New resting-state fMRI related studies at PubMed

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Longitudinal Observations Using Simultaneous fMRI, Multiple Channel Electrophysiology Recording, and Chemical Microiontophoresis in The Rat Brain.

Mon, 05/21/2018 - 12:00
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Longitudinal Observations Using Simultaneous fMRI, Multiple Channel Electrophysiology Recording, and Chemical Microiontophoresis in The Rat Brain.

J Neurosci Methods. 2018 May 17;:

Authors: Jaime S, Cavazos JE, Yang Y, Lu H

Abstract
BACKGROUND: fMRI blood oxygenation level-dependent (BOLD) signal has been widely used as a surrogate for neural activity. However, interpreting differences in BOLD fMRI based on underlying neuronal activity remains a challenge. Concurrent rsMRI data collection and electrophysiological recording in combination with microiontophoretically injected modulatory chemicals allows for improved understanding of the relationship between resting state BOLD and neuronal activity.
NEW METHODS: Simultaneous fMRI, multi-channel intracortical electrophysiology and focal pharmacological manipulation data to be acquired longitudinally in rats for up to 2 months. Our artifact replacing technique is optimized for combined LFP and rsMRI data collection.
RESULTS: Intracortical implantation of a multichannel microelectrode array resulted in minimal distortion and signal loss in fMRI images inside a 9.4 T MRI scanner. rsMRI-induced electrophysiology artifacts were replaced using an in-house developed algorithm. Microinjection of AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) enhanced dopaminergic neuronal activity in the ventral tegmental area (VTA) and altered LFP signal and fMRI functional connectivity in the striatum.
COMPARISONS WITH EXISTING METHOD(S): Nanomanufacturing advances permit the production of MRI-compatible microelectrode arrays (with 16 or more channels), extending research beyond conventional methods limited to fewer channels. Our method permits longitudinal data collection of LFP and rsMRI and our algorithm effectively detects and replaces fMRI-induced electrophysiological noise, permitting rsMRI data collection concomitant with LFP recordings.
CONCLUSIONS: Our model consists of longitudinal concurrent fMRI and multichannel intracortical electrophysiological recording during microinjection of pharmacological agents to modulate neural activity in the rat brain. We used commercial micro-electrodes and recording system and can be readily generalized to other labs.

PMID: 29778509 [PubMed - as supplied by publisher]

Mutual connectivity analysis of resting-state functional MRI data with local models.

Mon, 05/21/2018 - 05:40
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Mutual connectivity analysis of resting-state functional MRI data with local models.

Neuroimage. 2018 May 16;:

Authors: DSouza AM, Abidin AZ, Chockanathan U, Schifitto G, Wismüller A

Abstract
Functional connectivity analysis of functional MRI (fMRI) can represent brain networks and reveal insights into interactions amongst different brain regions. However, most connectivity analysis approaches adopted in practice are linear and non-directional. In this paper, we demonstrate the advantage of a data-driven, directed connectivity analysis approach called Mutual Connectivity Analysis using Local Models (MCA-LM) that approximates connectivity by modeling nonlinear dependencies of signal interaction, over more conventionally used approaches, such as Pearson's and partial correlation, Patel's conditional dependence measures, etcetera. We demonstrate on realistic simulations of fMRI data that, at long sampling intervals, i.e. high repetition time (TR) of fMRI signals, MCA-LM performs better than or comparable to correlation-based methods and Patel's measures. However, at fast image acquisition rates corresponding to low TR, MCA-LM significantly outperforms these methods. This insight is particularly useful in the light of recent advances in fast fMRI acquisition techniques. Methods that can capture the complex dynamics of brain activity, such as MCA-LM, should be adopted to extract as much information as possible from the improved representation. Furthermore, MCA-LM works very well for simulations generated at weak neuronal interaction strengths, and simulations modeling inhibitory and excitatory connections as it disentangles the two opposing effects between pairs of regions/voxels. Additionally, we demonstrate that MCA-LM is capable of capturing meaningful directed connectivity on experimental fMRI data. Such results suggest that it introduces sufficient complexity into modeling fMRI time-series interactions that simple, linear approaches cannot, while being data-driven, computationally practical and easy to use. In conclusion, MCA-LM can provide valuable insights towards better understanding brain activity.

PMID: 29777828 [PubMed - as supplied by publisher]

Brain network segregation and integration during an epoch-related working memory fMRI experiment.

Mon, 05/21/2018 - 05:40
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Brain network segregation and integration during an epoch-related working memory fMRI experiment.

