New resting-state fMRI related studies at PubMed

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Disrupted Functional Connectivity of Cornu Ammonis Subregions in Amnestic Mild Cognitive Impairment: A Longitudinal Resting-State fMRI Study.

Wed, 11/14/2018 - 16:40
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Disrupted Functional Connectivity of Cornu Ammonis Subregions in Amnestic Mild Cognitive Impairment: A Longitudinal Resting-State fMRI Study.

Front Hum Neurosci. 2018;12:413

Authors: Li H, Jia X, Qi Z, Fan X, Ma T, Pang R, Ni H, Li CR, Lu J, Li K

Abstract
Background: The cornu ammonis (CA), as part of the hippocampal formation, represents a primary target region of neural degeneration in amnestic mild cognitive impairment (aMCI). Previous studies have revealed subtle structural deficits of the CA subregions (CA1-CA3, bilateral) in aMCI; however, it is not clear how the network function is impacted by aMCI. The present study examined longitudinal changes in resting state functional connectivity (FC) of each CA subregion and how these changes relate to neuropsychological profiles in aMCI. Methods: Twenty aMCI and 20 healthy control (HC) participants underwent longitudinal cognitive assessment and resting state functional MRI scans at baseline and 15 months afterward. Imaging data were processed with published routines in SPM8 and CONN software. Two-way analysis of covariance was performed with covariates of age, gender, education level, follow up interval, gray matter volume, mean FD, as well as global correlation (GCOR). Pearson's correlation was conducted to evaluate the relationship between the longitudinal changes in CA subregional FC and neuropsychological performance in aMCI subjects. Results: Resting state FC between the right CA1 and right middle temporal gyrus (MTG) as well as between the left CA2 and bilateral cuneal cortex (CC) were decreased in aMCI subjects as compared to HC. Longitudinal decrease in FC between the right CA1 and right MTG was correlated with reduced capacity of episodic memory in aMCI subjects. Conclusion: The current findings suggest functional alterations in the CA subregions. CA1 connectivity with the middle temporal cortex may represent an important neural marker of memory dysfunction in aMCI.

PMID: 30420801 [PubMed]

Psychotic symptoms influence the development of anterior cingulate BOLD variability in 22q11.2 deletion syndrome.

Wed, 11/14/2018 - 16:40
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Psychotic symptoms influence the development of anterior cingulate BOLD variability in 22q11.2 deletion syndrome.

Schizophr Res. 2018 03;193:319-328

Authors: Zöller D, Padula MC, Sandini C, Schneider M, Scariati E, Van De Ville D, Schaer M, Eliez S

Abstract
Chromosome 22q11.2 deletion syndrome (22q11DS) is a neurodevelopmental disorder associated with a broad phenotype of clinical, cognitive and psychiatric features. Due to the very high prevalence of schizophrenia (30-40%), the investigation of psychotic symptoms in the syndrome is promising to reveal biomarkers for the development of psychosis, also in the general population. Since schizophrenia is seen as a disorder of the dynamic interactions between brain networks, we here investigated brain dynamics, assessed by the variability of blood oxygenation level dependent (BOLD) signals, in patients with psychotic symptoms. We included 28 patients with 22q11DS presenting higher positive psychotic symptoms, 29 patients with lower positive psychotic symptoms and 69 healthy controls between 10 and 30years old. To overcome limitations of mass-univariate approaches, we employed multivariate analysis, namely partial least squares correlation, combined with proper statistical testing, to analyze resting-state BOLD signal variability and its age-relationship in patients with positive psychotic symptoms. Our results revealed a missing positive age-relationship in the dorsal anterior cingulate cortex (dACC) in patients with higher positive psychotic symptoms, leading to globally lower variability in the dACC in those patients. Patients without positive psychotic symptoms and healthy controls had the same developmental trajectory in this region. Alterations of brain structure and function in the ACC have been previously reported in 22q11DS and linked to psychotic symptoms. The present results support the implication of this region in the development of psychotic symptoms and suggest aberrant BOLD signal variability development as a potential biomarker for psychosis.

PMID: 28803847 [PubMed - indexed for MEDLINE]

Intrinsic functional clustering of anterior cingulate cortex in the common marmoset.

Tue, 11/13/2018 - 15:20

Intrinsic functional clustering of anterior cingulate cortex in the common marmoset.

