New resting-state fMRI related studies at PubMed

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Functional Connectivity Alterations Reveal Complex Mechanisms Based on Clinical and Radiological Status in Mild Relapsing Remitting Multiple Sclerosis.

Wed, 09/05/2018 - 12:00
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Functional Connectivity Alterations Reveal Complex Mechanisms Based on Clinical and Radiological Status in Mild Relapsing Remitting Multiple Sclerosis.

Front Neurol. 2018;9:690

Authors: Castellazzi G, Debernard L, Melzer TR, Dalrymple-Alford JC, D'Angelo E, Miller DH, Gandini Wheeler-Kingshott CAM, Mason DF

Abstract
Resting state functional MRI (rs-fMRI) has provided important insights into functional reorganization in subjects with Multiple Sclerosis (MS) at different stage of disease. In this cross-sectional study we first assessed, by means of rs-fMRI, the impact of overall T2 lesion load (T2LL) and MS severity score (MSSS) on resting state networks (RSNs) in 62 relapsing remitting MS (RRMS) patients with mild disability (MSSS < 3). Independent Component Analysis (ICA) followed by dual regression analysis confirmed functional connectivity (FC) alterations of many RSNs in RRMS subjects compared to healthy controls. The anterior default mode network (DMNa) and the superior precuneus network (PNsup) showed the largest areas of decreased FC, while the sensory motor networks area M1 (SMNm1) and the medial visual network (MVN) showed the largest areas of increased FC. In order to better understand the nature of these alterations as well as the mechanisms of functional alterations in MS we proposed a method, based on linear regression, that takes into account FC changes and their correlation with T2LL and MSSS. Depending on the sign of the correlation between FC and T2LL, and furthermore the sign of the correlation with MSSS, we suggested the following possible underlying mechanisms to interpret altered FC: (1) FC reduction driven by MS lesions, (2) "true" functional compensatory mechanism, (3a) functional compensation attempt, (3b) "false" functional compensation, (4a) neurodegeneration, (4b) pre-symptomatic condition (damage precedes MS clinical manifestation). Our data shows areas satisfying 4 of these 6 conditions (i.e., 1,2,3b,4b), supporting the suggestion that increased FC has a complex nature that may exceed the simplistic assumption of an underlying compensatory mechanism attempting to limit the brain damage caused by MS progression. Exploring differences between RRMS subjects with short disease duration (MSshort) and RRMS with similar disability but longer disease duration (MSlong), we found that MSshort and MSlong were characterized by clearly distinct pattern of FC, involving predominantly sensory and cognitive networks respectively. Overall, these results suggest that the analysis of FC alterations in multiple large-scale networks in relation to radiological (T2LL) and clinical (MSSS, disease duration) status may provide new insights into the pathophysiology of relapse onset MS evolution.

PMID: 30177910 [PubMed]

Task-Evoked Negative BOLD Response in the Default Mode Network Does Not Alter Its Functional Connectivity.

Wed, 09/05/2018 - 12:00
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Task-Evoked Negative BOLD Response in the Default Mode Network Does Not Alter Its Functional Connectivity.

Front Comput Neurosci. 2018;12:67

Authors: Razlighi QR

Abstract
While functional connectivity networks are often extracted from resting-state fMRI scans, they have been shown to be active during task performance as well. However, the effect of an in-scanner task on functional connectivity networks is not completely understood. While there is evidence that task-evoked positive BOLD response can alter functional connectivity networks, particularly in the primary sensorimotor cortices, the effect of task-evoked negative BOLD response on the functional connectivity of the Default mode network (DMN) is somewhat ambiguous. In this study, we aim to investigate whether task performance, which is associated with negative BOLD response in the DMN regions, alters the time-course of functional connectivity in the same regions obtained by independent component analysis (ICA). ICA has been used to effectively extract functional connectivity networks during task performance and resting-state. We first demonstrate that performing a simple visual-motor task alters the temporal time-course of the network extracted from the primary visual cortex. Then we show that despite detecting a robust task-evoked negative BOLD response in the DMN regions, a simple visual-motor task does not alter the functional connectivity of the DMN regions. Our findings suggest that different mechanisms may underlie the relationship between task-related activation/deactivation networks and the overlapping functional connectivity networks in the human large-scale brain networks.

PMID: 30177878 [PubMed]

Awake Rat Brain Functional Magnetic Resonance Imaging Using Standard Radio Frequency Coils and a 3D Printed Restraint Kit.

Wed, 09/05/2018 - 12:00
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Awake Rat Brain Functional Magnetic Resonance Imaging Using Standard Radio Frequency Coils and a 3D Printed Restraint Kit.

