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Altered intrinsic functional connectivity in the latent period of epileptogenesis in a temporal lobe epilepsy model.

Sat, 07/22/2017 - 11:20
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Altered intrinsic functional connectivity in the latent period of epileptogenesis in a temporal lobe epilepsy model.

Exp Neurol. 2017 Jul 17;:

Authors: Lee H, Jung S, Lee P, Jeong Y

Abstract
The latent period, a seizure-free phase, is the duration between brain injury and the onset of spontaneous recurrent seizures (SRSs) during epileptogenesis. The latent period is thought to involve several progressive pathophysiological events that lead to the evolution of the chronic epilepsy phase. Hence, it is vital to investigate the changes in the latent period during epileptogenesis in order to better understand temporal lobe epilepsy (TLE), and to achieve early diagnosis and appropriate management of the condition. Accordingly, recent studies with patients with TLE using resting-state functional magnetic resonance imaging (rs-fMRI) have reported that alterations of resting-state functional connectivity (rsFC) during the chronic period are associated with some clinical manifestations, including learning and memory impairments, emotional instability, and social behavior deficits, in addition to repetitive seizure episodes. In contrast, the changes in the intrinsic rsFC during epileptogenesis, particularly during the latent period, remain unclear. In this study, we investigated the alterations in intrinsic rsFC during the latent and chronic periods in a pilocarpine-induced TLE mouse model using intrinsic optical signal imaging (IOSI). This technique can monitor the changes in the local hemoglobin concentration according to neuronal activity and can help investigate large-scale brain intrinsic networks. After seeding on the anatomical regions of interest (ROIs) and calculating the correlation coefficients between each ROI, we established and compared functional correlation matrices and functional connectivity maps during the latent and chronic periods of epilepsy. We found a decrease in the interhemispheric rsFC at the frontal and temporal regions during both the latent and chronic periods. Furthermore, a significant decrease in the interhemispheric rsFC was observed in the somatosensory area during the chronic period. Changes in network configurations during epileptogenesis were examined by graph theoretical network analysis. Interestingly, increase in the power of low frequency oscillations was observed during the latent period. These results suggest that, even if there are no apparent ictal seizure events during the latent period, there are ongoing changes in the rsFC in the epileptic brain. Furthermore, these results suggest that the pathophysiology of epilepsy may be related to widespread altered intrinsic functional connectivity. These findings can help enhance our understanding of epileptogenesis, and accordingly, changes in intrinsic functional connectivity can serve as an early diagnosis.

PMID: 28729114 [PubMed - as supplied by publisher]

Learning-based structurally-guided construction of resting-state functional correlation tensors.

Sat, 07/22/2017 - 11:20
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Learning-based structurally-guided construction of resting-state functional correlation tensors.

Magn Reson Imaging. 2017 Jul 17;:

Authors: Zhang L, Zhang H, Chen X, Wang Q, Yap PT, Shen D

Abstract
Functional magnetic resonance imaging (fMRI) measures changes in blood-oxygenation-level-dependent (BOLD) signals to detect brain activities. It has been recently reported that the spatial correlation patterns of resting-state BOLD signals in the white matter (WM) also give WM information often measured by diffusion tensor imaging (DTI). These correlation patterns can be captured using functional correlation tensor (FCT), which is analogous to the diffusion tensor (DT) obtained from DTI. In this paper, we propose a noise-robust FCT method aiming at further improving its quality, and making it eligible for further neuroscience study. The novel FCT estimation method consists of three major steps: First, we estimate the initial FCT using a patch-based approach for BOLD signal correlation to improve the noise robustness. Second, by utilizing the relationship between functional and diffusion data, we employ a regression forest model to learn the mapping between the initial FCTs and the corresponding DTs using the training data. The learned forest can then be applied to predict the DTI-like tensors given the initial FCTs from the testing fMRI data. Third, we re-estimate the enhanced FCT by utilizing the DTI-like tensors as a feedback guidance to further improve FCT computation. We have demonstrated the utility of our enhanced FCTs in Alzheimer's disease (AD) diagnosis by identifying mild cognitive impairment (MCI) patients from normal subjects.

PMID: 28729016 [PubMed - as supplied by publisher]

Difference in resting-state fractional amplitude of low-frequency fluctuation between bipolar depression and unipolar depression patients.

Sat, 07/22/2017 - 11:20
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Difference in resting-state fractional amplitude of low-frequency fluctuation between bipolar depression and unipolar depression patients.