Neuroimage. 2018 Nov 09;:

Authors: Schaeffer DJ, Gilbert KM, Ghahremani M, Gati JS, Menon RS, Everling S

Abstract
The common marmoset (Callithrix jacchus) has garnered recent attention as a potentially powerful preclinical model and complement to other canonical mammalian models of human brain diseases (e.g., rodents and Old World non-human primates). With a granular frontal cortex and the advent of transgenic modifications, marmosets are well positioned to serve as neuropsychiatric models of prefrontal cortex dysfunction. A critical step in the development of marmosets for such models is to characterize functional network topologies of frontal cortex in healthy, normally functioning marmosets. Here, we sought to characterize the intrinsic functional connectivity of anterior cingulate cortex (ACC) in marmosets using resting state functional magnetic resonance imaging (RS-fMRI). Seven lightly anesthetized marmosets were imaged at ultra-high field (9.4 T) and hierarchical clustering was employed to extract functional clusters of ACC from the RS-fMRI data. The data demonstrated three functionally discrete clusters within ACC. The functional connectivity between these clusters with the rest of the brain was also found to be distinct, supporting the hypothesis that ACC subregions serve different circuits and their concomitant functions. In a separate seed-based analysis, we also sought to delineate finer-grained patterns of ACC connectivity between marmoset primary motor area 4 ab and putative eye movement areas (8aD and 8 aV). This analysis demonstrated distinct patterns of ACC functional connectivity between motor and eye movement regions that overlapped well with what has been shown in humans and macaques. Overall, these results demonstrate that marmosets have a network topology of ACC that resembles that of Old World primates, giving further credence to the use of marmosets for preclinical studies of intractable human brain diseases.

PMID: 30419289 [PubMed - as supplied by publisher]

Predicting functional networks from region connectivity profiles in task-based versus resting-state fMRI data.

Tue, 11/13/2018 - 15:20

Predicting functional networks from region connectivity profiles in task-based versus resting-state fMRI data.

PLoS One. 2018;13(11):e0207385

Authors: Rasero J, Aerts H, Ontivero Ortega M, Cortes JM, Stramaglia S, Marinazzo D

Abstract
Intrinsic Connectivity Networks, patterns of correlated activity emerging from "resting-state" BOLD time series, are increasingly being associated with cognitive, clinical, and behavioral aspects, and compared with patterns of activity elicited by specific tasks. We study the reconfiguration of brain networks between task and resting-state conditions by a machine learning approach, to highlight the Intrinsic Connectivity Networks (ICNs) which are more affected by the change of network configurations in task vs. rest. To this end, we use a large cohort of publicly available data in both resting and task-based fMRI paradigms. By applying a battery of different supervised classifiers relying only on task-based measurements, we show that the highest accuracy to predict ICNs is reached with a simple neural network of one hidden layer. In addition, when testing the fitted model on resting state measurements, such architecture yields a performance close to 90% for areas connected to the task performed, which mainly involve the visual and sensorimotor cortex, whilst a relevant decrease of the performance is observed in the other ICNs. On one hand, our results confirm the correspondence of ICNs in both paradigms (task and resting) thus opening a window for future clinical applications to subjects whose participation in a required task cannot be guaranteed. On the other hand it is shown that brain areas not involved in the task display different connectivity patterns in the two paradigms.

PMID: 30419063 [PubMed - in process]

Capturing Dynamic Connectivity from Resting State fMRI using Time-Varying Graphical Lasso.

Tue, 11/13/2018 - 15:20

Capturing Dynamic Connectivity from Resting State fMRI using Time-Varying Graphical Lasso.

IEEE Trans Biomed Eng. 2018 Nov 09;:

Authors: Cai B, Zhang G, Zhang A, Stephen JM, Wilson TW, Calhoun VD, Wang Y

Abstract
Functional connectivity (FC) within the human brain evaluated through functional magnetic resonance imaging (fMRI) data has attracted increasing attention and has been employed to study the development of the brain or health conditions of the brain. Many different approaches have been proposed to estimate FC from fMRI data, whereas many of them rely on an implicit assumption that functional connectivity should be static throughout the fMRI scan session. Recently, the fMRI community has realized the limitation of assuming static connectivity and dynamic approaches are more prominent in the resting state fMRI (rs-fMRI) analysis. The sliding window technique has been widely used in many studies to capture network dynamics, but has a number of limitations. In this study, we apply a time-varying graphical lasso (TVGL) model, an extension from the traditional graphical lasso, to address the challenge, which can greatly improve the estimation of FC. The performance of estimating dynamic FC is evaluated with the TVGL through both simulated experiments and real rs-fMRI data from the Philadelphia Neurodevelopmental Cohort (PNC) project. Improved performance is achieved over the sliding window technique. In particular, group differences and transition behaviours between young adults and children are investigated using the estimated dynamic connectivity networks, which help us to better unveil the mechanisms underlying the evolution of the brain over time.

PMID: 30418876 [PubMed - as supplied by publisher]

Sensitive Period for Cognitive Repurposing of Human Visual Cortex.