Front Neurosci. 2018;12:548

Authors: Stenroos P, Paasonen J, Salo RA, Jokivarsi K, Shatillo A, Tanila H, Gröhn O

Abstract
Functional magnetic resonance imaging (fMRI) is a powerful noninvasive tool for studying spontaneous resting state functional connectivity (RSFC) in laboratory animals. Brain function can be significantly affected by generally used anesthetics, however, rendering the need for awake imaging. Only a few different awake animal habituation protocols have been presented, and there is a critical need for practical and improved low-stress techniques. Here we demonstrate a novel restraint approach for awake rat RSFC studies. Our custom-made 3D printed restraint kit is compatible with a standard Bruker Biospin MRI rat bed, rat brain receiver coil, and volume transmitter coil. We also implemented a progressive habituation protocol aiming to minimize the stress experienced by the rats, and compared RSFC between awake, lightly sedated, and isoflurane-anesthetized rats. Our results demonstrated that the 3D printed restraint kit was suitable for RSFC studies of awake rats. During the short 4-day habituation period, the plasma corticosterone concentration, movement, and heart rate, which were measured as stress indicators, decreased significantly, indicating adaptation to the restraint protocol. Additionally, 10 days after the awake MRI session, rats exhibited no signs of depression or anxiety based on open-field and sucrose preference behavioral tests. The RSFC data revealed significant changes in the thalamo-cortical and cortico-cortical networks between the awake, lightly sedated, and anesthetized groups, emphasizing the need for awake imaging. The present work demonstrates the feasibility of our custom-made 3D printed restraint kit. Using this kit, we found that isoflurane markedly affected brain connectivity compared with that in awake rats, and that the effect was less pronounced, but still significant, when light isoflurane sedation was used instead.

PMID: 30177870 [PubMed]

Socioeconomic status moderates age-related differences in the brain's functional network organization and anatomy across the adult lifespan.

Wed, 09/05/2018 - 12:00
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Socioeconomic status moderates age-related differences in the brain's functional network organization and anatomy across the adult lifespan.

Proc Natl Acad Sci U S A. 2018 05 29;115(22):E5144-E5153

Authors: Chan MY, Na J, Agres PF, Savalia NK, Park DC, Wig GS

Abstract
An individual's environmental surroundings interact with the development and maturation of their brain. An important aspect of an individual's environment is his or her socioeconomic status (SES), which estimates access to material resources and social prestige. Previous characterizations of the relation between SES and the brain have primarily focused on earlier or later epochs of the lifespan (i.e., childhood, older age). We broaden this work to examine the relationship between SES and the brain across a wide range of human adulthood (20-89 years), including individuals from the less studied middle-age range. SES, defined by education attainment and occupational socioeconomic characteristics, moderates previously reported age-related differences in the brain's functional network organization and whole-brain cortical structure. Across middle age (35-64 years), lower SES is associated with reduced resting-state system segregation (a measure of effective functional network organization). A similar but less robust relationship exists between SES and age with respect to brain anatomy: Lower SES is associated with reduced cortical gray matter thickness in middle age. Conversely, younger and older adulthood do not exhibit consistent SES-related difference in the brain measures. The SES-brain relationships persist after controlling for measures of physical and mental health, cognitive ability, and participant demographics. Critically, an individual's childhood SES cannot account for the relationship between their current SES and functional network organization. These findings provide evidence that SES relates to the brain's functional network organization and anatomy across adult middle age, and that higher SES may be a protective factor against age-related brain decline.

PMID: 29760066 [PubMed - indexed for MEDLINE]

Longitudinal Brain Functional Connectivity Changes of the Cortical Motor-Related Network in Subcortical Stroke Patients with Acupuncture Treatment.

Wed, 09/05/2018 - 12:00
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Longitudinal Brain Functional Connectivity Changes of the Cortical Motor-Related Network in Subcortical Stroke Patients with Acupuncture Treatment.

Neural Plast. 2017;2017:5816263

Authors: Li Y, Wang Y, Liao C, Huang W, Wu P

Abstract
In clinical practice, the effectiveness of the rehabilitation therapy such as acupuncture combining conventional Western medicine (AG) on stroke people's motor-related brain network and their behaviors has not been systematically studied. In the present study, seventeen adult ischemic patients were collected and divided into two groups: the conventional Western medicine treatment group (CG) and the AG. The neurological deficit scores (NDS) and resting-state functional MRI data were collected before and after treatment. Compared with the CG patients, AG patients exhibited a significant enhancement of the percent changes of NDS from pre- to posttreatment intervention. All patients showed significant changes of functional connectivity (FC) between the pair of cortical motor-related regions. After treatment, both patient groups showed a recovery of brain connectivity to the nearly normal level compared with the controls in these pairs. Moreover, a significant correlation between the percent changes of NDS and the pretreatment FC values of bilateral primary motor cortex (M1) in all patients was found. In conclusion, our results showed that AG therapy can be an effective means for ischemic stroke patients to recover their motor function ability. The FC strengths between bilateral M1 of stroke patients can predict stroke patients' treatment outcome after rehabilitation therapy.

