New resting-state fMRI related studies at PubMed

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Does development moderate the effect of early life assaultive violence on resting-state networks? An exploratory study.

Sat, 09/29/2018 - 14:40
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Does development moderate the effect of early life assaultive violence on resting-state networks? An exploratory study.

Psychiatry Res Neuroimaging. 2018 Aug 27;281:69-77

Authors: Zielinski MJ, Privratsky AA, Smitherman S, Kilts CD, Herringa RJ, Cisler JM

Abstract
Current neurocircuitry models of PTSD do not account for developmental effects, despite that early life assaultive violence is a potent risk factor for PTSD. Here, we preliminarily evaluated developmental stage as a moderator of the effect of early life assaultive violence on resting-state connectivity amongst regions associated with emotion generation and regulation using fMRI. Participants were adult women (n = 25) and adolescent girls (n = 36) who had or had not experienced early life assaultive violence. We found significant interactions between developmental stage and trauma exposure on resting-state functional connectivity (FC). Left amygdala connectivity with the left ventral anterior cingulate gyrus (BA 32) was reduced among trauma-exposed compared to control adolescents, but increased among trauma-exposed compared to control adults. A corresponding pattern of results was identified for FC between rostral anterior cingulate gyrus seed region and a similar right ventral anterior superior frontal gyrus cluster. Increased FC in both regions for assaulted adult women scaled positively with self-reported emotion regulation difficulties. Our results should be viewed tentatively due to sample limitations, but provide impetus to examine whether neurocircuitry models of PTSD may be strengthened by accounting for developmental stage.

PMID: 30266022 [PubMed - as supplied by publisher]

A preliminary randomized clinical trial of naltrexone reduces striatal resting state functional connectivity in people with methamphetamine use disorder.

Sat, 09/29/2018 - 14:40
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A preliminary randomized clinical trial of naltrexone reduces striatal resting state functional connectivity in people with methamphetamine use disorder.

Drug Alcohol Depend. 2018 Sep 21;192:186-192

Authors: Kohno M, Dennis LE, McCready H, Schwartz DL, Hoffman WF, Korthuis PT

Abstract
OBJECTIVE: Naltrexone has been shown to attenuate craving and the subjective effects of methamphetamine. Although naltrexone has modulatory effects on neural activity at dopaminergic synapses, the effect on striatal connectivity is unclear. As methamphetamine use is associated with greater resting-state functional connectivity (RSFC) in the dopaminergic system, we examined whether extended-release naltrexone (XR-NTX) can normalize striatal connectivity and whether changes in RSFC are associated with changes in craving and methamphetamine use.
METHODS: Thirty-seven participants in or seeking treatment for methamphetamine use disorder took part in this clinical trial at a university-based research clinic between May 2013 and March 2015 (Clinicaltrials.gov NCT01822132). Participants were randomized by a random number generator to a single four-week injection of XR-NTX or placebo. Functional magnetic resonance imaging (fMRI) and self-reported measures of craving and methamphetamine use were conducted before and after double-blinded randomization.
FINDINGS: There was a significant reduction in methamphetamine use in the naltrexone group and a significant treatment-by-time interaction on RSFC between the ventral striatum, amygdala, hippocampus, and midbrain. Connectivity was significantly reduced over time in participants randomized to naltrexone but unchanged in those randomized to placebo (p < 0.05, whole-brain corrected). Interactions between treatment and changes in connectivity show that significant reductions in connectivity were associated with reductions in methamphetamine use.
CONCLUSIONS: Neurobiological deficits associated with methamphetamine use may undermine the efficacy of pharmacotherapies that directly target the dopamine reward system. Naltrexone, via antagonism of indirect mu-opioid effects on dopamine neurons, may attenuate reward system connectivity and aid in methamphetamine use treatment.

PMID: 30266003 [PubMed - as supplied by publisher]

Quantifying and Visualizing Intraregional Connectivity in Resting-State Functional Magnetic Resonance Imaging with Correlation Densities.

Sat, 09/29/2018 - 14:40
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Quantifying and Visualizing Intraregional Connectivity in Resting-State Functional Magnetic Resonance Imaging with Correlation Densities.

Brain Connect. 2018 Sep 28;:

Authors: Petersen A, Chen CJ, Müller HG

Abstract
The use of correlation densities is introduced to quantify and provide visual interpretation for intraregional functional connectivity in the brain. For each brain region, pairwise correlations are computed between a seed voxel and other gray matter voxels within the region, and the distribution of the ensemble of these correlation values is represented as a probability density, the correlation density. The correlation density can be estimated by kernel smoothing. It provides an intuitive and comprehensive representation of subject-specific functional connectivity strength at the local level for each region. To address the challenge of interpreting and utilizing this rich connectivity information when multiple regions are considered, methods from functional data analysis are implemented, including a recently developed method of dimensionality reduction specifically tailored to the analysis of probability distributions. To illustrate the utility of these methods in neuroimaging, experiments were carried out to identify the associations between local functional connectivity and a battery of neurocognitive scores. These experiments demonstrate that correlation densities facilitate the discovery and interpretation of specific region-score associations.

