New resting-state fMRI related studies at PubMed

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Brain networks of the imaginative mind: Dynamic functional connectivity of default and cognitive control networks relates to openness to experience.

Wed, 11/15/2017 - 14:20

Brain networks of the imaginative mind: Dynamic functional connectivity of default and cognitive control networks relates to openness to experience.

Hum Brain Mapp. 2017 Nov 14;:

Authors: Beaty RE, Chen Q, Christensen AP, Qiu J, Silvia PJ, Schacter DL

Abstract
Imagination and creative cognition are often associated with the brain's default network (DN). Recent evidence has also linked cognitive control systems to performance on tasks involving imagination and creativity, with a growing number of studies reporting functional interactions between cognitive control and DN regions. We sought to extend the emerging literature on brain dynamics supporting imagination by examining individual differences in large-scale network connectivity in relation to Openness to Experience, a personality trait typified by imagination and creativity. To this end, we obtained personality and resting-state fMRI data from two large samples of participants recruited from the United States and China, and we examined contributions of Openness to temporal shifts in default and cognitive control network interactions using multivariate structural equation modeling and dynamic functional network connectivity analysis. In Study 1, we found that Openness was related to the proportion of scan time (i.e., "dwell time") that participants spent in a brain state characterized by positive correlations among the default, executive, salience, and dorsal attention networks. Study 2 replicated and extended the effect of Openness on dwell time in a correlated brain state comparable to the state found in Study 1, and further demonstrated the robustness of this effect in latent variable models including fluid intelligence and other major personality factors. The findings suggest that Openness to Experience is associated with increased functional connectivity between default and cognitive control systems, a connectivity profile that may account for the enhanced imaginative and creative abilities of people high in Openness to Experience.

PMID: 29136310 [PubMed - as supplied by publisher]

Meta-Connectomic Analysis Reveals Commonly Disrupted Functional Architectures in Network Modules and Connectors across Brain Disorders.

Wed, 11/15/2017 - 14:20

Meta-Connectomic Analysis Reveals Commonly Disrupted Functional Architectures in Network Modules and Connectors across Brain Disorders.

Cereb Cortex. 2017 Nov 09;:1-16

Authors: Sha Z, Xia M, Lin Q, Cao M, Tang Y, Xu K, Song H, Wang Z, Wang F, Fox PT, Evans AC, He Y

Abstract
Neuropsychiatric disorders are increasingly conceptualized as disconnection syndromes that are associated with abnormal network integrity in the brain. However, whether different neuropsychiatric disorders show commonly dysfunctional connectivity architectures in large-scale brain networks remains largely unknown. Here, we performed a meta-connectomic study to identify disorder-related functional modules and brain regions by combining meta-analyses of 182 published resting-state functional MRI studies in 11 neuropsychiatric disorders and graph-theoretical analyses of 3 independent resting-state functional MRI datasets with healthy and diseased populations (Alzheimer's disease and major depressive disorder [MDD]). Three major functional modules, the default mode, frontoparietal, and sensorimotor networks were commonly abnormal across disorders. Moreover, most of the disorders preferred to target the network connector nodes that were primarily involved in intermodule communications and multiple cognitive components. Apart from these common dysfunctions, different brain disorders were associated with specific alterations in network modules and connector regions. Finally, these meta-connectomic findings were confirmed by two empirical example cases of Alzheimer's disease and MDD. Collectively, our findings shed light on the shared biological mechanisms of network dysfunctions of diverse disorders and have implications for clinical diagnosis and treatment from a network perspective.

PMID: 29136110 [PubMed - as supplied by publisher]

Superior colliculus resting state networks in post-traumatic stress disorder and its dissociative subtype.

Wed, 11/15/2017 - 14:20
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Superior colliculus resting state networks in post-traumatic stress disorder and its dissociative subtype.

Hum Brain Mapp. 2017 Nov 13;:

Authors: Olivé I, Densmore M, Harricharan S, Théberge J, McKinnon MC, Lanius R

Abstract
OBJECTIVES: The innate alarm system (IAS) models the neurocircuitry involved in threat processing in posttraumatic stress disorder (PTSD). Here, we investigate a primary subcortical structure of the IAS model, the superior colliculus (SC), where the SC is thought to contribute to the mechanisms underlying threat-detection in PTSD. Critically, the functional connectivity between the SC and other nodes of the IAS remains unexplored.
EXPERIMENTAL DESIGN: We conducted a resting-state fMRI study to investigate the functional architecture of the IAS, focusing on connectivity of the SC in PTSD (n = 67), its dissociative subtype (n = 41), and healthy controls (n = 50) using region-of-interest seed-based analysis.
PRINCIPAL OBSERVATIONS: We observed group-specific resting state functional connectivity between the SC for both PTSD and its dissociative subtype, indicative of dedicated IAS collicular pathways in each group of patients. When comparing PTSD to its dissociative subtype, we observed increased resting state functional connectivity between the left SC and the right dorsolateral prefrontal cortex (DLPFC) in PTSD. The DLPFC is involved in modulation of emotional processes associated with active defensive responses characterising PTSD. Moreover, when comparing PTSD to its dissociative subtype, increased resting state functional connectivity was observed between the right SC and the right temporoparietal junction in the dissociative subtype. The temporoparietal junction is involved in depersonalization responses associated with passive defensive responses typical of the dissociative subtype.
CONCLUSIONS: Our findings suggest that unique resting state functional connectivity of the SC parallels the unique symptom profile and defensive responses observed in PTSD and its dissociative subtype. Hum Brain Mapp, 2017. © 2017 Wiley Periodicals, Inc.