Neuroimage. 2018 May 16;:

Authors: Fransson P, Schiffler BC, Thompson WH

Abstract
The characterization of brain subnetwork segregation and integration has previously focused on changes that are detectable at the level of entire sessions or epochs of imaging data. In this study, we applied time-varying functional connectivity analysis together with temporal network theory to calculate point-by-point estimates in subnetwork segregation and integration during an epoch-based (2-back, 0-back, baseline) working memory fMRI experiment as well as during resting-state. This approach allowed us to follow task-related changes in subnetwork segregation and integration at a high temporal resolution. At a global level, the cognitively more taxing 2-back epochs elicited an overall stronger response of integration between subnetworks compared to the 0-back epochs. Moreover, the visual, sensorimotor and fronto-parietal subnetworks displayed characteristic and distinct temporal profiles of segregation and integration during the 0- and 2-back epochs. During the interspersed epochs of baseline, several subnetworks, including the visual, fronto-parietal, cingulo-opercular and dorsal attention subnetworks showed pronounced increases in segregation. Using a drift diffusion model we show that the response time for the 2-back trials are correlated with integration for the fronto-parietal subnetwork and correlated with segregation for the visual subnetwork. Our results elucidate the fast-evolving events with regard to subnetwork integration and segregation that occur in an epoch-related task fMRI experiment. Our findings suggest that minute changes in subnetwork integration are of importance for task performance.

PMID: 29777824 [PubMed - as supplied by publisher]

Effects of global signal regression and subtraction methods on resting-state functional connectivity using arterial spin labeling data.

Mon, 05/21/2018 - 05:40
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Effects of global signal regression and subtraction methods on resting-state functional connectivity using arterial spin labeling data.

Magn Reson Imaging. 2018 May 16;:

Authors: Silva JPS, da Mata Mônaco L, Paschoal AM, de Oliveira ÍAF, Leoni RF

Abstract
BACKGROUND: Arterial spin labeling (ASL) is an established magnetic resonance imaging (MRI) technique that is finding broader applications in functional studies of the healthy and diseased brain. To promote improvement in cerebral blood flow (CBF) signal specificity, many algorithms and imaging procedures, such as subtraction methods, were proposed to eliminate or, at least, minimize noise sources. Therefore, this study addressed the main considerations of how CBF functional connectivity (FC) is changed, regarding resting brain network (RBN) identification and correlations between regions of interest (ROI), by different subtraction methods and removal of residual motion artifacts and global signal fluctuations (RMAGSF).
METHODS: Twenty young healthy participants (13 M/7F, mean age = 25 ± 3 years) underwent an MRI protocol with a pseudo-continuous ASL (pCASL) sequence. Perfusion-based images were obtained using simple, sinc and running subtraction. RMAGSF removal was applied to all CBF time series. Independent Component Analysis (ICA) was used for RBN identification, while Pearson' correlation was performed for ROI-based FC analysis.
RESULTS: Temporal signal-to-noise ratio (tSNR) was higher in CBF maps obtained by sinc subtraction, although RMAGSF removal had a significant effect on maps obtained with simple and running subtractions. Neither the subtraction method nor the RMAGSF removal directly affected the identification of RBNs. However, the number of correlated and anti-correlated voxels varied for different subtraction and filtering methods. In an ROI-to-ROI level, changes were prominent in FC values and their statistical significance.
CONCLUSIONS: Our study showed that both RMAGSF filtering and subtraction method might influence resting-state FC results, especially in an ROI level, consequently affecting FC analysis and its interpretation. Taking our results and the whole discussion together, we understand that for an exploratory assessment of the brain, one could avoid removing RMAGSF to not bias FC measures, but could use sinc subtraction to minimize low-frequency contamination. However, CBF signal specificity and frequency range for filtering purposes still need to be assessed in future studies.

PMID: 29777822 [PubMed - as supplied by publisher]

Effect of phase-encoding direction on group analysis of resting-state functional magnetic resonance imaging.

Sat, 05/19/2018 - 14:40
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Effect of phase-encoding direction on group analysis of resting-state functional magnetic resonance imaging.

Psychiatry Clin Neurosci. 2018 May 17;:

Authors: Mori Y, Miyata J, Isobe M, Son S, Yoshihara Y, Aso T, Kouchiyama T, Murai T, Takahashi H

