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Abnormal frontoinsular-default network dynamics in adolescent depression and rumination: a preliminary resting-state co-activation pattern analysis.

Wed, 03/18/2020 - 11:40
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Abnormal frontoinsular-default network dynamics in adolescent depression and rumination: a preliminary resting-state co-activation pattern analysis.

Neuropsychopharmacology. 2019 08;44(9):1604-1612

Authors: Kaiser RH, Kang MS, Lew Y, Van Der Feen J, Aguirre B, Clegg R, Goer F, Esposito E, Auerbach RP, Hutchison RM, Pizzagalli DA

Abstract
Clinical depression commonly emerges in adolescence, which is also a time of developing cognitive ability and related large-scale functional brain networks implicated in depression. In depressed adults, abnormalities in the dynamic functioning of frontoinsular networks, in particular, have been observed and linked to negative rumination. Thus, network dynamics may provide new insight into teen pathophysiology. Here, adolescents (n = 45, ages 13-19) with varying severity of depressive symptoms completed a resting-state functional MRI scan. Functional networks were evaluated using co-activation pattern analysis to identify whole-brain states of spatial co-activation that recurred across participants and time. Measures included: dwell time (proportion of scan spent in that network state), persistence (volume-to-volume maintenance of a network state), and transitions (frequency of moving from state A to state B). Analyses tested associations between depression or trait rumination and dynamics of network states involving frontoinsular and default network systems. Results indicated that adolescents showing increased dwell time in, and persistence of, a frontoinsular-default network state involving insula, dorsolateral and medial prefrontal cortex, and posterior regions of default network, reported more severe symptoms of depression. Further, adolescents who transitioned more frequently between the frontoinsular-default state and a prototypical default network state reported higher depression. Increased dominance and transition frequency of frontoinsular-default network states were also associated with higher rumination, and rumination mediated the associations between network dynamics and depression. Findings support a model in which abnormal frontoinsular dynamics confer vulnerability to maladaptive introspection, which in turn contributes to symptoms of adolescent depression.

PMID: 31035283 [PubMed - indexed for MEDLINE]

Hippocampal functional network: The mediating role between obsession and anxiety in adult patients with obsessive-compulsive disorder.

Tue, 03/17/2020 - 10:40
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Hippocampal functional network: The mediating role between obsession and anxiety in adult patients with obsessive-compulsive disorder.

World J Biol Psychiatry. 2020 Mar 16;:1-11

Authors: Li K, Zhang H, Wang B, Yang Y, Zhang M, Li W, Li X, Lv L, Zhao J, Zhang H

Abstract
Objectives: Anxiety is a very common symptom and closely related to obsessive-compulsive symptoms in obsessive-compulsive disorder (OCD). However, the association between anxiety and obsessive-compulsive symptoms at the hippocampus network level remains unclear.Methods: This study enrolled 42 patients with OCD and 42 healthy controls (HCs), who underwent resting-state functional magnetic resonance imaging (fMRI) and clinical evaluation. Multiple linear regression analysis was performed to investigate the behavioural significance and interactive effects of obsessive-compulsive and anxiety symptoms on the hippocampus functional connectivity (HFC). The mediation analysis model was used to explore whether the hippocampus functional connectivity (FC) network indirectly mediated the relationship between obsessive-compulsive symptoms and anxiety.Results: Results showed that the FCs with the cerebellum, middle temporal gyrus (MTG) and anterior cingulate gyrus (ACG) were increased in the hippocampus FC network in patients with OCD compared with those in HCs. The regions of interactive effects between anxiety and obsession, which are mainly located in the prefrontal cortex and MTG, were positively correlated. The mediation effect is 0.018 between obsession and anxiety on the HFC networks in patients with OCD.Conclusions: The FC between the hippocampus and MTG plays a key role in the relationship between anxiety and obsession.

PMID: 32174208 [PubMed - as supplied by publisher]

Bootstrapping promotes the RSFC-behavior associations: An application of individual cognitive traits prediction.

Tue, 03/17/2020 - 10:40
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Bootstrapping promotes the RSFC-behavior associations: An application of individual cognitive traits prediction.

