New resting-state fMRI related studies at PubMed

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A systematic review on the quantitative relationship between structural and functional network connectivity strength in mammalian brains.

Wed, 10/31/2018 - 13:20
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A systematic review on the quantitative relationship between structural and functional network connectivity strength in mammalian brains.

J Cereb Blood Flow Metab. 2018 Oct 30;:271678X18809547

Authors: Straathof M, Sinke MR, Dijkhuizen RM, Otte WM

Abstract
The mammalian brain is composed of densely connected and interacting regions, which form structural and functional networks. An improved understanding of the structure-function relation is crucial to understand the structural underpinnings of brain function and brain plasticity after injury. It is currently unclear how functional connectivity strength relates to structural connectivity strength. We obtained an overview of recent papers that report on correspondences between quantitative functional and structural connectivity measures in the mammalian brain. We included network studies in which functional connectivity was measured with resting-state fMRI, and structural connectivity with either diffusion-weighted MRI or neuronal tract tracers. Twenty-seven of the 28 included studies showed a positive structure-function relationship. Large inter-study variations were found comparing functional connectivity strength with either quantitative diffusion-based (correlation coefficient (r) ranges: 0.18-0.82) or neuronal tracer-based structural connectivity measures (r = 0.24-0.74). Two functional datasets demonstrated lower structure-function correlations with neuronal tracer-based (r = 0.22 and r = 0.30) than with diffusion-based measures (r = 0.49 and r = 0.65). The robust positive quantitative structure-function relationship supports the hypothesis that structural connectivity provides the hardware from which functional connectivity emerges. However, methodological differences between the included studies complicate the comparison across studies, which emphasize the need for validation and standardization in brain structure-function studies.

PMID: 30375267 [PubMed - as supplied by publisher]

Atypical longitudinal development of functional connectivity in adolescents with autism spectrum disorder.

Wed, 10/31/2018 - 13:20
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Atypical longitudinal development of functional connectivity in adolescents with autism spectrum disorder.

Autism Res. 2018 Oct 30;:

Authors: Lawrence KE, Hernandez LM, Bookheimer SY, Dapretto M

Abstract
Autism spectrum disorder (ASD) is consistently associated with alterations in brain connectivity, but there are conflicting results as to where and when individuals with ASD display increased or reduced functional connectivity. Such inconsistent findings may be driven by atypical neurodevelopmental trajectories in ASD during adolescence, but no longitudinal studies to date have investigated this hypothesis. We thus examined the functional connectivity of three neurocognitive resting-state networks-the default mode network (DMN), salience network, and central executive network (CEN)-in a longitudinal sample of youth with ASD (n = 16) and without ASD (n = 22) studied during early/mid- and late adolescence. Functional connectivity between the CEN and the DMN displayed significantly altered developmental trajectories in ASD: typically developing (TD) controls-but not youth with ASD-exhibited an increase in negative functional connectivity between these two networks with age. This significant interaction was due to the ASD group displaying less negative functional connectivity than the TD group during late adolescence only, with no significant group differences in early/mid-adolescence. These preliminary findings suggest a localized age-dependency of functional connectivity alterations in ASD and underscore the importance of considering age when examining brain connectivity. Autism Research 2018. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Brain connectivity may develop differently during adolescence in youth with autism spectrum disorder (ASD). We looked at changes in brain connectivity over time within individuals and found that, for some brain regions, adolescents with ASD did not show the same changes in brain connectivity that typically developing adolescents did. This suggests it is important to consider age when studying brain connectivity in ASD.

PMID: 30375176 [PubMed - as supplied by publisher]

Subcentimeter epilepsy surgery targets by resting state functional magnetic resonance imaging can improve outcomes in hypothalamic hamartoma.

Wed, 10/31/2018 - 13:20
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Subcentimeter epilepsy surgery targets by resting state functional magnetic resonance imaging can improve outcomes in hypothalamic hamartoma.