Tue, 11/13/2018 - 15:20

Sensitive Period for Cognitive Repurposing of Human Visual Cortex.

Cereb Cortex. 2018 Nov 12;:

Authors: Kanjlia S, Pant R, Bedny M

Abstract
Studies of sensory loss are a model for understanding the functional flexibility of human cortex. In congenital blindness, subsets of visual cortex are recruited during higher-cognitive tasks, such as language and math tasks. Is such dramatic functional repurposing possible throughout the lifespan or restricted to sensitive periods in development? We compared visual cortex function in individuals who lost their vision as adults (after age 17) to congenitally blind and sighted blindfolded adults. Participants took part in resting-state and task-based fMRI scans during which they solved math equations of varying difficulty and judged the meanings of sentences. Blindness at any age caused "visual" cortices to synchronize with specific frontoparietal networks at rest. However, in task-based data, visual cortices showed regional specialization for math and language and load-dependent activity only in congenital blindness. Thus, despite the presence of long-range functional connectivity, cognitive repurposing of human cortex is limited by sensitive periods.

PMID: 30418533 [PubMed - as supplied by publisher]

Predicting chemo-brain in breast cancer survivors using multiple MRI features and machine-learning.

Tue, 11/13/2018 - 15:20

Predicting chemo-brain in breast cancer survivors using multiple MRI features and machine-learning.

Magn Reson Med. 2018 Nov 12;:

Authors: Chen VC, Lin TY, Yeh DC, Chai JW, Weng JC

Abstract
PURPOSE: Breast cancer (BC) is the most common cancer in women worldwide. There exist various advanced chemotherapy drugs for BC; however, chemotherapy drugs may result in brain damage during treatment. When a patient's brain is changed in response to chemo drugs, it is termed chemo-brain. In this study, we aimed to construct machine-learning models to detect the subtle alternations of the brain in postchemotherapy BC patients.
METHODS: Nineteen BC patients undergoing chemotherapy and 20 healthy controls (HCs) were recruited for this study. Both groups underwent resting-state functional MRI and generalized q-sampling imaging (GQI).
RESULTS: Logistic regression (LR) with GQI indices in standardized voxel-wise analysis, LR with mean regional homogeneity in regional summation analysis, decision tree classifier (CART) with generalized fractional anisotropy in voxel-wise analysis, and XGBoost (XGB) with normalized quantitative anisotropy had formidable performances in classifying subjects into a chemo-brain group or an HC group. Classifying the brain MRIs of HC and postchemotherapy patients by conducting leave-one-out cross-validation resulted in the highest accuracy of 84%, which was attained by LR, CART, and XGB with multiple feature sets.
CONCLUSIONS: In our study, we constructed the machine-learning models that were able to identify chemo-brains from normal brains. We are hopeful that these results will be helpful in clinically tracking chemo-brains in the future.

PMID: 30417933 [PubMed - as supplied by publisher]

Altered small-world, functional brain networks in patients with lower back pain.

Tue, 11/13/2018 - 15:20

Altered small-world, functional brain networks in patients with lower back pain.

Sci China Life Sci. 2018 Nov 02;:

Authors: Liu J, Zhang F, Liu X, Zhuo Z, Wei J, Du M, Chan Q, Wang X, Wang D

Abstract
In this study, we aimed to investigate the functional network changes that occur in patients with lower back pain (LBP). We also investigated the link between LBP and the small-world properties of functional networks within the brain. Functional MRI (fMRI) was performed on 20 individuals with LBP and 17 age and gender-matched normal controls during the resting state. The severity of the pain in the individuals with LBP ranged from 5 to 8 on a 0-10 scale, with 0 indicating no pain. Network-based statistics were performed to investigate the differences between the brain networks of individuals with LBP and those of normal controls. Several small-world parameters of brain networks were calculated, including the clustering coefficient, characteristic path length, local efficiency, and global efficiency. These criteria reflect the overall network efficiency. The brain networks in the individuals with LBP due to herniation of a lumbar disc demonstrated a significantly longer characteristic path length as well as a lower clustering coefficient, global efficiency, and local efficiency compared to those in control subjects. We found that LBP patients tended to have unstable and inefficient brain networks when compared with healthy controls. In addition, LBP individuals showed significantly decreased functional connectivity in the anterior cingulate cortex, middle cingulate cortex, post cingulate cortex, inferior frontal gyrus, middle temporal gyrus, occipital gyrus, postcentral gyrus, precentral gyrus, supplementary motor area, thalamus, fusiform, caudate, and cerebellum. We believe that these regions may be involved in the pathophysiology of lower back pain.

