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Cocaine attenuates blood flow but not neuronal responses to stimulation while preserving neurovascular coupling for resting brain activity.

Thu, 09/07/2017 - 12:00
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Cocaine attenuates blood flow but not neuronal responses to stimulation while preserving neurovascular coupling for resting brain activity.

Mol Psychiatry. 2016 Oct;21(10):1408-16

Authors: Chen W, Liu P, Volkow ND, Pan Y, Du C

Abstract
Cocaine affects neuronal activity and constricts cerebral blood vessels, making it difficult to determine whether cocaine-induced changes in cerebral blood flow (CBF) reflect neuronal activation or its vasoactive effects. Here we assessed the effects of acute cocaine on both resting-state and stimulation responses to investigate cocaine's effects on neurovascular coupling and to differentiate its effects on neuronal activity from its vasoactive actions. We concurrently measured cortical field potentials via thinned-skull electroencephalography recordings and CBF with laser Doppler flowmetry in the rat's somatosensory cortex for both resting state and forepaw stimulation before and following cocaine administration (1 mg kg(-1), intravenously). Results show both resting-state field potentials and CBF were depressed after cocaine administration (19.8±4.7% and 52.1±13.4%, respectively) and these changes were strongly correlated with each other (r=0.81, P<0.001), indicating that cocaine did not affect neurovascular coupling at rest and that the reduction in resting CBF reflected reduction in synchronized spontaneous neuronal activity rather than vasoconstriction. In contrast, the forepaw stimulation-evoked neuronal activity was not changed by cocaine (P=0.244), whereas the CBF to the stimulation was reduced 49.9±2.6% (P=0.028) gradually recovering ∼20 min after cocaine injection, indicating that neurovascular coupling during stimulation was temporarily disrupted by cocaine. Neurovascular uncoupling by cocaine during stimulation but not during rest indicates that distinct processes might underlie neurovascular regulation for both stimulation and spontaneous activity. The greater reductions by cocaine to the stimulation-induced CBF increases than to the background CBF should be considered when interpreting functional MRI studies comparing activation responses between controls and cocaine abusers. Neurovascular uncoupling could contribute to cocaine's neurotoxicity, particularly for stimulation conditions when CBF might be insufficient to cover for the energetic demands of neuronal tissue.

PMID: 26666202 [PubMed - indexed for MEDLINE]

Functional Brain Connectome and Its Relation to Hoehn and Yahr Stage in Parkinson Disease.

Wed, 09/06/2017 - 10:40

Functional Brain Connectome and Its Relation to Hoehn and Yahr Stage in Parkinson Disease.

Radiology. 2017 Sep 04;:162929

Authors: Suo X, Lei D, Li N, Cheng L, Chen F, Wang M, Kemp GJ, Peng R, Gong Q

Abstract
Purpose To use resting-state functional magnetic resonance (MR) imaging and graph theory approaches to investigate the brain functional connectome and its potential relation to disease severity in Parkinson disease (PD). Materials and Methods This case-control study was approved by the local research ethics committee, and all participants provided informed consent. There were 153 right-handed patients with PD and 81 healthy control participants recruited who were matched for age, sex, and handedness to undergo a 3-T resting-state functional MR examination. The whole-brain functional connectome was constructed by thresholding the Pearson correlation matrices of 90 brain regions, and the topologic properties were analyzed by using graph theory approaches. Nonparametric permutation tests were used to compare topologic properties, and their relationship to disease severity was assessed. Results The functional connectome in PD showed abnormalities at the global level (ie, decrease in clustering coefficient, global efficiency, and local efficiency, and increase in characteristic path length) and at the nodal level (decreased nodal centralities in the sensorimotor cortex, default mode, and temporal-occipital regions; P < .001, false discovery rate corrected). Further, the nodal centralities in left postcentral gyrus and left superior temporal gyrus correlated negatively with Unified Parkinson's Disease Rating Scale III score (P = .038, false discovery rate corrected, r = -0.198; and P = .009, false discovery rate corrected, r = -0.270, respectively) and decreased with increasing Hoehn and Yahr stage in patients with PD. Conclusion The configurations of brain functional connectome in patients with PD were perturbed and correlated with disease severity, notably with those responsible for motor functions. These results provide topologic insights into understanding the neural functional changes in relation to disease severity of PD. (©) RSNA, 2017 Online supplemental material is available for this article.

PMID: 28873046 [PubMed - as supplied by publisher]

Mechanisms of cognitive-behavioral therapy for obsessive-compulsive disorder involve robust and extensive increases in brain network connectivity.