PMID: 29134717 [PubMed - as supplied by publisher]

Altered connectivity patterns among resting state networks in patients with ischemic white matter lesions.

Wed, 11/15/2017 - 14:20
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Altered connectivity patterns among resting state networks in patients with ischemic white matter lesions.

Brain Imaging Behav. 2017 Nov 14;:

Authors: Ding JR, Ding X, Hua B, Xiong X, Wen Y, Ding Z, Wang Q, Thompson P

Abstract
White matter lesions (WMLs) have been associated with cognitive and motor decline. Resting state networks (RSNs) are spatially coherent patterns in the human brain and their interactions sustain our daily function. Therefore, investigating the altered intra- and inter-network connectivity among the RSNs may help to understand the association of WMLs with impaired cognitive and motor function. Here, we assessed alterations in functional connectivity patterns based on six well-defined RSNs-the default mode network (DMN), dorsal attention network (DAN), frontal-parietal control network (FPCN), auditory network (AN), sensory motor network (SMN) and visual network (VN)-in 15 patients with ischemic WMLs and 15 controls. In the patients, Spearman's correlation analysis was further performed between these alterations and cognitive test scores, including Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) scores. Our results showed wide alterations of inter-network connectivity mainly involving the SMN, DMN, FPCN and DAN, and some alterations correlated with cognitive test scores in the patients. The reduced functional connectivities in the SMN-AN, SMN-VN, FPCN-AN, DAN-VN pairs may account for the cognitive and motor decline in patients with ischemic WMLs, while the increased functional connectivities in the DMN-AN, DMN-FPCN and DAN-FPCN pairs may reflect a functional network reorganization after damage to white matter. It is unexpected that altered intra-network connectivities were found within the AN and VN, which may explain the impairments in verbal fluency and information retrieval associated with WMLs. This study highlights the importance of functional connectivity in understanding how WMLs influence cognitive and behavior dysfunction.

PMID: 29134612 [PubMed - as supplied by publisher]

Resting state network functional connectivity patterns associated with the Mindful Attention Awareness Scale.

Tue, 11/14/2017 - 13:20
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Resting state network functional connectivity patterns associated with the Mindful Attention Awareness Scale.

Brain Connect. 2017 Nov 12;:

Authors: Bilevicius E, Smith SD, Kornelsen J

Abstract
Mindfulness refers to attending to moment-to-moment experiences with acceptance and no judgment. Several scales have been developed to quantify different components of mindfulness. The Mindful Attention Awareness Scale (MAAS) is particularly sensitive to trait mindfulness and is proposed to measure the attentional component of mindfulness. The purpose of the current study was to identify the neural correlates of the MAAS in four resting state networks related to attention-the default mode network (DMN), the salience network (SN), and the left and right central executive network (lCEN and rCEN). Thirty-two university students naïve to mindfulness completed the MAAS and later underwent a resting state functional magnetic resonance imaging scan. Resting state data were analyzed using an independent component analysis; the scores from the MAAS were co-varied to the connectivity maps in an analysis of co-variance. The results indicate that variations in MAAS scores correlated with variations in functional connectivity patterns in resting state networks. Specifically, within the SN and CEN, the MAAS was negatively correlated with functional connectivity in the precuneus, even though the precuneus is a key component of the DMN. Negative correlations in the DMN between the MAAS and the insula and in the SN between the MAAS and the posterior cingulate cortex were also observed. These results suggest MAAS scores (1) are correlated with the functional connectivity of several brain structures related to attention, and (2) involve cross-network functional connectivity.

PMID: 29130326 [PubMed - as supplied by publisher]

Neural substrate of unrelenting negative symptoms in schizophrenia: a longitudinal resting-state fMRI study.

Mon, 11/13/2017 - 12:20

Neural substrate of unrelenting negative symptoms in schizophrenia: a longitudinal resting-state fMRI study.