PMID: 30417246 [PubMed - as supplied by publisher]

Grading of Frequency Spectral Centroid Across Resting-State Networks.

Tue, 11/13/2018 - 15:20

Grading of Frequency Spectral Centroid Across Resting-State Networks.

Front Hum Neurosci. 2018;12:436

Authors: Ries A, Chang C, Glim S, Meng C, Sorg C, Wohlschläger A

Abstract
Ongoing, slowly fluctuating brain activity is organized in resting-state networks (RSNs) of spatially coherent fluctuations. Beyond spatial coherence, RSN activity is governed in a frequency-specific manner. The more detailed architecture of frequency spectra across RSNs is, however, poorly understood. Here we propose a novel measure-the Spectral Centroid (SC)-which represents the center of gravity of the full power spectrum of RSN signal fluctuations. We examine whether spectral underpinnings of network fluctuations are distinct across RSNs. We hypothesize that spectral content differs across networks in a consistent way, thus, the aggregate representation-SC-systematically differs across RSNs. We therefore test for a significant grading (i.e., ordering) of SC across RSNs in healthy subjects. Moreover, we hypothesize that such grading is biologically significant by demonstrating its RSN-specific change through brain disease, namely major depressive disorder. Our results yield a highly organized grading of SC across RSNs in 820 healthy subjects. This ordering was largely replicated in an independent dataset of 25 healthy subjects, pointing toward the validity and consistency of found SC grading across RSNs. Furthermore, we demonstrated the biological relevance of SC grading, as the SC of the salience network-a RSN well known to be implicated in depression-was specifically increased in patients compared to healthy controls. In summary, results provide evidence for a distinct grading of spectra across RSNs, which is sensitive to major depression.

PMID: 30416439 [PubMed]

The regulation of positive and negative emotions through instructed causal attributions in lifetime depression - A functional magnetic resonance imaging study.

Mon, 11/12/2018 - 14:00

The regulation of positive and negative emotions through instructed causal attributions in lifetime depression - A functional magnetic resonance imaging study.

Neuroimage Clin. 2018 Oct 25;20:1233-1245

Authors: Loeffler LAK, Radke S, Habel U, Ciric R, Satterthwaite TD, Schneider F, Derntl B

Abstract
Adequate emotional control is essential for mental health. Deficiencies in emotion regulation are evident in many psychiatric disorders, including depression. Patients with depression show, for instance, disrupted neural emotion regulation in cognitive regulation regions such as lateral and medial prefrontal cortices. Since depressed individuals tend to attribute positive events to external circumstances and negative events to themselves, modifying this non-self-serving attributional style may represent a promising regulation strategy. Spontaneous causal attributions are generally processed in medial brain structures, particularly the precuneus. However, so far no study has investigated neural correlates of instructed causal attributions (e.g. instructing a person to intentionally relate positive events to the self) and their potential to regulate emotions. The current study therefore aimed to examine how instructed causal attributions of positive and negative events affect the emotional experience of depressed individuals as well as its neural bases. For this purpose pictures of sad and happy faces were presented to 26 patients with a lifetime major depression (MDD) and 26 healthy controls (HC) during fMRI. Participants should respond naturally ("view") or imagine that the person on the picture was sad/happy because of them ("internal attribution") or because something else happened ("external attribution"). Trait attributional style and depressive symptoms were assessed with questionnaires to examine potential influential factors on emotion regulation ability. Results revealed that patients compared to controls show a non-self-serving trait attributional style (i.e. more external attributions of positive events and more internal attributions of negative events). Intriguingly, when instructed to apply specific causal attributions during the emotion regulation task, patients and controls were similarly able to regulate positive and negative emotions. Regulating emotions through instructed attributions (internal/external attribution>view) generally engaged the precuneus, which was correlated with patients' trait attributional style (i.e. more precuneus activation during external>view was linked to a general tendency to relate positive events to external sources). Up-regulating happiness through internal (compared to external) attributions recruited the parahippocampal gyrus only in controls. The down-regulation of sadness (external>internal attribution), in contrast, engaged the superior frontal gyrus only in patients. Superior frontal gyrus activation thereby correlated with depression severity, which implies a greater need of cognitive resources for a successful regulation in more severely depressed. Patients and controls did not differ in activation in brain regions related to cognitive emotion regulation or attribution. However, results point to a disturbed processing of positive emotions in depression. Interestingly, increased precuneus resting-state connectivity with emotion regulation brain regions (inferior parietal lobule, middle frontal gyrus) was linked to healthier attributions (i.e. external attributions of negative events) in patients and controls. Adequate neural communication between these regions therefore seem to facilitate an adaptive trait attributional style. Findings of this study emphasize that despite patients' dysfunctional trait attributional style, explicitly applying causal attributions effectively regulates emotions. Future research should examine the efficacy of instructed attributions in reducing negative affect and anhedonia in depressed patients, for instance by means of attribution trainings during psychotherapy.