PMID: 30265561 [PubMed - as supplied by publisher]

Extending the human connectome project across ages: Imaging protocols for the Lifespan development and aging projects.

Fri, 09/28/2018 - 13:40
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Extending the human connectome project across ages: Imaging protocols for the Lifespan development and aging projects.

Neuroimage. 2018 Sep 24;:

Authors: Harms MP, Somerville LH, Ances BM, Andersson J, Barch DM, Bastiani M, Bookheimer SY, Brown TB, Buckner RL, Burgess GC, Coalson TS, Chappell MA, Dapretto M, Douaud G, Fischl B, Glasser MF, Greve DN, Hodge C, Jamison KW, Jbabdi S, Kandala S, Li X, Mair RW, Mangia S, Marcus D, Mascali D, Moeller S, Nichols TE, Robinson EC, Salat DH, Smith SM, Sotiropoulos SN, Terpstra M, Thomas KM, Tisdall MD, Ugurbil K, van der Kouwe A, Woods RP, Zöllei L, Van Essen DC, Yacoub E

Abstract
The Human Connectome Projects in Development (HCP-D) and Aging (HCP-A) are two large-scale brain imaging studies that will extend the recently completed HCP Young-Adult (HCP-YA) project to nearly the full lifespan, collecting structural, resting-state fMRI, task-fMRI, diffusion, and perfusion MRI in participants from 5 to 100 + years of age. HCP-D is enrolling 1300 + healthy children, adolescents, and young adults (ages 5-21), and HCP-A is enrolling 1200 + healthy adults (ages 36-100+), with each study collecting longitudinal data in a subset of individuals at particular age ranges. The imaging protocols of the HCP-D and HCP-A studies are very similar, differing primarily in the selection of different task-fMRI paradigms. We strove to harmonize the imaging protocol to the greatest extent feasible with the completed HCP-YA (1200 + participants, aged 22-35), but some imaging-related changes were motivated or necessitated by hardware changes, the need to reduce the total amount of scanning per participant, and/or the additional challenges of working with young and elderly populations. Here, we provide an overview of the common HCP-D/A imaging protocol including data and rationales for protocol decisions and changes relative to HCP-YA. The result will be a large, rich, multi-modal, and freely available set of consistently acquired data for use by the scientific community to investigate and define normative developmental and aging related changes in the healthy human brain.

PMID: 30261308 [PubMed - as supplied by publisher]

Disentangling common from specific processing across tasks using task potency.

Fri, 09/28/2018 - 13:40
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Disentangling common from specific processing across tasks using task potency.

Neuroimage. 2018 Sep 24;:

Authors: Chauvin RJ, Mennes M, Llera A, Buitelaar JK, Beckmann CF

Abstract
When an individual engages in a task, the associated evoked activities build upon already ongoing activity, shaped by an underlying functional connectivity baseline (Fox et al., 2009; Smith et al., 2009; Tavor et al., 2016). Building on the idea that rest represents the brain's full functional repertoire, we here incorporate the idea that task-induced functional connectivity modulations ought to be task-specific with respect to their underlying resting state functional connectivity. Various metrics such as clustering coefficient or average path length have been proposed to index processing efficiency, typically from single fMRI session data. We introduce a framework incorporating task potency, which provides direct access to task-specificity by enabling direct comparison between task paradigms. In particular, to study functional connectivity modulations related to cognitive involvement in a task we define task potency as the amplitude of a connectivity modulation away from its baseline functional connectivity architecture as observed during a resting state acquisition. We demonstrate the use of our framework by comparing three tasks (visuo-spatial working memory, reward processing, and stop signal task) available within a large cohort. Using task potency, we demonstrate that cognitive operations are supported by a set of common within-network interactions, supplemented by connections between large-scale networks in order to solve a specific task.

PMID: 30261307 [PubMed - as supplied by publisher]

Alterations in intrinsic fronto-thalamo-parietal connectivity are associated with cognitive control deficits in psychotic disorders.

Fri, 09/28/2018 - 13:40
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Alterations in intrinsic fronto-thalamo-parietal connectivity are associated with cognitive control deficits in psychotic disorders.