Eur Rev Med Pharmacol Sci. 2017 Apr;21(7):1541-1550

Authors: Yu HL, Liu WB, Wang T, Huang PY, Jie LY, Sun JZ, Wang C, Qian W, Xuan M, Gu QQ, Liu H, Zhang FL, Zhang MM

Abstract
OBJECTIVE: To investigate the difference in fractional amplitude of low-frequency fluctuation (fALFF) of localized brain activities in the resting-state between bipolar depression and unipolar depression patients and to find biological markers that differentiate the two groups of patients.
PATIENTS AND METHODS: Thirteen patients with bipolar depression, 15 patients with unipolar depression, and 16 healthy control subjects that were matched in age and years of education were subjected to 3.0 T resting-state functional magnetic resonance scans. The values of whole brain fALFF were calculated and statistical analysis was performed.
RESULTS: The fALFF-values of the right inferior temporal gyrus, left cerebellar posterior lobe, right middle temporal gyrus, left inferior frontal gyrus/insula, right inferior frontal gyrus/insula, left lingual gyrus and right middle temporal gyrus of the three groups showed significant differences (p < 0.05). Compared with the healthy control (HC) group, the fALFF-values of the unipolar depression (UD) patient group significantly increased in the right superior temporal gyrus, left insula, left inferior frontal gyrus, right inferior frontal gyrus, right supramarginal gyrus and right medial frontal gyrus but significantly decreased in the right medial occipital gyrus, left frontal lobe, right superior parietal lobule; the fALFF-values of the bipolar depression (BD) patient group significantly decreased in the left cerebellum posterior lobe, right lingual gyrus, left lingual gyrus, right middle temporal gyrus, left middle temporal gyrus, and left superior frontal gyrus and significantly increased in the right inferior frontal gyrus and left insula compared to those of the HC group; compared with those of the UD group, the fALFF-values of the BD group significantly decreased in the left middle occipital gyrus, right middle temporal gyrus, left middle frontal gyrus, and left medial frontal gyrus.
CONCLUSIONS: The brain activities of BD and UD patients in the resting-state exhibit abnormalities, which differ between the two groups of patients.

PMID: 28429352 [PubMed - indexed for MEDLINE]

Nonlinear modulation of interacting between COMT and depression on brain function.

Fri, 07/21/2017 - 10:20

Nonlinear modulation of interacting between COMT and depression on brain function.

Eur Psychiatry. 2017 Jun 09;45:6-13

Authors: Gong L, He C, Yin Y, Ye Q, Bai F, Yuan Y, Zhang H, Lv L, Zhang H, Zhang Z, Xie C

Abstract
BACKGROUND: The catechol-O-methyltransferase (COMT) gene is related to dopamine degradation and has been suggested to be involved in the pathogenesis of major depressive disorder (MDD). However, how this gene affects brain function properties in MDD is still unclear.
METHODS: Fifty patients with MDD and 35 cognitively normal participants underwent a resting-state functional magnetic resonance imaging scan. A voxelwise and data-drive global functional connectivity density (gFCD) analysis was used to investigate the main effects and the interactions of disease states and COMT rs4680 gene polymorphism on brain function.
RESULTS: We found significant group differences of the gFCD in bilateral fusiform area (FFA), post-central and pre-central cortex, left superior temporal gyrus (STG), rectal and superior temporal gyrus and right ventrolateral prefrontal cortex (vlPFC); abnormal gFCDs in left STG were positively correlated with severity of depression in MDD group. Significant disease×COMT interaction effects were found in the bilateral calcarine gyrus, right vlPFC, hippocampus and thalamus, and left SFG and FFA. Further post-hoc tests showed a nonlinear modulation effect of COMT on gFCD in the development of MDD. Interestingly, an inverted U-shaped modulation was found in the prefrontal cortex (control system) but U-shaped modulations were found in the hippocampus, thalamus and occipital cortex (processing system).
CONCLUSION: Our study demonstrated nonlinear modulation of the interaction between COMT and depression on brain function. These findings expand our understanding of the COMT effect underlying the pathophysiology of MDD.

PMID: 28728097 [PubMed - as supplied by publisher]

Local Brain Activity Differences Between Herpes Zoster and Postherpetic Neuralgia Patients: A Resting-State Functional MRI Study.

Fri, 07/21/2017 - 10:20

Local Brain Activity Differences Between Herpes Zoster and Postherpetic Neuralgia Patients: A Resting-State Functional MRI Study.