PMID: 30414987 [PubMed - as supplied by publisher]

Optimising neonatal fMRI data analysis: Design and validation of an extended dHCP preprocessing pipeline to characterise noxious-evoked brain activity in infants.

Mon, 11/12/2018 - 14:00

Optimising neonatal fMRI data analysis: Design and validation of an extended dHCP preprocessing pipeline to characterise noxious-evoked brain activity in infants.

Neuroimage. 2018 Nov 08;:

Authors: Baxter L, Fitzgibbon S, Moultrie F, Goksan S, Jenkinson M, Smith S, Andersson J, Duff E, Slater R

Abstract
The infant brain is unlike the adult brain, with considerable differences in morphological, neurodynamic, and haemodynamic features. As the majority of current MRI analysis tools were designed for use in adults, a primary objective of the Developing Human Connectome Project (dHCP) is to develop optimised methodological pipelines for the analysis of neonatal structural, resting state, and diffusion MRI data. Here, in an independent neonatal dataset we have extended and optimised the dHCP fMRI preprocessing pipeline for the analysis of stimulus-response fMRI data. We describe and validate this extended dHCP fMRI preprocessing pipeline to analyse changes in brain activity evoked following an acute noxious stimulus applied to the infant's foot. We compare the results obtained from this extended dHCP pipeline to results obtained from a typical FSL FEAT-based analysis pipeline, evaluating the pipelines' outputs using a wide range of tests. We demonstrate that a substantial increase in spatial specificity and sensitivity to signal can be attained with a bespoke neonatal preprocessing pipeline through optimised motion and distortion correction, ICA-based denoising, and haemodynamic modelling. The improved sensitivity and specificity, made possible with this extended dHCP pipeline, will be paramount in making further progress in our understanding of the development of sensory processing in the infant brain.

PMID: 30414984 [PubMed - as supplied by publisher]

Altered resting-state dynamics in autism spectrum disorder: Causal to the social impairment?

Sun, 11/11/2018 - 13:00
Related Articles

Altered resting-state dynamics in autism spectrum disorder: Causal to the social impairment?

Prog Neuropsychopharmacol Biol Psychiatry. 2018 Nov 07;:

Authors: Gotts SJ, Ramot M, Jasmin K, Martin A

Abstract
Autism spectrum disorder (ASD) is characterized by profound impairments in social abilities and by restricted interests and repetitive behaviors. Much work in the past decade has been dedicated to understanding the brain-bases of ASD, and in the context of resting-state functional connectivity fMRI in high-functioning adolescents and adults, the field has established a set of reliable findings: decreased cortico-cortical interactions among brain regions thought to be engaged in social processing, along with a simultaneous increase in thalamo-cortical and striato-cortical interactions. However, few studies have attempted to manipulate these altered patterns, leading to the question of whether such patterns are actually causally involved in producing the corresponding behavioral impairments. We discuss a few such recent attempts in the domains of fMRI neurofeedback and overt social interaction during scanning, and we conclude that the evidence of causal involvement is somewhat mixed. We highlight the potential role of the thalamus and striatum in ASD and emphasize the need for studies that directly compare scanning during multiple cognitive states in addition to the resting-state.

PMID: 30414457 [PubMed - as supplied by publisher]

Default Mode Network Lateralization and Memory in Healthy Aging and Alzheimer's Disease.

Sat, 11/10/2018 - 11:40

Default Mode Network Lateralization and Memory in Healthy Aging and Alzheimer's Disease.

J Alzheimers Dis. 2018 Nov 03;:

Authors: Banks SJ, Zhuang X, Bayram E, Bird C, Cordes D, Caldwell JZK, Cummings JL, Alzheimer’s Disease Neuroimaging Initiative

Abstract
Lateralization of default mode network (DMN) functioning has been shown to change with age. Similarly, lateralization of frontal lobe function has been shown to decline in age. The impact of amyloid pathology and the progression of Alzheimer's disease (AD) on resting state lateralization has not been investigated. Due to the preferential involvement of the left hemisphere in verbal tasks, there may be a benefit to higher levels of left-lateralization in the performance of verbal memory tasks. Here we compared functional lateralization of the anterior and posterior DMN between four groups of participants: amyloid negative (Aβ-) and amyloid positive (Aβ+) groups with normal cognition (NC), and Aβ+ groups with mild cognitive impairment (Aβ+MCI) or dementia (Aβ+AD). Differences were evident between groups in posterior DMN; the Aβ-NC group was more left-lateralized than both cognitively impaired Aβ+ groups. There was no difference in anterior DMN. No differences in overall network connectivity between groups were observed, suggesting that the functional lateralization finding is not secondary to general changes in connectivity. Left-lateralization of both networks was associated with better verbal recall performance. Older subjects, overall, had less left functional lateralization of the anterior DMN.