Epilepsia. 2018 Oct 30;:

Authors: Boerwinkle VL, Foldes ST, Torrisi SJ, Temkit H, Gaillard WD, Kerrigan JF, Desai VR, Raskin JS, Vedantam A, Jarrar R, Williams K, Lam S, Ranjan M, Broderson JS, Adelson D, Wilfong AA, Curry DJ

Abstract
OBJECTIVE: The purpose of this study is to investigate the outcomes of epilepsy surgery targeting the subcentimeter-sized resting state functional magnetic resonance imaging (rs-fMRI) epileptogenic onset zone (EZ) in hypothalamic hamartoma (HH).
METHODS: Fifty-one children with HH-related intractable epilepsy received anatomical MRI-guided stereotactic laser ablation (SLA) procedures. Fifteen of these children were control subjects (CS) not guided by rs-fMRI. Thirty-six had been preoperatively guided by rs-fMRI (RS) to determine EZs, which were subsequently targeted by SLA. The primary outcome measure for the study was a predetermined goal of 30% reduction in seizure frequency and improvement in class I Engel outcomes 1 year postoperatively. Quantitative and qualitative volumetric analyses of total HH and ablated tissue were also assessed.
RESULTS: In the RS group, the EZ target within the HH was ablated with high accuracy (>87.5% of target ablated in 83% of subjects). There was no difference between the groups in percentage of ablated hamartoma volume (P = 0.137). Overall seizure reduction was higher in the rs-fMRI group: 85% RS versus 49% CS (P = 0.0006, adjusted). The Engel Epilepsy Surgery Outcome Scale demonstrated significant differences in those with freedom from disabling seizures (class I), 92% RS versus 47% CS, a 45% improvement (P = 0.001). Compared to prior studies, there was improvement in class I outcomes (92% vs 76%-81%). No postoperative morbidity or mortality occurred.
SIGNIFICANCE: For the first time, surgical SLA targeting of subcentimeter-sized EZs, located by rs-fMRI, guided surgery for intractable epilepsy. Our outcomes demonstrated the highest seizure freedom rate without surgical complications and are a significant improvement over prior reports. The approach improved freedom from seizures by 45% compared to conventional ablation, regardless of hamartoma size or anatomical classification. This technique showed the same or reduced morbidity (0%) compared to recent non-rs-fMRI-guided SLA studies with as high as 20% permanent significant morbidity.

PMID: 30374947 [PubMed - as supplied by publisher]

Peer influence, Frontostriatal connectivity, and delay discounting in African American emerging adults.

Wed, 10/31/2018 - 13:20
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Peer influence, Frontostriatal connectivity, and delay discounting in African American emerging adults.

Brain Imaging Behav. 2018 Oct 30;:

Authors: Holmes C, Owens M, Beach SRH, McCormick M, Hallowell E, Clark US, Barton AW, Brody GH, MacKillop J, Sweet LH

Abstract
Prior research has demonstrated the importance of delay discounting in adverse health behaviors, such as addiction, attention deficit hyperactivity disorder, risk taking, and obesity. Nevertheless, the functional connectivity of neural circuitry associated with delay discounting and the ways in which the social environment may influence frontostriatal connectivity remain largely unknown, particularly in African Americans. Building on recent literature implicating frontostriatal connectivity during active delay discounting decision making and at rest, we used functional magnetic resonance imaging to assess the association between delay discounting and frontostriatal resting state connectivity (rsFC). We also examined the capacity of social relationships with parents and peers to longitudinally predict frontostriatal rsFC. The study cohort was composed of 91 rural African American emerging adults followed over a 6-year period. Greater (i.e., more positive) frontostriatal rsFC was associated with decreased delay discounting (i.e., less impulsive decision making). In addition, peer relationships at ages 20 and 21 significantly predicted frontostriatal rsFC at age 25 above and beyond parental influence. A significant indirect effect of peer affiliation on delay discounting through frontostriatal rsFC also emerged. These results indicate a role of frontostriatal connectivity in delay discounting decision making and highlight peers' unique influence on decision making behaviors through frontostriatal rsFC during emerging adulthood.