Pain Physician. 2017 Jul;20(5):E687-E699

Authors: Cao S, Li Y, Deng W, Qin B, Zhang Y, Xie P, Yuan J, Yu B, Yu T

Abstract
BACKGROUND: Herpes zoster (HZ) can develop into postherpetic neuralgia (PHN), both of which are painful diseases. PHN patients suffer chronic pain and emotional disorders. Previous studies showed that the PHN brain displayed abnormal activity and structural change, but the difference in brain activity between HZ and PHN is still not known.
OBJECTIVES: To identify regional brain activity changes in HZ and PHN brains with resting-state functional magnetic resonance imaging (rs-fMRI) technique, and to observe the differences between HZ and PHN patients.
STUDY DESIGN: Observational study.
SETTING: University hospital.
METHODS: Regional homogeneity (ReHo) and fractional aptitude of low-frequency fluctuation (fALFF) methods were employed to analysis resting-state brain activity. Seventy-three age and gender matched patients (50 HZ, 23 PHN) and 55 healthy controls were enrolled. ReHo and fALFF changes were analyzed to detect the functional abnormality in HZ and PHN brains.
RESULTS: Compared with healthy controls, HZ and PHN patients exhibited abnormal ReHo and fALFF values in classic pain-related brain regions (such as the frontal lobe, thalamus, insular, and cerebellum) as well as the brainstem, limbic lobe, and temporal lobe. When HZ developed to PHN, the activity in the vast area of the cerebellum significantly increased while that of some regions in the occipital lobe, temporal lobe, parietal lobe, and limbic lobe showed an apparent decrease.
LIMITATIONS: (a) Relatively short pain duration (mean 12.2 months) and small sample size (n = 23) for PHN group. (b) Comparisons at different time points (with paired t-tests) for each patient may minimize individual differences.
CONCLUSIONS: HZ and PHN induced local brain activity changed in the pain matrix, brainstem, and limbic system. HZ chronification induced functional change in the cerebellum, occipital lobe, temporal lobe, parietal lobe, and limbic lobe. These brain activity changes may be correlated with HZ-PHN transition.
KEY WORDS: Herpes zoster, postherpetic neuralgia, resting-state fMRI (rs-fMRI), regional homogeneity (ReHo), fractional aptitude of low-frequency fluctuation (fALFF).

PMID: 28727713 [PubMed - in process]

Altered putamen functional connectivity is associated with anxiety disorder in Parkinson's disease.

Fri, 07/21/2017 - 10:20

Altered putamen functional connectivity is associated with anxiety disorder in Parkinson's disease.

Oncotarget. 2017 Jul 05;:

Authors: Wang X, Li J, Yuan Y, Wang M, Ding J, Zhang J, Zhu L, Shen Y, Zhang H, Zhang K

Abstract
In this study, we used resting state-functional magnetic resonance imaging (rs-fMRI) to explore altered putamen functional connectivity (FC) in Parkinson's disease patients with anxiety disorder. We divided 65 Parkinson's disease patients into anxiety (PD-A; n=18) and non-anxiety (PD-NA; n=45) groups based on a Hamilton Anxiety Rating Scale cutoff score of 12. The PD-A patients exhibited altered putamen FC with cortical and subcortical regions. The PD-A patients showed enhanced putamen FC with the caudatum, which correlated with increased emotional processing during anxiety. Decreased putamen FC with the orbitofrontal gyrus and cerebellum also correlated with increased anxiety in Parkinson's disease. Our findings demonstrate that anxiety disorder in Parkinson's disease is associated with abnormal putamen FC networks, especially with caudatum, orbitofrontal gyrus and cerebellum.

PMID: 28727571 [PubMed - as supplied by publisher]

Columnar Segregation of Magnocellular and Parvocellular Streams in Human Extrastriate Cortex.

Fri, 07/21/2017 - 10:20
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Columnar Segregation of Magnocellular and Parvocellular Streams in Human Extrastriate Cortex.

J Neurosci. 2017 Jul 19;:

Authors: Tootell RBH, Nasr S

Abstract
'Magno- vs. parvo-cellular' (M-P) streams are fundamental to the organization of macaque visual cortex. Segregated, paired M-P streams extend from retina through LGN into V1. The M stream extends further into area V5/MT, and parts of V2. However elsewhere in visual cortex, it remains unclear whether M-P-derived information 1) becomes intermixed, or 2) remains segregated in M-P dominated columns and neurons. Here we tested whether M-P streams exist in extrastriate cortical columns, in 8 human subjects (4 female).We acquired high resolution fMRI at high field (7T), testing for M- and P-influenced columns within each of four cortical areas (V2, V3, V3A and V4), based on known functional distinctions in M-P streams in macaque: 1) color vs. luminance, 2) binocular disparity, 3) luminance contrast sensitivity, 4) peak spatial frequency, and 5) color/spatial interactions. Additional measurements of resting state activity (eyes closed) tested for segregated functional connections between these columns.We found M- and P-like functions and connections within and bbetween segregated cortical columns in V2, V3, and (in most experiments) area V4. Area V3A was dominated by the M stream, without significant influence from the P stream. These results suggest that M-P streams exist, and extend through, specific columns in early/middle stages of human extrastriate cortex.SIGNIFICANCE STATEMENTThe 'magnocellular' and 'parvocellular' (M-P) streams are fundamental components of primate visual cortical organization. These streams segregate both anatomical and functional properties in parallel, from retina through primary visual cortex. However in most higher order cortical sites, it is unknown whether such M-P streams exist, and/or what form those streams would take. Moreover it is unknown whether M-P streams exist in human cortex. Here, fMRI evidence measured at high field (7T) and high resolution revealed segregated M-P streams in four areas of human extrastriate cortex. These results suggest that M-P information is processed in segregated parallel channels throughout much of human visual cortex; the M-P streams are more than a convenient sorting property in earlier stages of the visual system.