Hum Brain Mapp. 2018 Sep 10;:

Authors: Lencer R, Yao L, Reilly JL, Keedy SK, McDowell JE, Keshavan MS, Pearlson GD, Tamminga CA, Gershon ES, Clementz BA, Lui S, Sweeney JA

Abstract
Despite a growing number of reports about alterations in intrinsic/resting brain activity observed in patients with psychotic disorders, their relevance to well-established cognitive control deficits in this patient group is not well understood. Totally 88 clinically stabilized patients with a psychotic disorder and 50 healthy controls participated in a resting-state magnetic resonance imaging study (rs-MRI) and performed an antisaccade task in the laboratory to assess voluntary inhibitory control ability. Deficits on this task are a well-established biomarker across psychotic disorders as we found in the present patient sample. First, regional cerebral function was evaluated by measuring the amplitude of low frequency fluctuations (ALFF) in rs-MRI BOLD signals. We found reduced ALFF in patients in regions known to be relevant to antisaccade task performance including bilateral frontal eye fields (FEF), supplementary eye fields (SEF) and thalamus. Second, areas with ALFF alterations were used as seed areas in whole-brain functional connectivity (FC) analysis. Altered FC was observed in a fronto-thalamo-parietal network that was associated with inhibition error rate in patients but not in controls. In contrast, faster time to generate a correct antisaccade was associated with FC in FEF and SEF in controls but this effect was not seen in patients. These findings establish a behavioral relevance of resting-state fMRI findings in psychotic disorders, and extend previous reports of alterations in fronto-thalamo-parietal network activation during antisaccade performance seen in task-based fMRI studies.

PMID: 30260540 [PubMed - as supplied by publisher]

Exposure-based therapy changes amygdala and hippocampus resting-state functional connectivity in patients with posttraumatic stress disorder.

Fri, 09/28/2018 - 13:40
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Exposure-based therapy changes amygdala and hippocampus resting-state functional connectivity in patients with posttraumatic stress disorder.

Depress Anxiety. 2018 Sep 10;:

Authors: Zhu X, Suarez-Jimenez B, Lazarov A, Helpman L, Papini S, Lowell A, Durosky A, Lindquist MA, Markowitz JC, Schneier F, Wager TD, Neria Y

Abstract
BACKGROUND: Recent research suggests that posttraumatic stress disorder (PTSD) is associated with altered amygdala and hippocampal resting-state functional connectivity (rsFC). However, less research has examined whether Prolonged Exposure (PE), a first line exposure-based treatment for PTSD, has the potential to alter resting state neural networks.
METHODS: A total of 24 patients with PTSD and 26 matched trauma-exposed healthy controls (TEHCs) underwent resting-state functional magnetic resonance imaging (fMRI) at baseline. PTSD patients were scanned a second time after completing 10-session PE in which patients narrated a detailed trauma account (imaginal exposure) and confronted trauma reminders (in vivo exposure) to extinguish trauma-related fear responses. TEHC were scanned again following a 10-week waiting period. Seed regions of interest (ROIs) included centromedial amygdala (CMA), basolateral amygdala (BLA), and the hippocampus.
RESULTS: Post- versus pretreatment comparisons indicated increased rsFC of the BLA and CMA with the orbitofrontal cortex (OFC), and hippocampus-medial prefrontal cortex (mPFC) among patients with PTSD, but not among TEHC participants.
CONCLUSIONS: Enhanced amygdala and hippocampus rsFC with prefrontal cortical regions following PE could underlie improved capacity for inhibition and re-evaluation of threat, and heightened memory encoding and retrieval ability, respectively. These findings encourage further investigation of this circuitry as a therapeutic target in PTSD.

PMID: 30260530 [PubMed - as supplied by publisher]

A Connectomic Atlas of the Human Cerebrum-Chapter 18: The Connectional Anatomy of Human Brain Networks.

Fri, 09/28/2018 - 13:40
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A Connectomic Atlas of the Human Cerebrum-Chapter 18: The Connectional Anatomy of Human Brain Networks.

Oper Neurosurg (Hagerstown). 2018 Sep 27;:

Authors: Briggs RG, Conner AK, Baker CM, Burks JD, Glenn CA, Sali G, Battiste JD, O'Donoghue DL, Sughrue ME

Abstract
BACKGROUND: It is widely understood that cortical functions are mediated by complex, interdependent brain networks. These networks have been identified and studied using novel technologies such as functional magnetic resonance imaging under both resting-state and task-based conditions. However, no one has attempted to describe these networks in terms of their cortical parcellations.
OBJECTIVE: To describe our approach to network modeling and discuss its significance for the future of neuronavigation in brain surgery using the cortical parcellation scheme detailed within this supplement.
METHODS: Using network models previously elucidated by our group using coordinate-based meta-analytic techniques, we show the anatomic position and underlying white matter tracts of the cortical regions comprising 8 functional networks of the human cerebrum. These network models are displayed using Synaptive's clinically available BrightMatter tractography software (Synaptive Medical, Toronto, Canada).
RESULTS: The relevant cortical parcellations of 8 different cerebral networks have been identified. The fiber tracts between these regions were used to construct anatomically precise models of the networks. Models are described for the dorsal attention, ventral attention, semantic, auditory, supplementary motor, ventral premotor, default mode, and salience networks.
CONCLUSION: Our goal is to move towards more precise, anatomically specific models of brain networks that can be constructed for individual patients and utilized in navigational platforms during brain surgery. We believe network modeling and future advances in navigation technology can provide a foundation for improving neurosurgical outcomes by allowing us to preserve complex brain networks.