Eur Arch Psychiatry Clin Neurosci. 2017 Nov 11;:

Authors: Li M, Deng W, Das T, Li Y, Zhao L, Ma X, Wang Y, Yu H, Li X, Meng YJ, Wang Q, Palaniyappan L, Li T

Abstract
Developing a mechanistic insight into the specific brain processes that underpin improvement in negative symptoms can help us design novel chemical and physical treatments against these unrelenting symptoms. The aim of the present study is to explore the longitudinal changes in the brain's regional functional efficiency that accompany improvement in negative symptoms seen in first-episode patients with schizophrenia when treated with antipsychotic for 1 year. Forty-seven first-episode patients with schizophrenia were scanned at a drug-naive baseline state and followed up for 1 year to identify negative symptom responders (Rn) and non-responders (NRn). Fractional amplitude of low-frequency fluctuations (fALFF) and Granger analysis of effective connectivity (EC) were used to examine the different patterns of regional function and connectivity between Rn and NRn during the 1 year follow-up. Increase of fALFF in the left superior temporal gyrus (STG) and increase of EC from the left STG to the dorsolateral prefrontal cortex (DLPFC) was found in Rn compared to NRn. We further validated that the identified changes in fALFF/EC of STG occur specifically in relation to negative symptoms only (i.e., not pseudo-specific in relation to positive, extrapyramidal or depressive symptoms), and occur irrespective of arbitrary clinical categorization of treatment response. An increase in fALFF in the precuneus and the inferior parietal lobule, and a decrease in EC from the left STG to the occipital cortex, were also found at the 1 year follow-up irrespective of improvement in negative symptoms. Interventions that improve the functional efficiency of left STG and its prefrontal connectivity may show efficacy in alleviating negative symptoms in first-episode schizophrenia.

PMID: 29128871 [PubMed - as supplied by publisher]

Corrigendum to "Mapping the end-tidal CO2 response function in the resting-state BOLD fMRI signal: Spatial specificity, test-retest reliability and effect of fMRI sampling rate."

Sun, 11/12/2017 - 11:20

Corrigendum to "Mapping the end-tidal CO2 response function in the resting-state BOLD fMRI signal: Spatial specificity, test-retest reliability and effect of fMRI sampling rate."

Neuroimage. 2017 Nov 07;:

Authors: Golestani AM, Chang C, Kwinta JB, Khatamian YB, Chen JJ

PMID: 29126709 [PubMed - as supplied by publisher]

Comparison of spontaneous brain activity revealed by regional homogeneity in AQP4-IgG neuromyelitis optica-optic neuritis versus MOG-IgG optic neuritis patients: a resting-state functional MRI study.

Sat, 11/11/2017 - 16:40

Comparison of spontaneous brain activity revealed by regional homogeneity in AQP4-IgG neuromyelitis optica-optic neuritis versus MOG-IgG optic neuritis patients: a resting-state functional MRI study.

Neuropsychiatr Dis Treat. 2017;13:2669-2679

Authors: Wang J, Tian Y, Shao Y, Feng H, Qin L, Xu W, Liu H, Xu Q, Wei S, Ma L

Abstract
Objective: Many previous studies have demonstrated that neuromyelitis optica (NMO) patients have abnormalities of brain anatomy and function. However, differences in spontaneous brain activity between myelin oligodendrocyte glycoprotein (MOG)-IgG ON and aquaporin 4(AQP4)-neuromyelitis optica-optic neuritis (ON) remain unknown. In the current study, we investigated the brain neural homogeneity in MOG-IgG ON versus AQP4-IgG NMO-ON subjects by regional homogeneity (ReHo) method using magnetic resonance imaging (MRI).
Patients and methods: A total of 32 NMO-ON and ON subjects (21 with AQP4-IgG+NMO-ON and 11 with MOG-IgG+ON) and 34 healthy controls (HCs) closely matched for age were recruited, and scans were performed for all subjects. A one-way analysis of variance (ANOVA) was performed to determine the regions in which the ReHo was different across the three groups. NMO-ON and ON subjects were distinguished from HCs by a receiver operating characteristic (ROC) curve. The relationship between the mean ReHo in many brain regions and clinical features in NMO subjects was calculated by Pearson correlation analysis.
Results: Compared with HCs, MOG-IgG+ON subjects had significantly decreased ReHo values in the posterior lobe of the left cerebellum and increased ReHo values in the left inferior frontal gyrus, right prefrontal gyrus, and left precentral/postcentral gyrus. AQP4-IgG+NMO-ON subjects showed higher ReHo values in the left inferior frontal gyrus and right middle temporal/occipital gyrus. Compared with MOG-IgG+ON subjects, AQP4-IgG+NMO-ON subjects had lower ReHo values in the posterior lobe of the right cerebellum. AQP4-Ig+NMO-ON subjects showed higher ReHo values in the left precentral/postcentral gyrus and right superior temporal gyrus.
Conclusion: AQP4-IgG+NMO-ON and MOG-IgG+ON subjects showed abnormal synchronized neuronal activity in many brain regions, which is consistent with deficits in visual, motor, and cognitive function. Furthermore, different patterns of synchronized neuronal activity occurred in the AQP4-IgG+NMO-ON and MOG-IgG+ON.