PMID: 28724749 [PubMed - as supplied by publisher]

Disrupted small-world brain network topology in pure conduct disorder.

Fri, 07/21/2017 - 10:20
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Disrupted small-world brain network topology in pure conduct disorder.

Oncotarget. 2017 Jul 08;:

Authors: Lu FM, Zhou JS, Zhang J, Wang XP, Yuan Z

Abstract
OBJECTIVES: Conduct disorder (CD) is characterized by the violation of the rights of others or basic social rules and a repetitive, persistent pattern of antisocial and aggressive behaviors. A large number of functional and structural neuroimaging studies have identified widely abnormalities in specific brain regions in CD, but the alterations in the topological organization of functional networks among them remain largely unknown.
METHODS: Resting-state functional magnetic resonance imaging was applied to investigate the intrinsic functional connectivity in 18 pure CD patients and eighteen typically developing healthy controls. We first constructed the functional networks and then examined the CD-related alteration in topology properties using graph theoretical analysis.
RESULTS: Both the CD group and healthy controls exhibited small-world topology. However, the CD group showed decreased global and local efficiency. Changes in the nodal characteristics in CD group were found predominantly in the default-mode network, visual, and striatum regions. In addition, altered fronto-limbic-striatum network topology was found to have a relationship with clinical scores.
CONCLUSIONS: Our findings indicate the altered nodal topology of brain functional connectivity networks in CD.
SIGNIFICANCE: The results provide unequivocal evidence of a topological disruption in the brain networks that suggest some possible pathophysiological mechanisms underlying CD.

PMID: 28723654 [PubMed - as supplied by publisher]

Interhemispheric disconnectivity in the sensorimotor network in bipolar disorder revealed by functional connectivity and diffusion tensor imaging analysis.

Thu, 07/20/2017 - 15:40
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Interhemispheric disconnectivity in the sensorimotor network in bipolar disorder revealed by functional connectivity and diffusion tensor imaging analysis.

Heliyon. 2017 Jun;3(6):e00335

Authors: Ishida T, Donishi T, Iwatani J, Yamada S, Takahashi S, Ukai S, Shinosaki K, Terada M, Kaneoke Y

Abstract
BACKGROUND: Little is known regarding interhemispheric functional connectivity (FC) abnormalities via the corpus callosum in subjects with bipolar disorder (BD), which might be a key pathophysiological basis of emotional processing alterations in BD.
METHODS: We performed tract-based spatial statistics (TBSS) using diffusion tensor imaging (DTI) in 24 healthy control (HC) and 22 BD subjects. Next, we analyzed the neural networks with independent component analysis (ICA) in 32HC and 25 BD subjects using resting-state functional magnetic resonance imaging.
RESULTS: In TBSS analysis, we found reduced fractional anisotropy (FA) in the corpus callosum of BD subjects. In ICA, functional within-connectivity was reduced in two clusters in the sensorimotor network (SMN) (right and left primary somatosensory areas) of BD subjects compared with HCs. FC between the two clusters and FA values in the corpus callosum of BD subjects was significantly correlated. Further, the functional within-connectivity was related to Young Mania Rating Scale (YMRS) total scores in the right premotor area in the SMN of BD subjects.
LIMITATIONS: Almost all of our BD subjects were taking several medications which could be a confounding factor.
CONCLUSIONS: Our findings suggest that interhemispheric FC dysfunction in the SMN is associated with the impaired nerve fibers in the corpus callosum, which could be one of pathophysiological bases of emotion processing dysregulation in BD patients.

PMID: 28721394 [PubMed]

Functional network integrity presages cognitive decline in preclinical Alzheimer disease.

Thu, 07/20/2017 - 15:40
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Functional network integrity presages cognitive decline in preclinical Alzheimer disease.

Neurology. 2017 Jul 04;89(1):29-37

Authors: Buckley RF, Schultz AP, Hedden T, Papp KV, Hanseeuw BJ, Marshall G, Sepulcre J, Smith EE, Rentz DM, Johnson KA, Sperling RA, Chhatwal JP

Abstract
OBJECTIVE: To examine the utility of resting-state functional connectivity MRI (rs-fcMRI) measurements of network integrity as a predictor of future cognitive decline in preclinical Alzheimer disease (AD).
METHODS: A total of 237 clinically normal older adults (aged 63-90 years, Clinical Dementia Rating 0) underwent baseline β-amyloid (Aβ) imaging with Pittsburgh compound B PET and structural and rs-fcMRI. We identified 7 networks for analysis, including 4 cognitive networks (default, salience, dorsal attention, and frontoparietal control) and 3 noncognitive networks (primary visual, extrastriate visual, motor). Using linear and curvilinear mixed models, we used baseline connectivity in these networks to predict longitudinal changes in preclinical Alzheimer cognitive composite (PACC) performance, both alone and interacting with Aβ burden. Median neuropsychological follow-up was 3 years.
RESULTS: Baseline connectivity in the default, salience, and control networks predicted longitudinal PACC decline, unlike connectivity in the dorsal attention and all noncognitive networks. Default, salience, and control network connectivity was also synergistic with Aβ burden in predicting decline, with combined higher Aβ and lower connectivity predicting the steepest curvilinear decline in PACC performance.
CONCLUSIONS: In clinically normal older adults, lower functional connectivity predicted more rapid decline in PACC scores over time, particularly when coupled with increased Aβ burden. Among examined networks, default, salience, and control networks were the strongest predictors of rate of change in PACC scores, with the inflection point of greatest decline beyond the fourth year of follow-up. These results suggest that rs-fcMRI may be a useful predictor of early, AD-related cognitive decline in clinical research settings.

