New resting-state fMRI related studies at PubMed

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Altered resting-state functional connectivity in children and adolescents born very preterm short title.

Sat, 11/03/2018 - 16:20

Altered resting-state functional connectivity in children and adolescents born very preterm short title.

Neuroimage Clin. 2018 Oct 03;20:1148-1156

Authors: Wehrle FM, Michels L, Guggenberger R, Huber R, Latal B, O'Gorman RL, Hagmann CF

Abstract
The formation of resting-state functional networks in infancy has been reported to be strongly impacted by very preterm birth. Studies in childhood and adolescence have largely focused on language processing networks and identified both decreased and increased functional connectivity. It is unclear, however, whether functional connectivity strength is altered globally in children and adolescents born very preterm and whether these alterations are related to the frequently occurring cognitive deficits. Here, resting-state functional MRI was assessed in a group of 32 school-aged children and adolescents born very preterm with normal intellectual and motor abilities and 39 healthy term-born peers. Functional connectivity within and between a comprehensive set of well-established resting-state networks was compared between the groups. IQ and executive function abilities were tested with standardized tasks and potential associations with connectivity strength were explored. Functional connectivity was weaker in the very preterm compared to the term-born group between the sensorimotor network and the visual and dorsal attention network, within the sensorimotor network and within the central executive network. In contrast, functional connectivity was stronger in the very preterm group between the sensorimotor network and parts of the salience and the central executive network. Little evidence was found that these alterations underlie lower IQ or poorer executive function abilities. This study provides evidence for a long-lasting impact of very preterm birth on the organization of resting-state networks. The potential consequence of these alterations for other neurodevelopmental domains than the ones investigated in the current study warrants further investigation.

PMID: 30388598 [PubMed - as supplied by publisher]

Effects of the KCNQ channel opener ezogabine on functional connectivity of the ventral striatum and clinical symptoms in patients with major depressive disorder.

Sat, 11/03/2018 - 16:20
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Effects of the KCNQ channel opener ezogabine on functional connectivity of the ventral striatum and clinical symptoms in patients with major depressive disorder.

Mol Psychiatry. 2018 Nov 01;:

Authors: Tan A, Costi S, Morris LS, Van Dam NT, Kautz M, Whitton AE, Friedman AK, Collins KA, Ahle G, Chadha N, Do B, Pizzagalli DA, Iosifescu DV, Nestler EJ, Han MH, Murrough JW

Abstract
Major depressive disorder (MDD) is a leading cause of disability worldwide, yet current treatment strategies remain limited in their mechanistic diversity. Recent evidence has highlighted a promising novel pharmaceutical target-the KCNQ-type potassium channel-for the treatment of depressive disorders, which may exert a therapeutic effect via functional changes within the brain reward system, including the ventral striatum. The current study assessed the effects of the KCNQ channel opener ezogabine (also known as retigabine) on reward circuitry and clinical symptoms in patients with MDD. Eighteen medication-free individuals with MDD currently in a major depressive episode were enrolled in an open-label study and received ezogabine up to 900 mg/day orally over the course of 10 weeks. Resting-state functional magnetic resonance imaging data were collected at baseline and posttreatment to examine brain reward circuitry. Reward learning was measured using a computerized probabilistic reward task. After treatment with ezogabine, subjects exhibited a significant reduction of depressive symptoms (Montgomery-Asberg Depression Rating Scale score change: -13.7 ± 9.7, p < 0.001, d = 2.08) and anhedonic symptoms (Snaith-Hamilton Pleasure Scale score change: -6.1 ± 5.3, p < 0.001, d = 1.00), which remained significant even after controlling for overall depression severity. Improvement in depression was associated with decreased functional connectivity between the ventral caudate and clusters within the mid-cingulate cortex and posterior cingulate cortex (n = 14, voxel-wise p < 0.005). In addition, a subgroup of patients tested with a probabilistic reward task (n = 9) showed increased reward learning following treatment. These findings highlight the KCNQ-type potassium channel as a promising target for future drug discovery efforts in mood disorders.

PMID: 30385872 [PubMed - as supplied by publisher]

Interaction of Developmental Venous Anomalies with Resting-State Functional MRI Measures.

Sat, 11/03/2018 - 16:20
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Interaction of Developmental Venous Anomalies with Resting-State Functional MRI Measures.