PMID: 30260432 [PubMed - as supplied by publisher]

Neural correlates of future-oriented coping: Preliminary evidence from a resting-state functional connectivity study.

Fri, 09/28/2018 - 13:40
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Neural correlates of future-oriented coping: Preliminary evidence from a resting-state functional connectivity study.

Psych J. 2018 Sep 26;:

Authors: Zhang RT, Yang TX, Wang Y, Sui YX, Yao JJ, Yang ZY, Lui SSY, Cheung EFC, Chan RCK

Abstract
Future-oriented coping is a strategy for coping with events that may happen in the future, including efforts to ensure positive outcome and protection from potential threats. Appropriate future-oriented coping is essential for well-being and influences mental health and life satisfaction. However, little is known about the neural mechanism of future-oriented coping. We examined the neural basis of this coping strategy using resting-state functional connectivity analysis. Thirty healthy volunteers underwent resting-state functional magnetic resonance imaging scanning and completed the Future-Oriented Coping Inventory. Seed-based functional connectivity analysis was used to investigate potentially correlated regions, with 11 nodes in the default mode network defined as regions of interest. Multiple regression analysis was performed to measure the correlation between coping behavior and functional connectivity. We found that proactive coping was significantly correlated with the functional connectivity strength between the parahippocampal cortex (PHC) and the claustrum/insula. These novel findings suggest that cooperation between the PHC and the claustrum/insula plays an important role in proactive coping. Moreover, cognitive components, such as future thinking (the PHC) and sensory judgment (the claustrum/insula) could be important process factors in proactive coping.

PMID: 30259698 [PubMed - as supplied by publisher]

Complexity of brain activity and connectivity in functional neuroimaging.

Fri, 09/28/2018 - 13:40
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Complexity of brain activity and connectivity in functional neuroimaging.

J Neurosci Res. 2018 Nov;96(11):1741-1757

Authors: Dimitriadis SI

Abstract
Understanding the complexity of human brain dynamics and brain connectivity across the repertoire of functional neuroimaging and various conditions, is of paramount importance. Novel measures should be designed tailored to the input focusing on multichannel activity and dynamic functional brain connectivity (DFBC). Here, we defined a novel complexity index (CI) from the field of symbolic dynamics that quantifies patterns of different words up to a length from a symbolic sequence. The CI characterizes the complexity of the brain activity. We analysed DFBC by adopting the sliding window approach using imaginary part of phase locking value (iPLV) for EEG/ECoG/MEG and wavelet coherence (WC) for fMRI. Both intra and cross-frequency couplings (CFC) namely phase-to-amplitude were estimated using iPLV/WC at every snapshot of the DFBC. Using proper surrogate analysis, we defined the dominant intrinsic coupling mode (DICM) per pair of regions-of-interest (ROI). The spatiotemporal probability distribution of DICM were reported to reveal the most prominent coupling modes per condition and modality. Finally, a novel flexibility index is defined that quantifies the transition of DICM per pair of ROIs between consecutive time windows. The whole methodology was demonstrated using four neuroimaging datasets (EEG/ECoG/MEG/fMRI). Finally, we succeeded to totally discriminate healthy controls from schizophrenic using FI and dynamic reconfiguration of DICM. Anaesthesia independently of the drug caused a global decreased of complexity in all frequency bands with the exception in δ and alters the dynamic reconfiguration of DICM. CI and DICM of MEG/fMRI resting-state recordings in two spatial scales were high reliable.

PMID: 30259561 [PubMed - in process]

Dysregulation within the salience network and default mode network in hyperthyroid patients: a follow-up resting-state functional MRI study.

Fri, 09/28/2018 - 13:40
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Dysregulation within the salience network and default mode network in hyperthyroid patients: a follow-up resting-state functional MRI study.

Brain Imaging Behav. 2018 Sep 26;:

Authors: Liu B, Wen L, Ran Q, Zhang S, Hu J, Gong M, Zhang D

Abstract
This study investigated the aberrant connectivity of the salience network (SN) and default mode network (DMN) and the relevance between these abnormalities and symptom improvement in hyperthyroid patients using resting-state functional magnetic resonance imaging (rs-fMRI). Seed-based functional connectivity (FC) analyses were performed on state fMRI data to reveal possible differences in critical node connectivity in the SN and DMN between 41 new-onset, untreated hyperthyroid patients and 41 healthy controls. Subsequently, follow-up data were available for 25 patients treated with methimazole for one month. Compared with the healthy controls, the patients exhibited abnormal internetwork FC from the SN to the DMN and the executive control network (ECN) and decreased intra-network FC within the SN. Relative to the hyperthyroid state, the antithyroid therapy induced reversible connectivity of the left insula to the dorsal anterior cingulate cortex(dACC)and ECN, and persistently increased connectivity between the SN and DMN in patients with improved thyroid function. Finally, Pearson's correlation analyses were performed among the abnormal FC, neuropsychological assessment and serum free triiodothyronine(FT3)level data. The results indicated that aberrant intra- and internetwork FC in the SN and DMN might underlie the pathogenesis of hyperthyroidism, and antithyroid treatment could regulate the FC of certain key brain regions within the SN and DMN in hyperthyroid patients.