PMID: 28592457 [PubMed - indexed for MEDLINE]

The Relationship between Structural and Functional Brain Changes and Altered Emotion and Cognition in Chronic Low Back Pain: A Systematic Review of MRI and fMRI Studies.

Thu, 07/20/2017 - 03:00
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The Relationship between Structural and Functional Brain Changes and Altered Emotion and Cognition in Chronic Low Back Pain: A Systematic Review of MRI and fMRI Studies.

Clin J Pain. 2017 Jul 17;:

Authors: Ng SK, Urquhart DM, Fitzgerald PB, Cicuttini FM, Hussain SM, Fitzgibbon BM

Abstract
OBJECTIVES: Chronic low back pain (CLBP) is a major health issue, yet its underlying mechanisms remain unknown. Studies have demonstrated the importance of emotion and cognition in chronic pain, however, the relevant brain physiology in magnetic resonance imaging (MRI) studies are unclear in CLBP populations. Therefore, this review aimed to identify MRI brain changes and examine their potential relationship with emotional and cognitive processes in CLBP.
METHOD: A systematic search was conducted in 5 databases. Studies that recruited adult, chronic low back pain populations, and used brain MRI protocols were included.
RESULTS: Fifty-five studies met the inclusion criteria. Of the structural MRI studies, 10 of 15 studies found decreased gray matter and 7 of 8 studies found white matter changes in CLBP groups compared to controls. Fourteen resting-state functional MRI (fMRI) studies all reported differences between CLBP and control groups in the default mode network. Interestingly, only 3 of 10 fMRI studies observed significant differences during noxious stimulation between CLBP and control groups, while 13 of 16 studies observed significant brain activation differences in CLBP groups during various external tasks. Finally, there were 3 studies that observed a degree of recovery in functional connectivity following intervention.
DISCUSSION: The brain changes in CLBP groups were mainly observed in areas and networks important in emotion and cognition, rather than those typically associated with nociception. This supports the understanding that emotional and cognitive processes may be the core contributor to the CLBP experience, however, future studies need to explore these processes further.

PMID: 28719509 [PubMed - as supplied by publisher]

Chronic antiepileptic drug use and functional network efficiency: A functional magnetic resonance imaging study.

Thu, 07/20/2017 - 03:00
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Chronic antiepileptic drug use and functional network efficiency: A functional magnetic resonance imaging study.

World J Radiol. 2017 Jun 28;9(6):287-294

Authors: van Veenendaal TM, IJff DM, Aldenkamp AP, Lazeron RHC, Hofman PAM, de Louw AJA, Backes WH, Jansen JFA

Abstract
AIM: To increase our insight in the neuronal mechanisms underlying cognitive side-effects of antiepileptic drug (AED) treatment.
METHODS: The relation between functional magnetic resonance-acquired brain network measures, AED use, and cognitive function was investigated. Three groups of patients with epilepsy with a different risk profile for developing cognitive side effects were included: A "low risk" category (lamotrigine or levetiracetam, n = 16), an "intermediate risk" category (carbamazepine, oxcarbazepine, phenytoin, or valproate, n = 34) and a "high risk" category (topiramate, n = 5). Brain connectivity was assessed using resting state functional magnetic resonance imaging and graph theoretical network analysis. The Computerized Visual Searching Task was used to measure central information processing speed, a common cognitive side effect of AED treatment.
RESULTS: Central information processing speed was lower in patients taking AEDs from the intermediate and high risk categories, compared with patients from the low risk category. The effect of risk category on global efficiency was significant (P < 0.05, ANCOVA), with a significantly higher global efficiency for patient from the low category compared with the high risk category (P < 0.05, post-hoc test). Risk category had no significant effect on the clustering coefficient (ANCOVA, P > 0.2). Also no significant associations between information processing speed and global efficiency or the clustering coefficient (linear regression analysis, P > 0.15) were observed.
CONCLUSION: Only the four patients taking topiramate show aberrant network measures, suggesting that alterations in functional brain network organization may be only subtle and measureable in patients with more severe cognitive side effects.

PMID: 28717415 [PubMed]

Investigation of the Changes in the Power Distribution in Resting-State Brain Networks Associated with Pure Conduct Disorder.