PMID: 29123400 [PubMed]

The neuronal network involved in self-attribution of an artificial hand: A lesion network-symptom-mapping study.

Sat, 11/11/2017 - 16:40

The neuronal network involved in self-attribution of an artificial hand: A lesion network-symptom-mapping study.

Neuroimage. 2017 Nov 06;:

Authors: Wawrzyniak M, Klingbeil J, Zeller D, Saur D, Classen J

Abstract
The feeling of body-ownership can be experimentally manipulated using the rubber hand illusion (RHI) paradigm. Participants experience a sense of ownership over an artificial hand when their hidden real hand and the visible artificial hand are synchronously stroked. Using lesion masks and behavioral data from a previous study on RHI failure in acute stroke patients, we here employed lesion network-symptom-mapping (LNSM) based on normative functional connectome data to identify lesion-dependent network connectivity related to the experience of self-attribution of an artificial hand in the RHI paradigm. We found that failure to experience the RHI was associated with higher normative lesion-dependent network connectivity to the right temporoparietal junction (rTPJ), right anterior Insula (raI) and right inferior frontal gyrus (rIFG). Since these areas were spared by the infarction in most patients with RHI failure (89% for rTPJ and 94% for raI/rIFG), the analysis suggests that remote dysfunction in rTPJ, raI, and rIFG accounted for RHI failure. These results highlight the potential role of rTPJ, raI, and rIFG in bodily self-consciousness. LNSM is a powerful tool capable of delineating the architecture of functional networks underlying complex cognitive function.

PMID: 29122723 [PubMed - as supplied by publisher]

Connectome-based predictive modeling of attention: Comparing different functional connectivity features and prediction methods across datasets.

Sat, 11/11/2017 - 16:40

Connectome-based predictive modeling of attention: Comparing different functional connectivity features and prediction methods across datasets.

Neuroimage. 2017 Nov 06;:

Authors: Yoo K, Rosenberg MD, Hsu WT, Zhang S, Li CR, Scheinost D, Constable RT, Chun MM

Abstract
Connectome-based predictive modeling (CPM; Finn et al., 2015; Shen et al., 2017) was recently developed to predict individual differences in traits and behaviors, including fluid intelligence (Finn et al., 2015) and sustained attention (Rosenberg et al., 2016a), from functional brain connectivity (FC) measured with fMRI. Here, using the CPM framework, we compared the predictive power of three different measures of FC (Pearson's correlation, accordance, and discordance) and two different prediction algorithms (linear and partial least square [PLS] regression) for attention function. Accordance and discordance are recently proposed FC measures that respectively track in-phase synchronization and out-of-phase anti-correlation (Meskaldji et al., 2016). We defined connectome-based models using task-based or resting-state FC data, and tested the effects of (1) functional connectivity measure and (2) feature-selection/prediction algorithm on individualized attention predictions. Models were internally validated in a training dataset using leave-one-subject-out cross-validation, and externally validated with three independent datasets. The training dataset included fMRI data collected while participants performed a sustained attention task and rested (N = 25; Rosenberg et al., 2016a). The validation datasets included: 1) data collected during performance of a stop-signal task and at rest (N = 83, including 19 participants who were administered methylphenidate prior to scanning; Rosenberg et al., 2016b; f al., 2014a), 2) data collected during Attention Network Task performance and rest (N = 41, Rosenberg et al., in press), and 3) resting-state data and ADHD symptom severity from the ADHD-200 Consortium (N = 113; Rosenberg et al., 2016a). Models defined using all combinations of functional connectivity measure (Pearson's correlation, accordance, and discordance) and prediction algorithm (linear and PLS regression) predicted attentional abilities, with correlations between predicted and observed measures of attention as high as 0.9 for internal validation, and 0.6 for external validation (all p's < 0.05). Models trained on task data outperformed models trained on rest data. Pearson's correlation and accordance features generally showed a small numerical advantage over discordance features, while PLS regression models were usually better than linear regression models. Overall, in addition to correlation features combined with linear models (Rosenberg et al., 2016a), it is useful to consider accordance features and PLS regression for CPM.

PMID: 29122720 [PubMed - as supplied by publisher]

Altered corticostriatal pathway in first-episode paranoid schizophrenia: Resting-state functional and causal connectivity analyses.

Sat, 11/11/2017 - 16:40

Altered corticostriatal pathway in first-episode paranoid schizophrenia: Resting-state functional and causal connectivity analyses.