Wed, 09/06/2017 - 10:40

Mechanisms of cognitive-behavioral therapy for obsessive-compulsive disorder involve robust and extensive increases in brain network connectivity.

Transl Psychiatry. 2017 Sep 05;7(9):e1230

Authors: Moody TD, Morfini F, Cheng G, Sheen C, Tadayonnejad R, Reggente N, O'Neill J, Feusner JD

Abstract
Cognitive-behavioral therapy (CBT) is effective for obsessive compulsive disorder (OCD); however, little is understood about its mechanisms related to brain network connectivity. We examined connectivity changes from resting-state functional magnetic resonance imaging data pre-to-post-CBT in 43 OCD participants, randomized to receive either 4 weeks of intensive CBT or 4 weeks waitlist followed by 4 weeks of CBT, and 24 healthy controls before and after 4 weeks of no treatment. Network-based-statistic analysis revealed large-magnitude increases in OCD connectivity in eight networks. Strongest increases involved connectivity between the cerebellum and caudate/putamen, and between the cerebellum and dorsolateral/ventrolateral prefrontal cortices. Connectivity increases were associated with increased resistance to compulsions. Mechanisms of CBT may involve enhanced cross-network integration, both within and outside of classical cortico-striatal-thalamo-cortical regions; those involving cerebellar to striatal and prefrontal regions may reflect acquisition of new non-compulsive goal-directed behaviors and thought patterns. Our findings have implications for identifying targets for enhancing treatment efficacy and monitoring treatment progress.

PMID: 28872637 [PubMed - in process]

Dynamic 3T pelvic floor magnetic resonance imaging in women progressing from the nulligravid to the primiparous state.

Wed, 09/06/2017 - 10:40
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Dynamic 3T pelvic floor magnetic resonance imaging in women progressing from the nulligravid to the primiparous state.

Int Urogynecol J. 2017 Sep 04;:

Authors: Lockhart ME, Bates GW, Morgan DE, Beasley TM, Richter HE

Abstract
INTRODUCTION AND HYPOTHESIS: The objective was to prospectively characterize dynamic pelvic 3-Tesla magnetic resonance imaging (dp3T MRI) findings in nulligravida women and characterize changes 6 months after delivery in the same woman.
METHODS: In this prospective study, nulligravida women seeking assisted reproductive technology for pregnancy were recruited. After physical examination by Pelvic Organ Prolapse Quantification (POP-Q), Brink assessment and measures including the Pelvic Floor Distress Inventory-20 and Pelvic Floor Impact Questionnaire-7, pre-pregnancy dp3T MRI at rest, with strain, and evacuation were performed. Assessments were repeated ≥6 months postpartum. Analysis included Welch and paired t tests for continuous variables, Fisher's exact test for differences in categorical outcomes, and paired t tests for postpartum symptoms.
RESULTS: Nineteen subjects (mean ± SD age, 31 ± 5 years) completed baseline clinical and dp3T MRI studies, 15 delivered and 10 (30.5 ± 3 years) completed pre-pregnancy and post-delivery clinical and dp3T MRI assessments. There were no significant changes in scores of validated questionnaires (all p > 0.05) or on POP-Q measures post-delivery. Two (20%) subjects without pre-pregnancy levator tears had tears on MRI post-delivery. MRI measures of pelvic organ descent were increased post-delivery. Seventeen pelvic soft-tissue parameters increased by greater than 10% post-delivery, including 5 out of 70 (7.1%), 17 out of 110 (15.5%), and 50 out of 110 (45.5%) values exceeding thresholds at rest, strain, and evacuation respectively.
CONCLUSIONS: Dynamic pelvic 3T MRI detected levator tears and increased pelvic organ descent, which can be directly attributed to pregnancy and delivery.

PMID: 28871385 [PubMed - as supplied by publisher]

Diagnosing Autism Spectrum Disorder from Brain Resting-State Functional Connectivity Patterns Using a Deep Neural Network with a Novel Feature Selection Method.

Wed, 09/06/2017 - 10:40
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Diagnosing Autism Spectrum Disorder from Brain Resting-State Functional Connectivity Patterns Using a Deep Neural Network with a Novel Feature Selection Method.