Hum Brain Mapp. 2020 Mar 16;:

Authors: Wei L, Jing B, Li H

Abstract
Resting-state functional connectivity (RSFC) records enormous functional interaction information between any pair of brain nodes, which enriches the individual-phenotypic prediction. To reduce high-dimensional features, correlation analysis is a common way for feature selection. However, resting state fMRI signal exhibits typically low signal-to-noise ratio and the correlation analysis is sensitive to outliers and data distribution, which may bring unstable features to prediction. To alleviate this problem, a bootstrapping-based feature selection framework was proposed and applied to connectome-based predictive modeling, support vector regression, least absolute shrinkage and selection operator, and Ridge regression to predict a series of cognitive traits based on Human Connectome Project data. To systematically investigate the influences of different parameter settings on the bootstrapping-based framework, 216 parameter combinations were evaluated and the best performance among them was identified as the final prediction result for each cognitive trait. By using the bootstrapping methods, the best prediction performances outperformed the baseline method in all four prediction models. Furthermore, the proposed framework could effectively reduce the feature dimension by retaining the more stable features. The results demonstrate that the proposed framework is an easy-to-use and effective method to improve RSFC prediction of cognitive traits and is highly recommended in future RSFC-prediction studies.

PMID: 32173976 [PubMed - as supplied by publisher]

Does higher sampling rate (multiband + SENSE) improve group statistics - An example from social neuroscience block design at 3T.

Tue, 03/17/2020 - 10:40
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Does higher sampling rate (multiband + SENSE) improve group statistics - An example from social neuroscience block design at 3T.

Neuroimage. 2020 Mar 12;:116731

Authors: Bhandari R, Kirilina E, Caan M, Suttrup J, De Sanctis T, De Angelis L, Keysers C, Gazzola V

Abstract
Multiband (MB) or Simultaneous multi-slice (SMS) acquisition schemes allow the acquisition of MRI signals from more than one spatial coordinate at a time. Commercial availability has brought this technique within the reach of many neuroscientists and psychologists. Most early evaluation of the performance of MB acquisition employed resting state fMRI or the most basic tasks. In this study, we tested whether the advantages of using MB acquisition schemes generalize to group analyses using a cognitive task more representative of typical cognitive neuroscience applications. Twenty-three subjects were scanned on a Philips 3 T scanner using five sequences up to eight-fold acceleration with MB-factors 1 to 4, SENSE factors up to 2 and corresponding TRs of 2.45s down to 0.63s, while they viewed (i) movie blocks showing complex actions with hand object interactions and (ii) control movie blocks without hand object interaction. Data were processed using a widely used analysis pipeline implemented in SPM12 including the unified segmentation and canonical HRF modelling. Using random effects group-level, voxel-wise analysis we found that all sequences were able to detect the basic action observation network known to be recruited by our task. The highest t-values were found for sequences with MB4 acceleration. For the MB1 sequence, a 50% bigger voxel volume was needed to reach comparable t-statistics. The group-level t-values for resting state networks (RSNs) were also highest for MB4 sequences. Here the MB1 sequence with larger voxel size did not perform comparable to the MB4 sequence. Altogether, we can thus recommend the use of MB4 (and SENSE 1.5 or 2) on a Philips scanner when aiming to perform group-level analyses using cognitive block design fMRI tasks and voxel sizes in the range of cortical thickness (e.g. 2.7 mm isotropic). While results will not be dramatically changed by the use of multiband, our results suggest that MB will bring a moderate but significant benefit.

PMID: 32173409 [PubMed - as supplied by publisher]

Causes and Consequences of Diagnostic Heterogeneity in Depression: Paths to Discovering Novel Biological Depression Subtypes.

Tue, 03/17/2020 - 10:40
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Causes and Consequences of Diagnostic Heterogeneity in Depression: Paths to Discovering Novel Biological Depression Subtypes.

Biol Psychiatry. 2020 Jan 28;:

Authors: Lynch CJ, Gunning FM, Liston C

Abstract
Depression is a highly heterogeneous syndrome that bears only modest correlations with its biological substrates, motivating a renewed interest in rethinking our approach to diagnosing depression for research purposes and new efforts to discover subtypes of depression anchored in biology. Here, we review the major causes of diagnostic heterogeneity in depression, with consideration of both clinical symptoms and behaviors (symptomatology and trajectory of depressive episodes) and biology (genetics and sexually dimorphic factors). Next, we discuss the promise of using data-driven strategies to discover novel subtypes of depression based on functional neuroimaging measures, including dimensional, categorical, and hybrid approaches to parsing diagnostic heterogeneity and understanding its biological basis. The merits of using resting-state functional magnetic resonance imaging functional connectivity techniques for subtyping are considered along with a set of technical challenges and potential solutions. We conclude by identifying promising future directions for defining neurobiologically informed depression subtypes and leveraging them in the future for predicting treatment outcomes and informing clinical decision making.

PMID: 32171465 [PubMed - as supplied by publisher]

Aging and the wandering brain: Age-related differences in the neural correlates of stimulus-independent thoughts.

Tue, 03/17/2020 - 10:40
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Aging and the wandering brain: Age-related differences in the neural correlates of stimulus-independent thoughts.

