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A posterior-anterior distinction between scene perception and scene construction in human medial parietal cortex.

Mon, 12/10/2018 - 21:49
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A posterior-anterior distinction between scene perception and scene construction in human medial parietal cortex.

J Neurosci. 2018 Nov 30;:

Authors: Silson EH, Gilmore AW, Kalinowski SE, Steel A, Kidder A, Martin A, Baker CI

Abstract
Human retrosplenial complex (RSC), located in medial parietal cortex, has been implicated in numerous cognitive functions, including scene perception, spatial navigation, and autobiographical memory retrieval. Recently, a posterior-anterior distinction within RSC was proposed, such that posterior aspects process scene-related visual information (constituting a "medial place area;" MPA), whereas anterior aspects process information that is vividly retrieved from memory, thereby supporting remembering and potentially navigation. Here, we tested this proposed distinction in a single group of participants (both male and female) using fMRI with both perceptual and mnemonic tasks. After completing a resting-state scan, participants performed a task that required constructing scenes from memory and completed a scene-selectivity localizer task. We tested directly perceptual and mnemonic responses in MPA and an anterior, connectivity-defined region (CON), that showed strong functional connectivity with anterior parahippocampal place area (PPA). A double dissociation was observed, such that CON was more strongly activated during scene construction than was MPA, whereas MPA was more perceptually responsive than CON. Further, peak responses from the scene construction task were anterior to perceptual peaks in all but one participant and hemisphere. Finally, through analyses of the posterior-anterior response profiles, we identify the fundus of the parieto-occipital sulcus (POS) as a potential location for the cross-over from perceptual to mnemonic representations and highlight a potential left-hemisphere advantage for mnemonic representations. Collectively, our results support a distinction between posterior and anterior aspects of the "RSC," suggesting that more specific functional-anatomic terms should be used in its place in future work.SIGNIFICANCE STATEMENTThe retrosplenial complex (RSC) has been implicated in vision, spatial cognition and memory. We previously speculated on a potential posterior-anterior distinction within RSC for scene perception and memory-based scene construction/navigation. Here, we tested this distinction through a combination of resting-state, perceptual and mnemonic task data. Consistent with our predictions, we demonstrate that perceptual responses peak consistently posterior of those elicited by memory-based scene construction within the broader RSC. Further, we highlight (1) the fundus of the parieto-occipital sulcus (POS) as a landmark for the transition between these representations, (2) the anterior bank of POS as the point of maximal separation between these representations and (3) identify a potential hemispheric asymmetry in mnemonic representations. These data support functional dissociations within RSC.

PMID: 30504281 [PubMed - as supplied by publisher]

Neural substrates of cognitive reserve in Alzheimer's disease spectrum and normal aging.

Mon, 12/10/2018 - 21:49
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Neural substrates of cognitive reserve in Alzheimer's disease spectrum and normal aging.

Neuroimage. 2018 Nov 29;:

Authors: Lee DH, Lee P, Seo SW, Roh JH, Oh M, Oh JS, Oh SJ, Kim JS, Jeong Y

Abstract
The concept of cognitive reserve (CR) originated from discrepancies between the degree of brain pathology and the severity of clinical manifestations. CR has been characterized through CR proxies, such as education and occupation complexity; however, such approaches have inherent limitations. Although several methods have been developed to overcome these limitations, they fail to reflect the entire Alzheimer's disease (AD) pathology. Meanwhile, graph theory analysis, one of most powerful and flexible approaches, have established remarkable network properties of the brain. The functional and structural brain networks are damaged in neurodegenerative diseases. Therefore, network analysis has been applied to clarify the characteristics of the disease or give insight. Here, using multimodal neuroimaging, we propose an intuitive model to estimate CR based on its original definition, and explore the neural substrates of CR from the perspective of networks and functional connectivity. A total of 87 subjects (21 AD, 32 mild cognitive impairment, and 34 normal aging) underwent tau and amyloid PET, 3D T1-weighted MR, and resting-state fMRI. We hypothesized CR as a residual of actual cognitive performance and expected performance to be related to quantitative factors, such as AD pathology, demographics, and a genetic factor. Then, we correlated this marker using education and occupation complexity as conventional CR proxies. We validated this marker by testing whether it would modulate the effect of brain pathology on memory function. To examine the neural substrates associated with CR, we performed graph analysis to investigate the association between the CR marker and network measures at different granularities in total subjects, AD spectrum and normal aging, respectively. The CR marker from our model was well associated with education and occupation complexity. More directly, the CR marker was revealed to modify the relationship between brain pathology and memory function among AD spectrum. The CR marker was correlated with the global efficiency of the entire network, nodal clustering coefficient, and local efficiency of the right middle-temporal pole. In connectivity analysis, one cluster of edges centered on right middle-temporal pole was significantly correlated with the CR marker. In subgroup analysis, the network measures of right middle-temporal pole still correlated with the CR marker among AD spectrum. However, right precentral gyrus was revealed to be associated with the CR marker in normal aging. This study demonstrates that our intuitive model using multimodal neuroimaging and network perspective adequately and comprehensively captures CR. From a network perspective, CR is associated with the capacity to process information efficiently in the brain. The right middle-temporal pole was revealed to be a pivotal neural substrate of CR in AD spectrum. These findings foster understanding of AD and will be useful to help identify individuals with vulnerability or resistance to AD pathology, and characterize patients for intervention or drug trials.