PMID: 30374665 [PubMed - as supplied by publisher]

Dynamic hub load predicts cognitive decline after resective neurosurgery.

Wed, 10/31/2018 - 13:20
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Dynamic hub load predicts cognitive decline after resective neurosurgery.

Sci Rep. 2017 02 07;7:42117

Authors: Carbo EW, Hillebrand A, van Dellen E, Tewarie P, de Witt Hamer PC, Baayen JC, Klein M, Geurts JJ, Reijneveld JC, Stam CJ, Douw L

Abstract
Resective neurosurgery carries the risk of postoperative cognitive deterioration. The concept of 'hub (over)load', caused by (over)use of the most important brain regions, has been theoretically postulated in relation to symptomatology and neurological disease course, but lacks experimental confirmation. We investigated functional hub load and postsurgical cognitive deterioration in patients undergoing lesion resection. Patients (n = 28) underwent resting-state magnetoencephalography and neuropsychological assessments preoperatively and 1-year after lesion resection. We calculated stationary hub load score (SHub) indicating to what extent brain regions linked different subsystems; high SHub indicates larger processing pressure on hub regions. Dynamic hub load score (DHub) assessed its variability over time; low values, particularly in combination with high SHub values, indicate increased load, because of consistently high usage of hub regions. Hypothetically, increased SHub and decreased DHub relate to hub overload and thus poorer/deteriorating cognition. Between time points, deteriorating verbal memory performance correlated with decreasing upper alpha DHub. Moreover, preoperatively low DHub values accurately predicted declining verbal memory performance. In summary, dynamic hub load relates to cognitive functioning in patients undergoing lesion resection: postoperative cognitive decline can be tracked and even predicted using dynamic hub load, suggesting it may be used as a prognostic marker for tailored treatment planning.

PMID: 28169349 [PubMed - indexed for MEDLINE]

DRD2 methylation is associated with executive control network connectivity and severity of alcohol problems among a sample of polysubstance users.

Tue, 10/30/2018 - 12:20
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DRD2 methylation is associated with executive control network connectivity and severity of alcohol problems among a sample of polysubstance users.

Addict Biol. 2018 Oct 29;:

Authors: Hagerty SL, YorkWilliams SL, Bidwell LC, Weiland BJ, Sabbineni A, Blaine SK, Bryan AD, Hutchison KE

Abstract
Chronic exposure to alcohol and other drugs of abuse has been associated with deleterious consequences, including functional connectivity deficits within neural networks associated with executive control. Altered functional connectivity within the executive control network (ECN) might underlie the progressive inability to control consumption of alcohol and other drugs as substance use disorders progress. Genetic and epigenetic factors have been associated with substance use disorders (SUDs). For example, dopamine receptor 2 (DRD2) functioning has been associated with alcohol use disorder (AUD) and related phenotypes, including correlates of executive functioning. The present study aims to explore the relationship between a continuous measure of alcohol-related problems, epigenetic markers (methylation) within the DRD2 gene, and functional connectivity within the ECN among a sample of polysubstance users. A community sample of 658 subjects, whose consumption of alcohol, nicotine, and cannabis span across a spectrum of quantity and frequency of use, were obtained across previous studies in polysubstance using populations. Resting state functional magnetic resonance imaging was analyzed to identify intrinsic connectivity networks using a priori regions of interest. Methylation measurement of functionally relevant sites within the DRD2 gene was achieved via pyrosequencing. Regression-based models, including mediation and moderation models, tested the association between DRD2 methylation, functional connectivity within intrinsic neural networks (including the ECN), and severity of alcohol problems. Results suggest that average DRD2 methylation was negatively associated with right ECN (RECN) and left ECN (LECN) connectivity, but not associated with other networks tested, and DRD2 methylation was significantly associated with alcohol problems severity. Mediation models were not supported, although moderation models suggested that connectivity between edges within the RECN moderated the relationship between DRD2 methylation and AUD severity. Results support a theoretical model in which epigenetic factors are associated with neurobiological correlates of alcohol consumption among a sample of polysubstance users.