PLoS One. 2019;14(10):e0223981

Authors: Maillet D, Beaty RE, Adnan A, Fox KCR, Turner GR, Spreng RN

Abstract
In recent years, several studies have indicated that healthy older adults exhibit a reduction in task-unrelated thoughts compared to young adults. However, much less is known regarding age-related differences in time spent engaging in stimulus-independent thoughts or in their neural correlates in the absence of an ongoing task. In the current study, we collected functional magnetic resonance imaging (fMRI) data while 29 young (mean age = 22y) and 22 older (mean age = 70y) adults underwent experience sampling in the absence of an ongoing task (i.e., at "rest"). Although both age groups reported spending a similar amount of time engaged in stimulus-independent thoughts, older adults rated their thoughts as more present-oriented (rather than atemporal) and more novel. Moreover, controlling for these age-related differences in content, we found that experiencing stimulus-independent thoughts was associated with increased posterior cingulate and left angular gyrus activation across age groups compared to exhibiting an external focus of attention. When experiencing stimulus-independent thoughts, younger adults engaged medial and left lateral prefrontal cortex as well as left superior temporal gyrus to a greater degree than older adults. Taken together, our results suggest that, in the absence of an ongoing task, although young and older adults spend a similar amount of time engaging in stimulus-independent thoughts, the content and neural correlates of these thoughts differ with age.

PMID: 31613920 [PubMed - indexed for MEDLINE]

Separable neural mechanisms for the pleiotropic association of copy number variants with neuropsychiatric traits.

Sun, 03/15/2020 - 14:40
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Separable neural mechanisms for the pleiotropic association of copy number variants with neuropsychiatric traits.

Transl Psychiatry. 2020 Mar 13;10(1):93

Authors: Reinwald JR, Sartorius A, Weber-Fahr W, Sack M, Becker R, Didriksen M, Stensbøl TB, Schwarz AJ, Meyer-Lindenberg A, Gass N

Abstract
22q11.2, 15q13.3, and 1q21.1 microdeletions attract considerable interest by conferring high risk for a range of neuropsychiatric disorders, including schizophrenia and autism. A fundamental open question is whether divergent or convergent neural mechanisms mediate this genetic pleiotropic association with the same behavioral phenotypes. We use a combination of rodent microdeletion models with high-field neuroimaging to perform a comparative whole-brain characterization of functional and structural mechanisms linked to high-risk states. Resting-state functional and structural magnetic resonance imaging data were acquired on mice carrying heterozygous microdeletions in 22q11.2 (N = 12), 15q13.3 (N = 11), and 1q21.1 (N = 11) loci. We performed network-based statistic, graph, and morphometric analyses. The three microdeletions did not share significant systems-level features. Instead, morphometric analyses revealed microcephaly in 1q21.1 and macrocephaly in 15q13.3 deletions, whereas cerebellar volume was specifically reduced in 22q11.2 deletion. In function, 22q11.2 deletion mice showed widespread cortical hypoconnectivity, accompanied by opposing hyperconnectivity in dopaminergic pathways, which was confirmed by graph analysis. 1q21.1 exhibited distinct changes in posterior midbrain morphology and function, especially in periaqueductal gray, whereas 15q13.3 demonstrated alterations in auditory/striatal system. The combination of cortical hypoconnectivity and dopaminergic hyperconnectivity and reduced cerebellum in 22q11.2 deletion mirrors key neurodevelopmental features of schizophrenia, whereas changes in midbrain and auditory/striatal morphology and topology in 1q21.1 and 15q13.3 rather indicate focal processes possibly linked to the emergence of abnormal salience perception and hallucinations. In addition to insights into pathophysiological processes in these microdeletions, our results establish the general point that microdeletions might increase risk for overlapping neuropsychiatric phenotypes through separable neural mechanisms.

PMID: 32170065 [PubMed - as supplied by publisher]

Altered fMRI-derived functional connectivity in patients with high-tension glaucoma.

Sun, 03/15/2020 - 14:40
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Altered fMRI-derived functional connectivity in patients with high-tension glaucoma.

