2019 Nov 07;9(1):16220

Authors: Zhang M, Savill N, Margulies DS, Smallwood J, Jefferies E

Abstract
Often, as we read, we find ourselves thinking about something other than the text; this tendency to mind-wander is linked to poor comprehension and reduced subsequent memory for texts. Contemporary accounts argue that periods of off-task thought are related to the tendency for attention to be decoupled from external input. We used fMRI to understand the neural processes that underpin this phenomenon. First, we found that individuals with poorer text-based memory tend to show reduced recruitment of left middle temporal gyrus in response to orthographic input, within a region located at the intersection of default mode, dorsal attention and frontoparietal networks. Voxels within these networks were taken as seeds in a subsequent resting-state study. The default mode network region (i) had greater connectivity with medial prefrontal cortex, falling within the same network, for individuals with better text-based memory, and (ii) was more decoupled from medial visual regions in participants who mind-wandered more frequently. These findings suggest that stronger intrinsic connectivity within the default mode network is linked to better text processing, while reductions in default mode network coupling to the visual system may underpin individual variation in the tendency for our attention to become disengaged from what we are reading.

PMID: 31700143 [PubMed - in process]

Morphological MRI phenotypes of multiple sclerosis differ in resting-state brain function.

Sun, 11/10/2019 - 03:17
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Morphological MRI phenotypes of multiple sclerosis differ in resting-state brain function.

Sci Rep. 2019 Nov 07;9(1):16221

Authors: Pinter D, Beckmann CF, Fazekas F, Khalil M, Pichler A, Gattringer T, Ropele S, Fuchs S, Enzinger C

Abstract
We aimed to assess differences in resting-state functional connectivity (FC) between distinct morphological MRI-phenotypes in multiple sclerosis (MS). Out of 180 MS patients, we identified those with high T2-hyperintense lesion load (T2-LL) and high normalized brain volume (NBV; a predominately white matter damage group, WMD; N = 37) and patients with low T2-LL and low NBV (N = 37; a predominately grey matter damage group; GMD). Independent component analysis of resting-state fMRI was used to test for differences in the sensorimotor network (SMN) between MS MRI-phenotypes and compared to 37 age-matched healthy controls (HC). The two MS groups did not differ regarding EDSS scores, disease duration and distribution of clinical phenotypes. WMD compared to GMD patients showed increased FC in all sub-units of the SMN (sex- and age-corrected). WMD patients had increased FC compared to HC and GMD patients in the central SMN (leg area). Only in the WMD group, higher EDSS scores and T2-LL correlated with decreased connectivity in SMN sub-units. MS patients with distinct morphological MRI-phenotypes also differ in brain function. The amount of focal white matter pathology but not global brain atrophy affects connectivity in the central SMN (leg area) of the SMN, consistent with the notion of a disconnection syndrome.

PMID: 31700126 [PubMed - in process]

Static and Dynamic Functional Connectivity of the Prefrontal Cortex during Resting-State Predicts Self-serving Bias in Depression.

Sat, 11/09/2019 - 00:16
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Static and Dynamic Functional Connectivity of the Prefrontal Cortex during Resting-State Predicts Self-serving Bias in Depression.

Behav Brain Res. 2019 Nov 04;:112335

Authors: Cui G, Wang Y, Wang X, Zheng L, Li L, Li P, Zhang L, Guo Y, Chen Y, Sun Z, Meng X

Abstract
Major depression disorder (MDD) is characterized by the lack of self-serving bias, which may inherently underlie the onset and maintenance of depression. Emerging neuroimaging evidences have indicated that the altered self-processing in MDD may be germane to the dysfunctional static resting-state functional connectivity (RSFC) of the prefrontal cortex (PFC). Although static RSFC studies provide tremendous amounts of evidences on functional changes in depression, explorations of dynamic RSFC among the PFC and other brain regions may elucidate the temporal changes of neural activities associated with depression. To further explore the behavioral and neural correlates of self-serving bias, 21 depressed and 23 non-depressed individuals underwent resting-state functional magnetic resonance imaging (fMRI) scan and completed a self-serving bias task. Static and dynamic RSFC analyses were conducted for specific subregions of the PFC, including the dorsomedial prefrontal cortex (dmPFC), the orbitofrontal cortex (OFC), the ventral prefrontal cortex (vlPFC) and the anterior cingulate cortex. Depressed patients showed an attenuated self-serving bias as compared with controls, and aberrant static and dynamic RSFC among these subregions of the PFC. In particular, the self-serving bias was associated with static dmPFC-to-OFC RSFC and dynamic vlPFC-to-OFC RSFC for MDD group. The aberrant RSFC of the PFC may serve as a predictor for self-serving bias in depression.