PMID: 30370960 [PubMed - as supplied by publisher]

Study of altered functional connectivity in individuals at risk for Alzheimer's Disease.

Tue, 10/30/2018 - 12:20
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Study of altered functional connectivity in individuals at risk for Alzheimer's Disease.

Technol Health Care. 2018;26(S1):103-111

Authors: Zhang Y, Liu X, Zhao K, Li L, Ding Y

Abstract
BACKGROUND: Mild Cognitive Impairment (MCI) has been considered to have a high risk in converting into Alzheimer's Disease (AD). Previous studies showed that AD was associated with changes in resting-state networks (RSNs). However, few studies have evaluated the altered functional connectivity in early mild cognitive impairment (EMCI) and late mild cognitive impairment (LMCI).
OBJECTIVE: The aim of this work was to evaluate the impaired network functional connectivity with the disease progression.
METHODS: In this paper, we evaluated the impaired function connectivity with the progression of disease based on a priori defined 246 regions of interest based on Brainnetome Atlas. Connectivity analysis based on three levels (node integrity, intra-network, and inter-network) was conducted.
RESULTS: Altered function connectivity was detected in several RSNs. These results provided insights into the dysfunction of more RSNs accompany the progression of AD. We also found that one brain region may belong to multiple RSNs and contribute to achieving different network function.
CONCLUSIONS: The aberrant intra- and inter-network dysfunctions might be potential biomarkers or predictors of MCI and AD progression and provide new insight into the pathophysiology of these diseases.

PMID: 29710743 [PubMed - indexed for MEDLINE]

Widespread temporo-occipital lobe dysfunction in amyotrophic lateral sclerosis.

Tue, 10/30/2018 - 12:20
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Widespread temporo-occipital lobe dysfunction in amyotrophic lateral sclerosis.

Sci Rep. 2017 01 09;7:40252

Authors: Loewe K, Machts J, Kaufmann J, Petri S, Heinze HJ, Borgelt C, Harris JA, Vielhaber S, Schoenfeld MA

Abstract
Recent studies suggest that amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) lie on a single clinical continuum. However, previous neuroimaging studies have found only limited involvement of temporal lobe regions in ALS. To better delineate possible temporal lobe involvement in ALS, the present study aimed to examine changes in functional connectivity across the whole brain, particularly with regard to extra-motor regions, in a group of 64 non-demented ALS patients and 38 healthy controls. To assess between-group differences in connectivity, we computed edge-level statistics across subject-specific graphs derived from resting-state functional MRI data. In addition to expected ALS-related decreases in functional connectivity in motor-related areas, we observed extensive changes in connectivity across the temporo-occipital cortex. Although ALS patients with comorbid FTD were deliberately excluded from this study, the pattern of connectivity alterations closely resembles patterns of cerebral degeneration typically seen in FTD. This evidence for subclinical temporal dysfunction supports the idea of a common pathology in ALS and FTD.

PMID: 28067298 [PubMed - indexed for MEDLINE]

Functional connectivity in cognitive control networks mitigates the impact of white matter lesions in the elderly.

Mon, 10/29/2018 - 11:20

Functional connectivity in cognitive control networks mitigates the impact of white matter lesions in the elderly.

Alzheimers Res Ther. 2018 Oct 27;10(1):109

Authors: Benson G, Hildebrandt A, Lange C, Schwarz C, Köbe T, Sommer W, Flöel A, Wirth M