AJNR Am J Neuroradiol. 2018 Nov 01;:

Authors: Sundermann B, Pfleiderer B, Minnerup H, Berger K, Douaud G

Abstract
BACKGROUND AND PURPOSE: Functional MR imaging of the brain, used for both clinical and neuroscientific applications, relies on measuring fluctuations in blood oxygenation. Such measurements are susceptible to noise of vascular origin. The purpose of this study was to assess whether developmental venous anomalies, which are frequently observed normal variants, can bias fMRI measures by appearing as true neural signal.
MATERIALS AND METHODS: Large developmental venous anomalies (1 in each of 14 participants) were identified from a large neuroimaging cohort (n = 814). Resting-state fMRI data were decomposed using independent component analysis, a data-driven technique that creates distinct component maps representing aspects of either structured noise or true neural activity. We searched all independent components for maps that exhibited a spatial distribution of their signals following the topography of developmental venous anomalies.
RESULTS: Of the 14 developmental venous anomalies identified, 10 were clearly present in 17 fMRI independent components in total. While 9 (52.9%) of these 17 independent components were dominated by venous contributions and 2 (11.8%) by motion artifacts, 2 independent components (11.8%) showed partial neural signal contributions and 5 independent components (29.4%) unambiguously exhibited typical neural signal patterns.
CONCLUSIONS: Developmental venous anomalies can strongly resemble neural signal as measured by fMRI. They are thus a potential source of bias in fMRI analyses, especially when present in the cortex. This could impede interpretation of local activity in patients, such as in presurgical mapping. In scientific studies with large samples, developmental venous anomaly confounds could be mainly addressed using independent component analysis-based denoising.

PMID: 30385467 [PubMed - as supplied by publisher]

Neuronal variability of Resting State activity in Eating Disorders: increase and decoupling in Ventral Attention Network and relation with clinical symptoms.

Fri, 11/02/2018 - 15:20
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Neuronal variability of Resting State activity in Eating Disorders: increase and decoupling in Ventral Attention Network and relation with clinical symptoms.

Eur Psychiatry. 2018 Oct 29;55:10-17

Authors: Spalatro AV, Amianto F, Huang Z, D'Agata F, Bergui M, Abbate Daga G, Fassino S, Northoff G

Abstract
BACKGROUND: Despite the great number of resting state functional connectivity studies on Eating Disorders (ED), no biomarkers could be detected yet. Therefore, we here focus on a different measure of resting state activity that is neuronal variability. The objective of this study was to investigate neuronal variability in the resting state of women with ED and to correlate possible differences with clinical and psychopathological indices.
METHODS: 58 women respectively 25 with Anorexia Nervosa (AN), 16 with Bulimia Nervosa (BN) and 17 matched healthy controls (CN) were enrolled for the study. All participants were tested with a battery of psychometric tests and underwent a functional Magnetic Resonance Imaging (fMRI) resting state scanning. We investigated topographical patterns of variability measured by the Standard Deviation (SD) of the Blood-Oxygen-Level-Dependent (BOLD) signal (as a measure of neuronal variability) in the resting-state and their relationship to clinical and psychopathological indices.
RESULTS: Neuronal variability was increased in both anorectic and bulimic subjects specifically in the Ventral Attention Network (VAN) compared to healthy controls. No significant differences were found in the other networks. Significant correlations were found between neuronal variability of VAN and various clinical and psychopathological indices.
CONCLUSIONS: We here show increased neuronal variability of VAN in ED patients. As the VAN is relevant for switching between endogenous and exogenous stimuli, our results showing increased neuronal variability suggest unstable balance between body attention and attention to external world. These results offer new perspective on the neurobiological basis of ED. Clinical and therapeutic implication will be discussed.

PMID: 30384106 [PubMed - as supplied by publisher]

The Effects of a Serious Game on Depressive Symptoms and Anxiety in Breast Cancer Patients with Depression: A Pilot Study Using Functional Magnetic Resonance Imaging.

Fri, 11/02/2018 - 15:20
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The Effects of a Serious Game on Depressive Symptoms and Anxiety in Breast Cancer Patients with Depression: A Pilot Study Using Functional Magnetic Resonance Imaging.

Games Health J. 2018 Oct 31;:

Authors: Kim SM, Kim HJ, Hwang HC, Hong JS, Bae S, Min KJ, Han DH

Abstract
OBJECTIVE: Depression is common in cancer patients. We investigated the effects of playing a serious game in breast cancer patients with mild to moderate depression using functional neuroimaging.
MATERIALS AND METHODS: Thirty-five participants were randomly assigned to the Game group and the Nongame group, and fifteen participants in each group completed the study protocol. Participants in the Game group were asked to play a serious game, "Hit the Cancer" (RAW HAND, Seoul, Korea), for at least 30 minutes/day, 5 days/week, for 3 weeks. Participants in the Nongame group received usual care. At baseline and follow-up, all participants were assessed with the Beck Depression Inventory (BDI), Beck Anxiety Inventory, Stress Response Inventory (SRI), and 3-Tesla resting-state functional magnetic resonance imaging. Changes in functional connectivity (FC) between the brain regions in the default mode network (DMN) and salience network (SN) were analyzed.
RESULTS: After the intervention, BDI and SRI scores in the Game group greatly decreased compared with those in the Nongame group. In addition, compared with the Nongame group, the Game group showed decreased postintervention FC between the right posterior cingulate cortex (PCC) of the DMN and right insula of the SN. The improvement in BDI and SRI scores correlated with the decrease in FC between the right PCC and right insula.
CONCLUSION: Selective attention training and repetitive stimulation of the insula by serious game play might cause normalization of the FC between the SN and DMN, thus improving depressive mood.

