New resting-state fMRI related studies at PubMed

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Identification of Subclinical Language Deficit using Machine Learning Classification based on Post-stroke Functional Connectivity derived from Low Frequency Oscillations.

Wed, 11/07/2018 - 14:40
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Identification of Subclinical Language Deficit using Machine Learning Classification based on Post-stroke Functional Connectivity derived from Low Frequency Oscillations.

Brain Connect. 2018 Nov 06;:

Authors: Mohanty R, Nair VA, Tellapragada N, Wiliams LM, Kang TJ, Prabhakaran V

Abstract
Post-stroke neuropsychological evaluation can take a long time to assess impairments in subjects without overt clinical deficits. We utilized functional connectivity (FC) from ten-minute non-invasive resting-state functional MRI (rs-fMRI) to identify stroke subjects at risk for subclinical language deficit (SLD) using a machine learning classifier. Discriminative ability of FC derived from slow-4 (0.027-0.073 Hz), slow-5 (0.01-0.027 Hz) and low frequency oscillations (LFO; 0.01-0.1 Hz) were compared. Sixty clinically non-aphasic right-handed subjects were categorized into three groups based on stroke status and normalized verbal fluency score (VFS): 20 ischemic stroke subjects at a higher risk of SLD (LD+; mean VFS=-1.77), 20 ischemic stroke subjects with lower risk of SLD (LD-; mean VFS=-0.05), 20 healthy controls (HC; mean VFS=0.29). T1-weighted and rs-fMRI scans were acquired within 30 days of stroke onset. Blood-oxygen-level-dependent signal was extracted from regions in the language network and FC based on Pearson's correlation was evaluated. Selected features were used by a multiclass support vector machine to classify test subject into one of the subgroups. Classifier performance was assessed using a nested leave-one-out cross-validation. FC derived from slow-4 (70%) band provided the best accuracy in comparison to LFO (65%) and slow-5 (50%) , reasonably higher than random chance (33.33%). Based on subgroup-specific accuracy, classification was best realized within the slow-4 band for LD+ (81.6%) and LD- (78.3%) and slow-4 and LFO bands for HC (80%), i.e., early stage stroke subjects showed a slow-4 FC dominance whereas HC also indicated the normalized involvement of FC in LFO. While frontal FC differentiated between stroke and healthy, occipital FC differentiated between the two stroke groups. We demonstrated that stroke subjects at risk for SLD can be differentiated from control subjects using rs-fMRI with a classifier with reasonable accuracy in an expedited manner, which otherwise could take longer to identify via neuropsychological assessments.

PMID: 30398379 [PubMed - as supplied by publisher]

Commute Time as a Method to Explore Brain Functional Connectomes.

Wed, 11/07/2018 - 14:40
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Commute Time as a Method to Explore Brain Functional Connectomes.

Brain Connect. 2018 Nov 06;:

Authors: Sato JR, Sato CM, Silva MC, Biazoli CE

Abstract
Graph theory has been extensively applied to investigate the brain complex networks in current neuroscience research. Many metrics derived from graph theory, such as local and global efficiencies, are based on the path length between nodes. These approaches are commonly used in the analyses of brain networks assessed by resting-state fMRI, though relying on the strong assumption that information flow throughout the network is restricted to the shortest paths. In this study, we propose the utilization of the commute time as a tool to investigate regional centrality on the functional Connectome. Our initial hypothesis was that an alternative approach that considers alternative routes (such as the commute time) could provide further information into the organization of functional networks. However, our empirical findings on the ADHD-200 database suggest that, at the group level, the commute time and shortest path are highly correlated. In contrast, at the subject level, we discovered that the commute time is much less susceptible to head motion artifacts when compared to metric based on shortest paths. Given the overall similarity between the measures, we argue that commute time might be advantageous particularly for connectomic studies in populations where motion artifacts are a major issue.

PMID: 30398376 [PubMed - as supplied by publisher]

Effective Connectivity Within the Default Mode Network In Left Temporal Lobe Epilepsy: Findings from the Epilepsy Connectome Project.