PMID: 30259292 [PubMed - as supplied by publisher]

A Heartbeat Away From Consciousness: Heart Rate Variability Entropy Can Discriminate Disorders of Consciousness and Is Correlated With Resting-State fMRI Brain Connectivity of the Central Autonomic Network.

Fri, 09/28/2018 - 13:40
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A Heartbeat Away From Consciousness: Heart Rate Variability Entropy Can Discriminate Disorders of Consciousness and Is Correlated With Resting-State fMRI Brain Connectivity of the Central Autonomic Network.

Front Neurol. 2018;9:769

Authors: Riganello F, Larroque SK, Bahri MA, Heine L, Martial C, Carrière M, Charland-Verville V, Aubinet C, Vanhaudenhuyse A, Chatelle C, Laureys S, Di Perri C

Abstract
Background: Disorders of consciousness are challenging to diagnose, with inconsistent behavioral responses, motor and cognitive disabilities, leading to approximately 40% misdiagnoses. Heart rate variability (HRV) reflects the complexity of the heart-brain two-way dynamic interactions. HRV entropy analysis quantifies the unpredictability and complexity of the heart rate beats intervals. We here investigate the complexity index (CI), a score of HRV complexity by aggregating the non-linear multi-scale entropies over a range of time scales, and its discriminative power in chronic patients with unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS), and its relation to brain functional connectivity. Methods: We investigated the CI in short (CIs) and long (CIl) time scales in 14 UWS and 16 MCS sedated. CI for MCS and UWS groups were compared using a Mann-Whitney exact test. Spearman's correlation tests were conducted between the Coma Recovery Scale-revised (CRS-R) and both CI. Discriminative power of both CI was assessed with One-R machine learning model. Correlation between CI and brain connectivity (detected with functional magnetic resonance imagery using seed-based and hypothesis-free intrinsic connectivity) was investigated using a linear regression in a subgroup of 10 UWS and 11 MCS patients with sufficient image quality. Results: Higher CIs and CIl values were observed in MCS compared to UWS. Positive correlations were found between CRS-R and both CI. The One-R classifier selected CIl as the best discriminator between UWS and MCS with 90% accuracy, 7% false positive and 13% false negative rates after a 10-fold cross-validation test. Positive correlations were observed between both CI and the recovery of functional connectivity of brain areas belonging to the central autonomic networks (CAN). Conclusion: CI of MCS compared to UWS patients has high discriminative power and low false negative rate at one third of the estimated human assessors' misdiagnosis, providing an easy, inexpensive and non-invasive diagnostic tool. CI reflects functional connectivity changes in the CAN, suggesting that CI can provide an indirect way to screen and monitor connectivity changes in this neural system. Future studies should assess the extent of CI's predictive power in a larger cohort of patients and prognostic power in acute patients.

PMID: 30258400 [PubMed]

Learning Brain Connectivity Sub-networks by Group- Constrained Sparse Inverse Covariance Estimation for Alzheimer's Disease Classification.

Fri, 09/28/2018 - 13:40
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Learning Brain Connectivity Sub-networks by Group- Constrained Sparse Inverse Covariance Estimation for Alzheimer's Disease Classification.

Front Neuroinform. 2018;12:58

Authors: Li Y, Liu J, Huang J, Li Z, Liang P

Abstract
Background/Aims: Brain functional connectivity networks constructed from resting-state functional magnetic resonance imaging (rs-fMRI) have been widely used for classifying Alzheimer's disease (AD) from normal controls (NC). However, conventional correlation analysis methods only capture the pairwise information, which may not be capable of revealing an adequate and accurate functional connectivity relationship among brain regions in the whole brain. Additionally, the non-sparse connectivity networks commonly contain a large number of spurious or insignificant connections, which are inconsistent with the sparse connectivity of actual brain networks in nature and may deteriorate the classification performance of Alzheimer's disease. Methods: To address these problems, in this paper, a new classification framework is proposed by combining the Group-constrained topology structure detection with sparse inverse covariance estimation (SICE) method to build the functional brain sub-network for each brain region. Particularly, to tune the sensitive analysis of the regularized parameters in the SICE method, a nested leave-one-out cross-validation (LOOCV) method is adopted. Sparse functional connectivity networks are thus effectively constructed by using the optimal regularized parameters. Finally, a decision classification tree (DCT) classifier is trained for classifying AD from NC based on these optimal functional brain sub-networks. The convergence performance of our proposed method is furthermore evaluated by the trend of coefficient variation. Results: Experiment results indicate that a LOOCV classification accuracy of 81.82% with a sensitivity of 80.00%, and a specificity of 83.33% can be obtained by using the proposed method for the classification AD from NC, and outperforms the most state-of-the-art methods in terms of the classification accuracy. Additionally, the experiment results of the convergence performance further suggest that our proposed scheme has a high rate of convergence. Particularly, the abnormal brain regions and functional connections identified by our proposed framework are highly associated with the underpinning pathological mechanism of the AD, which are consistent with previous studies. Conclusion: These results have demonstrated the effectiveness of the proposed Group- constrained SICE method, and are capable of clinical value to the diagnosis of Alzheimer's disease.