Abstract
AIM: Echo-planar imaging is a common technique used in functional magnetic resonance imaging (fMRI), however it suffers from image distortion and signal loss because of large susceptibility effects that are related to the phase-encoding direction of the scan. Despite this relationship, the majority of neuroimaging studies have not considered the influence of phase-encoding direction. Here, we aimed to clarify how phase-encoding direction can affect the outcome of an fMRI connectivity study of schizophrenia.
METHODS: Resting-state fMRI using anterior to posterior (A-P) and posterior to anterior (P-A) directions was used to examine 25 patients with schizophrenia (SC) and 37 matched healthy controls (HC). We conducted a functional connectivity analysis using independent component analysis and performed three group comparisons: A-P vs. P-A (all participants), SC vs. HC for the A-P and P-A datasets, and the interaction between phase-encoding direction and participant group.
RESULTS: The estimated functional connectivity differed between the two phase-encoding directions in areas that were more extensive than those where signal loss has been reported. Although functional connectivity in the SC group was lower than that in the HC group for both directions, the A-P and P-A conditions did not exhibit the same specific pattern of differences. Further, we observed an interaction between participant group and the phase-encoding direction in the left temporo-parietal junction and left fusiform gyrus.
CONCLUSION: Phase-encoding direction can influence the results of functional connectivity studies. Thus, appropriate selection and documentation of phase-encoding direction will be important in future resting-state fMRI studies. This article is protected by copyright. All rights reserved.

PMID: 29774625 [PubMed - as supplied by publisher]

Thalamocortical dysconnectivity in premenstrual syndrome.

Sat, 05/19/2018 - 14:40
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Thalamocortical dysconnectivity in premenstrual syndrome.

Brain Imaging Behav. 2018 May 17;:

Authors: Liu P, Wei Y, Liao H, Fan Y, Li R, Feng N, Duan G, Deng D, Qin W

Abstract
Premenstrual syndrome (PMS) is a menstrual cycle-related disorder. Although the precise pathophysiology is not fully understood, it is increasingly believed that the central nervous system plays a vital role in the development of PMS. The aim of this study is to elucidate specific functional connectivity between the thalamus and cerebral cortex. Resting-state functional magnetic resonance imaging (fMRI) data were obtained from 20 PMS patients and 21 healthy controls (HCs). Seed-based functional connectivity between the thalamus and six cortical regions of interest, including the prefrontal cortex (PFC), posterior parietal cortex, somatosensory cortex, motor cortex/supplementary motor area, temporal and occipital lobe, was adopted to identify specific thalamocortical connectivity in the two groups. Correlation analysis was then used to examine relationships between the neuroimaging findings and clinical symptoms. Activity in distinct cortical regions correlated with specific sub-regions of the thalamus in the two groups. Comparison between groups exhibited decreased prefrontal-thalamic connectivity and increased posterior parietal-thalamic connectivity in the PMS patients. Within the PMS group, the daily record of severity of problems (DRSP) score negatively correlated with the prefrontal-thalamic connectivity. Our findings may provide preliminary evidence for abnormal thalamocortical connectivity in PMS patients and may contribute to a better understanding of the pathophysiology of PMS.

PMID: 29774500 [PubMed - as supplied by publisher]

Classification and characterisation of brain network changes in chronic back pain: A multicenter study.

Sat, 05/19/2018 - 14:40
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Classification and characterisation of brain network changes in chronic back pain: A multicenter study.

Wellcome Open Res. 2018;3:19

Authors: Mano H, Kotecha G, Leibnitz K, Matsubara T, Nakae A, Shenker N, Shibata M, Voon V, Yoshida W, Lee M, Yanagida T, Kawato M, Rosa MJ, Seymour B

Abstract
Background. Chronic pain is a common, often disabling condition thought to involve a combination of peripheral and central neurobiological factors. However, the extent and nature of changes in the brain is poorly understood. Methods. We investigated brain network architecture using resting-state fMRI data in chronic back pain patients in the UK and Japan (41 patients, 56 controls), as well as open data from USA. We applied machine learning and deep learning (conditional variational autoencoder architecture) methods to explore classification of patients/controls based on network connectivity. We then studied the network topology of the data, and developed a multislice modularity method to look for consensus evidence of modular reorganisation in chronic back pain. Results. Machine learning and deep learning allowed reliable classification of patients in a third, independent open data set with an accuracy of 63%, with 68% in cross validation of all data. We identified robust evidence of network hub disruption in chronic pain, most consistently with respect to clustering coefficient and betweenness centrality. We found a consensus pattern of modular reorganisation involving extensive, bilateral regions of sensorimotor cortex, and characterised primarily by negative reorganisation - a tendency for sensorimotor cortex nodes to be less inclined to form pairwise modular links with other brain nodes. In contrast, intraparietal sulcus displayed a propensity towards positive modular reorganisation, suggesting that it might have a role in forming modules associated with the chronic pain state. Conclusion. The results provide evidence of consistent and characteristic brain network changes in chronic pain, characterised primarily by extensive reorganisation of the network architecture of the sensorimotor cortex.

PMID: 29774244 [PubMed]

Disrupted Spontaneous Neural Activity Related to Cognitive Impairment in Postpartum Women.