Abstract
BACKGROUND: Cerebrovascular pathology, quantified by white matter lesions (WML), is known to affect cognition in aging, and is associated with an increased risk of dementia. The present study aimed to investigate whether higher functional connectivity in cognitive control networks mitigates the detrimental effect of WML on cognition.
METHODS: Nondemented older participants (≥ 50 years; n = 230) underwent cognitive evaluation, fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI), and resting state functional magnetic resonance imaging (fMRI). Total WML volumes were quantified algorithmically. Functional connectivity was assessed in preselected higher-order resting state networks, namely the fronto-parietal, the salience, and the default mode network, using global and local measures. Latent moderated structural equations modeling examined direct and interactive relationships between WML volumes, functional connectivity, and cognition.
RESULTS: Larger WML volumes were associated with worse cognition, having a greater impact on executive functions (β = -0.37, p < 0.01) than on memory (β = -0.22, p < 0.01). Higher global functional connectivity in the fronto-parietal network and higher local connectivity between the salience network and medial frontal cortex significantly mitigated the impact of WML on executive functions, (unstandardized coefficients: b = 2.39, p = 0.01; b = 3.92, p = 0.01) but not on memory (b = -5.01, p = 0.51, b = 2.01, p = 0.07, respectively). No such effects were detected for the default mode network.
CONCLUSION: Higher functional connectivity in fronto-parietal and salience networks may protect against detrimental effects of WML on executive functions, the cognitive domain that was predominantly affected by cerebrovascular pathology. These results highlight the crucial role of cognitive control networks as a neural substrate of cognitive reserve in older individuals.

PMID: 30368250 [PubMed - in process]

Aberrant brain regional homogeneity in first-episode drug-naïve patients with major depressive disorder: A voxel-wise meta-analysis.

Sun, 10/28/2018 - 10:20

Aberrant brain regional homogeneity in first-episode drug-naïve patients with major depressive disorder: A voxel-wise meta-analysis.

J Affect Disord. 2018 Oct 19;245:63-71

Authors: Hao H, Chen C, Mao W, Zhong J, Dai Z

Abstract
BACKGROUND: Resting-state functional magnetic resonance imaging studies have reported aberrant brain regional homogeneity (ReHo) in patients with major depressive disorder (MDD). However, the findings across studies were confounded by medication status and different depressive episodes.
METHODS: A systematic literature search of the PubMed, Embase, and Web of Science databases was conducted. We conducted a quantitative voxel-wise meta-analysis of ReHo studies, using the Seed-based d Mapping approach, in first-episode drug-naïve patients with MDD.
RESULTS: We identified 10 studies with 12 datasets suitable for inclusion, consisting of 402 first-episode drug-naïve patients with MDD and 330 healthy controls. The most consistent and robust findings were that patients with MDD relative to healthy controls exhibited increased ReHo in the left hippocampus and decreased ReHo in the left orbitofrontal cortex.
LIMITATIONS: The patient samples included in our meta-analysis were all Chinese, thus limiting the applicability of the present findings to other populations.
CONCLUSIONS: ReHo alterations in these brain regions are likely to reflect the core disease-related functional abnormalities, which are implicated in emotional dysregulation and cognitive impairment that are seen in the early stage of MDD. These findings contribute to a better understanding of the neurobiological underpinnings of MDD, and the left hippocampus and orbitofrontal cortex could serve as specific regions of interest for further investigations.

PMID: 30368072 [PubMed - as supplied by publisher]

Alterations in resting-state local functional connectivity in obsessive-compulsive disorder.

Sun, 10/28/2018 - 10:20

Alterations in resting-state local functional connectivity in obsessive-compulsive disorder.