PMID: 30383458 [PubMed - as supplied by publisher]

Shared and specific functional connectivity alterations in unmedicated bipolar and major depressive disorders based on the triple-network model.

Fri, 11/02/2018 - 15:20
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Shared and specific functional connectivity alterations in unmedicated bipolar and major depressive disorders based on the triple-network model.

Brain Imaging Behav. 2018 Oct 31;:

Authors: Wang J, Wang Y, Wu X, Huang H, Jia Y, Zhong S, Wu X, Zhao L, He Y, Huang L, Huang R

Abstract
Bipolar disorder (BD) is frequently misdiagnosed as major depressive disorder (MDD) in clinical practice, especially during depressive episodes. A unifying triple-network model, involving the default mode network (DMN), central executive network (CEN) and salience network (SN), has been proposed to explain the neural physiopathology of psychiatric and neurological disorders. Although several studies revealed shared and specific alterations between BD and MDD in key regions of DMN, CEN, and SN, and a few studies used different measures to detect detailed alterations in the triple networks in BD and MDD, their shared and specific patterns of altered functional connectivity (FC) in the triple networks has remained unclear. In this study, we acquired resting-state fMRI (R-fMRI) data from 38 unmedicated BD and 35 unmedicated MDD patients during depressive episodes along with 47 healthy controls. We first determined the spatially independent components of the DMN, SN, and CEN by using independent component analysis (ICA); then we estimated the inter-ROI and inter-network FC for each group. By comparing the differences between the three groups, we obtained the following results: (1) both the BD and MDD patients showed shared weaker intra-network FC in the left mPFC and right precuneus within the DMN as well as weaker inter-ROI FC between the left AI and right AI compared with the healthy controls; (2) the BD had weaker while the MDD had stronger intra-network FC in the right dlPFC within the rCEN as well as stronger inter-ROI FC between the right dlPFC and right ANG compared with the healthy controls; (3) the BD showed specific, stronger inter-ROI FC between the left PPC and right AI as well as stronger inter-network FC between the lCEN and SN compared with either the MDD or the control group. Our findings provide new information for understanding the neural physiopathology and clinical symptoms of depressed BD and MDD patients.

PMID: 30382529 [PubMed - as supplied by publisher]

Repetitive Transcranial Magnetic Stimulation with Resting State Network Targeting for Treatment-Resistant Depression in Traumatic Brain Injury: a randomized, controlled, double blinded pilot study.

Fri, 11/02/2018 - 15:20
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Repetitive Transcranial Magnetic Stimulation with Resting State Network Targeting for Treatment-Resistant Depression in Traumatic Brain Injury: a randomized, controlled, double blinded pilot study.

J Neurotrauma. 2018 Nov 01;:

Authors: Siddiqi SH, Trapp NT, Hacker CD, Laumann TO, Kandala S, Hong X, Trillo L, Shahim PP, Leuthardt E, Carter AR, Brody D

Abstract
BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) has demonstrated antidepressant efficacy, but has limited evidence in depression associated with traumatic brain injury (TBI). Here, we investigate the use of rTMS targeted with individualized resting-state network mapping (RSNM) of dorsal attention network (DAN) and default mode network (DMN) in subjects with treatment-resistant depression associated with TBI.
METHODS: 14 Subjects with treatment-resistant depression and prior concussive or moderate TBI received resting-state fMRI scans with individual-level RSNM. Subjects were randomized to 20 sessions of bilateral rTMS (4000 left-sided excitatory pulses, 1000 right-sided inhibitory pulses) or sham. Treatment was targeted to the dorsolateral prefrontal cluster with maximal difference between DAN and DMN correlations. The primary outcome was Montgomery-Asberg Depression Rating Scale (MADRS).
RESULTS: Mean MADRS improvement was 56% ± 14% (n=9) with active treatment and 27% ± 25% (n=5) with sham (Cohen's d=1.43). One subject randomized to sham withdrew prior to starting treatment. There were no seizures or other significant adverse events. MADRS improvement was inversely correlated with functional connectivity between the right-sided stimulation site and the subgenual anterior cingulate cortex (sgACC) (r=-0.68, 95% CI 0.03 - 0.925). Active treatment led to increased sgACC-DMN connectivity (Cohen's d=1.55) and increased sgACC anti-correlation with the left- and right-sided stimulation sites (Cohen's d= -1.22 and -0.69, respectively).
CONCLUSIONS: This pilot study provides evidence that RSNM-targeted rTMS is feasible in TBI patients with depression. Given the dearth of existing evidence-based treatments for depression in this patient population, these preliminarily encouraging results indicate that larger controlled trials are warranted.

PMID: 30381997 [PubMed - as supplied by publisher]

Imaging & neuropsychological changes in brain with spiritual practice: A pilot study.

Fri, 11/02/2018 - 15:20
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Imaging & neuropsychological changes in brain with spiritual practice: A pilot study.