Sat, 05/19/2018 - 14:40
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Disrupted Spontaneous Neural Activity Related to Cognitive Impairment in Postpartum Women.

Front Psychol. 2018;9:624

Authors: Zheng JX, Chen YC, Chen H, Jiang L, Bo F, Feng Y, Tang WW, Yin X, Gu JP

Abstract
Purpose: Prior research has demonstrated that the postpartum period is associated with an increased risk of cognitive impairment. This study aims to investigate whether disrupted spontaneous neural activity exists in postpartum women without depression using resting-state functional magnetic resonance imaging (rs-fMRI) and to detect the relationship between these abnormalities and cognitive impairment. Materials and Methods: Postpartum women (n = 22) were compared with age- and education-matched nulliparous women (n = 23) using rs-fMRI. We calculated the amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) values to evaluate spontaneous neural activity and detect the relationship between rs-fMRI data and cognitive performance. Results: Relative to nulliparous women, postpartum women had significantly decreased ALFF and ReHo values primarily in the left posterior cingulate cortex (PCC) and prefrontal cortex and increased ALFF values in left cerebellar posterior lobe. We found a positive correlation between the ALFF and ReHo values in the PCC and the complex figure test (CFT)-delayed scores in postpartum women (r = 0.693, p = 0.001; r = 0.569, p = 0.011, respectively). Moreover, the clock-drawing test (CDT) scores showed positive correlations with the ALFF and ReHo values in the right superior frontal gyrus (SFG; r = 0.492, p = 0.033; r = 0.517, p = 0.023, respectively). Conclusion: Our combined ALFF and ReHo analyses revealed decreased spontaneous neural activity, mainly in the PCC and prefrontal cortex, which was correlated with specific impaired cognitive functioning in postpartum women. This study may elucidate the neurophysiological mechanisms underlying postpartum cognitive impairment and enhance our understanding of the neurobiological aspects of the postpartum period.

PMID: 29774003 [PubMed]

Functional brain networks related to individual differences in human intelligence at rest.

Sat, 05/19/2018 - 14:40
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Functional brain networks related to individual differences in human intelligence at rest.

Sci Rep. 2016 08 26;6:32328

Authors: Hearne LJ, Mattingley JB, Cocchi L

Abstract
Intelligence is a fundamental ability that sets humans apart from other animal species. Despite its importance in defining human behaviour, the neural networks responsible for intelligence are not well understood. The dominant view from neuroimaging work suggests that intelligent performance on a range of tasks is underpinned by segregated interactions in a fronto-parietal network of brain regions. Here we asked whether fronto-parietal interactions associated with intelligence are ubiquitous, or emerge from more widespread associations in a task-free context. First we undertook an exploratory mapping of the existing literature on functional connectivity associated with intelligence. Next, to empirically test hypotheses derived from the exploratory mapping, we performed network analyses in a cohort of 317 unrelated participants from the Human Connectome Project. Our results revealed a novel contribution of across-network interactions between default-mode and fronto-parietal networks to individual differences in intelligence at rest. Specifically, we found that greater connectivity in the resting state was associated with higher intelligence scores. Our findings highlight the need to broaden the dominant fronto-parietal conceptualisation of intelligence to encompass more complex and context-specific network dynamics.

PMID: 27561736 [PubMed - indexed for MEDLINE]

Cross-modal plasticity among sensory networks in neuromyelitis optica spectrum disorders.

Fri, 05/18/2018 - 13:40
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Cross-modal plasticity among sensory networks in neuromyelitis optica spectrum disorders.

Mult Scler. 2018 May 01;:1352458518778008

Authors: Rocca MA, Savoldi F, Valsasina P, Radaelli M, Preziosa P, Comi G, Falini A, Filippi M

Abstract
OBJECTIVE: To explore resting-state (RS) functional connectivity (FC) of the main sensory/motor networks of patients with neuromyelitis optica spectrum disorders (NMOSDs), clinically isolated optic neuritis (ON), and myelitis.
METHODS: Clinical evaluation and RS fMRI were obtained from 28 NMOSD, 11 recurrent ON, and 12 recurrent myelitis patients and 30 healthy controls. Between-group RS FC comparisons and correlations with motor performance were assessed (SPM12) on the main sensory/motor RS networks (RSNs) identified by independent component analysis. Functional network connectivity analysis estimated inter-network connectivity.
RESULTS: Intra- and inter-network RS FCs were reduced in RSNs associated to somatosensory modalities affected by pathology: regions of the primary visual network in ON patients, of the sensorimotor networks in myelitis patients, and of the sensorimotor and secondary visual networks in NMOSD patients. The opposite trend was observed in regions of RSNs spared by pathology: the auditory and part of visual networks in NMOSD, the secondary visual and sensorimotor networks in ON, and the primary visual network in myelitis patients. Better motor performance correlated with higher RS FC of spared RSNs.
CONCLUSION: Sensory and motor RSN abnormalities occur in NMOSD. Loss of function within disease-target networks may elicit cross-modal plasticity across sensory networks potentially preserving clinical function.