PMID: 30258358 [PubMed]

Assessing cortical plasticity after spinal cord injury by using resting-state functional magnetic resonance imaging in awake adult mice.

Fri, 09/28/2018 - 13:40
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Assessing cortical plasticity after spinal cord injury by using resting-state functional magnetic resonance imaging in awake adult mice.

Sci Rep. 2018 Sep 26;8(1):14406

Authors: Matsubayashi K, Nagoshi N, Komaki Y, Kojima K, Shinozaki M, Tsuji O, Iwanami A, Ishihara R, Takata N, Matsumoto M, Mimura M, Okano H, Nakamura M

Abstract
Neural connectivity has recently been shown to be altered after spinal cord injury (SCI) not only in the spinal cord but also in the brain. However, to date, no studies have analyzed the functional alterations after SCI in various areas of the cerebral cortex over time. To examine the plasticity of the neural connectivity in the brain after SCI, we performed resting-state functional magnetic resonance imaging (rs-fMRI) in awake adult mice pre- and post-SCI. After a complete thoracic SCI, the functional connectivity between the primary motor (MOp) and primary sensory (SSp) areas was significantly decreased during the chronic phase. In contrast, the connectivity between the MOp and motivation area was increased. Thus, impairments in sensory and motor connections after SCI led to a time-dependent compensatory upregulation of "motor functional motivation". Moreover, the functional connectivity between the SSp and pain-related areas, such as the caudoputamen (CP) and the anterior cingulate area (ACA), was strengthened during the chronic phase, thus suggesting that rs-fMRI can indicate the presence of neuropathic pain after SCI. Therefore, rs-fMRI is a useful tool for revealing the pathological changes that occur in the brain after SCI.

PMID: 30258091 [PubMed - in process]

Interaction of systemic oxidative stress and mesial temporal network degeneration in Parkinson's disease with and without cognitive impairment.

Fri, 09/28/2018 - 13:40
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Interaction of systemic oxidative stress and mesial temporal network degeneration in Parkinson's disease with and without cognitive impairment.

J Neuroinflammation. 2018 Sep 26;15(1):281

Authors: Chiang PL, Chen HL, Lu CH, Chen YS, Chou KH, Hsu TW, Chen MH, Tsai NW, Li SH, Lin WC

Abstract
BACKGROUND: To identify the vulnerable areas associated with systemic oxidative stress and further disruption of these vulnerable areas by measuring the associated morphology and functional network alterations in Parkinson's disease (PD) patients with and without cognitive impairment.
METHODS: This prospective study was approved by the institutional review board of KCGMH, and written informed consent was obtained. Between December 2010 and May 2015, 41 PD patients with different levels of cognitive functions and 29 healthy volunteers underwent peripheral blood sampling to quantify systemic oxidative stress, as well as T1W volumetric and resting state functional MRI (rs-fMRI) scans. Rs-fMRI was used to derive the healthy intrinsic connectivity patterns seeded by the vulnerable areas associated with any of the significant oxidative stress markers. The two groups were compared in terms of the functional connectivity correlation coefficient (fc-CC) and gray matter volume (GMV) of the network seeded by the vulnerable areas.
RESULTS: The levels of oxidative stress markers, including leukocyte apoptosis and adhesion molecules, were significantly higher in the PD group. Using whole-brain VBM-based correlation analysis, the bilateral mesial temporal lobes (MTLs) were identified as the most vulnerable areas associated with lymphocyte apoptosis (P < 0.005). We found that the MTL network of healthy subjects resembled the PD-associated atrophy pattern. Furthermore, reduced fc-CC and GMV were further associated with the aggravated cognitive impairment.
CONCLUSION: The MTLs are the vulnerable areas associated with peripheral lymphocyte infiltration, and disruptions of the MTL functional network in both architecture and functional connectivity might result in cognitive impairments in Parkinson's disease.

PMID: 30257698 [PubMed - in process]

Dorsal and ventral PCC switch network assignment via changes in relative functional connectivity strength to non-canonical networks.

Thu, 09/27/2018 - 12:40
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Dorsal and ventral PCC switch network assignment via changes in relative functional connectivity strength to non-canonical networks.