PMID: 29375914 [PubMed - indexed for MEDLINE]

Regional and long-range neural synchronization abnormality during passive hyperthermia.

Wed, 09/05/2018 - 12:00
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Regional and long-range neural synchronization abnormality during passive hyperthermia.

Behav Brain Res. 2018 04 02;341:9-15

Authors: Han W, Qian S, Jiang Q, Liu K, Li B, Sun G

Abstract
Passive hyperthermia would impair wide-domain cognitive performances (e.g. attention, working memory), which may involve abnormal regional and long-range neural activity. Combining the regional homogeneity (ReHo) and seed-based functional connectivity analysis, this study investigated the regional and long-range neural synchronization abnormality during passive hyperthermia. We acquired the resting-state blood oxygenation level dependent (BOLD) data from twenty-three healthy male participants in two simulated thermal conditions: normothermic condition (NC) with temperature at 25°C for 1 h and hyperthermic condition (HC) with temperature at 50°C for 1 h. After scanning, participants were asked to perform an attention network test (ANT). Relative to NC participants, the participants in HC group exhibited decreased regional neural synchronization in the frontal-occipital cortex, specifically in the left opercular part of inferior frontal gyrus/insula, bilateral middle occipital gyrus, and posterior cingulate cortex/precuneus, but increased one in the left dorsal superior/middle frontal gyrus. Using these significantly differed ReHo clusters as seeds, we further performed functional connectivity analysis and found aberrant long-range neural synchronization in the orbital medial frontal cortex, temporal-parietal junction areas. Further neurobehavioral correlation analysis showed significant positive correlation between the regional ReHo alteration in left dorsolateral superior/middle frontal gyrus and executive control effect. Additionally, the functional connectivity of the orbital medial frontal cortex with the seeds "left superior/middle frontal gyrus" and "posterior cingulate cortex/precuneus" were negatively correlated with the increase of rectal temperature. In current study, the participants showed hyperthermia-induced brain activity disruptions, appearing as altered local ReHo and long-range functional connectivity, which might help understand the relationship between neuronal and circuit activities and physiological thermal sensation and regulation as well as behavioral changes.

PMID: 29247749 [PubMed - indexed for MEDLINE]

The frequency of alpha oscillations: Task-dependent modulation and its functional significance.

Tue, 09/04/2018 - 11:00

The frequency of alpha oscillations: Task-dependent modulation and its functional significance.

Neuroimage. 2018 Aug 31;:

Authors: Babu Henry Samuel I, Wang C, Hu Z, Ding M

Abstract
Power (amplitude) and frequency are two important characteristics of EEG alpha oscillations (8-12 Hz). There is an extensive literature showing that alpha power can be modulated in a goal-oriented manner to either enhance or suppress sensory information processing. Only a few studies to date have examined the task-dependent modulation of alpha frequency. Instead, alpha frequency is often viewed as a trait variable, and used to characterize individual differences in cognitive functioning. We performed two experiments to examine the task-dependent modulation of alpha frequency and its functional significance. In the first experiment, high-density EEG was recorded from 21 participants performing a Sternberg working memory task. The results showed that: (1) during memory encoding, alpha frequency decreased with increasing memory load, whereas during memory retention and retrieval, alpha frequency increased with increasing memory load, (2) higher alpha frequency prior to the onset of probe was associated with longer reaction time, and (3) higher alpha frequency prior to the onset of cue or probe was associated with weaker early cue-evoked or probe-evoked neural responses. In the second experiment, simultaneous EEG-fMRI was recorded from 59 participants during resting state. An EEG-informed fMRI analysis revealed that the spontaneous fluctuations of alpha frequency, but not alpha power, were inversely associated with BOLD activity in the visual cortex. Taken together, these findings suggest that alpha frequency is task-dependent, may serve as an indicator of cortical excitability, and along with alpha power, provides more comprehensive indexing of sensory gating.

PMID: 30176369 [PubMed - as supplied by publisher]

Advances in functional magnetic resonance imaging data analysis methods using Empirical Mode Decomposition to investigate temporal changes in early Parkinson's disease.

Tue, 09/04/2018 - 11:00
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Advances in functional magnetic resonance imaging data analysis methods using Empirical Mode Decomposition to investigate temporal changes in early Parkinson's disease.