PMID: 29771186 [PubMed - as supplied by publisher]

Accurate nonlinear mapping between MNI volumetric and FreeSurfer surface coordinate systems.

Fri, 05/18/2018 - 13:40
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Accurate nonlinear mapping between MNI volumetric and FreeSurfer surface coordinate systems.

Hum Brain Mapp. 2018 May 16;:

Authors: Wu J, Ngo GH, Greve D, Li J, He T, Fischl B, Eickhoff SB, Yeo BTT

Abstract
The results of most neuroimaging studies are reported in volumetric (e.g., MNI152) or surface (e.g., fsaverage) coordinate systems. Accurate mappings between volumetric and surface coordinate systems can facilitate many applications, such as projecting fMRI group analyses from MNI152/Colin27 to fsaverage for visualization or projecting resting-state fMRI parcellations from fsaverage to MNI152/Colin27 for volumetric analysis of new data. However, there has been surprisingly little research on this topic. Here, we evaluated three approaches for mapping data between MNI152/Colin27 and fsaverage coordinate systems by simulating the above applications: projection of group-average data from MNI152/Colin27 to fsaverage and projection of fsaverage parcellations to MNI152/Colin27. Two of the approaches are currently widely used. A third approach (registration fusion) was previously proposed, but not widely adopted. Two implementations of the registration fusion (RF) approach were considered, with one implementation utilizing the Advanced Normalization Tools (ANTs). We found that RF-ANTs performed the best for mapping between fsaverage and MNI152/Colin27, even for new subjects registered to MNI152/Colin27 using a different software tool (FSL FNIRT). This suggests that RF-ANTs would be useful even for researchers not using ANTs. Finally, it is worth emphasizing that the most optimal approach for mapping data to a coordinate system (e.g., fsaverage) is to register individual subjects directly to the coordinate system, rather than via another coordinate system. Only in scenarios where the optimal approach is not possible (e.g., mapping previously published results from MNI152 to fsaverage), should the approaches evaluated in this manuscript be considered. In these scenarios, we recommend RF-ANTs (https://github.com/ThomasYeoLab/CBIG/tree/master/stable_projects/registration/Wu2017_RegistrationFusion).

PMID: 29770530 [PubMed - as supplied by publisher]

Adolescent Condom Use and Connectivity in the Social-Planful Brain.

Fri, 05/18/2018 - 01:00

Adolescent Condom Use and Connectivity in the Social-Planful Brain.

J Pediatr Psychol. 2018 May 14;:

Authors: Caouette JD, Hudson KA, Bryan AD, Feldstein Ewing SW

Abstract
Objective: To reduce rates of sexually transmitted infections (STIs) and unwanted pregnancy among adolescents, it is critical to investigate brain connectivity that may underlie adolescents' sexual health decision-making in the context of intercourse. This study explored relationships between adolescent condom use frequency and the brain's resting-state functional connectivity, to identify differential patterns of social-affective processing among sexually active youth.
Methods: In this study, N = 143 sexually active adolescents (68.5% male, Mage = 16.2 years, SD = 1.06) completed magnetic resonance imaging and reported past 3-month frequency of condom use. Resting-state connectivity, seeded on a social region of the brain, the temporoparietal junction (TPJ), was assessed to determine its correspondence with protected sex (condom use).
Results: Condom use was associated with positive connectivity between the left TPJ and bilateral inferior frontal gyrus (IFG). This relationship was observed in adolescent males only; no connectivity differences were observed with adolescent females.
Conclusions: This study reflects functional synchrony between nodes of the "social brain," including the TPJ, and a region of planfulness and control, the IFG. The relationship between these regions suggests that adolescents who have more coordinated systems of communication between these critical components of the brain are more likely to be successful in planning and engaging in safer sexual decision-making; for young males, this differentiated more frequent from less frequent condom use. In turn, interventions designed to reduce STIs/human immunodeficiency virus may benefit from targeting social-planfulness dimensions to help youth implement safer sex behaviors.

PMID: 29767781 [PubMed - as supplied by publisher]

Amyloid causes intermittent network disruptions in cognitively intact older subjects.

Fri, 05/18/2018 - 01:00

Amyloid causes intermittent network disruptions in cognitively intact older subjects.