PMID: 30503934 [PubMed - as supplied by publisher]

Multi-echo fMRI, resting-state connectivity, and high psychometric schizotypy.

Mon, 12/10/2018 - 21:49
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Multi-echo fMRI, resting-state connectivity, and high psychometric schizotypy.

Neuroimage Clin. 2018 Nov 20;:

Authors: Waltmann M, O'Daly O, Egerton A, McMullen K, Kumari V, Barker GJ, Williams SCR, Modinos G

Abstract
Disrupted striatal functional connectivity is proposed to play a critical role in the development of psychotic symptoms. Previous resting-state functional magnetic resonance imaging (rs-fMRI) studies typically reported disrupted striatal connectivity in patients with psychosis and in individuals at clinical and genetic high risk of the disorder relative to healthy controls. This has not been widely studied in healthy individuals with subclinical psychotic-like experiences (schizotypy). Here we applied the emerging technology of multi-echo rs-fMRI to examine corticostriatal connectivity in this group, which is thought to drastically maximize physiological noise removal and increase BOLD contrast-to-noise ratio. Multi-echo rs-fMRI data (echo times, 12, 28, 44, 60 ms) were acquired from healthy individuals with low (LS, n = 20) and high (HS, n = 19) positive schizotypy as determined with the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE). After preprocessing to ensure optimal contrast and removal of non-BOLD signal components, whole-brain functional connectivity from six striatal seeds was compared between the HS and LS groups. Effects were considered significant at cluster-level p < .05 family-wise error correction. Compared to LS, HS subjects showed lower rs-fMRI connectivity between ventromedial prefrontal regions and ventral striatal regions. Lower connectivity was also observed between the dorsal putamen and the hippocampus, occipital regions, as well as the cerebellum. These results demonstrate that subclinical positive psychotic-like experiences in healthy individuals are associated with striatal hypoconnectivity as detected using multi-echo rs-fMRI. Further application of this approach may aid in characterizing functional connectivity abnormalities across the extended psychosis phenotype.

PMID: 30503214 [PubMed - as supplied by publisher]

Spatial characteristics of spontaneous and stimulus-induced individual functional connectivity networks in severe disorders of consciousness.

Mon, 12/10/2018 - 21:49
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Spatial characteristics of spontaneous and stimulus-induced individual functional connectivity networks in severe disorders of consciousness.

Brain Cogn. 2018 Nov 27;:

Authors: Sitaram R, Yu T, Halsband U, Vogel D, Müller F, Lang S, Birbaumer N, Kotchoubey B

Abstract
BACKGROUND: Functional connectivity (fcMRI) analyses of resting state functional magnetic resonance imaging (fMRI) data revealed substantial differences between states of consciousness. The underlying cause-effect linkage, however, remains unknown to the present day. The aim of this study was to examine the relationship between fcMRI measures and Disorders of Consciousness (DOC) in resting state and under adequate stimulation.
METHODS AND FINDINGS: fMRI data from thirteen patients with unresponsive wakefulness syndrome, eight patients in minimally conscious state, and eleven healthy controls were acquired in rest and during the application of nociceptive and emotional acoustic stimuli. We compared spatial characteristics and anatomical topography of seed-based fcMRI networks on group and individual levels. The anatomical topography of fcMRI networks of patients was altered in all three conditions as compared with healthy controls. Spread and distribution of individual fcMRI networks, however, differed significantly between patients and healthy controls in stimulation conditions only. The exploration of individual metric values identified two patients whose spatial metrics did not deviate from metric distributions of healthy controls in a statistically meaningful manner.
CONCLUSIONS: These findings suggest that the disturbance of consciousness in DOC is related to deficits in global topographical network organization rather than a principal inability to establish long-distance connections. In addition, the results question the claim that task-free measurements are particularly valuable as a tool for individual diagnostics in severe neurological disorders. Further studies comparing connectivity indices with outcome of DOC patients are needed to determine the clinical relevance of spatial metrics and stimulation paradigms for individual diagnosis, prognosis and treatment in DOC.

PMID: 30502227 [PubMed - as supplied by publisher]

Reconfigured functional network dynamics in adult moyamoya disease: a resting-state fMRI study.

Thu, 12/06/2018 - 00:12

Reconfigured functional network dynamics in adult moyamoya disease: a resting-state fMRI study.