Thu, 07/20/2017 - 03:00
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Investigation of the Changes in the Power Distribution in Resting-State Brain Networks Associated with Pure Conduct Disorder.

Sci Rep. 2017 Jul 17;7(1):5528

Authors: Zhang J, Zhou J, Lu F, Chen L, Huang Y, Chen H, Xiang Y, Yang G, Yuan Z

Abstract
Conduct disorder (CD) is a psychiatric disorder in children and adolescence. To investigate changes in the power distribution in brain networks between CD and typically developing (TD) groups, resting-state functional magnetic resonance imaging (rsfMRI) data of thirty-six subjects were first recorded, and then the data were preprocessed using DPARSF and SPM8. Meanwhile, the power of the blood oxygenation level-dependent (BOLD) signals of ninety brain regions was acquired using the integral of the Welch power spectral density (PSD). Additionally, the powers of the brain regions that reached significance (p < 0.05) were extracted using the bootstrap statistics, in which the standardized z-scores of the powers were used as a reference. The results of the analysis of the changes in power exhibited that there were significant power differences in some pairs of brain regions between the CD and TD groups, indicating a change in the power distribution. In addition, the results also suggest that the total power consumption of brain networks in CD patients is less than that observed in the TD group. Consequently, the study provided a paradigm for establishing quantifiable indicators via the power spectrum approach for the comparison and analysis of the BOLD signal power between CD patients and healthy controls.

PMID: 28717223 [PubMed - in process]

The structural basis of large-scale functional connectivity in the mouse.

Thu, 07/20/2017 - 03:00
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The structural basis of large-scale functional connectivity in the mouse.

J Neurosci. 2017 Jul 17;:

Authors: Grandjean J, Zerbi V, Balsters J, Wenderoth N, Rudina M

Abstract
Translational neuroimaging requires approaches and techniques that can bridge between multiple different species and disease states. One candidate method, which offers insights into the brain's functional connectivity (FC), is resting state fMRI (rs-fMRI). In both humans and non-human primates, patterns of functional connectivity (often referred to as the functional connectome) have been related to the underlying structural connectivity (structural connectome). Given the recent rise in pre-clinical neuroimaging of mouse models it is an important question whether the mouse functional connectome conforms to the underlying structural connectivity. Here, we compared FC derived from rs-fMRI in female mice to the underlying monosynaptic structural connectome as provided by the Allen Brain Connectivity Atlas. We show that FC between inter-hemispheric homotopic cortical and hippocampal areas, as well as in cortical-striatal pathways, emerge primarily via monosynaptic structural connections. In particular, we demonstrate that the striatum can be segregated according to differential rs-fMRI connectivity patterns that mirror monosynaptic connectivity with isocortex. By contrast, for certain subcortical networks, FC emerges along polysynaptic pathways as shown for left and right striatum, which do not share direct anatomical connections, but high FC is putatively driven by a top-down cortical control. Finally, we show that FC involving cortico-thalamic pathways is limited, possibly confounded by the effect of anesthesia, small regional size and tracer injection volume. These findings provide a critical foundation for using rs-fMRI connectivity as a translational tool to study complex brain circuitry interactions and their pathology due to neurological or psychiatric diseases across species.SIGNIFICANCE STATEMENTA comprehensive understanding of how the anatomical architecture of the brain, often referred to as the "connectome", corresponds to its function is arguably one of the biggest challenges for understanding the brain and its pathologies. Here we use the mouse as a model for comparing functional connectivity derived from resting-state fMRI with gold standard structural connectivity measures based on tracer injections. In particular, we demonstrate high correspondence between functional connectivity measurements of cortico-cortico and cortico-striatal and their anatomical underpinnings. This work provides a critical foundation for studying the pathology of these circuits across mouse models and human patients.

PMID: 28716961 [PubMed - as supplied by publisher]

Functional parcellation using time courses of instantaneous connectivity.

Thu, 07/20/2017 - 03:00
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Functional parcellation using time courses of instantaneous connectivity.

Neuroimage. 2017 Jul 14;:

Authors: van Oort ESB, Mennes M, Navarro Schröder T, Kumar VJ, Zaragoza Jimenez NI, Grodd W, Doeller CF, Beckmann CF

Abstract
Functional neuroimaging studies have led to understanding the brain as a collection of spatially segregated functional networks. It is thought that each of these networks is in turn composed of a set of distinct sub-regions that together support each network's function. Considering the sub-regions to be an essential part of the brain's functional architecture, several strategies have been put forward that aim at identifying the functional sub-units of the brain by means of functional parcellations. Current parcellation strategies typically employ a bottom-up strategy, creating a parcellation by clustering smaller units. We propose a novel top-down parcellation strategy, using time courses of instantaneous connectivity to subdivide an initial region of interest into sub-regions. We use split-half reproducibility to choose the optimal number of sub-regions. We apply our Instantaneous Connectivity Parcellation (ICP) strategy on high-quality resting-state FMRI data, and demonstrate the ability to generate parcellations for thalamus, entorhinal cortex, motor cortex, and subcortex including brainstem and striatum. We evaluate the subdivisions against available cytoarchitecture maps to show that our parcellation strategy recovers biologically valid subdivisions that adhere to known cytoarchitectural features.