J Neuroradiol. 2020 Mar 10;:

Authors: Wang B, Yan T, Zhou J, Xie Y, Qiu J, Yi W, Weizhao L

Abstract
BACKGROUND: High-tension glaucoma (HTG) is associated with functional changes in the brain, and elevated intraocular pressure (IOP) is one of the major causes.
PURPOSE: To evaluate the effects of high IOP on the brain in patients with HTG by using resting-state functional magnetic resonance imaging (rs-fMRI).
MATERIALS AND METHODS: Thirty-six patients with HTG and 20 age- and gender-matched healthy controls (HCs) were recruited and underwent IOP examination and rs-fMRI scan. Voxel-wise FC values were obtained between the Brodmann Area (BA) 17 (primary visual cortex) and the rest of the brain, two-sample t test was performed between HTG group and HCs. Correlation analysis was performed between FC and clinical information.
RESULTS: Compared with HCs, HTG patients demonstrated decreased FC between BA 17 and the right precuneus gyrus, decreased FC between BA 17 and the right superior frontal gyrus (SFG) (GRF corrected at voxel level p < 0.001 and cluster level p < 0.05, two-tailed). FC between BA 17 and the right SFG showed significantly negative correlation with right eyes' IOP and mean IOP.
CONCLUSION: HTG patients had abnormal FC changes between the visual cortex and multiple functional brain regions related to visual sense, memory consolidation and cognitive processing, which provided image support for the pathophysiology research of HTG, and revealed new targets for the accurate treatment of HTG.

PMID: 32169470 [PubMed - as supplied by publisher]

Genetic influence on ageing-related changes in resting-state brain functional networks in healthy adults: a systematic review.

Sun, 03/15/2020 - 14:40
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Genetic influence on ageing-related changes in resting-state brain functional networks in healthy adults: a systematic review.

Neurosci Biobehav Rev. 2020 Mar 10;:

Authors: Foo H, Mather KA, Jiang J, Thalamuthu A, Wen W, Sachdev PS

Abstract
This systematic review examines the genetic and epigenetic factors associated with resting-state functional connectivity (RSFC) in healthy human adult brains across the lifespan, with a focus on genes associated with Alzheimer's disease (AD). There were 58 studies included. The key findings are: (i) genetic factors have a low to moderate contribution; (ii) the apolipoprotein E ε2/3/4 polymorphism was the most studied genetic variant, with the APOE-ε4 allele most consistently associated with deficits of the default mode network, but there were insufficient studies to determine the relationships with other AD candidate risk genes; (iii) a single genome-wide association study identified several variants related to RSFC; (iv) two epigenetic independent studies showed a positive relationship between blood DNA methylation of the SLC6A4 promoter and RSFC measures. Thus, there is emerging evidence that genetic and epigenetic variation influence the brain's functional organisation and connectivity over the adult lifespan. However, more studies are required to elucidate the roles genetic and epigenetic factors play in RSFC measures across the adult lifespan.

PMID: 32169413 [PubMed - as supplied by publisher]

Relationships between multiple dimensions of executive functioning and resting-state networks in adults.

Sun, 03/15/2020 - 14:40
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Relationships between multiple dimensions of executive functioning and resting-state networks in adults.

Neuropsychologia. 2020 Mar 10;:107418

Authors: Roye S, Castagna PJ, Calamia M, De Vito AN, Lee TH, Greening SG

Abstract
The current study sought to examine the functional connectivity of resting state networks (RSNs) as they relate to the individual domains of executive functioning (EF). Based on the Unity and Diversity model (Miyake et al., 2000), EF performance was captured using a three-factor model proposed by Karr et al. (2018), which includes inhibition, shifting, and fluency. Publicly available data was used from the Nathan Kline Institute -Rockland project was used. Of the 722 participants who completed the Delis-Kaplan Executive Function System (D-KEFS), which was used to measure EF performance, 269 of these individuals completed resting state fMRI scans. First, a confirmatory factory analysis replicated Karr et al. (2018) revealing three components: inhibition, shifting and fluency. Next, RSNs were identified across the sample using an Independent Components Analysis (ICA) and was compared to previously established intrinsic connectivity networks (Laird et al., 2011). Finally, dual regression was used to analyze the relationships between the functional connectivity of RSNs and EF performance, which indicated that RSNs were differentially associated with inhibition and shifting. Better inhibition was related to increased connectivity between the left striatum and the attentional control network. Better shifting performance was related to increased connectivity between the pre- and postcentral gyri and the speech and sensorimotor network. These results highlight individual differences within these RSNs that are unique to the literature, as non-EF confounds are mitigated within the current measurements of EF performance.

PMID: 32169318 [PubMed - as supplied by publisher]

KCNT1-related epilepsy: An international multicenter cohort of 27 pediatric cases.

Sat, 03/14/2020 - 13:40
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KCNT1-related epilepsy: An international multicenter cohort of 27 pediatric cases.