Psychiatry Res. 2017 Aug 15;:

Authors: Huang H, Shu C, Chen J, Zou J, Chen C, Wu S, Xiao L, Liu Z, Wang H, Zhou Y, Wang G, Jiang T

Abstract
Neuroimaging studies suggest the abnormal structure and function of basal ganglion may contribute to the pathophysiology of schizophrenia. However, little is investigated about the both aberrant functional and causal connectivity of striatum in first-episode paranoid schizophrenia (FEPS). Resting-state functional magnetic resonance imaging was used to characterize the functional connectivity (FC) and casual connectivity within the corticostriatal circuit in 31 patients with FEPS and 33 healthy controls. Degree centrality (DC) was used to explore the regions influenced in schizophrenia at the whole-brain level. Subsequently, a seed-based Granger causality analysis was performed to analyze the causal connectivity. We identified reduced DC of the bilateral putamen in the patients, compared to the controls. In the causal connectivity analysis, we found causal dysconnectivity between the putamen and several regions of default mode network, right orbital part of inferior frontal cortex and right fusiform in the patients. Further, the abnormal causal effect was associated with cognitive impairment in FEPS. The present study highlighted the abnormal functional and causal integrity of the striatum in the patients with FEPS during resting state and suggests a potentially implicated role for the cortical-striatal circuit, especially the striatal-default mode network loop, in the pathophysiology of schizophrenia.

PMID: 29122402 [PubMed - as supplied by publisher]

The parietal opercular auditory-sensorimotor network in musicians: A resting-state fMRI study.

Sat, 11/11/2017 - 16:40

The parietal opercular auditory-sensorimotor network in musicians: A resting-state fMRI study.

Brain Cogn. 2017 Nov 06;:

Authors: Tanaka S, Kirino E

Abstract
Auditory-sensorimotor coupling is critical for musical performance, during which auditory and somatosensory feedback signals are used to ensure desired outputs. Previous studies reported opercular activation in subjects performing or listening to music. A functional connectivity analysis suggested the parietal operculum (PO) as a connector hub that links auditory, somatosensory, and motor cortical areas. We therefore examined whether this PO network differs between musicians and non-musicians. We analyzed resting-state PO functional connectivity with Heschl's gyrus (HG), the planum temporale (PT), the precentral gyrus (preCG), and the postcentral gyrus (postCG) in 35 musicians and 35 non-musicians. In musicians, the left PO exhibited increased functional connectivity with the ipsilateral HG, PT, preCG, and postCG, whereas the right PO exhibited enhanced functional connectivity with the contralateral HG, preCG, and postCG and the ipsilateral postCG. Direct functional connectivity between an auditory area (the HG or PT) and a sensorimotor area (the preCG or postCG) did not significantly differ between the groups. The PO's functional connectivity with auditory and sensorimotor areas is enhanced in musicians relative to non-musicians. We propose that the PO network facilitates musical performance by mediating multimodal integration for modulating auditory-sensorimotor control.

PMID: 29122368 [PubMed - as supplied by publisher]

Frontostriatal and Dopamine Markers of Individual Differences in Reinforcement Learning: A Multi-modal Investigation.

Fri, 11/10/2017 - 15:40

Frontostriatal and Dopamine Markers of Individual Differences in Reinforcement Learning: A Multi-modal Investigation.

Cereb Cortex. 2017 Oct 31;:1-10

Authors: Kaiser RH, Treadway MT, Wooten DW, Kumar P, Goer F, Murray L, Beltzer M, Pechtel P, Whitton A, Cohen AL, Alpert NM, El Fakhri G, Normandin MD, Pizzagalli DA

Abstract
Prior studies have shown that dopamine (DA) functioning in frontostriatal circuits supports reinforcement learning (RL), as phasic DA activity in ventral striatum signals unexpected reward and may drive coordinated activity of striatal and orbitofrontal regions that support updating of action plans. However, the nature of DA functioning in RL is complex, in particular regarding the role of DA clearance in RL behavior. Here, in a multi-modal neuroimaging study with healthy adults, we took an individual differences approach to the examination of RL behavior and DA clearance mechanisms in frontostriatal learning networks. We predicted that better RL would be associated with decreased striatal DA transporter (DAT) availability and increased intrinsic functional connectivity among DA-rich frontostriatal regions. In support of these predictions, individual differences in RL behavior were related to DAT binding potential in ventral striatum and resting-state functional connectivity between ventral striatum and orbitofrontal cortex. Critically, DAT binding potential had an indirect effect on reinforcement learning behavior through frontostriatal connectivity, suggesting potential causal relationships across levels of neurocognitive functioning. These data suggest that individual differences in DA clearance and frontostriatal coordination may serve as markers for RL, and suggest directions for research on psychopathologies characterized by altered RL.

PMID: 29121332 [PubMed - as supplied by publisher]

Human neural correlates of sevoflurane-induced unconsciousness.

Fri, 11/10/2017 - 15:40

Human neural correlates of sevoflurane-induced unconsciousness.