Wed, 11/07/2018 - 14:40
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Effective Connectivity Within the Default Mode Network In Left Temporal Lobe Epilepsy: Findings from the Epilepsy Connectome Project.

Brain Connect. 2018 Nov 06;:

Authors: Cook CJ, Hwang G, Mathis J, Nair VA, Conant L, Allen L, Almane DN, Birn R, DeYoe E, Felton E, Forseth C, Humphries C, Kraegel P, Nencka A, Nwoke O, Raghavan M, Rivera-Bonet C, Rozman M, Tellapragada N, Ustine C, Ward D, Struck A, Maganti R, Hermann B, Prabhakaran V, Binder J, Meyerand ME

Abstract
The Epilepsy Connectome Project examines the differences in connectomes between temporal lobe epilepsy (TLE) patients and healthy controls. Using this data, the effective connectivity of the default mode network in patients with left TLE compared to healthy controls was investigated using spectral dynamic causal modeling of resting state functional magnetic resonance imaging data. Group comparisons were made using two parametric empirical Bayes (PEB) models. The first level of each PEB model consisted of each participant's spectral dynamic causal modeling. Two different second level models were constructed: the first comparing effective connectivity of the groups directly and the second using the Rey Auditory Verbal Learning Test (RAVLT) delayed free recall index as a covariate at the second level in order to assess effective connectivity controlling for the poor memory performance of left TLE patients. After an automated search over the nested parameter space and thresholding parameters at 95% posterior probability, both models revealed numerous connections in the DMN which lead to inhibition of the left hippocampal formation. Left hippocampal formation inhibition may be an inherent result of the left temporal epileptogenic focus as memory differences were controlled for in one model and the same connections remained. An excitatory connection from the posterior cingulate cortex to the medial prefrontal cortex was found to be concomitant with left hippocampal formation inhibition in TLE patients when including RAVLT delayed free recall at the second level.

PMID: 30398367 [PubMed - as supplied by publisher]

Characterizing directed functional pathways in the visual system by multivariate nonlinear coherence of fMRI data.

Wed, 11/07/2018 - 14:40
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Characterizing directed functional pathways in the visual system by multivariate nonlinear coherence of fMRI data.

Sci Rep. 2018 Nov 05;8(1):16362

Authors: Goelman G, Dan R, Keadan T

Abstract
A multivariate measure of directed functional connectivity is used with resting-state fMRI data of 40 healthy subjects to identify directed pathways of signal progression in the human visual system. The method utilizes 4-nodes networks of mutual interacted BOLD signals to obtains their temporal hierarchy and functional connectivity. Patterns of signal progression were defined at frequency windows by appealing to a hierarchy based upon phase differences, and their significance was assessed by permutation testing. Assuming consistent phase relationship between neuronal and fMRI signals and unidirectional coupling, we were able to characterize directed pathways in the visual system. The ventral and dorsal systems were found to have different functional organizations. The dorsal system, particularly of the left hemisphere, had numerous feedforward pathways connecting the striate and extrastriate cortices with non-visual regions. The ventral system had fewer pathways primarily of two types: (1) feedback pathways initiated in the fusiform gyrus that were either confined to the striate and the extrastriate cortices or connected to the temporal cortex, (2) feedforward pathways initiated in V2, excluded the striate cortex, and connected to non-visual regions. The multivariate measure demonstrated higher specificity than bivariate (pairwise) measure. The analysis can be applied to other neuroimaging and electrophysiological data.

PMID: 30397245 [PubMed - in process]

Intrinsic insula network engagement underlying children's reading and arithmetic skills.

Wed, 11/07/2018 - 14:40
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Intrinsic insula network engagement underlying children's reading and arithmetic skills.