Indian J Med Res. 2018 Aug;148(2):190-199

Authors: Gupta SS, Maheshwari SM, Shah UR, Bharath RD, Dawra NS, Mahajan MS, Desai A, Prajapati A, Ghodke M

Abstract
Background & objectives: Some studies have systematically assessed the effects of spiritual practice (SP) on the brain using combined neuropsychological testing and functional imaging. The objective of the present study was to compare imaging and neuropsychological changes in healthy individuals after SP and those with only physical exercise.
Methods: Healthy adult male volunteers, aged 25-45 yr were randomized into two groups. Group 1 (SP group) underwent the SP and group 2 (controls) did brisk walk for 30 min daily. Detailed neuropsychological evaluation, resting-state functional magnetic resonance imaging (fMRI) and brain 99mTc ethyl cysteinate dimer single-photon emission computed tomography (SPECT) were carried out for both groups before and three months after intervention.
Results: Post-intervention, resting state fMRI showed increased connections of left precuneus (in the posterior cingulate cortex area of default mode network) in group 1 and increased left frontal connections in group 2. The neuropsychological tests showed significant improvement in 'Speed of Processing' (Digit Symbol Test) in group 1 and in Focused Attention (Trail Making A) in group 2. The SPECT data in group 1 showed significant improvement in perfusion of the frontal areas, with relatively lesser improvement in parietal areas. Group 2 showed significant improvement in perfusion predominantly in parietal areas, as compared to frontal areas. In addition, significantly improved mood was reported by group 1 and not by group 2.
Interpretation & conclusions: This pilot study shows important functional imaging and neuropsychological changes in the brain with SP.

PMID: 30381542 [PubMed - in process]

Family-based case-control study of homotopic connectivity in first-episode, drug-naive schizophrenia at rest.

Fri, 11/02/2018 - 15:20
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Family-based case-control study of homotopic connectivity in first-episode, drug-naive schizophrenia at rest.

Sci Rep. 2017 03 03;7:43312

Authors: Guo W, Liu F, Chen J, Wu R, Li L, Zhang Z, Zhao J

Abstract
Family-based case-control design is rarely used but powerful to reduce the confounding effects of environmental factors on schizophrenia. Twenty-eight first-episode, drug-naive patients with schizophrenia, 28 family-based controls (FBC), and 40 healthy controls (HC) underwent resting-state functional MRI. Voxel-mirrored homotopic connectivity (VMHC), receiver operating characteristic curve (ROC), and support vector machine (SVM) were used to process the data. Compared with the FBC, the patients showed lower VMHC in the precuneus, fusiform gyrus/cerebellum lobule VI, and lingual gyrus/cerebellum lobule VI. The patients exhibited lower VMHC in the precuneus relative to the HC. ROC analysis exhibited that the VMHC values in these brain regions might not be ideal biomarkers to distinguish the patients from the FBC/HC. However, SVM analysis indicated that a combination of VMHC values in the precuneus and lingual gyrus/cerebellum lobule VI might be used as a potential biomarker to distinguish the patients from the FBC with a sensitivity of 96.43%, a specificity of 89.29%, and an accuracy of 92.86%. Results suggested that patients with schizophrenia have decreased homotopic connectivity in the motor and low level sensory processing regions. Neuroimaging studies can adopt family-based case-control design as a viable option to reduce the confounding effects of environmental factors on schizophrenia.

PMID: 28256527 [PubMed - indexed for MEDLINE]

Brain state and polarity dependent modulation of brain networks by transcranial direct current stimulation.

Thu, 11/01/2018 - 14:00
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Brain state and polarity dependent modulation of brain networks by transcranial direct current stimulation.

Hum Brain Mapp. 2018 Oct 30;:

Authors: Li LM, Violante IR, Leech R, Ross E, Hampshire A, Opitz A, Rothwell JC, Carmichael DW, Sharp DJ

Abstract
Despite its widespread use in cognitive studies, there is still limited understanding of whether and how transcranial direct current stimulation (tDCS) modulates brain network function. To clarify its physiological effects, we assessed brain network function using functional magnetic resonance imaging (fMRI) simultaneously acquired during tDCS stimulation. Cognitive state was manipulated by having subjects perform a Choice Reaction Task or being at "rest." A novel factorial design was used to assess the effects of brain state and polarity. Anodal and cathodal tDCS were applied to the right inferior frontal gyrus (rIFG), a region involved in controlling activity large-scale intrinsic connectivity networks during switches of cognitive state. tDCS produced widespread modulation of brain activity in a polarity and brain state dependent manner. In the absence of task, the main effect of tDCS was to accentuate default mode network (DMN) activation and salience network (SN) deactivation. In contrast, during task performance, tDCS increased SN activation. In the absence of task, the main effect of anodal tDCS was more pronounced, whereas cathodal tDCS had a greater effect during task performance. Cathodal tDCS also accentuated the within-DMN connectivity associated with task performance. There were minimal main effects of stimulation on network connectivity. These results demonstrate that rIFG tDCS can modulate the activity and functional connectivity of large-scale brain networks involved in cognitive function, in a brain state and polarity dependent manner. This study provides an important insight into mechanisms by which tDCS may modulate cognitive function, and also has implications for the design of future stimulation studies.