Brain Imaging Behav. 2018 May 16;:

Authors: Mueller SG

Abstract
Recent findings in AD models but also human patients suggest that amyloid can cause intermittent neuronal hyperactivity. The overall goal of this study was to use dynamic fMRI analysis combined with graph analysis to a) characterize the graph analytical signature of two types of intermittent hyperactivity (spike-like (spike) and hypersynchronus-like (synchron)) in simulated data and b) to attempt to identify one of these signatures in task-free fMRIs of cognitively intact subjects (CN) with or without increased brain amyloid. The toolbox simtb was used to generate 33 data sets with 2 short spike events, 33 with 2 synchron and 33 baseline data sets. A combination of sliding windows, hierarchical cluster analysis and graph analysis was used to characterize the spike and the synchron signature. Florbetapir-F18 PET and task-free 3 T fMRI was acquired in 49 CN (age = 70.7 ± 6.4). Processing the real data with the same approach as the simulated data identified phases whose graph analytical signature resembled that of the synchron signature in the simulated data. The duration of these phases was positively correlated with amyloid load (r = 0.42, p < 0.05) and negatively with memory performance (r = -0.43, p < 0.05). In conclusion, amyloid positivity is associated with intermittent hyperactivity that is caused by short phases of hypersynchronous activity. The negative association with memory performance suggests that these disturbances have the potential to interfere with cognitive processes and could lead to cognitive impairment if they become more frequent or more severe with increasing amyloid deposition.

PMID: 29767302 [PubMed - as supplied by publisher]

Associations Between Daily Mood States and Brain Gray Matter Volume, Resting-State Functional Connectivity and Task-Based Activity in Healthy Adults.

Fri, 05/18/2018 - 01:00
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Associations Between Daily Mood States and Brain Gray Matter Volume, Resting-State Functional Connectivity and Task-Based Activity in Healthy Adults.

Front Hum Neurosci. 2018;12:168

Authors: Ismaylova E, Di Sante J, Gouin JP, Pomares FB, Vitaro F, Tremblay RE, Booij L

Abstract
Numerous studies have shown differences in the functioning in the areas of the frontal-limbic circuitry between depressed patients and controls. However, current knowledge on frontal-limbic neural substrates of individual differences in mood states in everyday life in healthy individuals is scarce. The present study investigates anatomical, resting-state, and functional neural correlates of daily mood states in healthy individuals. We expected to observe associations between mood and the frontal-limbic circuitry and the default-mode network (DMN). A total of 42 healthy adults (19 men, 23 women; 34 ± 1.2 years) regularly followed for behavior and psychosocial functioning since age of 6, underwent a functional magnetic resonance imaging scan, and completed a daily diary of mood states and related cognitions for 5 consecutive days. Results showed that individuals with smaller left hippocampal gray matter volumes experienced more negative mood and rumination in their daily life. Greater resting-state functional connectivity (rsFC) within the DMN, namely between posterior cingulate cortex (PCC) and medial prefrontal cortex regions as well as between PCC and precuneus, was associated with both greater negative and positive mood states in daily life. These rsFC results could be indicative of the role of the DMN regional functioning in emotional arousal, irrespective of valence. Lastly, greater daily positive mood was associated with greater activation in response to negative emotional stimuli in the precentral gyri, previously linked to emotional interference on cognitive control. Altogether, present findings might reflect neural mechanisms underlying daily affect and cognition among healthy individuals.

PMID: 29765312 [PubMed]

Ultrasound-guided fine needle aspiration of retropharyngeal lymph nodes after radiotherapy for nasopharyngeal carcinoma: a novel technique for accurate diagnosis.

Fri, 05/18/2018 - 01:00
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Ultrasound-guided fine needle aspiration of retropharyngeal lymph nodes after radiotherapy for nasopharyngeal carcinoma: a novel technique for accurate diagnosis.

Cancer Commun (Lond). 2018 May 09;38(1):20

Authors: He LJ, Xie C, Li Y, Luo LN, Pan K, Gao XY, Liu LZ, Gao JM, Luo GY, Shan HB, Chen MY, Zhao C, Fan WJ, Yang P, Xu GL, Li JJ