Brain Imaging Behav. 2018 Dec 03;:

Authors: Lei Y, Song B, Chen L, Su J, Zhang X, Ni W, Yu Y, Xu B, Yu L, Gu Y, Mao Y

Abstract
Treatment of vascular cognitive impairment (VCI) in adult moyamoya disease (MMD) is still unclear because of its unveiled neural synchronization. This study introduced a dynamic measurement of connectivity number entropy (CNE) to characterize both spatial and temporal dimensions of network interactions. Fifty-one patients with MMD were recruited (27 with VCI and 24 with intact cognition), as well as 26 normal controls (NCs). Static network properties were first examined to confirm its aberrance in MMD with VCI. Then, the dynamic measurement of CNE was used to detect the deteriorated flexibility of MMD with VCI at global, regional, and network levels. Finally, dynamic reconfiguration of flexible and specialized regions was traced across the three groups. Graph theory analysis indicated that MMD exhibited "small-world" network topology but presented with a deviating pattern from NC as the disease progressed in all topologic metrics of integration, segregation, and small-worldness. Subsequent dynamic analysis showed significant CNE differences among the three groups at both global (p < 0.001) and network levels (default mode network, p = 0.004; executive control network, p = 0.001). Specifically, brain regions related to key aspects of information processing exhibited significant CNE changes across the three groups. Furthermore, CNE values of both flexible and specialized regions changed with impaired cognition. This study not only sheds light on both the static and dynamic organizational principles behind network changes in adult MMD for the first time, but also provides a new methodologic viewpoint to acquire more knowledge of its pathophysiology and treatment direction.

PMID: 30511114 [PubMed - as supplied by publisher]

Abnormal functional connectivity and degree centrality in anterior cingulate cortex in patients with long-term sensorineural hearing loss.

Thu, 12/06/2018 - 00:12

Abnormal functional connectivity and degree centrality in anterior cingulate cortex in patients with long-term sensorineural hearing loss.

Brain Imaging Behav. 2018 Dec 03;:

Authors: Luan Y, Wang C, Jiao Y, Tang T, Zhang J, Lu C, Salvi R, Teng GJ

Abstract
Wide-ranging functional remodeling is involved in sensorineural hearing loss (SNHL), which has been demonstrated to have accumulated risk of cognitive and emotional dysfunction. Anterior cingulate cortex (ACC) has close connections with the auditory area and plays a vital role in regulating the cognitive, emotional and auditory processing. However, the functional reorganization of the ACC and its associations with potential cognitive and emotional impairments involved in SNHL have never been explored. Thirty-five patients with long-term bilateral SNHL and thirty-five well-matched healthy controls were recruited for this study. We analyzed resting-state functional MRI data and neuropsychological test scores from these participants. Functional connectivity of the ACC subdivisions, voxel-wise degree centrality (DC) and intra-/internetwork connectivity were computed to evaluate the functional changes related to cognitive, emotional and multiple sensory functions. ANCOVA and post hoc analyses were conducted to identify differences between normal controls and patients for each measure. Widespread alterations of functional coupling with the subdivisions of the ACC were observed in regions involved in cognitive, emotional and multiple sensory processing, particularly within the cingulo-opercular network (CON), default mode network (DMN) and auditory network (AN) in the SNHL patients. Outstandingly increased DC was found in the ACC. Network analyses showed significant intra- and inter-network hypo-synchronization in the SNHL patients. Importantly, the functional alterations were associated with the anxiety states and the processing speed. The functional reorganization in the ACC and the disturbance of intrinsic multiple network functional connectivity among the CON, DMN, and AN were found in the SNHL patient, which might shed more lights on potential substrates underlying the cognitive and emotional impairments related to the SNHL.

PMID: 30511112 [PubMed - as supplied by publisher]

Dimensional Complexity of the Resting Brain in Healthy Aging, Using a Normalized MPSE.

Thu, 12/06/2018 - 00:12

Dimensional Complexity of the Resting Brain in Healthy Aging, Using a Normalized MPSE.

Front Hum Neurosci. 2018;12:451

Authors: Scheel N, Franke E, Münte TF, Madany Mamlouk A

Abstract
Spontaneous fluctuations of resting-state functional connectivity have been studied in many ways, but grasping the complexity of brain activity has been difficult. Dimensional complexity measures, which are based on Eigenvalue (EV) spectrum analyses (e.g., Ω entropy) have been successfully applied to EEG data, but have not been fully evaluated on functional MRI recordings, because only through the recent introduction of fast multiband fMRI sequences, feasable temporal resolutions are reached. Combining the Eigenspectrum normalization of Ω entropy and the scalable architecture of the so called Multivariate Principal Subspace Entropy (MPSE) leads to a new complexity measure, namely normalized MPSE (nMPSE). It allows functional brain complexity analyses at varying levels of EV energy, independent from global shifts in data variance. Especially the restriction of the EV spectrum to the first dimensions, carrying the most prominent data variance, can act as a filter to reveal the most discriminant factors of dependent variables. Here we look at the effects of healthy aging on the dimensional complexity of brain activity. We employ a large open access dataset, providing a great number of high quality fast multiband recordings. Using nMPSE on whole brain, regional, network and searchlight approaches, we were able to find many age related changes, i.e., in sensorimotoric and right inferior frontal brain regions. Our results implicate that research on dimensional complexity of functional MRI recordings promises to be a unique resource for understanding brain function and for the extraction of biomarkers.