Epilepsia. 2020 Mar 13;:

Authors: Borlot F, Abushama A, Morrison-Levy N, Jain P, Puthenveettil Vinayan K, Abukhalid M, Aldhalaan HM, Almuzaini HS, Gulati S, Hershkovitz T, Konanki R, Lingappa L, Luat AF, Shafi S, Tabarki B, Thomas M, Yoganathan S, Alfadhel M, Arya R, Donner EJ, Ehaideb SN, Gowda VK, Jain V, Madaan P, Myers KA, Otsubo H, Panda P, Sahu JK, Sampaio LPB, Sharma S, Simard-Tremblay E, Zak M, Whitney R

Abstract
OBJECTIVE: Through international collaboration, we evaluated the phenotypic aspects of a multiethnic cohort of KCNT1-related epilepsy and explored genotype-phenotype correlations associated with frequently encountered variants.
METHODS: A cross-sectional analysis of children harboring pathogenic or likely pathogenic KCNT1 variants was completed. Children with one of the two more common recurrent KCNT1 variants were compared with the rest of the cohort for the presence of particular characteristics.
RESULTS: Twenty-seven children (15 males, mean age = 40.8 months) were included. Seizure onset ranged from 1 day to 6 months, and half (48.1%) exhibited developmental plateauing upon onset. Two-thirds had epilepsy of infancy with migrating focal seizures (EIMFS), and focal tonic seizures were common (48.1%). The most frequent recurrent KCNT1 variants were c.2800G>A; p.Ala934Thr (n = 5) and c.862G>A; p.Gly288Ser (n = 4). De novo variants were found in 96% of tested parents (23/24). Sixty percent had abnormal magnetic resonance imaging (MRI) findings. Delayed myelination, thin corpus callosum, and brain atrophy were the most common. One child had gray-white matter interface indistinctness, suggesting a malformation of cortical development. Several antiepileptic drugs (mean = 7.4/patient) were tried, with no consistent response to any one agent. Eleven tried quinidine; 45% had marked (>50% seizure reduction) or some improvement (25%-50% seizure reduction). Seven used cannabidiol; 71% experienced marked or some improvement. Fourteen tried diet therapies; 57% had marked or some improvement. When comparing the recurrent variants to the rest of the cohort with respect to developmental trajectory, presence of EIMFS, >500 seizures/mo, abnormal MRI, and treatment response, there were no statistically significant differences. Four patients died (15%), none of sudden unexpected death in epilepsy.
SIGNIFICANCE: Our cohort reinforces common aspects of this highly pleiotropic entity. EIMFS manifesting with refractory tonic seizures was the most common. Cannabidiol, diet therapy, and quinidine seem to offer the best chances of seizure reduction, although evidence-based practice is still unavailable.

PMID: 32167590 [PubMed - as supplied by publisher]

Frontoparietal and salience network alterations in obsessive–compulsive disorder: insights from independent component and sliding time window analyses

Sat, 03/14/2020 - 13:40
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Frontoparietal and salience network alterations in obsessive–compulsive disorder: insights from independent component and sliding time window analyses

J Psychiatry Neurosci. 2020 Mar 13;45(3):190038

Authors: Gürsel DA, Reinholz L, Bremer B, Schmitz-Koep B, Franzmeier N, Avram M, Koch K

Abstract
Background: Resting-state functional MRI (fMRI) studies commonly report alterations in 3 core networks in obsessive–compulsive disorder (OCD) — the frontoparietal network, the default mode network and the salience network — defined by functionally connected infraslow oscillations in ongoing brain activity. However, most of these studies observed static functional connectivity in the brains of patients with OCD.
Methods: To investigate dynamic functional connectivity alterations and widen the evidence base toward the triple network model in OCD, we performed group-based independent component and sliding time window analyses in 49 patients with OCD and 41 healthy controls.
Results: The traditional independent component analysis showed alterations in the left frontoparietal network as well as between the left and right frontoparietal networks in patients with OCD compared with healthy controls. For dynamic functional connectivity, the sliding time window approach revealed peak dysconnectivity between the left and right frontoparietal networks and between the left frontoparietal network and the salience network.
Limitations: The number of independent components, noise in the resting-state fMRI images, the heterogeneity of the OCD sample, and comorbidities and medication status in the patients could have biased the results.
Conclusion: Disrupted modulation of these intrinsic brain networks may contribute to the pathophysiology of OCD.

PMID: 32167267 [PubMed - as supplied by publisher]

Examining Brain Maturation during Adolescence Using Graph Laplacian Learning Based Fourier Transform.

Sat, 03/14/2020 - 13:40
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Examining Brain Maturation during Adolescence Using Graph Laplacian Learning Based Fourier Transform.