PMID: 30378206 [PubMed - as supplied by publisher]

Secondary prevention of Alzheimer's dementia: neuroimaging contributions.

Thu, 11/01/2018 - 14:00
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Secondary prevention of Alzheimer's dementia: neuroimaging contributions.

Alzheimers Res Ther. 2018 Oct 30;10(1):112

Authors: Ten Kate M, Ingala S, Schwarz AJ, Fox NC, Chételat G, van Berckel BNM, Ewers M, Foley C, Gispert JD, Hill D, Irizarry MC, Lammertsma AA, Molinuevo JL, Ritchie C, Scheltens P, Schmidt ME, Visser PJ, Waldman A, Wardlaw J, Haller S, Barkhof F

Abstract
BACKGROUND: In Alzheimer's disease (AD), pathological changes may arise up to 20 years before the onset of dementia. This pre-dementia window provides a unique opportunity for secondary prevention. However, exposing non-demented subjects to putative therapies requires reliable biomarkers for subject selection, stratification, and monitoring of treatment. Neuroimaging allows the detection of early pathological changes, and longitudinal imaging can assess the effect of interventions on markers of molecular pathology and rates of neurodegeneration. This is of particular importance in pre-dementia AD trials, where clinical outcomes have a limited ability to detect treatment effects within the typical time frame of a clinical trial. We review available evidence for the use of neuroimaging in clinical trials in pre-dementia AD. We appraise currently available imaging markers for subject selection, stratification, outcome measures, and safety in the context of such populations.
MAIN BODY: Amyloid positron emission tomography (PET) is a validated in-vivo marker of fibrillar amyloid plaques. It is appropriate for inclusion in trials targeting the amyloid pathway, as well as to monitor treatment target engagement. Amyloid PET, however, has limited ability to stage the disease and does not perform well as a prognostic marker within the time frame of a pre-dementia AD trial. Structural magnetic resonance imaging (MRI), providing markers of neurodegeneration, can improve the identification of subjects at risk of imminent decline and hence play a role in subject inclusion. Atrophy rates (either hippocampal or whole brain), which can be reliably derived from structural MRI, are useful in tracking disease progression and have the potential to serve as outcome measures. MRI can also be used to assess comorbid vascular pathology and define homogeneous groups for inclusion or for subject stratification. Finally, MRI also plays an important role in trial safety monitoring, particularly the identification of amyloid-related imaging abnormalities (ARIA). Tau PET to measure neurofibrillary tangle burden is currently under development. Evidence to support the use of advanced MRI markers such as resting-state functional MRI, arterial spin labelling, and diffusion tensor imaging in pre-dementia AD is preliminary and requires further validation.
CONCLUSION: We propose a strategy for longitudinal imaging to track early signs of AD including quantitative amyloid PET and yearly multiparametric MRI.

PMID: 30376881 [PubMed - in process]

Prenatal neural origins of infant motor development: Associations between fetal brain and infant motor development.

Thu, 11/01/2018 - 14:00
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Prenatal neural origins of infant motor development: Associations between fetal brain and infant motor development.

Dev Psychopathol. 2018 08;30(3):763-772

Authors: Thomason ME, Hect J, Waller R, Manning JH, Stacks AM, Beeghly M, Boeve JL, Wong K, van den Heuvel MI, Hernandez-Andrade E, Hassan SS, Romero R

Abstract
Functional circuits of the human brain emerge and change dramatically over the second half of gestation. It is possible that variation in neural functional system connectivity in utero predicts individual differences in infant behavioral development, but this possibility has yet to be examined. The current study examines the association between fetal sensorimotor brain system functional connectivity and infant postnatal motor ability. Resting-state functional connectivity data was obtained in 96 healthy human fetuses during the second and third trimesters of pregnancy. Infant motor ability was measured 7 months after birth using the Bayley Scales of Infant Development. Increased connectivity between the emerging motor network and regions of the prefrontal cortex, temporal lobes, posterior cingulate, and supplementary motor regions was observed in infants that showed more mature motor functions. In addition, females demonstrated stronger fetal-brain to infant-behavior associations. These observations extend prior longitudinal research back into prenatal brain development and raise exciting new ideas about the advent of risk and the ontogeny of early sex differences.

PMID: 30068433 [PubMed - indexed for MEDLINE]

Altered Functional Connectivity of the Primary Visual Cortex in Adult Comitant Strabismus: A Resting-State Functional MRI Study.

Wed, 10/31/2018 - 13:20
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Altered Functional Connectivity of the Primary Visual Cortex in Adult Comitant Strabismus: A Resting-State Functional MRI Study.