PMID: 30510506 [PubMed]

Replication of Resting State-Task Network Correspondence and Novel Findings on Brain Network Activation During Task fMRI in the Human Connectome Project Study.

Thu, 12/06/2018 - 00:12

Replication of Resting State-Task Network Correspondence and Novel Findings on Brain Network Activation During Task fMRI in the Human Connectome Project Study.

Sci Rep. 2018 Dec 03;8(1):17543

Authors: Nickerson LD

Abstract
There have been many recent reports highlighting a crisis in replication and reliability of research in psychology, neuroscience, and neuroimaging. After a series of reports uncovered various methodological problems with functional magnetic resonance imaging (fMRI) research, considerable attention has been given to principles and practices to improve reproducibility of neuroimaging findings, including promotion of openness, transparency, and data sharing. However, much less attention has been given to use of open access neuroimaging datasets to conduct replication studies. A major barrier to reproducing neuroimaging studies is their high cost, in money and labor, and utilizing such datasets is an obvious solution for breaking down this barrier. The Human Connectome Project (HCP) is an open access dataset consisting of extensive neurological, behavioral, and genetics assessments and neuroimaging data from over 1,100 individuals. In the present study, findings supporting the replication of a highly cited neuroimaging study that showed correspondence between resting state and task brain networks, and novel findings on activation of brain networks during task performance that arose with this exercise are presented as a demonstration of use of the HCP for replication studies.

PMID: 30510165 [PubMed - in process]

Combining resting state functional MRI with intraoperative cortical stimulation to map the mentalizing network.

Wed, 12/05/2018 - 10:53
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Combining resting state functional MRI with intraoperative cortical stimulation to map the mentalizing network.

Neuroimage. 2018 Nov 27;:

Authors: Yordanova YN, Cochereau J, Duffau H, Herbet G

Abstract
OBJECTIVE: To infer the face-based mentalizing network from resting-state functional MRI (rsfMRI) using a seed-based correlation analyses with regions of interest identified during intraoperative cortical electrostimulation.
METHODS: We retrospectively included 23 patients in whom cortical electrostimulation induced transient face-based mentalizing impairment during 'awake' craniotomy for resection of a right-sided diffuse low-grade glioma. Positive stimulation sites were recorded and transferred to the patients' preoperative normalized MRI, and then used as seeds for subsequent seed-to-voxel functional connectivity analyses. The analyses, conducted with an uncorrected voxel-level p-value of 0.001 and a false-discovery-rate cluster-level p-value of 0.05, allowed identification of the cortical structures, functionally coupled with the mentalizing-related sites.
RESULTS: Two clusters of responsive stimulations were identified intraoperatively - one in the right dorsolateral prefrontal cortex (dlPFC, n = 13) and the other in the right inferior frontal gyrus (IFG, n = 10). A whole group level analysis revealed that stimulation sites correlated mainly with voxels located in the pars triangularis of the IFG, the dorsolateral and dorsomedial prefrontal cortices, the temporo-parietal junction, the posterior superior temporal sulcus, and the posterior inferior temporal/fusiform gyrus. Other analyses, taking into consideration the location of the responsive sites (IFG versus dlPFC cluster), highlighted only minor differences between both groups.
CONCLUSIONS: The present study successfully demonstrated the involvement of a large-scale neural network in the face-based mentalizing that perfectly matches networks, classically identified using task-based fMRI paradigms. We thus validated the combination of rsfMRI and stimulation mapping as a powerful approach to identify functional networks in brain-damaged patients.

PMID: 30500423 [PubMed - as supplied by publisher]

Dual-contrast pCASL using simultaneous gradient-echo/spin-echo multiband EPI.

Wed, 12/05/2018 - 10:53
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Dual-contrast pCASL using simultaneous gradient-echo/spin-echo multiband EPI.