Brain Connect. 2018 Sep 26;:

Authors: Fan Y, Borchardt V, von Düring F, Leutritz AL, Dietz M, Herrera-Meléndez AL, Bajbouj M, Li M, Grimm S, Walter M

Abstract
The Posterior Cingulate Cortex (PCC) is often used as seed region for probing Default Mode Network (DMN) connectivity. However, there is evidence for a functional segregation between its dorsal (dPCC) and ventral (vPCC) subregions, which suggests differential involvements of d-/vPCC in regulating cognitive demands. Our paradigm included fMRI measures for baseline resting-state, affective or cognitive tasks, and post-task resting-states. We investigated the effect of task demands on intra-PCC coupling and d-/vPCC network assignment to major intrinsic connectivity networks (ICNs), which was estimated via edge weights of a graph network encompassing DMN, Dorsal Attention Network, and Central Executive Network (CEN). While PCC subregions were functionally coupled during both resting-state conditions and cognitive tasks, they decoupled during affective stimulation. For dPCC, functional connectivity strength (FCS) to CEN was higher than to the other two ICNs, whereas for vPCC FCS to DMN was highest. We hence defined CEN and DMN as the canonical networks at rest for dPCC and vPCC, respectively. Switching from rest to affective stimulation however induced strongest effects to relative network assignments between non-canonical networks of dorsal and ventral PCC. While vPCC showed a durable FC to DMN, dPCC played a crucial role during switches of between-network FC depending on cognitive versus affective task requirements. Our results underline that it is crucial for future seed-based FC studies to consider these two subregions separately in terms of seed location and discussion of findings. Finally, our findings highlight the functional importance of connectivity changes towards regions outside the canonical networks.

PMID: 30255708 [PubMed - as supplied by publisher]

Altered Dynamic Functional Network Connectivity in Frontal Lobe Epilepsy.

Thu, 09/27/2018 - 12:40
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Altered Dynamic Functional Network Connectivity in Frontal Lobe Epilepsy.

Brain Topogr. 2018 Sep 25;:

Authors: Klugah-Brown B, Luo C, He H, Jiang S, Armah GK, Wu Y, Li J, Yin W, Yao D

Abstract
Frontal lobe epilepsy has recently been associated with disrupted brain functional connectivity; variations among various resting-state networks (RSNs) across time remains largely unclear. This study applied dynamic functional network connectivity (dFNC) analysis to investigate functional patterns in the temporal and spatial domains of various functional systems in FLE. Resting-state fMRI data were acquired from 19 FLE patients and 18 controls. Independent component analysis was used to decompose RSNs, which were grouped into seven functional systems. Sliding windows and clustering approach were used to identify the dFNC patterns. Then, state-specific connectivity pattern and dynamic functional state interactions (dFSIs) were evaluated. Compared with healthy controls, FLE patients exhibited decreased dFNC in almost all four patterns, changes that were mostly related to the frontoparietal system, suggesting a disturbed communication of the frontoparietal system with other systems in FLE. Additionally, regarding the fundamental connectivity pattern (state 3 in this study), FLE showed decreased time spent in this state. Moreover, the duration positively correlated with seizure onset. Furthermore, significantly reduced dynamic connections in this state were observed in the frontoparietal system linked to the cerebellar and subcortical systems. These findings imply abnormal fundamental dynamic interactions and dysconnectivity associated with the subcortical and cerebellar regulation of dysfunctions in frontoparietal regions in FLE. Finally, based on the developed FSI analysis, temporal dynamic abnormalities among states were observed in FLE. Therefore, this altered dynamic FNC extended our understanding of the abnormalities in the frontoparietal system in FLE. The dynamic FNC provided novel insight into the fundamental pathophysiological mechanisms in FLE.

PMID: 30255350 [PubMed - as supplied by publisher]

Voxel-Mirrored Homotopic Connectivity of Resting-State Functional Magnetic Resonance Imaging in Blepharospasm.

Thu, 09/27/2018 - 12:40
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Voxel-Mirrored Homotopic Connectivity of Resting-State Functional Magnetic Resonance Imaging in Blepharospasm.