Curr Eye Res. 2018 Oct 30;:

Authors: Yan X, Wang Y, Xu L, Liu Y, Song S, Ding K, Zhou Y, Jiang T, Lin X

Abstract
PURPOSE: The aim of this study was to examine the functional connectivity between the primary visual cortex and other cortical areas during rest in normal subjects and patients with comitant strabismus using functional magnetic resonance imaging (fMRI).
METHODS: A prospective, observational study was conducted. Ten patients with comitant exotropia and eleven matched healthy subjects underwent resting-state fMRI with their eyes closed. Resting-state fMRI was performed using a 3.0T MR scanner. The primary visual cortex was subdivided into anterior and posterior subdivisions. The resting-state functional connectivities within the primary visual cortex and between the primary visual cortex and other cortical areas were calculated for each group and compared between the strabismic and normal control groups. fMRI data were analyzed using Statistical Parametric Mapping software and Analysis of Functional NeuroImages software (AFNI).
RESULTS: Compared with the normal controls, patients with comitant strabismus had increased functional connectivity between the posterior primary visual cortex and other cortical areas, especially the visual cortex (BA19) and other oculomotor regions, such as the frontal eye field (BA6).
CONCLUSIONS: The fMRI results suggest that ongoing and permanent cortical changes occur in patients with comitant strabismus. Disrupted brain functional connectivities are associated with abnormal eye movement and loss of stereopsis. Our study provides a neurological basis for understanding the pathophysiology of comitant strabismus, which may prompt new areas of research to more precisely define this basis and extend these findings to enhance diagnosis and treatment.

PMID: 30375900 [PubMed - as supplied by publisher]

A systematic review on the quantitative relationship between structural and functional network connectivity strength in mammalian brains.

Wed, 10/31/2018 - 13:20
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A systematic review on the quantitative relationship between structural and functional network connectivity strength in mammalian brains.

J Cereb Blood Flow Metab. 2018 Oct 30;:271678X18809547

Authors: Straathof M, Sinke MR, Dijkhuizen RM, Otte WM

Abstract
The mammalian brain is composed of densely connected and interacting regions, which form structural and functional networks. An improved understanding of the structure-function relation is crucial to understand the structural underpinnings of brain function and brain plasticity after injury. It is currently unclear how functional connectivity strength relates to structural connectivity strength. We obtained an overview of recent papers that report on correspondences between quantitative functional and structural connectivity measures in the mammalian brain. We included network studies in which functional connectivity was measured with resting-state fMRI, and structural connectivity with either diffusion-weighted MRI or neuronal tract tracers. Twenty-seven of the 28 included studies showed a positive structure-function relationship. Large inter-study variations were found comparing functional connectivity strength with either quantitative diffusion-based (correlation coefficient (r) ranges: 0.18-0.82) or neuronal tracer-based structural connectivity measures (r = 0.24-0.74). Two functional datasets demonstrated lower structure-function correlations with neuronal tracer-based (r = 0.22 and r = 0.30) than with diffusion-based measures (r = 0.49 and r = 0.65). The robust positive quantitative structure-function relationship supports the hypothesis that structural connectivity provides the hardware from which functional connectivity emerges. However, methodological differences between the included studies complicate the comparison across studies, which emphasize the need for validation and standardization in brain structure-function studies.

PMID: 30375267 [PubMed - as supplied by publisher]

Atypical longitudinal development of functional connectivity in adolescents with autism spectrum disorder.

Wed, 10/31/2018 - 13:20
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Atypical longitudinal development of functional connectivity in adolescents with autism spectrum disorder.

Autism Res. 2018 Oct 30;:

Authors: Lawrence KE, Hernandez LM, Bookheimer SY, Dapretto M

Abstract
Autism spectrum disorder (ASD) is consistently associated with alterations in brain connectivity, but there are conflicting results as to where and when individuals with ASD display increased or reduced functional connectivity. Such inconsistent findings may be driven by atypical neurodevelopmental trajectories in ASD during adolescence, but no longitudinal studies to date have investigated this hypothesis. We thus examined the functional connectivity of three neurocognitive resting-state networks-the default mode network (DMN), salience network, and central executive network (CEN)-in a longitudinal sample of youth with ASD (n = 16) and without ASD (n = 22) studied during early/mid- and late adolescence. Functional connectivity between the CEN and the DMN displayed significantly altered developmental trajectories in ASD: typically developing (TD) controls-but not youth with ASD-exhibited an increase in negative functional connectivity between these two networks with age. This significant interaction was due to the ASD group displaying less negative functional connectivity than the TD group during late adolescence only, with no significant group differences in early/mid-adolescence. These preliminary findings suggest a localized age-dependency of functional connectivity alterations in ASD and underscore the importance of considering age when examining brain connectivity. Autism Research 2018. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Brain connectivity may develop differently during adolescence in youth with autism spectrum disorder (ASD). We looked at changes in brain connectivity over time within individuals and found that, for some brain regions, adolescents with ASD did not show the same changes in brain connectivity that typically developing adolescents did. This suggests it is important to consider age when studying brain connectivity in ASD.