J Neurosci Methods. 2020 Mar 09;:108649

Authors: Wang J, Xiao L, Wilson TW, Stephen JM, Calhoun VD, Wang YP

Abstract
BACKGROUND: Longitudinal neuroimaging studies have demonstrated that adolescence is a crucial developmental period of continued brain growth and change. Motivated by both achievements in graph signal processing and recent evidence that some brain areas act as hubs connecting functionally specialized systems, we propose an approach to detect these regions from a spectral analysis perspective. In particular, as the human brain undergoes substantial development throughout adolescence, we evaluate functional network difference among age groups from functional magnetic resonance imaging (fMRI) measurements. New Methods: We treated these measurements as graph signals defined on the parcellated functional brain regions and proposed a graph Laplacian learning based Fourier Transform (GLFT) to transform the original graph signals into the frequency domain. Eigen-analysis was conducted afterwards to study the behaviors of the corresponding brain regions, which enabled the characterization of brain maturation.
RESULT: We first evaluated our method on the synthetic data and then applied it to resting state and task fMRI data from the Philadelphia Neurodevelopmental Cohort (PNC) dataset, comprised of normally developing adolescents from 8 to 22 years of age. The method provided an accuracy of 94.9% in distinguishing different adolescent stages and we detected 13 hubs from resting state fMRI and 16 hubs from task fMRI related to brain maturation. Comparison with Existing Methods: The proposed GLFT demonstrated its superiority over conventional graph Fourier transform and alternative graph Fourier transform with high predictive power.
CONCLUSION: The method provides a powerful approach for extracting brain connectivity patterns and identifying hub regions.

PMID: 32165231 [PubMed - as supplied by publisher]

Network basis of the dysexecutive and posterior cortical cognitive profiles in Parkinson's disease.

Sat, 03/14/2020 - 13:40
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Network basis of the dysexecutive and posterior cortical cognitive profiles in Parkinson's disease.

Mov Disord. 2019 06;34(6):893-902

Authors: Lang S, Hanganu A, Gan LS, Kibreab M, Auclair-Ouellet N, Alrazi T, Ramezani M, Cheetham J, Hammer T, Kathol I, Sarna J, Monchi O

Abstract
BACKGROUND: The dual syndrome hypothesis of cognitive impairment in PD suggests that two cognitive profiles exist with distinct pathological mechanisms and a differential risk for further cognitive decline. How these profiles relate to network dysfunction has never been explicitly characterized.
OBJECTIVE: First, to assess intranetwork functional connectivity while considering global connectivity, and second, to relate network connectivity with measures of the dysexecutive and posterior cortical profiles.
METHODS: Eighty-two subjects with idiopathic PD and 37 age-matched controls underwent resting-state functional MRI and comprehensive neuropsychological assessment. Intranetwork and global connectivity was compared between groups. Measures of the dysexecutive and posterior cortical profiles were related to network connectivity while considering demographic and disease-related covariates.
RESULTS: PD subjects show decreased connectivity within several cortical networks. However, only the sensorimotor network displayed a loss of connectivity independent of the observed decreased global connectivity. The dysexecutive factor was independently related to increased motor severity, less education, and decreased connectivity in the sensorimotor network. The posterior cortical factor was related to increased age, less education, decreased connectivity in the central executive network, as well as increased connectivity in the temporal network.
CONCLUSIONS: Our results provide evidence supporting a network-specific process of degeneration in the sensorimotor network which contributes to the dysexecutive cognitive profile. In contrast, connectivity of the temporal and central executive network is related to the posterior cortical profile, representing a distinct network signature of this syndrome. © 2019 International Parkinson and Movement Disorder Society.

PMID: 30924964 [PubMed - indexed for MEDLINE]

Amygdala-prefrontal connectivity during appraisal of symptom-related stimuli in obsessive-compulsive disorder.

Sat, 03/14/2020 - 13:40
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Amygdala-prefrontal connectivity during appraisal of symptom-related stimuli in obsessive-compulsive disorder.