Front Neurosci. 2017;11:460

Authors: Guo X, Dominick KC, Minai AA, Li H, Erickson CA, Lu LJ

Abstract
The whole-brain functional connectivity (FC) pattern obtained from resting-state functional magnetic resonance imaging data are commonly applied to study neuropsychiatric conditions such as autism spectrum disorder (ASD) by using different machine learning models. Recent studies indicate that both hyper- and hypo- aberrant ASD-associated FCs were widely distributed throughout the entire brain rather than only in some specific brain regions. Deep neural networks (DNN) with multiple hidden layers have shown the ability to systematically extract lower-to-higher level information from high dimensional data across a series of neural hidden layers, significantly improving classification accuracy for such data. In this study, a DNN with a novel feature selection method (DNN-FS) is developed for the high dimensional whole-brain resting-state FC pattern classification of ASD patients vs. typical development (TD) controls. The feature selection method is able to help the DNN generate low dimensional high-quality representations of the whole-brain FC patterns by selecting features with high discriminating power from multiple trained sparse auto-encoders. For the comparison, a DNN without the feature selection method (DNN-woFS) is developed, and both of them are tested with different architectures (i.e., with different numbers of hidden layers/nodes). Results show that the best classification accuracy of 86.36% is generated by the DNN-FS approach with 3 hidden layers and 150 hidden nodes (3/150). Remarkably, DNN-FS outperforms DNN-woFS for all architectures studied. The most significant accuracy improvement was 9.09% with the 3/150 architecture. The method also outperforms other feature selection methods, e.g., two sample t-test and elastic net. In addition to improving the classification accuracy, a Fisher's score-based biomarker identification method based on the DNN is also developed, and used to identify 32 FCs related to ASD. These FCs come from or cross different pre-defined brain networks including the default-mode, cingulo-opercular, frontal-parietal, and cerebellum. Thirteen of them are statically significant between ASD and TD groups (two sample t-test p < 0.05) while 19 of them are not. The relationship between the statically significant FCs and the corresponding ASD behavior symptoms is discussed based on the literature and clinician's expert knowledge. Meanwhile, the potential reason of obtaining 19 FCs which are not statistically significant is also provided.

PMID: 28871217 [PubMed]

Conjoint and dissociated structural and functional abnormalities in first-episode drug-naive patients with major depressive disorder: a multimodal meta-analysis.

Wed, 09/06/2017 - 10:40
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Conjoint and dissociated structural and functional abnormalities in first-episode drug-naive patients with major depressive disorder: a multimodal meta-analysis.

Sci Rep. 2017 Sep 04;7(1):10401

Authors: Wang W, Zhao Y, Hu X, Huang X, Kuang W, Lui S, Kemp GJ, Gong Q

Abstract
Published MRI evidence of structural and resting-state functional brain abnormalities in MDD has been inconsistent. To eliminate interference by repeated disease episodes and antidepressant treatment, we conducted the first multimodal voxel-wise meta-analysis of studies of voxel-based morphometry (VBM) and the amplitude of low-frequency fluctuation (ALFF) in first-episode drug-naive MDD patients, using the Seed-based d Mapping method (SDM). Fifteen VBM data sets and 11 ALFF data sets were included. SDM-based multimodal meta-analysis was used to highlight brain regions with both structural and functional abnormalities. This identified conjoint structural and functional abnormalities in left lateral orbitofrontal cortex and right supplementary motor area, and also dissociated abnormalities of structure (decreased grey matter in right dorsolateral prefrontal cortex and right inferior temporal gyrus; increased grey matter in right insula, right putamen, left temporal pole, and bilateral thalamus) and function (increased brain activity in left supplementary motor area, left parahippocampal gyrus, and hippocampus; decreased brain activity in right lateral orbitofrontal cortex). This study reveals a complex pattern of conjoint and dissociated structural and functional abnormalities, supporting the involvement of basal ganglia-thalamocortical circuits, representing emotional, cognitive and psychomotor abnormalities, in the pathophysiology of early-stage MDD. Specifically, this study adds to Psychoradiology, an emerging subspecialty of radiology, which seems primed to play a major clinical role in guiding diagnostic and treatment planning decisions in patients with mental disorder.

PMID: 28871117 [PubMed - in process]

Changes in intrinsic local connectivity after reading intervention in children with autism.

Tue, 09/05/2017 - 15:40

Changes in intrinsic local connectivity after reading intervention in children with autism.