Abstract
BACKGROUND: Enlarged retropharyngeal lymph nodes (RLNs) are very common in patients with nasopharyngeal carcinoma (NPC) undergoing radiotherapy. The most suitable treatment option for enlarged RLNs depends on the pathological results. However, RLN sampling is difficult and imminent in the clinic setting. We recently developed a novel minimally invasive technique termed endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) for sampling RLN tissues sufficient for pathological or cytological diagnosis.
METHODS: We enrolled 30 post-radiotherapy patients with NPC with suspected RLN metastasis detected via magnetic resonance imaging (MRI). The EUS probe was introduced into the nasopharynx via the nostrils, and EUS was then used to scan the retropharyngeal space and locate the RLN in the anterior carotid sheath. EUS-FNA was subsequently performed. The safety and efficacy of using EUS-FNA to sample the RLN tissues were assessed.
RESULTS: Strips of tissue were successfully sampled from all patients using EUS-FNA. Of the 30 patients, 23 were confirmed to have cancer cells in the biopsied tissues via pathology or cytology examinations with 1 EUS-FNA biopsy session. The seven cases without confirmed cancer cells were subsequently reanalyzed by using another EUS-FNA biopsy session, and two more cases were confirmed possessing cancer cells. The other five patients without confirmed cancer cells were closely followed with MRI every month for 3 months. After follow-up for 3 months, three patients were still considered cancer-free due to the presence of RLNs with stable or shrinking diameters. The rest two patients who showed progressive disease underwent a third EUS-FNA biopsy procedure and were further confirmed to be cancer cell-positive. In the whole cohort reported here, the EUS-FNA procedure was not associated with any severe complications.
CONCLUSION: EUS-FNA is a safe and effective diagnostic approach for sampling tissues from the RLNs in patients with suspected recurrent NPC.

PMID: 29764509 [PubMed - in process]

Functional connectivity of hippocampal subregions in PTSD: relations with symptoms.

Fri, 05/18/2018 - 01:00
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Functional connectivity of hippocampal subregions in PTSD: relations with symptoms.

BMC Psychiatry. 2018 May 15;18(1):129

Authors: Malivoire BL, Girard TA, Patel R, Monson CM

Abstract
BACKGROUND: Posttraumatic stress disorder (PTSD) is associated with abnormal hippocampal activity; however, the functional connectivity (FC) of the hippocampus with other brain regions in PTSD and its relations with symptoms warrants further attention. We investigated subregional hippocampal FC in PTSD during a resting state compared with a trauma-exposed control (TEC) group. Based on extant research, we targeted the FCs of the anterior and posterior hippocampal subregions with the amygdala, medial prefrontal cortex (mPFC), and the posterior cingulate (PCC).
METHODS: Resting-state functional magnetic resonance images were acquired from 11 individuals with PTSD and 13 trauma-exposed controls. Anterior and posterior hippocampal FC was compared between groups. Within the PTSD and TEC groups, subregional hippocampal FC was correlated with scores on the Clinician-Administered PTSD Scale (CAPS) at time of scan and 4 months post-scan.
RESULTS: Those with PTSD had significantly greater FC compared with the TEC group between the left posterior hippocampus and the bilateral PCC (g's > .96). Direct contrasts of the Fisher z-transformed coefficients indicated that the correlations between CAPS scores 4 months post scan and the FC between the left hippocampal head and the right PCC (z = - 2.07, p = .039) as well as the FC between the right hippocampal tail and the right mPFC (z = - 2.19, p = .029) were significantly greater in the PTSD group compared to the TEC group.
CONCLUSIONS: These results support between-group differences in posterior hippocampal FC and different relations with PTSD future symptoms, underscoring associations with the anterior and posterior hippocampus. These findings enrich our understanding of PTSD pathophysiology and provide support for future investigations of imaging biomarkers predictive of disease progression.

PMID: 29764396 [PubMed - in process]

Relationship between Duration of Untreated Psychosis and Intrinsic Corticostriatal Connectivity in Patients with Early Phase Schizophrenia.

Fri, 05/18/2018 - 01:00
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Relationship between Duration of Untreated Psychosis and Intrinsic Corticostriatal Connectivity in Patients with Early Phase Schizophrenia.

Neuropsychopharmacology. 2017 Oct;42(11):2214-2221

Authors: Sarpal DK, Robinson DG, Fales C, Lencz T, Argyelan M, Karlsgodt KH, Gallego JA, John M, Kane JM, Szeszko PR, Malhotra AK

Abstract
Patients with first-episode psychosis experience psychotic symptoms for a mean of up to 2 years prior to initiation of treatment, and long duration of untreated psychosis (DUP) is associated with poor clinical outcomes. Meanwhile, evidence compiled from numerous studies suggests that longer DUP is not associated with structural brain abnormalities. To date, few studies have examined the relationship between DUP and functional neuroimaging measures. In the present study, we used seed-based resting-state functional connectivity to examine the impact of DUP on corticostriatal circuitry. We included 83 patients with early phase schizophrenia and minimal exposure to antipsychotic drugs (<2 years), who underwent resting state scanning while entering 12 weeks of prospective treatment with second-generation antipsychotic drugs. Functional connectivity maps of the striatum were generated and examined in relation to DUP as a covariate. Mediation analyses were performed on a composite measure of corticostriatal connectivity derived from the significant results of our DUP analysis. We found that longer DUP correlated with worse response to treatment as well as overall decreased functional connectivity between striatal nodes and specific regions within frontal and parietal cortices. Moreover, the relationship between DUP and treatment response was significantly mediated by corticostriatal connectivity. Our results indicate that variation in corticostriatal circuitry may play a role in the relationship between longer DUP and worsened response to treatment. Future prospective studies are necessary to further characterize potential causal links between DUP, striatal circuitry and clinical outcomes.