Alzheimers Dement (N Y). 2018;4:372-386

Authors: Cordes D, Zhuang X, Kaleem M, Sreenivasan K, Yang Z, Mishra V, Banks SJ, Bluett B, Cummings JL

Abstract
Introduction: Previous neuroimaging studies of Parkinson's disease (PD) patients have shown changes in whole-brain functional connectivity networks. Whether connectivity changes can be detected in the early stages (first 3 years) of PD by resting-state functional magnetic resonance imaging (fMRI) remains elusive. Research infrastructure including MRI and analytic capabilities is required to investigate this issue. The National Institutes of Health/National Institute of General Medical Sciences Center for Biomedical Research Excellence awards support infrastructure to advance research goals.
Methods: Static and dynamic functional connectivity analyses were conducted on early stage never-medicated PD subjects (N = 18) and matched healthy controls (N = 18) from the Parkinson's Progression Markers Initiative.
Results: Altered static and altered dynamic functional connectivity patterns were found in early PD resting-state fMRI data. Most static networks (with the exception of the default mode network) had a reduction in frequency and energy in specific low-frequency bands. Changes in dynamic networks in PD were associated with a decreased switching rate of brain states.
Discussion: This study demonstrates that in early PD, resting-state fMRI networks show spatial and temporal differences of fMRI signal characteristics. However, the default mode network was not associated with any measurable changes. Furthermore, by incorporating an optimum window size in a dynamic functional connectivity analysis, we found altered whole-brain temporal features in early PD, showing that PD subjects spend significantly more time than healthy controls in a specific brain state. These findings may help in improving diagnosis of early never-medicated PD patients. These key observations emerged in a Center for Biomedical Research Excellence-supported research environment.

PMID: 30175232 [PubMed]

Real-time fMRI amygdala neurofeedback positive emotional training normalized resting-state functional connectivity in combat veterans with and without PTSD: a connectome-wide investigation.

Tue, 09/04/2018 - 11:00
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Real-time fMRI amygdala neurofeedback positive emotional training normalized resting-state functional connectivity in combat veterans with and without PTSD: a connectome-wide investigation.

Neuroimage Clin. 2018;20:543-555

Authors: Misaki M, Phillips R, Zotev V, Wong CK, Wurfel BE, Krueger F, Feldner M, Bodurka J

Abstract
Self-regulation of brain activation using real-time functional magnetic resonance imaging neurofeedback (rtfMRI-nf) is an emerging approach for treating mood and anxiety disorders. The effect of neurofeedback training on resting-state functional connectivity warrants investigation as changes in spontaneous brain activation could reflect the association between sustained symptom relief and brain alteration. We investigated the effect of amygdala-focused rtfMRI-nf training on resting-state functional connectivity in combat veterans with and without posttraumatic stress disorder (PTSD) who were trained to increase a feedback signal reflecting left amygdala activity while recalling positive autobiographical memories (Zotev et al., 2018). The analysis was performed in three stages: i) first, we investigated the connectivity in the left amygdala region; ii) next, we focused on the abnormal resting-state functional connectivity identified in our previous analysis of this data (Misaki et al., 2018); and iii) finally, we performed a novel data-driven longitudinal connectome-wide analysis. We introduced a longitudinal multivariate distance matrix regression (MDMR) analysis to comprehensively examine neurofeedback training effects beyond those associated with abnormal baseline connectivity. These comprehensive exploratory analyses suggested that abnormal resting-state connectivity for combat veterans with PTSD was partly normalized after the training. This included hypoconnectivities between the left amygdala and the left ventrolateral prefrontal cortex (vlPFC) and between the supplementary motor area (SMA) and the dorsal anterior cingulate cortex (dACC). The increase of SMA-dACC connectivity was associated with PTSD symptom reduction. Longitudinal MDMR analysis found a connectivity change between the precuneus and the left superior frontal cortex. The connectivity increase was associated with a decrease in hyperarousal symptoms. The abnormal connectivity for combat veterans without PTSD - such as hypoconnectivity in the precuneus with a superior frontal region and hyperconnectivity in the posterior insula with several regions - could also be normalized after the training. These results suggested that the rtfMRI-nf training effect was not limited to a feedback target region and symptom relief could be mediated by brain modulation in several regions other than in a feedback target area. While further confirmatory research is needed, the results may provide valuable insight into treatment effects on the whole brain resting-state connectivity.

PMID: 30175041 [PubMed - in process]

A Mini Review on the Contribution of the Anterior Cingulate Cortex in the Risk of Psychosis in 22q11.2 Deletion Syndrome.

Tue, 09/04/2018 - 11:00
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A Mini Review on the Contribution of the Anterior Cingulate Cortex in the Risk of Psychosis in 22q11.2 Deletion Syndrome.