Brain Lang. 2017 Sep 01;175:11-17

Authors: Maximo JO, Murdaugh DL, O'Kelley S, Kana RK

Abstract
Most of the existing behavioral and cognitive intervention programs in autism spectrum disorders (ASD) have not been tested at the neurobiological level, thus falling short of finding quantifiable neurobiological changes underlying behavioral improvement. The current study takes a translational neuroimaging approach to test the impact of a structured visual imagery-based reading intervention on improving reading comprehension and assessing its underlying local neural circuitry. Behavioral and resting state functional MRI (rs-fMRI) data were collected from children with ASD who were randomly assigned to an Experimental group (ASD-EXP; n=14) and a Wait-list control group (ASD-WLC; n=14). Participants went through an established reading intervention training program (Visualizing and Verbalizing for language comprehension and thinking or V/V; 4-h per day, 10-weeks, 200h of face-to-face instruction). Local functional connectivity was examined using a connection density approach from graph theory focusing on brain areas considered part of the Reading Network. The main results are as follows: (I) the ASD-EXP group showed significant improvement, compared to the ASD-WLC group, in their reading comprehension ability evidenced from change in comprehension scores; (II) the ASD-EXP group showed increased local brain connectivity in Reading Network regions compared to the ASD-WLC group post-intervention; (III) intervention-related changes in local brain connectivity were observed in the ASD-EXP from pre to post-intervention; and (IV) improvement in language comprehension significantly predicted changes in local connectivity. The findings of this study provide novel insights into brain plasticity in children with developmental disorders using targeted intervention programs.

PMID: 28869842 [PubMed - as supplied by publisher]

Effect of Attention Training in Mild Cognitive Impairment Patients with Subcortical Vascular Changes: The RehAtt Study.

Tue, 09/05/2017 - 15:40

Effect of Attention Training in Mild Cognitive Impairment Patients with Subcortical Vascular Changes: The RehAtt Study.

J Alzheimers Dis. 2017 Aug 30;:

Authors: Pantoni L, Poggesi A, Diciotti S, Valenti R, Orsolini S, Della Rocca E, Inzitari D, Mascalchi M, Salvadori E

Abstract
BACKGROUND AND OBJECTIVE: Mild cognitive impairment (MCI) patients with small vessel disease (SVD) are at high dementia risk. We tested the effects of cognitive rehabilitation in these patients using the Attention Process Training-II (APT-II) program in a single-blinded, randomized clinical trial.
METHODS: Patients were randomized to APT-II or standard care and evaluated at baseline, 6, and 12 months with functional, quality of life, cognitive tests, and resting state functional MRI (rsfMRI).
RESULTS: Forty-six patients were enrolled and 43 (mean±SD age 75.1±6.8) completed the study. No change was seen in functionality and quality of life between treated and non-treated patients. However, the Rey Auditory-Verbal Learning Test immediate recall showed a significant improvement in treated compared to non-treated group (change score 6 versus 12 months: 1.8±4.9 and -1.4±3.8, p = 0.021; baseline versus 12 months: 3.8±6.1 and 0.2±4.4, p = 0.032). A higher proportion of treated patients had stable/better evaluation compared to non-treated group on Visual search test (6 versus 12 months: 95% versus 71%, p = 0.038) and Rey-Osterrieth Complex Figure copy (6 versus 12 months: 95% versus 67%, p = 0.027). RsfMRI, performed in a subsample, showed that the difference between follow-up and baseline in synchronization of activity in cerebellar areas was significantly greater in treated than in non-treated patients.
CONCLUSION: We were unable to show a significant effect in quality of life or functional status in treated patients with MCI and SVD. However, APT-II produces some beneficial effects in focused attention and working memory and seems to increase activity in brain circuits involved in cognitive processes.

PMID: 28869475 [PubMed - as supplied by publisher]

Time-Varying Networks of Inter-Ictal Discharging Reveal Epileptogenic Zone.

Tue, 09/05/2017 - 15:40
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Time-Varying Networks of Inter-Ictal Discharging Reveal Epileptogenic Zone.

Front Comput Neurosci. 2017;11:77

Authors: Zhang L, Liang Y, Li F, Sun H, Peng W, Du P, Si Y, Song L, Yu L, Xu P

Abstract
The neuronal synchronous discharging may cause an epileptic seizure. Currently, most of the studies conducted to investigate the mechanism of epilepsy are based on EEGs or functional magnetic resonance imaging (fMRI) recorded during the ictal discharging or the resting-state, and few studies have probed into the dynamic patterns during the inter-ictal discharging that are much easier to record in clinical applications. Here, we propose a time-varying network analysis based on adaptive directed transfer function to uncover the dynamic brain network patterns during the inter-ictal discharging. In addition, an algorithm based on the time-varying outflow of information derived from the network analysis is developed to detect the epileptogenic zone. The analysis performed revealed the time-varying network patterns during different stages of inter-ictal discharging; the epileptogenic zone was activated prior to the discharge onset then worked as the source to propagate the activity to other brain regions. Consistence between the epileptogenic zones detected by our proposed approach and the actual epileptogenic zones proved that time-varying network analysis could not only reveal the underlying neural mechanism of epilepsy, but also function as a useful tool in detecting the epileptogenic zone based on the EEGs in the inter-ictal discharging.