PMID: 28294137 [PubMed - indexed for MEDLINE]

Modulation of functional activity and connectivity by acupuncture in patients with Alzheimer disease as measured by resting-state fMRI.

Wed, 05/16/2018 - 12:00
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Modulation of functional activity and connectivity by acupuncture in patients with Alzheimer disease as measured by resting-state fMRI.

PLoS One. 2018;13(5):e0196933

Authors: Zheng W, Su Z, Liu X, Zhang H, Han Y, Song H, Lu J, Li K, Wang Z

Abstract
Acupuncture has been used in the therapy of Alzheimer disease (AD); however, its neural mechanisms are still unclear. The aim of this study is to examine the effect of acupuncture on the functional connectivity in AD by using resting-state functional magnetic resonance imaging (rs-fMRI). Twenty-eight subjects (14 AD and 14 normal controls) participated in this study. The rs-fMRI data were acquired before and after acupuncture stimulation at the acupoints of Tai chong (Liv3) and Hegu (LI4). During the baseline resting state, by using the amplitude of low-frequency fluctuations (ALFF), we found a significantly decreased or increased ALFF in the AD patients relative to the controls. These regions were located in the right superior frontal gyrus (SFG), left postcentral gyrus, subgenual cingulate cortex (SCC), right middle cingulate cortex (MCC), right inferior frontal gyrus (IFG), right hippocampus and the right inferior temporal gyrus (ITG). Then, we selected these brain regions as seeds to investigate whether regional activity and functional connectivity could be modulated by acupuncture in the AD patients. When compared to the pre-acupuncture stage, several of the above regions showed an increased or decreased ALFF after acupuncture in the AD patients. In addition, the functional connectivity between the hippocampus and the precentral gyrus showed enhancement after acupuncture in the AD patients. Finally, there were close correlations between the functional activity, connectivity and clinical performance in the AD patients. The current study confirmed that acupuncture at Tai chong (Liv3) and He gu (LI4) can modulate functional activity and connectivity of specific cognition-related regions in AD patients.

PMID: 29763448 [PubMed - in process]

Functional magnetic resonance imaging in glioma patients: from clinical applications to future perspectives.

Wed, 05/16/2018 - 12:00
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Functional magnetic resonance imaging in glioma patients: from clinical applications to future perspectives.

Q J Nucl Med Mol Imaging. 2018 May 14;:

Authors: Volz LJ, Kocher M, Lohmann P, Shah NJ, Fink GR, Galldiks N

Abstract
Functional magnetic resonance imaging (fMRI) allows the non-invasive assessment of human brain activity in-vivo. In glioma patients, fMRI is frequently used to determine the individual functional anatomy of the motor and language network in a pre-surgical setting to optimize surgical procedures and prevent extensive damage to functionally eloquent areas. Novel developments based on resting- state fMRI may help to improve pre-surgical planning for patients which are unable to perform structured tasks and might extend pre-surgical mapping to include additional functional networks. Recent advances indicate a promising potential for future applications of fMRI in glioma patients which might help to identify neoplastic tissue or predict the long-term functional outcome of individual patients.

PMID: 29761998 [PubMed - as supplied by publisher]

[Degree centrality of the functional network in schizophrenia patients].

Wed, 05/16/2018 - 12:00
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[Degree centrality of the functional network in schizophrenia patients].

Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2017 Dec 01;34(6):837-841

Authors: Duan M, Jiang Y, Chen X, Luo C, Yao D

Abstract
The aim of the present study was to investigate the alternations of brain functional networks at resting state in the schizophrenia (SCH) patients using voxel-wise degree centrality (DC) method. The resting-state functional magnetic resonance imaging (rfMRI) data were collected from 41 SCH patients and 41 matched healthy control subjects and then analyzed by voxel-wise DC method. The DC maps between the patient group and the control group were compared using by two sample t test. The correlation analysis was also performed between DC values and clinical symptom and illness duration in SCH group. Results showed that compared with the control group, SCH patients exhibited significantly decreased DC value in primary sensorimotor network, and increased DC value in executive control network. In addition, DC value of the regions with obvious differences between the two groups significantly correlated to Positive and Negative Syndrome Scale (PANSS) scores and illness duration of SCH patients. The study showed the abnormal functional integration in primary sensorimotor network and executive control network in SCH patients.

PMID: 29761976 [PubMed]

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