Front Psychiatry. 2018;9:372

Authors: Padula MC, Scariati E, Schaer M, Eliez S

Abstract
22q11.2 deletion syndrome (22q11DS) is a neurogenetic disorder that causes a high risk of developing schizophrenia, thus representing a unique model for the investigation of biomarkers of psychosis. Cognitive and clinical risk factors have been identified as reliable predictors of schizophrenia in patients with 22q11DS and are currently used in the clinical practice. However, biomarkers based on neuroimaging are still lacking, mainly because of the analytic approaches adopted so far, which are almost uniquely based on the comparison of 22q11DS patients with healthy controls. Such comparisons do not take into account the heterogeneity within patients with 22q11DS, who indeed show various clinical manifestations. More recently, a number of studies compared measures of brain morphology and connectivity between patients with 22q11DS with different symptomatic profiles. The aim of this short review is to highlight the brain alterations found in patients with 22q11DS fulfilling ultra-high risk (UHR) criteria. Findings point to alterations in brain morphology and connectivity in frontal brain regions, and in particular in the anterior cingulate cortex, in patients with 22q11DS presenting UHR symptoms. These alterations may represent valuable biomarkers of psychosis in 22q11DS.

PMID: 30174623 [PubMed]

Characterizing the functional connectivity diversity of the insula cortex: Subregions, diversity curves and behavior.

Sun, 09/02/2018 - 15:20
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Characterizing the functional connectivity diversity of the insula cortex: Subregions, diversity curves and behavior.

Neuroimage. 2018 Aug 29;:

Authors: Tian Y, Zalesky A

Abstract
The connectivity of the insula cortex is diverse. We present new models to characterize the resting-state connectional diversity of the human insula cortex and perform model selection using high-quality fMRI data from the Human Connectome Project. We first attempt to parcellate the insula into distinct subregions using traditional clustering methods, but find that the resulting subregions are not homogeneous and that the optimal number of subregions is substantially influenced by data smoothness. We then introduce the concept of a diversity curve, which we use to continuously parameterize the insula's Laplacian eigenmap with respect to streamlines propagated through the eigenmap's gradient field. To perform model selection, we compare the insula's diversity curve to benchmark diversity curves for: i) two distinct regions; ii) a continuum of gradual change; and, iii) an absence of any connectional diversity (i.e. homogenous region). Of the three benchmarks (models) tested, we find that the insula's connectional diversity is most parsimoniously modeled as continuum of gradual change, from dorsal-posterior to ventral-anterior. We find that connectional diversity is greatest within the posterior insula among individuals with heightened sensitivity to temperature sensation (hot or cold), whereas individuals who score high on measures of positive affect, self-efficacy, emotion recognition, motor dexterity and gustation show greater diversity within the anterior insula. Our findings are replicated using data from a second fMRI session. We conclude that the functional connectivity diversity of the insula can be characterized parsimoniously as a continuum, avoiding the vexed task of determining an optimal number of insula subregions, and that inter-individual variation in this continuum can explain significant variation in behavior.

PMID: 30172005 [PubMed - as supplied by publisher]

Salience-Default Mode Functional Network Connectivity Linked to Positive and Negative Symptoms of Schizophrenia.

Sat, 09/01/2018 - 14:00
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Salience-Default Mode Functional Network Connectivity Linked to Positive and Negative Symptoms of Schizophrenia.

Schizophr Bull. 2018 Aug 30;:

Authors: Hare SM, Ford JM, Mathalon DH, Damaraju E, Bustillo J, Belger A, Lee HJ, Mueller BA, Lim KO, Brown GG, Preda A, van Erp TGM, Potkin SG, Calhoun VD, Turner JA

Abstract
Schizophrenia is a complex, debilitating mental disorder characterized by wide-ranging symptoms including delusions, hallucinations (so-called positive symptoms), and impaired motor and speech/language production (so-called negative symptoms). Salience-monitoring theorists propose that abnormal functional communication between the salience network (SN) and default mode network (DMN) begets positive and negative symptoms of schizophrenia, yet prior studies have predominately reported links between disrupted SN/DMN functional communication and positive symptoms. It remains unclear whether disrupted SN/DMN functional communication explains (1) solely positive symptoms or (2) both positive and negative symptoms of schizophrenia. To address this question, we incorporate time-lag-shifted functional network connectivity (FNC) analyses that explored coherence of the resting-state functional magnetic resonance imaging signal of 3 networks (anterior DMN, posterior DMN, and SN) with fixed time lags introduced between network time series (1 TR = 2 s; 2 TR = 4 s). Multivariate linear regression analysis revealed that severity of disordered thought and attentional deficits were negatively associated with 2 TR-shifted FNC between anterior DMN and posterior DMN. Meanwhile, severity of flat affect and bizarre behavior were positively associated with 1 TR-shifted FNC between anterior DMN and SN. These results provide support favoring the hypothesis that lagged SN/DMN functional communication is associated with both positive and negative symptoms of schizophrenia.