PMID: 30375176 [PubMed - as supplied by publisher]

Subcentimeter epilepsy surgery targets by resting state functional magnetic resonance imaging can improve outcomes in hypothalamic hamartoma.

Wed, 10/31/2018 - 13:20
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Subcentimeter epilepsy surgery targets by resting state functional magnetic resonance imaging can improve outcomes in hypothalamic hamartoma.

Epilepsia. 2018 Oct 30;:

Authors: Boerwinkle VL, Foldes ST, Torrisi SJ, Temkit H, Gaillard WD, Kerrigan JF, Desai VR, Raskin JS, Vedantam A, Jarrar R, Williams K, Lam S, Ranjan M, Broderson JS, Adelson D, Wilfong AA, Curry DJ

Abstract
OBJECTIVE: The purpose of this study is to investigate the outcomes of epilepsy surgery targeting the subcentimeter-sized resting state functional magnetic resonance imaging (rs-fMRI) epileptogenic onset zone (EZ) in hypothalamic hamartoma (HH).
METHODS: Fifty-one children with HH-related intractable epilepsy received anatomical MRI-guided stereotactic laser ablation (SLA) procedures. Fifteen of these children were control subjects (CS) not guided by rs-fMRI. Thirty-six had been preoperatively guided by rs-fMRI (RS) to determine EZs, which were subsequently targeted by SLA. The primary outcome measure for the study was a predetermined goal of 30% reduction in seizure frequency and improvement in class I Engel outcomes 1 year postoperatively. Quantitative and qualitative volumetric analyses of total HH and ablated tissue were also assessed.
RESULTS: In the RS group, the EZ target within the HH was ablated with high accuracy (>87.5% of target ablated in 83% of subjects). There was no difference between the groups in percentage of ablated hamartoma volume (P = 0.137). Overall seizure reduction was higher in the rs-fMRI group: 85% RS versus 49% CS (P = 0.0006, adjusted). The Engel Epilepsy Surgery Outcome Scale demonstrated significant differences in those with freedom from disabling seizures (class I), 92% RS versus 47% CS, a 45% improvement (P = 0.001). Compared to prior studies, there was improvement in class I outcomes (92% vs 76%-81%). No postoperative morbidity or mortality occurred.
SIGNIFICANCE: For the first time, surgical SLA targeting of subcentimeter-sized EZs, located by rs-fMRI, guided surgery for intractable epilepsy. Our outcomes demonstrated the highest seizure freedom rate without surgical complications and are a significant improvement over prior reports. The approach improved freedom from seizures by 45% compared to conventional ablation, regardless of hamartoma size or anatomical classification. This technique showed the same or reduced morbidity (0%) compared to recent non-rs-fMRI-guided SLA studies with as high as 20% permanent significant morbidity.

PMID: 30374947 [PubMed - as supplied by publisher]

Peer influence, Frontostriatal connectivity, and delay discounting in African American emerging adults.

Wed, 10/31/2018 - 13:20
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Peer influence, Frontostriatal connectivity, and delay discounting in African American emerging adults.

Brain Imaging Behav. 2018 Oct 30;:

Authors: Holmes C, Owens M, Beach SRH, McCormick M, Hallowell E, Clark US, Barton AW, Brody GH, MacKillop J, Sweet LH

Abstract
Prior research has demonstrated the importance of delay discounting in adverse health behaviors, such as addiction, attention deficit hyperactivity disorder, risk taking, and obesity. Nevertheless, the functional connectivity of neural circuitry associated with delay discounting and the ways in which the social environment may influence frontostriatal connectivity remain largely unknown, particularly in African Americans. Building on recent literature implicating frontostriatal connectivity during active delay discounting decision making and at rest, we used functional magnetic resonance imaging to assess the association between delay discounting and frontostriatal resting state connectivity (rsFC). We also examined the capacity of social relationships with parents and peers to longitudinally predict frontostriatal rsFC. The study cohort was composed of 91 rural African American emerging adults followed over a 6-year period. Greater (i.e., more positive) frontostriatal rsFC was associated with decreased delay discounting (i.e., less impulsive decision making). In addition, peer relationships at ages 20 and 21 significantly predicted frontostriatal rsFC at age 25 above and beyond parental influence. A significant indirect effect of peer affiliation on delay discounting through frontostriatal rsFC also emerged. These results indicate a role of frontostriatal connectivity in delay discounting decision making and highlight peers' unique influence on decision making behaviors through frontostriatal rsFC during emerging adulthood.

PMID: 30374665 [PubMed - as supplied by publisher]

Dynamic hub load predicts cognitive decline after resective neurosurgery.

Wed, 10/31/2018 - 13:20
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Dynamic hub load predicts cognitive decline after resective neurosurgery.