PMID: 30412488 [PubMed - as supplied by publisher]

Predictors of Attrition in Longitudinal Neuroimaging Research: Inhibitory Control, Head Movement, and Resting-State Functional Connectivity.

Sat, 11/10/2018 - 11:40

Predictors of Attrition in Longitudinal Neuroimaging Research: Inhibitory Control, Head Movement, and Resting-State Functional Connectivity.

Brain Connect. 2018 Nov 09;:

Authors: Stange JP, Jenkins LM, Bessette KL, Kling LR, Bark J, Shepard R, Hamlat EJ, DelDonno SR, Phan L, Passarotti AM, Ajilore O, Langenecker SA

Abstract
OBJECTIVE: Attrition is a major problem in longitudinal neuroimaging studies, as it may lead to unreliable estimates of the stability of trait-like processes over time, of the identification of risk factors for clinical outcomes, and of the effects of treatment. Identification of characteristics associated with attrition has implications for participant recruitment and participant retention to achieve representative longitudinal samples. We investigated inhibitory control deficits, head motion, and resting-state functional connectivity within the cognitive control network as predictors of attrition.
MATERIALS AND METHODS: Ninety-seven individuals with remitted major depressive disorder or healthy controls completed a functional MRI scan, which included a go/no-go task and resting-state functional connectivity. Approximately two months later, participants were contacted and invited to return for a second scan.
RESULTS: Seventeen individuals were lost to follow-up or declined to participate in the follow-up scan. Worse inhibitory control was correlated with greater movement within the scanner, and each predicted a greater likelihood of attrition, with movement mediating the effects of inhibitory control on attrition. Individuals who dropped out of the study exhibited greater movement than non-dropouts across 9 of the 14 runs of the scan, with medium-to-large effect sizes. Finally, exploratory analyses suggested that attenuated resting-state connectivity with the cognitive control network (particularly in bilateral dorsolateral prefrontal cortex) was associated with greater likelihood of attrition after accounting for head motion at several levels of analysis.
CONCLUSIONS: Inhibitory control and movement within the scanner are associated with attrition, and should be considered for strategic oversampling and participant retention strategies to ensure generalizability of results in longitudinal studies.

PMID: 30411975 [PubMed - as supplied by publisher]

Somatosensory regions show limited functional connectivity differences in youth with Autism Spectrum Disorder.

Sat, 11/10/2018 - 11:40

Somatosensory regions show limited functional connectivity differences in youth with Autism Spectrum Disorder.

Brain Connect. 2018 Nov 09;:

Authors: Cechmanek B, Johnson H, Vazhappilly S, Lebel C, Bray S

Abstract
An estimated 70-90% of children with Autism Spectrum Disorder (ASD) have sensory symptoms, which may present as hyper- or hypo-responsivity in one or more sensory modalities. These sensitivities correlate with social symptoms, activity and social interaction levels. Interestingly, sensory symptoms appear to be most prevalent in late childhood, suggesting a developmental component. While the neural basis of sensory sensitivities remains unclear, atypical functional connectivity of sensory brain regions has been suggested as a potential mechanism. Tactile sensitivities are among the most predictive of social functioning, yet no studies to our knowledge have examined somatosensory functional connectivity in children and adolescents with ASD, when symptoms are typically most prominent. Here, we used human data from the Autism Brain Imaging Data Exchange (ABIDE-I) to assess functional connectivity differences of somatosensory regions during resting state functional magnetic resonance imaging (fMRI), in youth aged 8-15 years. After head-motion exclusion our sample included 67 participants with ASD and 121 typically developing (TD) controls. We additionally examined associations between functional connectivity and age, as well as ASD symptom severity. Together, these seed-based analyses showed limited differences in functional connectivity between groups, either to hypothesized target regions or in terms of global connectivity. Our findings suggest that hyper-or hypo- somatosensory functional connectivity at rest is not a population-level feature in ASD. However, this does not preclude increased variability of somatosensory networks across the ASD population. Further, as sensory sensitivities were not specifically assessed in this sample, future studies may be better able to identify patterns of functional connectivity reflecting individual differences in sensory symptoms.

PMID: 30411970 [PubMed - as supplied by publisher]

Salience network connectivity and social processing in children with nonverbal learning disability or autism spectrum disorder.