PMID: 28867999 [PubMed]

Autism Spectrum Disorder Related Functional Connectivity Changes in the Language Network in Children, Adolescents and Adults.

Tue, 09/05/2017 - 15:40
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Autism Spectrum Disorder Related Functional Connectivity Changes in the Language Network in Children, Adolescents and Adults.

Front Hum Neurosci. 2017;11:418

Authors: Lee Y, Park BY, James O, Kim SG, Park H

Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disability with global implication. Altered brain connectivity in the language network has frequently been reported in ASD patients using task-based functional magnetic resonance imaging (fMRI) compared to typically developing (TD) participants. Most of these studies have focused on a specific age group or mixed age groups with ASD. In the current study, we investigated age-related changes in functional connectivity related measure, degree centrality (DC), in the language network across three age groups with ASD (113 children, 113 adolescents and 103 adults) using resting-state fMRI data collected from the autism brain imaging data exchange repository. We identified regions with significant group-wise differences between ASD and TD groups for three age cohorts using DC based on graph theory. We found that both children and adolescents with ASD showed decreased DC in Broca's area compared to age-matched TD groups. Adults with ASD showed decreased DC in Wernicke's area compared to TD adults. We also observed increased DC in the left inferior parietal lobule (IPL) and left middle temporal gyrus (MTG) for children with ASD compared to TD children and for adults with ASD compared to TD adults, respectively. Overall, functional differences occurred in key language processing regions such as the left inferior frontal gyrus (IFG) and superior temporal gyrus (STG) related to language production and comprehension across three age cohorts. We explored correlations between DC values of our findings with autism diagnostic observation schedule (ADOS) scores related to severity of ASD symptoms in the ASD group. We found that DC values of the left IFG demonstrated negative correlations with ADOS scores in children and adolescents with ASD. The left STG showed significant negative correlations with ADOS scores in adults with ASD. These results might shed light on the language network regions that should be further explored for prognosis, diagnosis, and monitoring of ASD in three age groups.

PMID: 28867997 [PubMed]

Phase-synchronization-based parcellation of resting state fMRI signals reveals topographically organized clusters in early visual cortex.

Tue, 09/05/2017 - 15:40
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Phase-synchronization-based parcellation of resting state fMRI signals reveals topographically organized clusters in early visual cortex.

Neuroimage. 2017 Aug 31;:

Authors: Gravel NG, Harvey BM, Renken RK, Dumoulin SO, Cornelissen FW

Abstract
Resting-state fMRI is widely used to study brain function and connectivity. However, interpreting patterns of resting state (RS) fMRI activity remains challenging as they may arise from different neuronal mechanisms than those triggered by exogenous events. Currently, this limits the use of RS-fMRI for understanding cortical function in health and disease. Here, we examine the phase synchronization (PS) properties of blood-oxygen level dependent (BOLD) signals obtained during visual field mapping (VFM) and RS with 7T fMRI. This data-driven approach exploits spatiotemporal covariations in the phase of BOLD recordings to establish the presence of clusters of synchronized activity. We find that, in both VFM and RS data, selecting the most synchronized neighboring recording sites identifies spatially localized PS clusters that follow the topographic organization of the visual cortex. However, in activity obtained during VFM, PS is spatially more extensive than in RS activity, likely reflecting stimulus-driven interactions between local responses. Nevertheless, the similarity of the PS clusters obtained for RS and stimulus-driven fMRI suggest that they share a common neuroanatomical origin. Our finding justifies and facilitates direct comparison of RS and stimulus-evoked activity.

PMID: 28867341 [PubMed - as supplied by publisher]

Multimodal neural correlates of cognitive control in the Human Connectome Project.

Tue, 09/05/2017 - 15:40
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Multimodal neural correlates of cognitive control in the Human Connectome Project.