PMID: 30169884 [PubMed - as supplied by publisher]

Brain anomaly networks uncover heterogeneous functional reorganization patterns after stroke.

Sat, 09/01/2018 - 14:00
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Brain anomaly networks uncover heterogeneous functional reorganization patterns after stroke.

Neuroimage Clin. 2018;20:523-530

Authors: Zou Y, Zhao Z, Yin D, Fan M, Small M, Liu Z, Hilgetag CC, Kurths J

Abstract
Stroke has a large physical, psychological, and financial burden on patients, their families, and society. Based on functional networks (FNs) constructed from resting state fMRI data, network connectivity after stroke is commonly conjectured to be more randomly reconfigured. We find that this hypothesis depends on the severity of stroke. Head movement-corrected, resting-state fMRI data were acquired from 32 patients after stroke, and 37 healthy volunteers. We constructed anomaly FNs, which combine time series information of a patient with the healthy control group. We propose data-driven techniques to automatically identify regions of interest that are stroke relevant. Graph analysis based on anomaly FNs suggests consistently that strong connections in healthy controls are broken down specifically and characteristically for brain areas that are related to sensorimotor functions and frontoparietal control systems, but new links in stroke patients are rebuilt randomly from all possible areas. Entropic measures of complexity are proposed for characterizing the functional connectivity reorganization patterns, which are correlated with hand and wrist function assessments of stroke patients and show high potential for clinical use.

PMID: 30167372 [PubMed - in process]

Empathy by default: Correlates in the brain at rest.

Sat, 09/01/2018 - 14:00
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Empathy by default: Correlates in the brain at rest.

Psicothema. 2018 Feb;30(1):97-103

Authors: Oliveira Silva P, Maia L, Coutinho J, Frank B, Soares JM, Sampaio A, Gonçalves Ó

Abstract
BACKGROUND: Empathy, defined as the ability to access and respond to the inner world of another person, is a multidimensional construct involving cognitive, emotional and self-regulatory mechanisms. Neuroimaging studies report that empathy recruits brain regions which are part of the social cognition network. Among the different resting state networks, the Default Mode Network (DMN) may be of particular interest for the study of empathy since it has been implicated in social cognition tasks.
METHOD: The current study compared the cognitive and emotional empathy scores, as measured by the Interpersonal Reactivity Index, with the patterns of activation within the DMN, through the neuroimaging methodology of resting-state functional magnetic resonance.
RESULTS: Results suggest a significant positive correlation between cognitive empathy and activation of the bilateral superior medial frontal cortex nodes of the DMN. Contrastingly, a negative correlation was found between emotional empathy and the same brain region.
CONCLUSIONS: Overall, this data highlights a critical role of the medial cortical regions of the DMN, specifically its anterior node, for both cognitive and emotional domains of the empathic process.

PMID: 29363477 [PubMed - indexed for MEDLINE]

Variability and reliability of effective connectivity within the core default mode network: A multi-site longitudinal spectral DCM study.

Fri, 08/31/2018 - 13:00

Variability and reliability of effective connectivity within the core default mode network: A multi-site longitudinal spectral DCM study.

Neuroimage. 2018 Aug 27;:

Authors: Almgren H, Van de Steen F, Kühn S, Razi A, Friston K, Marinazzo D

Abstract
Dynamic causal modelling (DCM) for resting state fMRI - namely spectral DCM - is a recently developed and widely adopted method for inferring effective connectivity in intrinsic brain networks. Most applications of spectral DCM have focused on group-averaged connectivity within large-scale intrinsic brain networks; however, the consistency of subject- and session-specific estimates of effective connectivity has not been evaluated. Establishing reliability (within subjects) is crucial for its clinical use; e.g., as a neurophysiological phenotype of disease progression. Effective connectivity during rest is likely to vary due to changes in cognitive, and physiological states. Quantifying these variations may help understand functional brain architectures - and inform clinical applications. In the present study, we investigated the consistency of effective connectivity within and between subjects, as well as potential sources of variability (e.g., hemispheric asymmetry). We also addressed the effects on consistency of standard data processing procedures. DCM analyses were applied to four longitudinal resting state fMRI datasets. Our sample comprised 17 subjects with 589 resting state fMRI sessions in total. These data allowed us to quantify the robustness of connectivity estimates for each subject, and to generalise our conclusions beyond specific data features. We found that subjects showed systematic and reliable patterns of hemispheric asymmetry. When asymmetry was taken into account, subjects showed very similar connectivity patterns. We also found that various processing procedures (e.g. global signal regression and ROI size) had little effect on inference and the reliability of connectivity estimates for the majority of subjects. Finally, Bayesian model reduction significantly increased the consistency of connectivity patterns.