Neuroimage. 2018 02 15;167:162-177

Authors: Chang TT, Lee PH, Metcalfe AWS

Abstract
The neural substrates of children's reading and arithmetic skills have long been of great interest to cognitive neuroscientists. However, most previous studies have focused on the contrast between these skills as specific domains. Here, we investigate the potentially shared processes across these domains by focusing on how the neural circuits associated with cognitive control influence reading and arithmetic proficiency in 8-to-10-year-old children. Using a task-free resting state approach, we correlated the intrinsic functional connectivity of the right anterior insula (rAI) network with performance on assessments of Chinese character recognition, reading comprehension, subtraction, and multiplication performance. A common rAI network strengthened for reading and arithmetic skill, including the right middle temporal gyrus (MTG) and superior temporal gyrus (STG) in the lateral temporal cortex, as well as the inferior frontal gyrus (IFG). In addition, performance measures evidenced rAI network specializations. Single character recognition was uniquely associated with connectivity to the right superior parietal lobule (SPL). Reading comprehension only, rather than character recognition, was associated with connectivity to the right IFG, MTG and angular gyrus (AG). Furthermore, subtraction was associated with connectivity to premotor cortex whereas multiplication was associated with the supramarginal gyrus. Only reading comprehension and multiplication were associated with hyper connectivity within local rAI network. These results indicate that during a critical period for children's acquisition of reading and arithmetic, these skills are supported by both intra-network synchronization and inter-network connectivity of rAI circuits. Domain-general intrinsic insular connectivity at rest contained also, functional components that segregated into different sets of skill-related networks. The embedded components of cognitive control may be essential to understanding the interplay of multiple functional circuits necessary to more fully characterize cognitive skill acquisition.

PMID: 29162521 [PubMed - indexed for MEDLINE]

resting state fMRI; +21 new citations

Tue, 11/06/2018 - 13:07

21 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results:

resting state fMRI

These pubmed results were generated on 2018/11/06

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Decreased subregional specificity of the putamen in Parkinson's Disease revealed by dynamic connectivity-derived parcellation.

Sat, 11/03/2018 - 16:20

Decreased subregional specificity of the putamen in Parkinson's Disease revealed by dynamic connectivity-derived parcellation.

Neuroimage Clin. 2018 Oct 23;20:1163-1175

Authors: Liu A, Lin SJ, Mi T, Chen X, Chan P, Wang ZJ, McKeown MJ

Abstract
Parkinson's Disease (PD) is associated with decreased ability to perform habitual tasks, relying instead on goal-directed behaviour subserved by different cortical/subcortical circuits, including parts of the putamen. We explored the functional subunits in the putamen in PD using novel dynamic connectivity features derived from resting state fMRI recorded from thirty PD subjects and twenty-eight age-matched healthy controls (HC). Dynamic functional segmentation of the putamina was obtained by determining the correlation between each voxel in each putamen along a moving window and applying a joint temporal clustering algorithm to establish cluster membership of each voxel at each window. Contiguous voxels that had consistent cluster membership across all windows were then considered to be part of a homogeneous functional subunit. As PD subjects robustly had two homogenous clusters in the putamina, we also segmented the putamina in HC into two dynamic clusters for a fair comparison. We then estimated the dynamic connectivity using sliding windowed correlation between the mean signal from the identified homogenous subunits and 56 other predefined cortical and subcortical ROIs. Specifically, the mean dynamic connectivity strength and connectivity deviation were then compared to evaluate subregional differences. HC subjects had significant differences in mean dynamic connectivity and connectivity deviation between the two putaminal subunits. The posterior subunit connected strongly to sensorimotor areas, the cerebellum, as well as the middle frontal gyrus. The anterior subunit had strong mean dynamic connectivity to the nucleus accumbens, hippocampus, amygdala, caudate and cingulate. In contrast, PD subjects had fewer differences in mean dynamic connectivity between subunits, indicating a degradation of subregional specificity. Overall UPDRS III and MoCA scores could be predicted using mean dynamic connectivity strength and connectivity deviation. Side of onset of the disease was also jointly related with functional connectivity features. Our results suggest a robust loss of specificity of mean dynamic connectivity and connectivity deviation in putaminal subunits in PD that is sensitive to disease severity. In addition, altered mean dynamic connectivity and connectivity deviation features in PD suggest that looking at connectivity dynamics offers an additional dimension for assessment of neurodegenerative disorders.

PMID: 30388599 [PubMed - as supplied by publisher]

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
Related Articles

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]

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