Neuroimage. 2017 Aug 31;:

Authors: Lerman-Sinkoff DB, Sui J, Rachakonda S, Kandala S, Calhoun VD, Barch DM

Abstract
Cognitive control is a construct that refers to the set of functions that enable decision-making and task performance through the representation of task states, goals, and rules. The neural correlates of cognitive control have been studied in humans using a wide variety of neuroimaging modalities, including structural MRI, resting-state fMRI, and task-based fMRI. The results from each of these modalities independently have implicated the involvement of a number of brain regions in cognitive control, including dorsal prefrontal cortex, and frontal parietal and cingulo-opercular brain networks. However, it is not clear how the results from a single modality relate to results in other modalities. Recent developments in multimodal image analysis methods provide an avenue for answering such questions and could yield more integrated models of the neural correlates of cognitive control. In this study, we used multiset canonical correlation analysis with joint independent component analysis (mCCA + jICA) to identify multimodal patterns of variation related to cognitive control. We used two independent cohorts of participants from the Human Connectome Project, each of which had data from four imaging modalities. We replicated the findings from the first cohort in the second cohort using both independent and predictive analyses. The independent analyses identified a component in each cohort that was highly similar to the other and significantly correlated with cognitive control performance. The replication by prediction analyses identified two independent components that were significantly correlated with cognitive control performance in the first cohort and significantly predictive of performance in the second cohort. These components identified positive relationships across the modalities in neural regions related to both dynamic and stable aspects of task control, including regions in both the frontal-parietal and cingulo-opercular networks, as well as regions hypothesized to be modulated by cognitive control signaling, such as visual cortex. Taken together, these results illustrate the potential utility of multi-modal analyses in identifying the neural correlates of cognitive control across different indicators of brain structure and function.

PMID: 28867339 [PubMed - as supplied by publisher]

Changes in extra-striatal functional connectivity in patients with schizophrenia in a psychotic episode.

Tue, 09/05/2017 - 15:40
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Changes in extra-striatal functional connectivity in patients with schizophrenia in a psychotic episode.

Br J Psychiatry. 2017 Jan;210(1):75-82

Authors: Peters H, Riedl V, Manoliu A, Scherr M, Schwerthöffer D, Zimmer C, Förstl H, Bäuml J, Sorg C, Koch K

Abstract
BACKGROUND: In patients with schizophrenia in a psychotic episode, intra-striatal intrinsic connectivity is increased in the putamen but not ventral striatum. Furthermore, multimodal changes have been observed in the anterior insula that interact extensively with the putamen.
AIMS: We hypothesised that during psychosis, putamen extra-striatal functional connectivity is altered with both the anterior insula and areas normally connected with the ventral striatum (i.e. altered functional connectivity distinctiveness of putamen and ventral striatum).
METHOD: We acquired resting-state functional magnetic resonance images from 21 patients with schizophrenia in a psychotic episode and 42 controls.
RESULTS: Patients had decreased functional connectivity: the putamen with right anterior insula and dorsal prefrontal cortex, the ventral striatum with left anterior insula. Decreased functional connectivity between putamen and right anterior insula was specifically associated with patients' hallucinations. Functional connectivity distinctiveness was impaired only for the putamen.
CONCLUSIONS: Results indicate aberrant extra-striatal connectivity during psychosis and a relationship between reduced putamen-right anterior insula connectivity and hallucinations. Data suggest that altered intrinsic connectivity links striatal and insular pathophysiology in psychosis.

PMID: 26892851 [PubMed - indexed for MEDLINE]

Dispositional use of emotion regulation strategies and resting-state cortico-limbic functional connectivity.

Mon, 09/04/2017 - 14:40

Dispositional use of emotion regulation strategies and resting-state cortico-limbic functional connectivity.

Brain Imaging Behav. 2017 Sep 02;:

Authors: Picó-Pérez M, Alonso P, Contreras-Rodríguez O, Martínez-Zalacaín I, López-Solà C, Jiménez-Murcia S, Verdejo-García A, Menchón JM, Soriano-Mas C

Abstract
Neuroimaging functional connectivity (FC) analyses have shown that the negative coupling between the amygdala and cortical regions is linked to better emotion regulation in experimental settings. Nevertheless, no studies have examined the association between resting-state cortico-amygdalar FC and the dispositional use of emotion regulation strategies. We aim at assessing the relationship between the resting-state FC patterns of two different amygdala territories, with different functions in the emotion response process, and trait-like measures of cognitive reappraisal and expressive suppression. Forty-eight healthy controls completed the Emotion Regulation Questionnaire (ERQ) and underwent a resting-state functional magnetic resonance imaging acquisition. FC maps of basolateral and centromedial amygdala (BLA/CMA) with different cortical areas were estimated with a seed-based approach, and were then correlated with reappraisal and suppression scores from the ERQ. FC between left BLA and left insula and right BLA and the supplementary motor area (SMA) correlated inversely with reappraisal scores. Conversely, FC between left BLA and the dorsal anterior cingulate cortex correlated directly with suppression scores. Finally, FC between left CMA and the SMA was inversely correlated with suppression. Top-down regulation from the SMA seems to account for the dispositional use of both reappraisal and suppression depending on the specific amygdala nucleus being modulated. In addition, modulation of amygdala activity from cingulate and insular cortices seem to also account for the habitual use of the different emotion regulation strategies.