PMID: 31697986 [PubMed - as supplied by publisher]

Resting-state functional connectivity modulates the BOLD activation induced by nucleus accumbens stimulation in the swine brain.

Sat, 11/09/2019 - 00:16
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Resting-state functional connectivity modulates the BOLD activation induced by nucleus accumbens stimulation in the swine brain.

Brain Behav. 2019 Nov 07;:e01431

Authors: Cho S, Hachmann JT, Balzekas I, In MH, Andres-Beck LG, Lee KH, Min HK, Jo HJ

Abstract
INTRODUCTION: While the clinical efficacy of deep brain stimulation (DBS) the treatment of motor-related symptoms is well established, the mechanism of action of the resulting cognitive and behavioral effects has been elusive.
METHODS: By combining functional magnetic resonance imaging (fMRI) and DBS, we investigated the pattern of blood-oxygenation-level-dependent (BOLD) signal changes induced by stimulating the nucleus accumbens in a large animal model.
RESULTS: We found that diffused BOLD activation across multiple functional networks, including the prefrontal, limbic, and thalamic regions during the stimulation, resulted in a significant change in inter-regional functional connectivity. More importantly, the magnitude of the modulation was closely related to the strength of the inter-regional resting-state functional connectivity.
CONCLUSIONS: Nucleus accumbens stimulation affects the functional activity in networks that underlie cognition and behavior. Our study provides an insight into the nature of the functional connectivity, which mediates activation effect via brain networks.

PMID: 31697455 [PubMed - as supplied by publisher]

Acupuncture Effect and Mechanism for Treating Pain in Patients With Parkinson's Disease.

Fri, 11/08/2019 - 06:15
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Acupuncture Effect and Mechanism for Treating Pain in Patients With Parkinson's Disease.

Front Neurol. 2019;10:1114

Authors: Yu SW, Lin SH, Tsai CC, Chaudhuri KR, Huang YC, Chen YS, Yeh BY, Wu YR, Wang JJ

Abstract
Non-motor symptoms of Parkinson's disease (PD) have been receiving increasing attention. Approximately half of patients with PD have experience PD-related pain. We investigated the effect and mechanism of acupuncture in patients with PD who have pain. PD patients with pain were divided into acupuncture group and control group. Nine patients completed acupuncture treatment; seven patients who received only an analgesic agent underwent resting-state functional magnetic resonance imaging (rs-fMRI) twice. fMRI was performed to evaluate the functional connectivity of the brain regions. After treatment, a decrease in total scores on the King's Parkinson's Disease Pain Scale (KPPS) and Unified Parkinson's Disease Rating Scale was observed in the acupuncture group (-46.2 and -21.6%, respectively). In the acupuncture group, increased connectivity was observed in four connections, one in the left hemisphere between the middle temporal gyrus (MTG) and precentral gyrus, and three in the right hemisphere between the postcentral gyrus and precentral gyrus, supramarginal gyrus and precentral gyrus, and MTG and insular cortex. A significant correlation was noted between the changes in functional connectivity and KPPS. The involved connection was between the left middle frontal gyrus and the right precentral gyrus (R = -0.698, P = 0.037). Acupuncture could relieve pain in PD patients by modulating brain regions related to both sensory-discriminative and emotional aspects. The present study might increase the confidence of users that acupuncture is an effective and safe analgesic tool that can relieve PD-related pain.

PMID: 31695670 [PubMed]

Disrupted interhemispheric functional coordination in patients with chronic low back-related leg pain: a multiscale frequency-related homotopic connectivity study.

Fri, 11/08/2019 - 06:15
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Disrupted interhemispheric functional coordination in patients with chronic low back-related leg pain: a multiscale frequency-related homotopic connectivity study.