Magn Reson Imaging. 2018 Nov 27;:

Authors: Zhang K, Sturm VJ, Buschle LR, Hahn A, Yun SD, Jon Shah N, Bendszus M, Heiland S, Schlemmer HP, Ziener CH, Kurz FT

Abstract
A 2D gradient-echo EPI is commonly employed for arterial spin labeling (ASL) readout to achieve fast whole brain coverage measurements. However, such a readout suffers from susceptibility artifacts induced by magnetic field inhomogeneities. To reduce these susceptibility effects, single-shot spin-echo EPI was proposed to be used for acquisitions in continuous ASL (CASL). To minimize functional and physiological variations, a gradient-echo (GE)/spin-echo (SE) dual-echo EPI readout of the CASL sequence is needed for a comparison between GE- and SE-based determination of cerebral blood flow (CBF). In this study, we employed a simultaneous GE/SE multiband EPI as the readout of a pseudo-CASL (pCASL) sequence. Motor cortex activations derived from a finger-tapping task and functional networks from resting state fMRI were compared for both GE and SE contrasts. Direct comparison of SE and GE contrasts revealed that GE ASL provides an improved sensitivity of functional activity in finger-tapping and in resting-state imaging. SE ASL, on the other hand, suffered less from susceptibility artifacts induced by magnetic field inhomogeneities and pulsatile flow artifacts.

PMID: 30500347 [PubMed - as supplied by publisher]

Measuring abnormal intrinsic brain activities in patients with retinal detachment using amplitude of low-frequency fluctuation: a resting-state fMRI study.

Sun, 12/02/2018 - 10:33

Measuring abnormal intrinsic brain activities in patients with retinal detachment using amplitude of low-frequency fluctuation: a resting-state fMRI study.

Int J Neurosci. 2018 Nov 30;:1-13

Authors: Kang HH, Shu YQ, Yang L, Zhu PW, Li D, Li QH, Min YL, Ye L, Zhou Q, Shao Y

Abstract
OBJECTIVE: The targets of this study was to access the alternations of spontaneous brain activity in RD patients by amplitude of low-frequency fluctuation (ALFF) method and to explore their relationships with clinical behavioral performance.
METHODS: 20 patients with RD (6 males and 14 females), and 20 healthy controls (HCs) (6 males and 14 females) were recruited, and were matched in sex and age. All participants finished the functional magnetic resonance imaging (fMRI) scanning. We applied the ALFF method to detect the spontaneous brain activity. Receiver operating characteristic (ROC) curve was applied to distinguish RD Patients from HCs.
RESULTS: RD patients showed decreased ALFF values in the right occipital lobe and right medial frontal gyrus and increased ALFF values in the right frontal superior orbital and left inferior temporal gyrus when compared with HCs. In RD patients, we did not find any relationship between the mean ALFF values and the clinical behavioral performances.
CONCLUSION: The RD patients exhibited abnormal spontaneous brain activity in vision and vision related brain regions, which might explore potential pathological mechanism of acute vision loss in RD patients.

PMID: 30499735 [PubMed - as supplied by publisher]

Behavioral and Functional Connectivity Basis for Peer-Influenced Bystander Participation in Bullying.

Wed, 11/28/2018 - 19:45

Behavioral and Functional Connectivity Basis for Peer-Influenced Bystander Participation in Bullying.

Soc Cogn Affect Neurosci. 2018 Nov 27;:

Authors: Takami K, Haruno M

Abstract
Recent studies have shown that the reactions of bystanders who witness bullying significantly affect whether the bullying persists. However, the underlying behavioral and neural mechanisms that determine a peer-influenced bystander's participation in bullying remain largely unknown. Here, we designed a new "catch-ball" task where four players choose to throw a sequence of normal or strong (aggressive) balls in turn and examined whether the players (n=43) participated in other players' bullying. We analyzed behaviors with a computational model that quantifies the tendencies of a participant's 1) baseline propensity for bullying, 2) reactive revenge, 3) conformity to bullying, and 4) capitulation to threat and estimated these effects on the choice of balls. We found only conformity had a positive effect on the throwing of strong balls. Furthermore, we identified a correlation between a participant's conformity and social anxiety. Our mediation analysis of resting-state fMRI revealed that there were significant relationships of each participant's functional connectivity between the amygdala and right temporoparietal junction (TPJ) and social anxiety to the participant's conformity to bullying. We also found that amygdala-TPJ connectivity partially mediated the relationship between social anxiety and conformity. These results highlighted the anxiety-based conformity and amygdala network on peer-influenced bystander participation in bullying.

PMID: 30481351 [PubMed - as supplied by publisher]

Low-frequency fluctuation characteristics in rhesus macaques with SIV infection: a resting-state fMRI study.

Wed, 11/28/2018 - 19:45
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Low-frequency fluctuation characteristics in rhesus macaques with SIV infection: a resting-state fMRI study.