PMID: 28866781 [PubMed - as supplied by publisher]

Functional Connectivity Pattern of the Internal Hippocampal Network in Awake Pigeons: A Resting-State fMRI Study.

Mon, 09/04/2017 - 14:40

Functional Connectivity Pattern of the Internal Hippocampal Network in Awake Pigeons: A Resting-State fMRI Study.

Brain Behav Evol. 2017;90(1):62-72

Authors: Behroozi M, Ströckens F, Stacho M, Güntürkün O

Abstract
In the last two decades, the avian hippocampus has been repeatedly studied with respect to its architecture, neurochemistry, and connectivity pattern. We review these insights and conclude that we unfortunately still lack proper knowledge on the interaction between the different hippocampal subregions. To fill this gap, we need information on the functional connectivity pattern of the hippocampal network. These data could complement our structural connectivity knowledge. To this end, we conducted a resting-state fMRI experiment in awake pigeons in a 7-T MR scanner. A voxel-wise regression analysis of blood oxygenation level-dependent (BOLD) fluctuations was performed in 6 distinct areas, dorsomedial (DM), dorsolateral (DL), triangular shaped (Tr), dorsolateral corticoid (CDL), temporo-parieto-occipital (TPO), and lateral septum regions (SL), to establish a functional connectivity map of the avian hippocampal network. Our study reveals that the system of connectivities between CDL, DL, DM, and Tr is the functional backbone of the pigeon hippocampal system. Within this network, DM is the central hub and is strongly associated with DL and CDL BOLD signal fluctuations. DM is also the only hippocampal region to which large Tr areas are functionally connected. In contrast to published tracing data, TPO and SL are only weakly integrated in this network. In summary, our findings uncovered a structurally otherwise invisible architecture of the avian hippocampal formation by revealing the dynamic blueprints of this network.

PMID: 28866684 [PubMed - in process]

Multivariate brain network graph identification in functional MRI.

Mon, 09/04/2017 - 14:40

Multivariate brain network graph identification in functional MRI.

Med Image Anal. 2017 Aug 30;42:228-240

Authors: Aggarwal P, Gupta A, Garg A

Abstract
Motivated by recent interest in identification of functional brain networks, we develop a new multivariate approach for functional brain network identification and name it as Multivariate Vector Regression-based Connectivity (MVRC). The proposed MVRC method regresses time series of all regions to those of other regions simultaneously and estimates pairwise association between two regions with consideration of influence of other regions and builds the adjacency matrix. Next, modularity method is applied on the adjacency matrix to detect communities or functional brain networks. We compare the proposed MVRC method with existing methods ranging from simple Pearson correlation to advanced Multivariate Adaptive Sparse Representation (ASR) methods. Experimental results on simulated and real fMRI dataset demonstrate that MVRC is able to extract functional brain networks that are consistent with the literature. Also, the proposed MVRC method is 650-750 times faster compared to the existing ASR method on 90 node network.

PMID: 28866433 [PubMed - as supplied by publisher]

Disrupted topology of hippocampal connectivity is associated with short-term antidepressant response in major depressive disorder.

Mon, 09/04/2017 - 14:40

Disrupted topology of hippocampal connectivity is associated with short-term antidepressant response in major depressive disorder.

J Affect Disord. 2017 Aug 31;225:539-544

Authors: Gong L, Hou Z, Wang Z, He C, Yin Y, Yuan Y, Zhang H, Lv L, Zhang H, Xie C, Zhang Z

Abstract
BACKGROUND: Graph theoretical analyses have identified disrupted functional topological organization across the brain in patients with major depressive disorder (MDD). However, the relationship between brain topology and short-term treatment responses in patients with MDD remains unknown.
METHODS: Sixty-eight patients with MDD and 63 cognitively normal (CN) subjects were recruited at baseline and underwent resting-state functional magnetic resonance imaging scans. Graph theory analysis was used to examine group differences in the whole-brain functional topological properties. The association between altered brain topology and the early antidepressant response was examined.
RESULTS: Patients with MDD showed lower normalized clustering coefficients, lower small-worldness scalars and increased nodal efficiencies in the default mode network and decreased nodal efficiencies in basal ganglia and hippocampal networks. In addition, the decreased nodal efficiency in left hippocampus was negatively correlated with depressive severity at baseline and positively correlated with changes in the depressive scores after two weeks of antidepressant treatment.
LIMITATIONS: The patients in the present study received different medications.
CONCLUSION: These findings indicated that the altered brain functional topological organization in patients with MDD is associated with the treatment response in the early phase of medication. Therefore, brain topology assessments might be considered a useful and convenient predictor of short-term antidepressant responses.