Br J Anaesth. 2017 Oct 01;119(4):573-582

Authors: Palanca BJA, Avidan MS, Mashour GA

Abstract
Sevoflurane, a volatile anaesthetic agent well-tolerated for inhalation induction, provides a useful opportunity to elucidate the processes whereby halogenated ethers disrupt consciousness and cognition. Multiple molecular targets of sevoflurane have been identified, complementing imaging and electrophysiologic markers for the mechanistically obscure progression from wakefulness to unconsciousness. Recent investigations have more precisely detailed scalp EEG activity during this transition, with practical clinical implications. The relative timing of scalp potentials in frontal and parietal EEG signals suggests that sevoflurane might perturb the propagation of neural information between underlying cortical regions. Spatially distributed brain activity during general anaesthesia has been further investigated with positron emission tomography (PET) and resting-state functional magnetic resonance imaging (fMRI). Combined EEG and PET investigations have identified changes in cerebral blood flow and metabolic activity in frontal, parietal, and thalamic regions during sevoflurane-induced loss of consciousness. More recent fMRI investigations have revealed that sevoflurane weakens the signal correlations among brain regions that share functionality and specialization during wakefulness. In particular, two such resting-state networks have shown progressive breakdown in intracortical and thalamocortical connectivity with increasing anaesthetic concentrations: the Default Mode Network (introspection and episodic memory) and the Ventral Attention Network (orienting of attention to salient feature of the external world). These data support the hypotheses that perturbations in temporally correlated activity across brain regions contribute to the transition between states of sevoflurane sedation and general anaesthesia.

PMID: 29121298 [PubMed - in process]

Brain functional connectivity differentiates dexmedetomidine from propofol and natural sleep.

Fri, 11/10/2017 - 15:40

Brain functional connectivity differentiates dexmedetomidine from propofol and natural sleep.

Br J Anaesth. 2017 Oct 01;119(4):674-684

Authors: Guldenmund P, Vanhaudenhuyse A, Sanders RD, Sleigh J, Bruno MA, Demertzi A, Bahri MA, Jaquet O, Sanfilippo J, Baquero K, Boly M, Brichant JF, Laureys S, Bonhomme V

Abstract
Background: We used functional connectivity measures from brain resting state functional magnetic resonance imaging to identify human neural correlates of sedation with dexmedetomidine or propofol and their similarities with natural sleep.
Methods: Connectivity within the resting state networks that are proposed to sustain consciousness generation was compared between deep non-rapid-eye-movement (N3) sleep, dexmedetomidine sedation, and propofol sedation in volunteers who became unresponsive to verbal command. A newly acquired dexmedetomidine dataset was compared with our previously published propofol and N3 sleep datasets.
Results: In all three unresponsive states (dexmedetomidine sedation, propofol sedation, and N3 sleep), within-network functional connectivity, including thalamic functional connectivity in the higher-order (default mode, executive control, and salience) networks, was significantly reduced as compared with the wake state. Thalamic functional connectivity was not reduced for unresponsive states within lower-order (auditory, sensorimotor, and visual) networks. Voxel-wise statistical comparisons between the different unresponsive states revealed that thalamic functional connectivity with the medial prefrontal/anterior cingulate cortex and with the mesopontine area was reduced least during dexmedetomidine-induced unresponsiveness and most during propofol-induced unresponsiveness. The reduction seen during N3 sleep was intermediate between those of dexmedetomidine and propofol.
Conclusions: Thalamic connectivity with key nodes of arousal and saliency detection networks was relatively preserved during N3 sleep and dexmedetomidine-induced unresponsiveness as compared to propofol. These network effects may explain the rapid recovery of oriented responsiveness to external stimulation seen under dexmedetomidine sedation.
Trial registry number: Committee number: 'Comité d'Ethique Hospitalo-Facultaire Universitaire de Liège' (707); EudraCT number: 2012-003562-40; internal reference: 20121/135; accepted on August 31, 2012; Chair: Prof G. Rorive. As it was considered a phase I clinical trial, this protocol does not appear on the EudraCT public website.

PMID: 29121293 [PubMed - in process]

Increased resting-state global functional connectivity density of default mode network in schizophrenia subjects treated with electroconvulsive therapy.

Fri, 11/10/2017 - 15:40
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Increased resting-state global functional connectivity density of default mode network in schizophrenia subjects treated with electroconvulsive therapy.