J Pain Res. 2019;12:2615-2626

Authors: Zhang Y, Zhu Y, Pei Y, Zhao Y, Zhou F, Huang M, Wu L, Zhang D, Gong H

Abstract
Objective: Chronic low back pain has been observed to decrease movement coordination. However, it is unclear whether the existing alteration of inter-hemispheric synchrony of intrinsic activity in patients with chronic low back-related leg pain (cLBLP). The present study aims to investigate the alteration of homotopic connectivity and its clinical association with the cLBLP patients.
Participants and methods: A cohort of cLBLP patients (n=25) and well-matched healthy controls (HCs) (n=27) were recruited and underwent MRI scanning and a battery of clinical tests. The voxel-mirrored homotopic connectivity (VMHC) was used to analyze the interhemispheric coordination in the typical (0.01-0.1 Hz) as well as five specific (slow-6 to slow-2) frequency bands and associated with clinical index in cLBLP patients.
Results: We observed that cLBLP patients with lower homotopic connectivity than HCs in the inferior temporal gyrus, the superior temporal gyrus, the basal ganglia, the middle frontal gyrus, and the medial prefrontal cortex in the typical and five specific frequency bands, respectively. In the typical and five specific frequency bands, significant positive correlations were observed between the VMHC values of medial prefrontal cortex and the visual analogue scale scores, while the VMHC values of basal ganglia negative correlated with the values of two-point tactile discrimination (2PD) test for the right hand in cLBLP patients, etc. Further receiver operating characteristic curve analysis revealed that VMHC in the above regions with decreased could be used to differentiate the cerebral functional plasticity of cLBLP from healthy individuals with high sensitivity and specificity.
Conclusion: Our results imply that multiscale frequency-related interhemispheric disconnectivity may underlie the central pathogenesis of functional coordination in patients with cLBLP.

PMID: 31695477 [PubMed]

From state-to-trait meditation: Reconfiguration of central executive and default mode networks.

Fri, 11/08/2019 - 06:15
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From state-to-trait meditation: Reconfiguration of central executive and default mode networks.

eNeuro. 2019 Nov 06;:

Authors: Bauer CCC, Whitfield-Gabrieli S, Díaz JL, Pasaye EH, Barrios FA

Abstract
While brain default mode network (DMN) activation in human subjects has been associated with mind wandering, meditation practice has been found to suppress it and to increase psychological well-being. Additionally to DMN activity reduction, experienced meditators during meditation practice show and increased connectivity between the DMN and the central executive network (CEN). However, the gradual change between DMN and CEN configuration from pre-meditation, during meditation, and post-meditation are unknown. Here we investigated the change in DMN and CEN configuration by means of brain activity and functional connectivity analyses in experienced meditators across three back-to-back functional magnetic resonance imaging scans: Pre-meditation baseline (trait), meditation (state), and post-meditation (state-to-trait). Pre-meditation baseline group comparison was also performed between experienced meditators and healthy controls. Meditation trait was characterized by a significant reduction in activity and functional connectivity within DMN and increased anticorrelations between DMN and CEN. Conversely, meditation state and meditation state-to-trait periods showed increased activity and functional connectivity within the DMN and between DMN and CEN. However, the latter anticorrelations were only present in experienced meditators with limited practice. The interactions between networks during these states by means of Positive Diametric Activity (PDA) of the fractional Amplitude of Low-Frequency Fluctuations (fALFF) defined as [Formula: see text] revealed no trait differences, but significant increases during meditation state that persisted in meditation state-to-trait. The gradual reconfiguration in DMN and CEN suggest a neural mechanism by which the CEN negatively regulates the DMN and is probably responsible for the long-term trait changes seen in meditators and reported psychological well-being.Significance Statement We introduce a Positive Diametric Activity (PDA) metric to measure the relation between two anticorrelated rs-fMRI networks in experienced meditators. PDA as well as functional connectivity (FC) are increased during meditation compared to resting state and persists in the post meditation resting state. Conversely, meditation trait is characterized by positive PDA but with significant reduction in activity and functional connectivity within Default Mode Network (DMN) and increased anticorrelations between DMN and central executive network (CEN). PDA and FC between DMN and CEN distinguish meditation state-to-trait effects.

PMID: 31694816 [PubMed - as supplied by publisher]