Sci Rep. 2017 02 07;7:42117

Authors: Carbo EW, Hillebrand A, van Dellen E, Tewarie P, de Witt Hamer PC, Baayen JC, Klein M, Geurts JJ, Reijneveld JC, Stam CJ, Douw L

Abstract
Resective neurosurgery carries the risk of postoperative cognitive deterioration. The concept of 'hub (over)load', caused by (over)use of the most important brain regions, has been theoretically postulated in relation to symptomatology and neurological disease course, but lacks experimental confirmation. We investigated functional hub load and postsurgical cognitive deterioration in patients undergoing lesion resection. Patients (n = 28) underwent resting-state magnetoencephalography and neuropsychological assessments preoperatively and 1-year after lesion resection. We calculated stationary hub load score (SHub) indicating to what extent brain regions linked different subsystems; high SHub indicates larger processing pressure on hub regions. Dynamic hub load score (DHub) assessed its variability over time; low values, particularly in combination with high SHub values, indicate increased load, because of consistently high usage of hub regions. Hypothetically, increased SHub and decreased DHub relate to hub overload and thus poorer/deteriorating cognition. Between time points, deteriorating verbal memory performance correlated with decreasing upper alpha DHub. Moreover, preoperatively low DHub values accurately predicted declining verbal memory performance. In summary, dynamic hub load relates to cognitive functioning in patients undergoing lesion resection: postoperative cognitive decline can be tracked and even predicted using dynamic hub load, suggesting it may be used as a prognostic marker for tailored treatment planning.

PMID: 28169349 [PubMed - indexed for MEDLINE]

DRD2 methylation is associated with executive control network connectivity and severity of alcohol problems among a sample of polysubstance users.

Tue, 10/30/2018 - 12:20
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DRD2 methylation is associated with executive control network connectivity and severity of alcohol problems among a sample of polysubstance users.

Addict Biol. 2018 Oct 29;:

Authors: Hagerty SL, YorkWilliams SL, Bidwell LC, Weiland BJ, Sabbineni A, Blaine SK, Bryan AD, Hutchison KE

Abstract
Chronic exposure to alcohol and other drugs of abuse has been associated with deleterious consequences, including functional connectivity deficits within neural networks associated with executive control. Altered functional connectivity within the executive control network (ECN) might underlie the progressive inability to control consumption of alcohol and other drugs as substance use disorders progress. Genetic and epigenetic factors have been associated with substance use disorders (SUDs). For example, dopamine receptor 2 (DRD2) functioning has been associated with alcohol use disorder (AUD) and related phenotypes, including correlates of executive functioning. The present study aims to explore the relationship between a continuous measure of alcohol-related problems, epigenetic markers (methylation) within the DRD2 gene, and functional connectivity within the ECN among a sample of polysubstance users. A community sample of 658 subjects, whose consumption of alcohol, nicotine, and cannabis span across a spectrum of quantity and frequency of use, were obtained across previous studies in polysubstance using populations. Resting state functional magnetic resonance imaging was analyzed to identify intrinsic connectivity networks using a priori regions of interest. Methylation measurement of functionally relevant sites within the DRD2 gene was achieved via pyrosequencing. Regression-based models, including mediation and moderation models, tested the association between DRD2 methylation, functional connectivity within intrinsic neural networks (including the ECN), and severity of alcohol problems. Results suggest that average DRD2 methylation was negatively associated with right ECN (RECN) and left ECN (LECN) connectivity, but not associated with other networks tested, and DRD2 methylation was significantly associated with alcohol problems severity. Mediation models were not supported, although moderation models suggested that connectivity between edges within the RECN moderated the relationship between DRD2 methylation and AUD severity. Results support a theoretical model in which epigenetic factors are associated with neurobiological correlates of alcohol consumption among a sample of polysubstance users.

PMID: 30370960 [PubMed - as supplied by publisher]

Study of altered functional connectivity in individuals at risk for Alzheimer's Disease.

Tue, 10/30/2018 - 12:20
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Study of altered functional connectivity in individuals at risk for Alzheimer's Disease.

Technol Health Care. 2018;26(S1):103-111

Authors: Zhang Y, Liu X, Zhao K, Li L, Ding Y

Abstract
BACKGROUND: Mild Cognitive Impairment (MCI) has been considered to have a high risk in converting into Alzheimer's Disease (AD). Previous studies showed that AD was associated with changes in resting-state networks (RSNs). However, few studies have evaluated the altered functional connectivity in early mild cognitive impairment (EMCI) and late mild cognitive impairment (LMCI).
OBJECTIVE: The aim of this work was to evaluate the impaired network functional connectivity with the disease progression.
METHODS: In this paper, we evaluated the impaired function connectivity with the progression of disease based on a priori defined 246 regions of interest based on Brainnetome Atlas. Connectivity analysis based on three levels (node integrity, intra-network, and inter-network) was conducted.
RESULTS: Altered function connectivity was detected in several RSNs. These results provided insights into the dysfunction of more RSNs accompany the progression of AD. We also found that one brain region may belong to multiple RSNs and contribute to achieving different network function.
CONCLUSIONS: The aberrant intra- and inter-network dysfunctions might be potential biomarkers or predictors of MCI and AD progression and provide new insight into the pathophysiology of these diseases.

PMID: 29710743 [PubMed - indexed for MEDLINE]

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