Sat, 11/10/2018 - 11:40

Salience network connectivity and social processing in children with nonverbal learning disability or autism spectrum disorder.

Neuropsychology. 2018 Nov 08;:

Authors: Margolis AE, Pagliaccio D, Thomas L, Banker S, Marsh R

Abstract
OBJECTIVE: Nonverbal learning disability (NVLD) is a putative neurodevelopmental disorder characterized by spatial processing deficits as well as social deficits similar to those characteristic of autism spectrum disorder (ASD). Nonetheless, NVLD may be a distinct disorder that is differentially associated with the functioning and connectivity of the salience (SN) and default mode (DMN) networks that support social processing. Thus, we sought to assess and compare connectivity across these networks in children with NVLD, ASD, and typically developing children.
METHOD: Resting-state fMRI data were examined in 17 children with NVLD, 17 children with ASD selected from the Autism Brain Imaging Data Exchange (ABIDE), and 40 TD children (20 from ABIDE). Average DMN and SN functional connectivity and pairwise region-to-region connectivity were compared across groups. Associations with social impairment and IQ were assessed.
RESULTS: Children with NVLD showed reduced connectivity between SN regions (anterior insula to anterior cingulate and to rostral prefrontal cortex [rPFC]), whereas children with ASD showed greater connectivity between SN regions (supramarginal gyrus to rPFC) relative to the other groups. Both clinical groups showed higher levels of parent-reported social problems, which related to altered SN connectivity in the NVLD group. No differences were detected in overall average connectivity within or between networks.
CONCLUSIONS: The social deficits common across children with NVLD and ASD may derive from distinct alterations in connectivity within the SN. Such findings represent the first step toward identifying a neurobiological signature of NVLD. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

PMID: 30411904 [PubMed - as supplied by publisher]

Innovative imaging methods in heart failure: a shifting paradigm in cardiac assessment. Position statement on behalf of the Heart Failure Association of the European Society of Cardiology.

Sat, 11/10/2018 - 11:40

Innovative imaging methods in heart failure: a shifting paradigm in cardiac assessment. Position statement on behalf of the Heart Failure Association of the European Society of Cardiology.

Eur J Heart Fail. 2018 Nov 09;:

Authors: Čelutkienė J, Plymen CM, Flachskampf FA, de Boer RA, Grapsa J, Manka R, Anderson L, Garbi M, Barberis V, Filardi PP, Gargiulo P, Zamorano JL, Lainscak M, Seferovic P, Ruschitzka F, Rosano GMC, Nihoyannopoulos P

Abstract
Myriad advances in all fields of cardiac imaging have stimulated and reflected new understanding of cardiac performance, myocardial damage and the mechanisms of heart failure. In this paper, the Heart Failure Association assesses the potential usefulness of innovative imaging modalities in enabling more precise diagnostic and prognostic evaluation, as well as in guiding treatment strategies. Many new methods have gradually penetrated clinical practice and are on their way to becoming a part of routine evaluation. This paper focuses on myocardial deformation and three-dimensional ultrasound imaging; stress tests for the evaluation of contractile and filling function; the progress of magnetic resonance techniques; molecular imaging and other sound innovations. The Heart Failure Association aims to highlight the ways in which paradigms have shifted in several areas of cardiac assessment. These include reassessing of the simplified concept of ejection fraction and implementation of the new parameters of cardiac performance applicable to all heart failure phenotypes; switching from two-dimensional to more accurate and reproducible three-dimensional ultrasound volumetric evaluation; greater tissue characterization via recently developed magnetic resonance modalities; moving from assessing cardiac function and congestion at rest to assessing it during stress; from invasive to novel non-invasive hybrid techniques depicting coronary anatomy and myocardial perfusion; as well as from morphometry to the imaging of pathophysiologic processes such as inflammation and apoptosis. This position paper examines the specific benefits of imaging innovations for practitioners dealing with heart failure aetiology, risk stratification and monitoring, and, in addition, for scientists involved in the development of future research.

PMID: 30411833 [PubMed - as supplied by publisher]

A practical protocol for measurements of spinal cord functional connectivity.

Sat, 11/10/2018 - 11:40
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A practical protocol for measurements of spinal cord functional connectivity.

Sci Rep. 2018 Nov 08;8(1):16512

Authors: Barry RL, Conrad BN, Smith SA, Gore JC

Abstract
Resting state functional magnetic resonance imaging (fMRI) has been used to study human brain function for over two decades, but only recently has this technique been successfully translated to the human spinal cord. The spinal cord is structurally and functionally unique, so resting state fMRI methods developed and optimized for the brain may not be appropriate when applied to the cord. This report therefore investigates the relative impact of different acquisition and processing choices (including run length, echo time, and bandpass filter width) on the detectability of resting state spinal cord networks at 3T. Our results suggest that frequencies beyond 0.08 Hz should be included in resting state analyses, a run length of ~8-12 mins is appropriate for reliable detection of the ventral (motor) network, and longer echo times - yet still shorter than values typically used for fMRI in the brain - may increase the detectability of the dorsal (sensory) network. Further studies are required to more fully understand and interpret the nature of resting state spinal cord networks in health and in disease, and the protocols described in this report are designed to assist such studies.