Psychol Med. 2019 01;49(2):278-286

Authors: Paul S, Beucke JC, Kaufmann C, Mersov A, Heinzel S, Kathmann N, Simon D

Abstract
BACKGROUND: Cognitive models of obsessive-compulsive disorder (OCD) posit dysfunctional appraisal of disorder-relevant stimuli in patients, suggesting disturbances in the processes relying on amygdala-prefrontal connectivity. Recent neuroanatomical models add to the traditional view of dysfunction in corticostriatal circuits by proposing alterations in an affective circuit including amygdala-prefrontal connections. However, abnormalities in amygdala-prefrontal coupling during symptom provocation, and particularly during conditions that require stimulus appraisal, remain to be demonstrated directly.
METHODS: Amygdala-prefrontal connectivity was examined in unmedicated OCD patients during appraisal (v. distraction) of symptom-provoking stimuli compared with an emotional control condition. Subsequent analyses tested whether hypothesized connectivity alterations could be also identified during passive viewing and the resting state in two independent samples.
RESULTS: During symptom provocation, reductions in positive coupling between amygdala and orbitofrontal cortex were observed in OCD patients relative to healthy control participants during appraisal and passive viewing of OCD-relevant stimuli, whereas abnormally high amygdala-ventromedial prefrontal cortex coupling was found when appraisal was distracted by a secondary task. In contrast, there were no group differences in amygdala connectivity at rest.
CONCLUSIONS: Our finding of abnormal amygdala-prefrontal connectivity during appraisal of symptom-related (relative to generally aversive) stimuli is consistent with the involvement of affective circuits in the functional neuroanatomy of OCD. Aberrant connectivity can be assumed to impact stimulus appraisal and emotion regulation, but might also relate to fear extinction deficits, which have recently been described in OCD. Taken together, we propose to integrate abnormalities in amygdala-prefrontal coupling in affective models of OCD.

PMID: 29622050 [PubMed - indexed for MEDLINE]

Reduced dynamic functional connectivity between salience and executive brain networks in insomnia disorder.

Fri, 03/13/2020 - 19:00
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Reduced dynamic functional connectivity between salience and executive brain networks in insomnia disorder.

J Sleep Res. 2020 Apr;29(2):e12953

Authors: Wei Y, Leerssen J, Wassing R, Stoffers D, Perrier J, Van Someren EJW

Abstract
Research into insomnia disorder has pointed to large-scale brain network dysfunctions. Dynamic functional connectivity is instrumental to cognitive functions but has not been investigated in insomnia disorder. This study assessed between-network functional connectivity strength and variability in patients with insomnia disorder as compared with matched controls without sleep complaints. Twelve-minute resting-state functional magnetic resonance images and T1-weighed images were acquired in 65 people diagnosed with insomnia disorder (21-69 years, 48 female) and 65 matched controls without sleep complaints (22-70 years, 42 female). Pairwise correlations between the activity time series of 14 resting-state networks and temporal variability of the correlations were compared between cases and controls. After false discovery rate correction for multiple comparisons, people with insomnia disorder and controls did not differ significantly in terms of mean between-network functional connectivity strength; people with insomnia disorder did, however, show less functional connectivity variability between the anterior salience network and the left executive-control network. The finding suggests less flexible interactions between the networks during the resting state in people with insomnia disorder.

PMID: 32164035 [PubMed - as supplied by publisher]

A Neural Signature of Parkinsonism in Patients With Schizophrenia Spectrum Disorders: A Multimodal MRI Study Using Parallel ICA.

Fri, 03/13/2020 - 19:00
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A Neural Signature of Parkinsonism in Patients With Schizophrenia Spectrum Disorders: A Multimodal MRI Study Using Parallel ICA.

Schizophr Bull. 2020 Mar 12;:

Authors: Wolf RC, Rashidi M, Fritze S, Kubera KM, Northoff G, Sambataro F, Calhoun VD, Geiger LS, Tost H, Hirjak D

Abstract
Motor abnormalities in schizophrenia spectrum disorders (SSD) have increasingly attracted scientific interest in the past years. However, the neural mechanisms underlying parkinsonism in SSD are unclear. The present multimodal magnetic resonance imaging (MRI) study examined SSD patients with and without parkinsonism, as defined by a Simpson and Angus Scale (SAS) total score of ≥4 (SAS group, n = 22) or <4 (non-SAS group, n = 22). Parallel independent component analysis (p-ICA) was used to examine the covarying components among gray matter volume maps computed from structural MRI (sMRI) and fractional amplitude of low-frequency fluctuations (fALFF) maps computed from resting-state functional MRI (rs-fMRI) patient data. We found a significant correlation (P = .020, false discovery rate [FDR] corrected) between an sMRI component and an rs-fMRI component, which also significantly differed between the SAS and non-SAS group (P = .042, z = -2.04). The rs-fMRI component comprised the cortical sensorimotor network, and the sMRI component included predominantly a frontothalamic/cerebellar network. Across the patient sample, correlations adjusted for the Positive and Negative Syndrome Scale (PANSS) total scores showed a significant relationship between tremor score and loadings of the cortical sensorimotor network, as well as between glabella-salivation score, frontothalamic/cerebellar and cortical sensorimotor network loadings. These data provide novel insights into neural mechanisms of parkinsonism in SSD. Aberrant bottom-up modulation of cortical motor regions may account for these specific motor symptoms, at least in patients with SSD.