J Neurovirol. 2018 Nov 26;:

Authors: Zhao J, Chen F, Ren M, Li L, Li A, Jing B, Li H

Abstract
Simian immunodeficiency virus (SIV)-infected macaque is a widely used model to study human immunodeficiency virus. The purpose of the study is to discover the amplitude of low-frequency fluctuation (ALFF) and fractional ALFF (fALFF) changes in SIV-infected macaques. Seven rhesus macaques were involved in the longitudinal MRI scans: (1) baseline (healthy state); (2) SIV infection stage (12 weeks after SIV inoculation). ALFF and fALFF were subsequently computed and compared to ascertain the changes caused by SIV infection. Whole-brain correlation analysis was further used to explore the possible associations between ALFF/fALFF values and immune status parameters (CD4+ T cell counts, CD4/CD8 ratio and virus load). Compared with the baseline, macaques in SIV infection stage displayed strengthened ALFF values in left precuneus, postcentral gyrus, and temporal gyrus, and weakened ALFF values in orbital gyrus and inferior temporal gyrus. Meanwhile, increased fALFF values were found in left superior frontal gyrus, right precentral gyrus, and superior temporal gyrus, while decreased fALFF values existed in left hippocampus, left caudate, and right inferior frontal gyrus. Furthermore, ALFF and fALFF values in several brain regions showed significant relationships with CD4+ T cell counts, CD4/CD8 ratio, and plasma virus load. Our findings could promote the understanding of neuroAIDS caused by HIV infection, which may provide supplementary evidences for the future therapy study in SIV model.

PMID: 30478797 [PubMed - as supplied by publisher]

Dissociable Disruptions in Thalamic and Hippocampal Resting-State Functional Connectivity in Youth with 22q11.2 Deletions.

Wed, 11/28/2018 - 19:45
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Dissociable Disruptions in Thalamic and Hippocampal Resting-State Functional Connectivity in Youth with 22q11.2 Deletions.

J Neurosci. 2018 Nov 26;:

Authors: Schleifer C, Lin A, Kushan L, Lisa Ji J, Yang G, Bearden CE, Anticevic A

Abstract
22q11.2 deletion syndrome (22q11DS) is a recurrent copy number variant (CNV) with high penetrance for developmental neuropsychiatric disorders. Study of individuals with 22q11DS therefore may offer key insights into neural mechanisms underlying such complex illnesses. Resting-state functional connectivity MRI (rs-fcMRI) studies in idiopathic schizophrenia have consistently revealed disruption of thalamic and hippocampal circuitry. Here, we sought to test whether this circuitry is similarly disrupted in the context of this genetic high-risk condition. To this end, resting-state functional connectivity patterns were assessed in a sample of human youth with 22q11DS (n=42; 59.5% female) and demographically matched healthy controls (n=39; 53.8% female). Neuroimaging data were acquired via single-band protocols, and analyzed in line with methods provided by the Human Connectome Project (HCP). We computed functional relationships between individual-specific anatomically-defined thalamic and hippocampal seeds and all gray matter voxels in the brain. Whole-brain type I error protection was achieved through nonparametric permutation-based methods. 22q11DS patients displayed dissociable disruptions in thalamic and hippocampal functional connectivity relative to control subjects. Thalamo-cortical coupling was increased in somatomotor regions, and reduced across associative networks. The opposite effect was observed for the hippocampus in regards to somatomotor and associative network connectivity. The thalamic and hippocampal dysconnectivity observed in 22q11DS suggest that high genetic risk for psychiatric illness is linked with disruptions in large-scale cortico-subcortical networks underlying higher-order cognitive functions. These effects highlight the translational importance of large-effect CNVs for informing mechanisms underlying neural disruptions observed in idiopathic developmental neuropsychiatric disorders.SIGNIFICANCE STATEMENTInvestigation of neuroimaging biomarkers in highly penetrant genetic syndromes represents a more biologically tractable approach to identify neural circuit disruptions underlying developmental neuropsychiatric conditions. 22q11.2 deletion syndrome confers particularly high risk for psychotic disorders, and is thus an important translational model in which to investigate systems-level mechanisms implicated in idiopathic illness. Here, we show resting-state fMRI evidence of large-scale sensory and executive network disruptions in youth with 22q11DS. In particular, this study provides the first evidence that these networks are disrupted in a dissociable fashion with regard to the functional connectivity of the thalamus and hippocampus, suggesting circuit-level dysfunction.

PMID: 30478034 [PubMed - as supplied by publisher]

Graph theory analysis reveals how sickle cell disease impacts neural networks of patients with more severe disease.

Wed, 11/28/2018 - 19:45
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Graph theory analysis reveals how sickle cell disease impacts neural networks of patients with more severe disease.

Neuroimage Clin. 2018 Nov 14;:

Authors: Case M, Shirinpour S, Vijayakumar V, Zhang H, Datta Y, Nelson S, Pergami P, Darbari DS, Gupta K, He B

Abstract
Sickle cell disease (SCD) is a hereditary blood disorder associated with many life-threatening comorbidities including cerebral stroke and chronic pain. The long-term effects of this disease may therefore affect the global brain network which is not clearly understood. We performed graph theory analysis of functional networks using non-invasive fMRI and high resolution EEG on thirty-one SCD patients and sixteen healthy controls. Resting state data were analyzed to determine differences between controls and patients with less severe and more severe sickle cell related pain. fMRI results showed that patients with higher pain severity had lower clustering coefficients and local efficiency. The neural network of the more severe patient group behaved like a random network when performing a targeted attack network analysis. EEG results showed the beta1 band had similar results to fMRI resting state data. Our data show that SCD affects the brain on a global level and that graph theory analysis can differentiate between patients with different levels of pain severity.