PMID: 30410122 [PubMed - in process]

Altered functional connectivity between sub-regions in the thalamus and cortex in schizophrenia patients measured by resting state BOLD fMRI at 7T.

Sat, 11/10/2018 - 11:40
Related Articles

Altered functional connectivity between sub-regions in the thalamus and cortex in schizophrenia patients measured by resting state BOLD fMRI at 7T.

Schizophr Res. 2018 Nov 05;:

Authors: Hua J, Blair NIS, Paez A, Choe A, Barber AD, Brandt A, Lim IAL, Xu F, Kamath V, Pekar JJ, van Zijl PCM, Ross CA, Margolis RL

Abstract
The thalamus is a small brain structure that relays neuronal signals between subcortical and cortical regions. Abnormal thalamocortical connectivity in schizophrenia has been reported in previous studies using blood-oxygenation-level-dependent (BOLD) functional MRI (fMRI) performed at 3T. However, anatomically the thalamus is not a single entity, but is subdivided into multiple distinct nuclei with different connections to various cortical regions. We sought to determine the potential benefit of using the enhanced sensitivity of BOLD fMRI at ultra-high magnetic field (7T) in exploring thalamo-cortical connectivity in schizophrenia based on subregions in the thalamus. Seeds placed in thalamic subregions of 14 patients and 14 matched controls were used to calculate whole-brain functional connectivity. Our results demonstrate impaired thalamic connectivity to the prefrontal cortex and the cerebellum, but enhanced thalamic connectivity to the motor/sensory cortex in schizophrenia. This altered functional connectivity significantly correlated with disease duration in the patients. Remarkably, comparable effect sizes observed in previous 3T studies were detected in the current 7T study with a heterogeneous and much smaller cohort, providing evidence that ultra-high field fMRI may be a powerful tool for measuring functional connectivity abnormalities in schizophrenia. Further investigation with a larger cohort is merited to validate the current findings.

PMID: 30409697 [PubMed - as supplied by publisher]

Anhedonia in Trauma-Exposed Individuals: Functional Connectivity and Decision-Making Correlates.

Sat, 11/10/2018 - 11:40
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Anhedonia in Trauma-Exposed Individuals: Functional Connectivity and Decision-Making Correlates.

Biol Psychiatry Cogn Neurosci Neuroimaging. 2018 Nov;3(11):959-967

Authors: Olson EA, Kaiser RH, Pizzagalli DA, Rauch SL, Rosso IM

Abstract
BACKGROUND: Reward processing deficits have been increasingly associated with trauma exposure and are a core feature of posttraumatic stress disorder (PTSD). While altered resting-state functional connectivity (rsFC) of ventral striatal regions, including the nucleus accumbens (NAcc), has been associated with anhedonia in some stress-related disorders, relationships between NAcc rsFC and anhedonia have not previously been investigated in trauma-exposed individuals. Additionally, relationships between anhedonia and reward-related decision making remain unexplored in relation to trauma exposure. We hypothesized that elevated anhedonia would be associated with altered rsFC between NAcc and default mode network regions and with increased delay discounting.
METHODS: The sample included 51 participants exposed to a DSM-IV PTSD Criterion A event related to community trauma. Participants completed the Clinician Administered PTSD Scale, the Snaith-Hamilton Pleasure Scale, the Beck Depression Inventory, a computerized delay discounting paradigm, and resting-state functional magnetic resonance imaging. rsFC data were analyzed in SPM12 and CONN.
RESULTS: Higher levels of anhedonia were associated with increased rsFC between seed regions of bilateral NAcc and areas of right dorsomedial prefrontal cortex. This relationship remained significant after accounting for Clinician Administered PTSD Scale total scores, Beck Depression Inventory total scores, or diagnostic group in the regression. Additionally, anhedonia was associated with elevated (increased) delay discounting.
CONCLUSIONS: Greater anhedonia was related to higher positive connectivity between NAcc and right dorsomedial prefrontal cortex and to increased delay discounting, i.e., greater preference for smaller immediate versus larger delayed rewards. These findings contribute to a growing body of literature emphasizing the importance of anhedonia in trauma-exposed individuals.

PMID: 30409390 [PubMed - in process]

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