PMID: 28866298 [PubMed - as supplied by publisher]

Resting-state functional connectivity: An emerging method for the study of language networks in post-stroke aphasia.

Mon, 09/04/2017 - 14:40

Resting-state functional connectivity: An emerging method for the study of language networks in post-stroke aphasia.

Brain Cogn. 2017 Aug 30;:

Authors: Klingbeil J, Wawrzyniak M, Stockert A, Saur D

Abstract
Aphasia results both from direct effects of focal damage to eloquent cortical areas as well as dysfunction of interconnected remote areas within the language network. Resting-state functional MRI (rsfMRI) can be used to examine functional connectivity (FC) within these networks. Herein we review publications, which applied rsfMRI to understand network pathology in post stroke aphasia. A common finding in this research is an acute disruption of connectivity within the language network, which is correlated with loss of language function and tends to resolve with recovery from aphasia. All studies are limited by small sample sizes, heterogeneous patient characteristics and a wide range of analytical approaches, which further hinder deduction of common patterns across studies. One recent large-scale study examining FC and behavior across various cognitive domains, however, has made substantial progress with the description of a "network phenotype of stroke injury", which consists of a disruption of interhemispheric connectivity and reduced segregation of intrahemispheric networks. Unlike in other domains, language functions showed substantial dependence on intact left intrahemispheric connectivity (Siegel, Ramsey et al., 2016). In the future, such analyses of network pathology might support prognosis and development of effective treatment strategies in individual patients with aphasia.

PMID: 28865994 [PubMed - as supplied by publisher]

Altered patterns of resting-state functional connectivity between the caudate and other brain regions in medication-naïve children with attention deficit hyperactivity disorder.

Sat, 09/02/2017 - 12:00
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Altered patterns of resting-state functional connectivity between the caudate and other brain regions in medication-naïve children with attention deficit hyperactivity disorder.

Clin Imaging. 2017 Jul 28;47:47-51

Authors: Yang Z, Li H, Tu W, Wang S, Ren Y, Yi Y, Wu T, Jiang K, Shen H, Wu J, Dong X

Abstract
BACKGROUND: Structural and functional alterations occur in the caudate of patients with attention-deficit/hyperactivity disorder (ADHD). Here we aimed to investigate the functional connectivity between the dorsal caudate and other brain regions in ADHD children.
METHODS: Resting-state functional connectivity from 30 ADHD and 33 age- and gender-matched "normal" children were measured by functional Magnetic Resonance Imaging.
RESULTS: Positive connectivity with dorsal caudate was observed in the prefrontal areas, cingulate cortex and temporal lobe. Negative functional connectivity was observed in the precuneus, occipital cortices and cerebellum. The connectivity of left dorsal caudate to left inferior frontal gyrus was correlated with severity of ADHD.
CONCLUSIONS: Connectivity of dorsal caudate with several brain regions was identified in ADHD children.

PMID: 28863310 [PubMed - as supplied by publisher]

Hemodynamic response function parameters obtained from resting-state functional MRI data in soldiers with trauma.

Sat, 09/02/2017 - 12:00
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Hemodynamic response function parameters obtained from resting-state functional MRI data in soldiers with trauma.

Data Brief. 2017 Oct;14:558-562

Authors: Rangaprakash D, Dretsch MN, Yan W, Katz JS, Denney TS, Deshpande G

Abstract
Functional magnetic resonance imaging (fMRI) is an indirect measure of brain activity, i.e. it is a convolution of the latent (unmeasured) neural signal and the hemodynamic response function (HRF). As such, the HRF has been shown to vary across brain regions and individuals. The shape of the HRF is controlled by both neural and non-neural factors. The shape of the HRF can be characterized by three parameters (response height, time-to-peak and full-width at half-max). The data presented here provides the three HRF parameters at every voxel, obtained from U.S. Army soldiers (N=87) diagnosed with posttraumatic stress disorder (PTSD), with comorbid PTSD and mild-traumatic brain injury (mTBI), and matched healthy combat controls. Findings from this data and further interpretations are available in our recent research study (Rangaprakash et al., 2017) [1]. This data is a valuable asset in studying the impact of HRF variability on fMRI data analysis, specifically resting state functional connectivity.

PMID: 28861454 [PubMed]

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