PMID: 28716715 [PubMed - as supplied by publisher]

Functional density and edge maps: Characterizing functional architecture in individuals and improving cross-subject registration.

Thu, 07/20/2017 - 03:00
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Functional density and edge maps: Characterizing functional architecture in individuals and improving cross-subject registration.

Neuroimage. 2017 Jul 14;:

Authors: Tong T, Aganj I, Ge T, Polimeni JR, Fischl B

Abstract
Population-level inferences and individual-level analyses are two important aspects in functional magnetic resonance imaging (fMRI) studies. Extracting reliable and informative features from fMRI data that capture biologically meaningful inter-subject variation is critical for aligning and comparing functional networks across subjects, and connecting the properties of functional brain organization with variations in behavior, cognition and genetics. In this study, we derive two new measures, which we term functional density map and edge map, and demonstrate their usefulness in characterizing the function of individual brains. Specifically, using data from the Human Connectome Project (HCP), we show that (1) both functional maps capture intrinsic properties of the functional connectivity pattern in individuals while exhibiting large variation across subjects; (2) functional maps derived from either resting-state or task-evoked fMRI can be used to accurately identify subjects from a population; and (3) cross-subject alignment using these functional maps considerably reduces functional variation and improves functional correspondence across subjects over state-of-the-art multimodal registration algorithms. Our results suggest that the proposed functional density and edge maps are promising features in characterizing the functional architecture in individuals and provide an alternative way to explore the functional variation across subjects.

PMID: 28716714 [PubMed - as supplied by publisher]

Selective Effects of Psychotherapy on Frontopolar Cortical Function in PTSD.

Thu, 07/20/2017 - 03:00
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Selective Effects of Psychotherapy on Frontopolar Cortical Function in PTSD.

Am J Psychiatry. 2017 Jul 18;:appiajp201716091073

Authors: Fonzo GA, Goodkind MS, Oathes DJ, Zaiko YV, Harvey M, Peng KK, Weiss ME, Thompson AL, Zack SE, Mills-Finnerty CE, Rosenberg BM, Edelstein R, Wright RN, Kole CA, Lindley SE, Arnow BA, Jo B, Gross JJ, Rothbaum BO, Etkin A

Abstract
OBJECTIVE: Exposure therapy is an effective treatment for posttraumatic stress disorder (PTSD), but a comprehensive, emotion-focused perspective on how psychotherapy affects brain function is lacking. The authors assessed changes in brain function after prolonged exposure therapy across three emotional reactivity and regulation paradigms.
METHOD: Individuals with PTSD underwent functional MRI (fMRI) at rest and while completing three tasks assessing emotional reactivity and regulation. Individuals were then randomly assigned to immediate prolonged exposure treatment (N=36) or a waiting list condition (N=30) and underwent a second scan approximately 4 weeks after the last treatment session or a comparable waiting period, respectively.
RESULTS: Treatment-specific changes were observed only during cognitive reappraisal of negative images. Psychotherapy increased lateral frontopolar cortex activity and connectivity with the ventromedial prefrontal cortex/ventral striatum. Greater increases in frontopolar activation were associated with improvement in hyperarousal symptoms and psychological well-being. The frontopolar cortex also displayed a greater variety of temporal resting-state signal pattern changes after treatment. Concurrent transcranial magnetic stimulation and fMRI in healthy participants demonstrated that the lateral frontopolar cortex exerts downstream influence on the ventromedial prefrontal cortex/ventral striatum.
CONCLUSIONS: Changes in frontopolar function during deliberate regulation of negative affect is one key mechanism of adaptive psychotherapeutic change in PTSD. Given that frontopolar connectivity with ventromedial regions during emotion regulation is enhanced by psychotherapy and that the frontopolar cortex exerts downstream influence on ventromedial regions in healthy individuals, these findings inform a novel conceptualization of how psychotherapy works, and they identify a promising target for stimulation-based therapeutics.

PMID: 28715907 [PubMed - as supplied by publisher]

Abdominal Pain, the Adolescent and Altered Brain Structure and Function.

Thu, 07/20/2017 - 03:00
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Abdominal Pain, the Adolescent and Altered Brain Structure and Function.