Front Psychol. 2018;9:1620

Authors: Wei J, Wei S, Yang R, Yang L, Yin Q, Li H, Qin Y, Lei Y, Qin C, Tang J, Luo S, Guo W

Abstract
Objective: Several networks in human brain are involved in the development of blepharospasm. However, the underlying mechanisms for this disease are poorly understood. A voxel-mirrored homotopic connectivity (VMHC) method was used to quantify the changes in functional connectivity between two hemispheres of the brain in patients with blepharospasm. Methods: Twenty-four patients with blepharospasm and 24 healthy controls matched by age, sex, and education were recruited. The VMHC method was employed to analyze the fMRI data. The support vector machine (SVM) method was utilized to examine whether these abnormalities could be applied to distinguish the patients from the controls. Results: Compared with healthy controls, patients with blepharospasm showed significantly high VMHC in the inferior temporal gyrus, interior frontal gyrus, posterior cingulate cortex, and postcentral gyrus. No significant correlation was found between abnormal VMHC values and clinical variables. SVM analysis showed a combination of increased VMHC values in two brain areas with high sensitivities and specificities (83.33 and 91.67% in the combined inferior frontal gyrus and posterior cingulate cortex; and 83.33 and 87.50% in the combined inferior temporal gyrus and postcentral gyrus). Conclusion: Enhanced homotopic coordination in the brain regions associated with sensory integration networks and default-mode network may be underlying the pathophysiology of blepharospasm. This phenomenon may serve as potential image markers to distinguish patients with blepharospasm from healthy controls.

PMID: 30254593 [PubMed]

Migraine and the Hippocampus.

Thu, 09/27/2018 - 12:40
Related Articles

Migraine and the Hippocampus.

Curr Pain Headache Rep. 2018 Feb 05;22(2):13

Authors: Liu HY, Chou KH, Chen WT

Abstract
PURPOSE OF REVIEW: The hippocampus is involved in pain processing, pain-related attention and anxiety, and stress response. The present review compiles the present knowledge of hippocampal volume, activity, and connectivity regarding migraine.
RECENT FINDINGS: For hippocampal volume, a longitudinal study discovered decreased volume in newly diagnosed migraine patients after 1 year. Two cross-sectional studies suggested an adaptive increase of volume at low headache frequency and a maladaptive decrease of volume at higher headache frequency. Patients who carried a COMT Val homozygous were found to have larger hippocampi on both sides compared with healthy controls with the same polymorphism. For hippocampal activation, one study showed greater nociceptive activation in patients with migraine compared to healthy controls, with the activity correlated to headache frequency. Another study showed greater deactivation and higher functional connectivity linked to other pain-processing regions in low frequency compared to high-frequency migraineurs. At resting state, intraregional functional connectivity of hippocampus was demonstrated to be lower, and connectivity of the hippocampus with other brain regions was different in patients carrying specific genetic variants. For structural connectivity, two studies suggest a stronger connectivity between the hippocampus and other corticolimbic regions, and the altered connectivities are responsible for migraine-associated allodynia or placebo effect of migraine. Factors including headache frequency, accumulative number of migraine attacks, anxiety score, depression score, and genetic variants are related to hippocampal morphology and functional changes in people with migraine. Future studies should select participants precisely and appropriately control for genetic variants to investigate the complex relationship between the hippocampus and migraine.

PMID: 29404714 [PubMed - indexed for MEDLINE]

Intrinsic functional and structural connectivity of emotion regulation networks in obsessive-compulsive disorder.

Wed, 09/26/2018 - 18:00

Intrinsic functional and structural connectivity of emotion regulation networks in obsessive-compulsive disorder.

Depress Anxiety. 2018 Sep 25;:

Authors: Picó-Pérez M, Ipser J, Taylor P, Alonso P, López-Solà C, Real E, Segalàs C, Roos A, Menchón JM, Stein DJ, Soriano-Mas C

Abstract
Despite emotion regulation being altered in patients with obsessive-compulsive disorder (OCD), no studies have investigated its relation to multimodal amygdala connectivity. We compared corticolimbic functional and structural connectivity between OCD patients and healthy controls (HCs), and correlated this with the dispositional use of emotion regulation strategies and with OCD severity. OCD patients (n = 73) and HCs (n = 42) were assessed for suppression and reappraisal strategies using the Emotion Regulation Questionnaire (ERQ) and for OCD severity using the Yale-Brown Obsessive-Compulsive Scale. Resting-state functional magnetic resonance imaging (rs-fMRI) connectivity maps were generated using subject-specific left amygdala (LA) and right amygdala (RA) masks. We identified between-group differences in amygdala whole-brain connectivity, and evaluated the moderating effect of ERQ strategies. Significant regions and amygdala seeds were used as targets in probabilistic tractography analysis. Patients scored higher in suppression and lower in reappraisal. We observed higher rs-fMRI RA-right postcentral gyrus (PCG) connectivity in HC, and in patients this was correlated with symptom severity. Reappraisal scores were associated with higher negative LA-left insula connectivity in HC, and suppression scores were negatively associated with LA-precuneus and angular gyri connectivity in OCD. Structurally, patients showed higher mean diffusivity in tracts connecting the amygdala with the other targets. RA-PCG connectivity is diminished in patients, while disrupted emotion regulation is related to altered amygdala connectivity with the insula and posterior brain regions. Our results are the first showing, from a multimodal perspective, the association between amygdala connectivity and specific emotional processing domains, emphasizing the importance of amygdala connectivity in OCD pathophysiology.

PMID: 30253000 [PubMed - as supplied by publisher]

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