Schizophr Res. 2017 Nov 06;:

Authors: Huang H, Jiang Y, Xia M, Tang Y, Zhang T, Cui H, Wang J, Li Y, Xu L, Curtin A, Sheng J, Jia Y, Yao D, Li C, Luo C, Wang J

Abstract
Modified electroconvulsive therapy (MECT) has been widely applied to help treat schizophrenia patients who are treatment-resistant to pharmaceutical therapy. Although the technique is increasingly prevalent, the underlying neural mechanisms have not been well clarified. We conducted a longitudinal study to investigate the alteration of global functional connectivity density (gFCD) in schizophrenia patients undergoing MECT using resting state fMRI (functional magnetic resonance imaging). Two groups of schizophrenia inpatients were recruited. One group received a four-week MECT together with antipsychotic drugs (ECT+Drug, n=21); the other group only received antipsychotic drugs (Drug, n=21). Both groups were compared to a sample of healthy controls (HC, n=23). fMRI scans were obtained from the schizophrenia patients twice at baseline (t1) and after 4-week treatment (t2), and from healthy controls at baseline. gFCD was computed using resting state fMRI. Repeated ANCOVA showed a significant interaction effect of group×time in the schizophrenia patients in left precuneus (Pcu), ventral medial prefrontal cortex (vMPFC), and dorsal medial prefrontal cortex (dMPFC) (GRF-corrected P<0.05), which are mainly located within the default mode network (DMN). Post-hoc analysis revealed that compared with baseline (t1), an increased gFCD was found in the ECT+Drug group in the dMPFC (t=3.87, p=0.00095), vMPFC (t=3.95, p=0.00079) and left Pcu (t=3.33, p=0.0034), but no significant effect was identified in the Drug group. The results suggested that increased global functional connectivity density within the DMN might be one important neural mechanism of MECT in schizophrenia.

PMID: 29117910 [PubMed - as supplied by publisher]

Detecting Perfusion Pattern based on the Background Low-frequency Fluctuation in Resting-State Functional MRI Data and its Influence on Resting-State Networks: An Iterative Post-processing Approach.

Fri, 11/10/2017 - 15:40
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Detecting Perfusion Pattern based on the Background Low-frequency Fluctuation in Resting-State Functional MRI Data and its Influence on Resting-State Networks: An Iterative Post-processing Approach.

Brain Connect. 2017 Nov 08;:

Authors: Qian T, Zanchi D, Rodriguez C, Ackermann M, Giannakopoulos P, Haller S

Abstract
INTRODUCTION: RS-fMRI is based on the assumption that the vascular response and the blood oxygenation level dependent (BOLD) response are homogenous across the entire brain. However, this a priori hypothesis is not consistent with the well-known variability of cerebral vascular territories. In order to explore whether the RS networks are influenced by varied vascular speed in different vascular territories, we assessed the time-shift maps that give an estimate of the local timing of the vascular response and check whether local differences in this timing have an impact on the estimates of RS networks.
METHODS: 217 elderly (>=60 years), healthy participants (73.74 ± 4.41 years, 143 female, 203 right-handed) underwent one MRI examination including an RS-fMRI session. After preprocessing, statistical analyses included time-shift analyses and RS-fMRI analyses using as regressor the delay maps obtained from the time-shift analyses. The functional connectivity map of default mode network of each participant was then calculated by using the seed-to-voxel analysis in the REST toolbox.
RESULTS: Faster cerebrovascular responses were notably present in the primary motor and somatosensory and peri-insular cortex while slower responses were present in various regions including notably the posterior cingulate cortex (PCC). Moreover, significant changes notably in the default mode network (DMN), including medial pre-frontal cortex (t=11.95), posterior cingulate cortex (t=11.52), right middle temporal lobe (t=10.72) and right angular gyrus (t=10.88), were observed also taking into account the cerebrovascular delayed maps.
DISCUSSION: As the most prominent example of the RS networks, DMN activation patterns change as a function of the cerebrovascular delay. These data suggest that a group correction for vascular maps in RS-fMRI measurements is essential to correctly depict functional differences and exclude potential confounding effects, notably in the elderly with increasing prevalence of vascular co-morbidity.

PMID: 29117709 [PubMed - as supplied by publisher]

Successful group psychotherapy of depression in adolescents alters fronto-limbic resting-state connectivity.

Fri, 11/10/2017 - 15:40
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Successful group psychotherapy of depression in adolescents alters fronto-limbic resting-state connectivity.