PMID: 30477765 [PubMed - as supplied by publisher]

Abnormal resting state activity of left middle occipital gyrus and its functional connectivity in female patients with major depressive disorder.

Wed, 11/28/2018 - 19:45
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Abnormal resting state activity of left middle occipital gyrus and its functional connectivity in female patients with major depressive disorder.

BMC Psychiatry. 2018 Nov 26;18(1):370

Authors: Teng C, Zhou J, Ma H, Tan Y, Wu X, Guan C, Qiao H, Li J, Zhong Y, Wang C, Zhang N

Abstract
BACKGROUND: Women are more susceptible to major depressive disorder (MDD). A possible explanation is that women have a trait tendency to engage in a ruminative response style. Depending on cognitive model of depression, attention bias, memory bias and self-referential bias were closely related among depressed patients. Previous studies have explored the neural mechanism of the cognitive biases by using amplitude of low frequency fluctuations (ALFF) or functional connectivity (FC), and few combined these two metrics, especially focusing on female patients.
METHODS: We assessed 25 female patients diagnosed with MDD and 13 well matched healthy controls (HCs) using Rs-fMRI. Two metrics ALFF and FC based on abnormal ALFF were explored and made comparisons.
RESULTS: Compared with HCs, female patients with MDD showed that one cluster with significantly decreased ALFF in the left middle occipital gyrus(L-MOG). Furtherly we founded depressed female subjects showed significantly lower FC between the L-MOG seed and left orbitofrontal cortex, and significantly higher FC between the L-MOG seed and left medial prefrontal gyrus and left hippocampus.
CONCLUSIONS: Our results showed L-MOG may act as a connection, which involved in the processing of cognitive biases of MDD by connected with limbic-cortical regions in resting state. These findings may enhance the understanding of the neurobiological mechanism in female patients with MDD.

PMID: 30477561 [PubMed - in process]

Towards a Complete Taxonomy of Resting State Networks Across Wakefulness and Sleep: An Assessment of Spatially Distinct Resting State Networks Using Independent Component Analysis.

Tue, 11/27/2018 - 19:31

Towards a Complete Taxonomy of Resting State Networks Across Wakefulness and Sleep: An Assessment of Spatially Distinct Resting State Networks Using Independent Component Analysis.

Sleep. 2018 Nov 26;:

Authors: Houldin E, Fang Z, Ray LB, Owen AM, Fogel SM

Abstract
Resting state network (RSN) functional connectivity (FC) has been investigated under a wealth of different healthy and compromised conditions. However such investigations are often dependent on the defined spatial boundaries and nodes of so-called canonical RSNs, themselves the product of extensive deliberations over distinctions between functional magnetic resonance imaging (fMRI) noise and neural signal, specifically in the context of the healthy waking state. However, a similar unbiased cataloguing of noise and networks remains to be done in other states, particularly sleep, a healthy alternate mode of the brain that supports distinct operations from wakefulness, such as dreaming and memory consolidation. The purpose of this study was to explicitly test the hypothesis that there are RSNs unique to sleep. Simultaneous electroencephalography (EEG) and fMRI was used to record brain activity of non-sleep-deprived subjects. Independent component analysis (ICA) was performed on both rapid eye movement (REM; N = 7) and non-REM sleep stage fMRI data (non-REM2; N = 28, non-REM3; N = 11), with the resulting components spatially correlated with the canonical RSNs, for the purpose of identifying spatially distinct RSNs. Surprisingly, all low-correlation components were positively identified as noise, and all high-correlation components comprised the canonical set of RSNs typically observed in wake, indicating that sleep is supported by much the same RSN architecture as wakefulness, despite the unique operations performed during sleep. This further indicates that the implicit assumptions of prior studies, i.e., that the canonical RSNs apply to sleep FC analysis, are valid and have not overlooked sleep-specific RSNs.

PMID: 30476346 [PubMed - as supplied by publisher]

Aberrant functional connectivity of neural circuits associated with social and sensorimotor deficits in young children with autism spectrum disorder.

Tue, 11/27/2018 - 19:31

Aberrant functional connectivity of neural circuits associated with social and sensorimotor deficits in young children with autism spectrum disorder.