PMID: 32162660 [PubMed - as supplied by publisher]

Fatigue in multiple sclerosis: Does the functional or structural damage prevail?

Fri, 03/13/2020 - 19:00
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Fatigue in multiple sclerosis: Does the functional or structural damage prevail?

Mult Scler. 2020 Mar 12;:1352458520912175

Authors: Bertoli M, Tecchio F

Abstract
Fatigue in multiple sclerosis (MS) is a highly invalidating symptom, lacking efficacious drugs. This topical review aims at assessing the signs in the literature of functional versus structural damage prevalence at the origin of MS fatigue by focusing on papers that assessed the two counterparts in the same patients, paying attention that the fatigue levels do not correlate with clinical severity. We summarize and discuss evidence of increased levels of fatigue occurring together with the alterations of functional connectivity at multiple levels, in the absence of any relationship with lesion load and local atrophy of the involved structures. Specifically, neuronal communication mainly altered in the corticomuscular synchronizations, between hemispheric homologs and in the resting-state networks involved in emotion (cingulate cortex) and effort-reward balance (striatum and inferior parietal lobule). Finally, given the functional prevalence in neuronal network alterations at the origin of fatigue in MS, we highlight the relevance of developing treatments aiming at compensating the neuronal electric communication dysfunctions.

PMID: 32162579 [PubMed - as supplied by publisher]

A Matched Filter Decomposition of fMRI into Resting and Task Components.

Fri, 03/13/2020 - 19:00
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A Matched Filter Decomposition of fMRI into Resting and Task Components.

Med Image Comput Comput Assist Interv. 2019 Oct;11766:673-681

Authors: Joshi AA, Akrami H, Li J, Leahy RM

Abstract
The human brain exhibits dynamic interactions among brain regions when responding to stimuli and executing tasks, which can be recorded using functional magnetic resonance imaging (fMRI). Functional MRI signals collected in response to specific tasks consist of a combination of task-related and spontaneous (task-independent) activity. By exploiting the highly structured spatiotemporal patterns of resting state networks, this paper presents a matched-filter approach to decomposing fMRI signals into task and resting-state components. To perform the decomposition, we first use a temporal alignment procedure that is a windowed version of the brainsync transform to synchronize a resting template to the brain's response to tasks. The resulting 'matched filter' removes the components of the fMRI signal that can be described by resting connectivity, leaving the portion of brain activity directly related to tasks. We present a closed-form expression for the windowed synchronization transform that is used by the matched filter. We demonstrate performance of this procedure in application to motor task and language task fMRI data. We show qualitatively and quantitatively that by removing the resting activity, we are able to identify task activated regions in the brain more clearly. Additionally, we show improved prediction accuracy in multivariate pattern analysis when using the matched filtered fMRI data.

PMID: 32161932 [PubMed]

Oxytocin induces long-lasting adaptations within amygdala circuitry in autism: a treatment-mechanism study with randomized placebo-controlled design.

Fri, 03/13/2020 - 19:00
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Oxytocin induces long-lasting adaptations within amygdala circuitry in autism: a treatment-mechanism study with randomized placebo-controlled design.

Neuropsychopharmacology. 2020 Mar 11;:

Authors: Alaerts K, Bernaerts S, Prinsen J, Dillen C, Steyaert J, Wenderoth N

Abstract
Intranasal administration of the neuropeptide oxytocin (IN-OT) is increasingly explored as a potential treatment for targeting the core symptoms of autism spectrum disorder (ASD). To date, however, the impact of multiple-dose IN-OT treatment on human neural circuitry is largely unknown, and also the possibility that long-term IN-OT use may induce long-lasting neural adaptations remains unexplored. Using a double-blind, randomized, placebo-controlled, between-subject design (including 38 adult men with ASD), this treatment-mechanism study showed that 4 weeks of daily oxytocin administration (24 IU/day) significantly altered intrinsic (resting-state fMRI) functional connectivity of the amygdala to core regions of the "social brain" (particularly orbitofrontal cortex and superior temporal sulcus) up to 4 weeks and 1 year post treatment. The neural adaptations in functional coupling of the amygdala to the orbitofrontal cortex were associated with reduced feelings of avoidance toward others and-at the trend level-reduced repetitive behaviors. These observations contribute to a deeper mechanistic understanding of the neural substrates that underlie behavioral effects of multiple-dose IN-OT treatment, and provide initial insights into the long-lasting neural consequences of chronic IN-OT use on amygdala circuitry. Future studies are however warranted to further elucidate the long-term impact of IN-OT treatment on human neural circuitry and its behavioral consequences.

PMID: 32161366 [PubMed - as supplied by publisher]

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