J Affect Disord. 2017 Feb;209:135-139

Authors: Straub J, Metzger CD, Plener PL, Koelch MG, Groen G, Abler B

Abstract
BACKGROUND: Current resting state imaging findings support suggestions that the neural signature of depression and therefore also its therapy should be conceptualized as a network disorder rather than a dysfunction of specific brain regions. In this study, we compared neural connectivity of adolescent patients with depression (PAT) and matched healthy controls (HC) and analysed pre-to-post changes of seed-based network connectivities in PAT after participation in a cognitive behavioral group psychotherapy (CBT).
METHODS: 38 adolescents (30 female; 19 patients; 13-18 years) underwent an eyes-closed resting-state scan. PAT were scanned before (pre) and after (post) five sessions of CBT. Resting-state functional connectivity was analysed in a seed-based approach for right-sided amygdala and subgenual anterior cingulate cortex (sgACC). Symptom severity was assessed using the Beck Depression Inventory Revision (BDI-II).
RESULTS: Prior to group CBT, between groups amygdala and sgACC connectivity with regions of the default mode network was stronger in the patients group relative to controls. Within the PAT group, a similar pattern significantly decreased after successful CBT. Conversely, seed-based connectivity with affective regions and regions processing cognition and salient stimuli was stronger in HC relative to PAT before CBT. Within the PAT group, a similar pattern changed with CBT. Changes in connectivity correlated with the significant pre-to-post symptom improvement, and pre-treatment amygdala connectivity predicted treatment response in depressed adolescents.
LIMITATIONS: Sample size and missing long-term follow-up limit the interpretability.
CONCLUSIONS: Successful group psychotherapy of depression in adolescents involved connectivity changes in resting state networks to that of healthy controls.

PMID: 27912160 [PubMed - indexed for MEDLINE]

Ruminative brooding is associated with salience network coherence in early pubertal youth.

Fri, 11/10/2017 - 15:40
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Ruminative brooding is associated with salience network coherence in early pubertal youth.

Soc Cogn Affect Neurosci. 2017 Feb 01;12(2):298-310

Authors: Ordaz SJ, LeMoult J, Colich NL, Prasad G, Pollak M, Popolizio M, Price A, Greicius M, Gotlib IH

Abstract
Rumination, and particularly ruminative brooding, perpetuates dysphoric mood states and contributes to the emergence of depression. Studies of adults and older adolescents have characterized the association between rumination and intrinsic functional connectivity within default mode (DMN), salience (SN) and executive control (ECN) networks; we know little, however, about the brain network basis of rumination during early puberty, a sensitive period for network reorganization. 112 early puberty boys and girls completed resting-state scans, the Ruminative Response Scale, and the Youth Self-Report questionnaire. Using independent components analysis and dual regression, we quantified coherence for each individual in networks of interest (SN, ECN, DMN) and in non-relevant networks (motor, visual) in which we predicted no correlations with behavioral measures. Boys and girls did not differ in levels of rumination or internalizing symptoms, or in coherence for any network. The relation between SN network coherence and rumination; however, and specifically ruminative brooding, was moderated by sex: greater SN coherence was associated with higher levels of brooding in girls but not in boys. Further, in girls, brooding mediated the relation between SN coherence and internalizing symptoms. These results point to coherence within the SN as a potential neurodevelopmental marker of risk for depression in early pubertal girls.

PMID: 27633394 [PubMed - indexed for MEDLINE]

Automatic Classification on Multi-Modal MRI Data for Diagnosis of the Postural Instability and Gait Difficulty Subtype of Parkinson's Disease.

Fri, 11/10/2017 - 15:40
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Automatic Classification on Multi-Modal MRI Data for Diagnosis of the Postural Instability and Gait Difficulty Subtype of Parkinson's Disease.

J Parkinsons Dis. 2016 May 11;6(3):545-56

Authors: Gu Q, Zhang H, Xuan M, Luo W, Huang P, Xia S, Zhang M

Abstract
BACKGROUND: Patients with the postural instability and gait difficulty subtype (PIGD) of Parkinson's disease (PD) are a refractory challenge in clinical practice. Despite previous attempts that have been made at studying subtype-specific brain alterations across PD population, conclusive neuroimaging biomarkers on patients with the PIGD subtype are still lacking. Machine learning-based classifications are a promising tool for differential diagnosis that effectively integrate complex and multivariate data.
OBJECTIVE: Our present study aimed to introduce the machine learning-based automatic classification for the first time to distinguish patients with the PIGD subtype from those with the non-PIGD subtype of PD at the individual level.
METHODS: Fifty-two PD patients and forty-five normal controls (NCs) were recruited and underwent multi-modal MRI scans including a set of resting-state functional, 3D T1-weighted and diffusion tensor imaging sequences. By comparing the PD patients with the NCs, features that were not conducive to the subtype-specific classification were ruled out from massive brain features. We applied a support vector machine classifier with the recursive feature elimination method to multi-modal MRI data for selecting features with the best discriminating power, and evaluated the proposed classifier with the leave-one-out cross-validation.
RESULTS: Using this classifier, we obtained satisfactory diagnostic rates (accuracy = 92.31%, specificity = 96.97%, sensitivity = 84.21% and AUCmax  = 0.9585). The diagnostic agreement evaluated by the Kappa test showed an almost perfect agreement with the existing clinical categorization (Kappa value = 0.83).
CONCLUSIONS: With these favorable results, our findings suggested the machine learning-based classification as an alternative technique to classifying clinical subtypes in PD.

PMID: 27176623 [PubMed - indexed for MEDLINE]

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