PMID: 30165254 [PubMed - as supplied by publisher]

Neural correlates of creative insight: Amplitude of low-frequency fluctuation of resting-state brain activity predicts creative insight.

Fri, 08/31/2018 - 13:00

Neural correlates of creative insight: Amplitude of low-frequency fluctuation of resting-state brain activity predicts creative insight.

PLoS One. 2018;13(8):e0203071

Authors: Lin J, Cui X, Dai X, Chen Y, Mo L

Abstract
Creative insight has attracted much attention across cultures. Although previous studies have explored the neural correlates of creative insight by functional magnetic resonance imaging (fMRI), little is known about intrinsic resting-state brain activity associated with creative insight. In the present study, we used amplitude of low-frequency fluctuation (ALFF) as an index in resting-state fMRI (rs-fMRI) to identify brain regions involved in individual differences in creative insight, which was measured by the response time of creative Chinese character chunk decomposition. Our results showed that ALFF in the superior frontal gyrus (SFG) positively predicted creative insight, while ALFF in the middle cingulate cortex/insula cortex (MCC/IC), superior temporal gyrus/angular gyrus (STG/AG), anterior cingulate cortex/caudate nucleus (ACC/CN), and culmen/declive (CU/DC) negatively predicted creative insight. Moreover, these findings indicate that spontaneous brain activity in multiple regions related to breaking mental sets, solutions exploring, evaluation of novel solutions, forming task-related associations, and emotion experience contributes to creative insight. In conclusion, the present study provides new evidence to further understand the cognitive processing and neural correlates of creative insight.

PMID: 30161187 [PubMed - in process]

Prospective Administration of Anti-NGF Treatment Effectively Suppresses Functional Connectivity Alterations Following Cancer-Induced Bone Pain in Mice.

Fri, 08/31/2018 - 13:00

Prospective Administration of Anti-NGF Treatment Effectively Suppresses Functional Connectivity Alterations Following Cancer-Induced Bone Pain in Mice.

Pain. 2018 Aug 29;:

Authors: Buehlmann D, Ielacqua GD, Xandry J, Rudin M

Abstract
Cancer-induced bone pain is abundant among advanced stage cancer patients and arises from a primary tumor in the bone or skeletal metastasis of common cancer types such as breast, lung or prostate cancer. Recently, antibodies targeting nerve growth factor (NGF) have been shown to effectively relieve neuropathic and inflammatory pain states in mice and in humans. While efficacy has been shown in mice on a behavioral level, effectiveness in preventing pain-induced functional rearrangements in the central nervous system has not been shown. Therefore we assessed longitudinal whole-brain functional connectivity using resting-state fMRI in a mouse model of cancer-induced bone pain. We found functional connectivity between major hubs of ascending and descending pain pathways such as the periaqueductal gray, amygdala, thalamus as well as cortical somatosensory regions to be affected by a developing cancer pain state. These changes could be successfully prevented through prospective administration of a monoclonal anti-NGF antibody (mAb911). This indicates efficacy of anti-NGF treatment to prevent pain-induced adaptations in brain functional networks following persistent nociceptive input from cancer-induced bone pain. Additionally, it highlights the suitability of resting-state fMRI readouts as an indicator of treatment response on the basis of longitudinal functional network changes.

PMID: 30161041 [PubMed - as supplied by publisher]

Frequency specific resting state functional abnormalities in psychosis.

Fri, 08/31/2018 - 13:00

Frequency specific resting state functional abnormalities in psychosis.

Hum Brain Mapp. 2018 Aug 30;:

Authors: Gohel S, Gallego JA, Robinson DG, DeRosse P, Biswal B, Szeszko PR

Abstract
Resting state functional magnetic resonance imaging studies of psychosis have focused primarily on the amplitude of low-frequency fluctuations in the blood oxygen level dependent (BOLD) signal ranging from .01 to 0.1 Hz. Few studies, however, have investigated the amplitude of frequency fluctuations within discrete frequency bands and higher than 0.1 Hz in patients with psychosis at different illness stages. We investigated BOLD signal within three frequency ranges including slow-4 (.027-.073 Hz), slow-3 (.074-0.198 Hz) and slow-2 (0.199-0.25 Hz) in 89 patients with either first-episode or chronic psychosis and 119 healthy volunteers. We investigated the amplitude of frequency fluctuations within three frequency bands using 47 regions-of-interest placed within 14 known resting state networks derived using group independent component analysis. There were significant group x frequency interactions for the visual and motor cortex networks, with the largest significant group differences (patients < healthy volunteers) evident in slow-4 and slow-3, respectively. Also, healthy volunteers had an overall higher amplitude of frequency fluctuations compared to patients across the three frequency ranges in the visual cortex, dorsal attention and motor cortex networks with the opposite effect (patients > healthy volunteers) evident within the salience and frontal gyrus networks. Subsequent analyses indicated that these effects were evident in both first-episode and chronic patients. Our study provides new data regarding the importance of BOLD signal fluctuations within different frequency bands in the neurobiology of psychosis.

PMID: 30160325 [PubMed - as supplied by publisher]

Machine learning technique reveals intrinsic characteristics of schizophrenia: an alternative method.

Fri, 08/31/2018 - 13:00
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Machine learning technique reveals intrinsic characteristics of schizophrenia: an alternative method.

Brain Imaging Behav. 2018 Aug 29;:

Authors: Li J, Sun Y, Huang Y, Bezerianos A, Yu R

Abstract
Machine learning technique has long been utilized to assist disease diagnosis, increasing clinical physicians' confidence in their decision and expediting the process of diagnosis. In this case, machine learning technique serves as a tool for distinguishing patients from healthy people. Additionally, it can also serve as an exploratory method to reveal intrinsic characteristics of a disease based on discriminative features, which was demonstrated in this study. Resting-state functional magnetic resonance imaging (fMRI) data were obtained from 148 participants (including patients with schizophrenia and healthy controls). Connective strengths were estimated by Pearson correlation for each pair of brain regions partitioned according to automated anatomical labelling atlas. Subsequently, consensus connections with high discriminative power were extracted under the circumstance of the best classification accuracy. Investigating these consensus connections, we found that schizophrenia group predominately exhibited weaker strengths of inter-regional connectivity compared to healthy group. Aberrant connectivities in both intra- and inter-hemispherical connections were observed. Within intra-hemispherical connections, the number of aberrant connections in the right hemisphere was more than that of the left hemisphere. In the exploration of large regions, we revealed that the serious dysconnectivities mainly appeared on temporal and occipital regions for the within-large-region connections; while connectivity disruption was observed on the connections from temporal region to occipital, insula and limbic regions for the between-large-region connections. The findings of this study corroborate previous conclusion of dysconnectivity in schizophrenia and further shed light on distribution patterns of dysconnectivity, which deepens the understanding of pathological mechanism of schizophrenia.

PMID: 30159765 [PubMed - as supplied by publisher]

Disrupted local neural activity and functional connectivity in subjective tinnitus patients: evidence from resting-state fMRI study.

Fri, 08/31/2018 - 13:00
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Disrupted local neural activity and functional connectivity in subjective tinnitus patients: evidence from resting-state fMRI study.

Neuroradiology. 2018 Aug 29;:

Authors: Han Q, Zhang Y, Liu D, Wang Y, Feng Y, Yin X, Wang J

Abstract
PURPOSE: The study aimed to investigate the abnormal alterations of both the intra-regional brain activity and inter-regional functional connectivity (FC) in patients with subjective tinnitus (ST) using resting-state functional MRI (rs-fMRI) methods.
METHODS: Twenty-five ST patients and 25 normal controls (NCs) were included and underwent resting-state functional magnetic resonance imaging scans. ReHo, fALFF, and seed-based FC were calculated and compared between ST patients and NCs. Meanwhile, correlation analyses were calculated between altered connectivity and clinical data in ST patients.
RESULTS: Compared with NCs, ST patients exhibited increased ReHo and fALFF values in the right middle temporal gyrus (MTG), and the ReHo values were also increased in the right cuneus. In contrast, decreased ReHo values in ST patients were observed in the right middle frontal gyrus (MFG) and left cerebellar anterior lobe. Considering these brain areas with altered ReHo and fALFF clusters as seeds, the right MTG (ReHo) exhibited decreased connectivity with the right MFG, lingual gyrus, and left cerebellar posterior lobe, besides, the right cuneus showed decreased connectivity with the right MTG. In ST patients, the decreased FC between the right MTG (ReHo) and the right MFG was also positively correlated with the Tinnitus handicap inventory score (r = 0.675, P = 0.001).
CONCLUSION: The present study revealed that ST patients had altered regional neural activity and inter-regional connectivity in partial auditory and non-auditory brain regions, mainly involving the default mode network and audio-visual network, which could further improve our understanding of the neuroimaging mechanism in ST.

PMID: 30159629 [PubMed - as supplied by publisher]

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