Autism Res. 2018 Nov 26;:

Authors: Chen H, Wang J, Uddin LQ, Wang X, Guo X, Lu F, Duan X, Wu L, Chen H

Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by atypical functional integration of brain regions. The vast majority of neuroimaging studies of ASD have focused on older children, adolescents, and adults with the disorder. Very little work has explored whole-brain functional connectivity of young children with ASD. Here, we collected resting-state functional magnetic resonance imaging data from 58 young children (mean age 4.98 years; 29 with ASD; 29 matched healthy controls [HC]). All children were under sedation during scanning. A functional "connectedness" method was first used to seek for brain regions showing atypical functional connectivity (FC) in children with ASD. Then, a recurrent-seek strategy was applied to reveal atypical FC circuits in ASD children. FC matrices between regions-of-interest (ROIs) were compared between ASD and HC. Finally, a support vector regression (SVR) method was used to assess the relationship between the FC circuits and ASD symptom severity. Two atypical FC circuits comprising 23 ROIs in ASD were revealed: one predominantly comprised brain regions involved with social cognition showing under-connectivity in ASD; the other predominantly comprised sensory-motor and visual brain regions showing over-connectivity in ASD. The SVR analysis showed that the two FC circuits were separately related to social deficits and restricted behavior scores. These findings indicate disrupted FC of neural circuits involved in the social and sensorimotor processes in young children with ASD. The finding of the atypical FC patterns in young children with ASD underscores the utility of studying younger children with the disorder, and highlights nuanced patterns of brain connectivity underlying behavior closer to disorder onset. Autism Res 2018. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Autism spectrum disorder (ASD) is an early-onset neurodevelopmental disorder. Understanding brain functional alterations at early ages is important for understanding biological mechanisms of ASD. Here, we found two atypical brain functional circuits in young children with ASD that were related to social and sensorimotor function. These results show how atypical patterns of brain functional connectivity in young children with of ASD may underlie core symptoms of the disorder.

PMID: 30475453 [PubMed - as supplied by publisher]

Resting-state brain activity in Chinese boys with low functioning autism spectrum disorder.

Tue, 11/27/2018 - 19:31
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Resting-state brain activity in Chinese boys with low functioning autism spectrum disorder.

Ann Gen Psychiatry. 2018;17:47

Authors: Li G, Rossbach K, Jiang W, Du Y

Abstract
Background: This study aimed to explore the resting-state fMRI changes in Chinese boys with low functioning autism spectrum disorder (LFASD) and the correlation with clinical symptoms.
Methods: The current study acquired resting-state fMRI data from 15 Chinese boys with LFASD and 15 typically developing (TD) boys to examine the local brain activity using the regional homogeneity (ReHo) and amplitude of low-frequency fluctuation (ALFF) indexes; the researchers also examined these measures and their possible relationships with clinical symptoms using the autism behavior checklist.
Results: Results indicated that boys with LFASD exhibited increased ReHo in the right precuneus and inferior parietal gyrus (IPG), increased ALFF in right middle temporal gyrus, angular gyrus and IPG. However, no correlation was found between the ALFF/ReHo score and clinical symptoms in the LFASD group.
Conclusions: Some of the brain regions had ReHo/ALFF values that were higher in the boys with LFASD than the TD group and these differentiated brain areas in boys with LFASD were all on the right cerebrum, which supported 'atypical rightward asymmetry' in boys with LFASD.

PMID: 30473720 [PubMed]

Increased cognitive complexity reveals abnormal brain network activity in individuals with corpus callosum dysgenesis.

Tue, 11/27/2018 - 19:31
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Increased cognitive complexity reveals abnormal brain network activity in individuals with corpus callosum dysgenesis.

Neuroimage Clin. 2018 Nov 14;:

Authors: Hearne LJ, Dean RJ, Robinson GA, Richards LJ, Mattingley JB, Cocchi L

Abstract
Cognitive reasoning is thought to require functional interactions between whole-brain networks. Such networks rely on both cerebral hemispheres, with the corpus callosum providing cross-hemispheric communication. Here we used high-field functional magnetic resonance imaging (7 T fMRI), a well validated cognitive task, and brain network analyses to investigate the functional networks underlying cognitive reasoning in individuals with corpus callosum dysgenesis (CCD), an anatomical abnormality that affects the corpus callosum. Participants with CCD were asked to solve cognitive reasoning problems while their brain activity was measured using fMRI. The complexity of these problems was parametrically varied by changing the complexity of relations that needed to be established between shapes within each problem matrix. Behaviorally, participants showed a typical reduction in task performance as problem complexity increased. Task-evoked neural activity was observed in brain regions known to constitute two key cognitive control systems: the fronto-parietal and cingulo-opercular networks. Under low complexity demands, network topology and the patterns of local neural activity in the CCD group closely resembled those observed in neurotypical controls. By contrast, when asked to solve more complex problems, participants with CCD showed a reduction in neural activity and connectivity within the fronto-parietal network. These complexity-induced, as opposed to resting-state, differences in functional network activity help resolve the apparent paradox between preserved network architecture found at rest in CCD individuals, and the heterogeneous deficits they display in response to cognitive task demands [preprint: https://doi.org/10.1101/312629].

PMID: 30473430 [PubMed - as supplied by publisher]