PLoS One. 2016;11(5):e0156545

Authors: Hubbard CS, Becerra L, Heinz N, Ludwick A, Rasooly T, Wu R, Johnson A, Schechter NL, Borsook D, Nurko S

Abstract
Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder of unknown etiology. Although relatively common in children, how this condition affects brain structure and function in a pediatric population remains unclear. Here, we investigate brain changes in adolescents with IBS and healthy controls. Imaging was performed with a Siemens 3 Tesla Trio Tim MRI scanner equipped with a 32-channel head coil. A high-resolution T1-weighted anatomical scan was acquired followed by a T2-weighted functional scan. We used a surface-based morphometric approach along with a seed-based resting-state functional connectivity (RS-FC) analysis to determine if groups differed in cortical thickness and whether areas showing structural differences also showed abnormal RS-FC patterns. Patients completed the Abdominal Pain Index and the GI Module of the Pediatric Quality of Life Inventory to assess abdominal pain severity and impact of GI symptoms on health-related quality of life (HRQOL). Disease duration and pain intensity were also assessed. Pediatric IBS patients, relative to controls, showed cortical thickening in the posterior cingulate (PCC), whereas cortical thinning in posterior parietal and prefrontal areas were found, including the dorsolateral prefrontal cortex (DLPFC). In patients, abdominal pain severity was related to cortical thickening in the intra-abdominal area of the primary somatosensory cortex (SI), whereas HRQOL was associated with insular cortical thinning. Disease severity measures correlated with cortical thickness in bilateral DLPFC and orbitofrontal cortex. Patients also showed reduced anti-correlations between PCC and DLPFC compared to controls, a finding that may reflect aberrant connectivity between default mode and cognitive control networks. We are the first to demonstrate concomitant structural and functional brain changes associated with abdominal pain severity, HRQOL related to GI-specific symptoms, and disease-specific measures in adolescents with IBS. It is possible such changes will be responsive to therapeutic intervention and may be useful as potential markers of disease progression or reversal.

PMID: 27244227 [PubMed - indexed for MEDLINE]

Age-Related Decline in the Variation of Dynamic Functional Connectivity: A Resting State Analysis.

Tue, 07/18/2017 - 13:00
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Age-Related Decline in the Variation of Dynamic Functional Connectivity: A Resting State Analysis.

Front Aging Neurosci. 2017;9:203

Authors: Chen Y, Wang W, Zhao X, Sha M, Liu Y, Zhang X, Ma J, Ni H, Ming D

Abstract
Normal aging is typically characterized by abnormal resting-state functional connectivity (FC), including decreasing connectivity within networks and increasing connectivity between networks, under the assumption that the FC over the scan time was stationary. In fact, the resting-state FC has been shown in recent years to vary over time even within minutes, thus showing the great potential of intrinsic interactions and organization of the brain. In this article, we assumed that the dynamic FC consisted of an intrinsic dynamic balance in the resting brain and was altered with increasing age. Two groups of individuals (N = 36, ages 20-25 for the young group; N = 32, ages 60-85 for the senior group) were recruited from the public data of the Nathan Kline Institute. Phase randomization was first used to examine the reliability of the dynamic FC. Next, the variation in the dynamic FC and the energy ratio of the dynamic FC fluctuations within a higher frequency band were calculated and further checked for differences between groups by non-parametric permutation tests. The results robustly showed modularization of the dynamic FC variation, which declined with aging; moreover, the FC variation of the inter-network connections, which mainly consisted of the frontal-parietal network-associated and occipital-associated connections, decreased. In addition, a higher energy ratio in the higher FC fluctuation frequency band was observed in the senior group, which indicated the frequency interactions in the FC fluctuations. These results highly supported the basis of abnormality and compensation in the aging brain and might provide new insights into both aging and relevant compensatory mechanisms.

PMID: 28713261 [PubMed]

59-year-old female with breathlessness.

Tue, 07/18/2017 - 13:00
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59-year-old female with breathlessness.

Heart. 2016 Oct 15;102(20):1654

Authors: Scatteia A, De Garate E, Bucciarelli-Ducci C

Abstract
CLINICAL INTRODUCTION: A 59-year-old female underwent an electrocardiogram (ECG) and echocardiographic screening. Her brother died at quite a young age of kidney failure. Resting ECG showed borderline voltage criteria for left ventricular hypertrophy (LVH), with marked widespread T-wave inversion. Echocardiogram was normal, but in consideration of exertional breathlessness and abnormal baseline ECG, she underwent a coronary angiogram, which showed unobstructed coronaries. She was then referred to have a cardiac MR (CMR) for further characterisation. CMR images were acquired with a 1.5 T scanner and the imaging protocol included Steady-State Free Precession (SSFP) cine images (Figure 1A) as well as late gadolinium enhancement (LGE) images in the long-axis and short-axis planes covering the whole left ventricle (Figure 1B). In addition, native and postcontrast T1 mapping (Modified Look-Locker (MOLLI)) images were acquired for further tissue characterisation (Figure 1C and D, respectively).
QUESTION: What is the most likely diagnosis based on CMR findings? Anderson-Fabry's disease (AFD)Cardiac amyloidosisGenotype (+), phenotype (-) hypertrophic cardiomyopathy (HCM)Myocardial iron overloadNormal heart.

PMID: 27333905 [PubMed - indexed for MEDLINE]

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