J Affect Disord. 2018 Oct 19;245:113-119

Authors: Hao H, Chen C, Mao W, Xia W, Yi Z, Zhao P, Pan P, Dai Z

Abstract
BACKGROUND: Obsessive-compulsive disorder (OCD) is increasingly conceptualized as a brain connectivity disorder. Recently, abnormalities in remote resting-state functional connectivity (FC) have been well demonstrated in the frontoparietal areas that linked impairments in large-scale intrinsic brain networks with aberrant fronto-striatal interactions. Beyond the remote FC abnormalities in OCD, many studies using regional homogeneity (ReHo) analysis have reported local FC alterations. However, their results were not entirely consistent.
METHODS: We conducted a voxel-wise meta-analysis of ReHo studies to identify consistent local FC abnormalities in patients with OCD. A seed-based d mapping approach was used.
RESULTS: Eight studies that compared 200 patients with OCD and 187 healthy controls were included. Increased ReHo in the lateral orbitofrontal cortices and dorsomedial prefrontal cortices bilaterally, and decreased ReHo in the fusiform gyri bilaterally were the most consistent and reliable findings in patients with OCD relative to healthy controls.
LIMITATIONS: The number of available studies included in the meta-analysis was relatively small. Many potential confounds on changes in ReHo warrant further attention.
CONCLUSIONS: These regions are critically implicated in the pathophysiology of OCD. Our findings in local FC alterations are complementary to the abnormalities in remote FC in OCD, contributing to the modeling of brain functional connectomes in OCD.

PMID: 30368070 [PubMed - as supplied by publisher]

Convergent and divergent altered patterns of default mode network in deficit and non-deficit schizophrenia.

Sun, 10/28/2018 - 10:20

Convergent and divergent altered patterns of default mode network in deficit and non-deficit schizophrenia.

Prog Neuropsychopharmacol Biol Psychiatry. 2018 Oct 24;:

Authors: Zhou C, Yu M, Tang X, Wang X, Zhang X, Zhang X, Chen J

Abstract
OBJECTIVE: Previous studies suggested likely mechanisms underlying the dysfunction of the default mode network (DMN) in schizophrenia. However, altered patterns of the intrinsic activity of the DMN in both deficit schizophrenia (DS) and non-deficit schizophrenia (NDS) patients, as well as the neurocognitive relationships among them, remain unknown. This study explores the resting-state characteristics of the DMN activity in both DS and NDS patients, and further investigates correlations with neurocognitive features.
METHODS: Demographic, resting-state functional MRI, and neurocognitive data were collected in 37 DS and 38 NDS patients, as well as in 38 matched healthy control subjects (HCs). Independent component analysis was conducted to investigate the characteristics of DMN activity and to further distinguish between common and specific altered regions. In addition, partial correlation analysis was conducted to examine associations between the activity of altered regions and neurocognitive assessments.
RESULTS: Overlapping altered brain activity was observed in both DS and NDS patients in the left middle frontal gyrus (MFG), the left angular gyrus (ANG), and the calcarine sulcus (CAL) region. Furthermore, compared to HCs, DS patients showed less activity in the right inferior temporal gyrus, the right para-hippocampal gyrus / hippocampus (PHP / HIP), and the left precuneus (PCUN), while they showed increased activity in the posterior cingulate cortex (PCC). Notably, NDS patients showed less activity in the bilateral middle occipital gyrus. Correlation analysis indicated that, in the DS group, both Trail Making Test (TMT)-B and spatial processing scores were positively associated with the activities of the left PCUN and the right PHP / HIP, while the Stroop color scores were negatively associated with PCC activity. In the NDS group, the TMT-B scores were associated with activities of the left MFG and CAL regions, while the scores of the Wechsler adult intelligence scale (Chinese revision) were negatively associated with CAL region activity.
CONCLUSION: The present study demonstrates convergent and divergent altered patterns of the DMN in both DS and NDS patients. Importantly, the specific altered regions of the DMN in DS patients may be associated with extensive deficient neurocognition, indicating novel insights into the pathogenesis of cognitive impairment in schizophrenia.

PMID: 30367960 [PubMed - as supplied by publisher]

Disentangling phonological and articulatory processing: A neuroanatomical study in aphasia.

Sun, 10/28/2018 - 10:20

Disentangling phonological and articulatory processing: A neuroanatomical study in aphasia.

Neuropsychologia. 2018 Oct 24;:

Authors: Ripamonti E, Frustaci M, Zonca G, Aggujaro S, Molteni F, Luzzatti C

Abstract
Phonological and articulatory programming impairments may co-occur in aphasic patients and previous research does not offer a clear-cut picture of their anatomical counterparts. Hickok and Poeppel (e.g., Hickok, G., Poeppel, D., 2007. The cortical organization of speech processing. Nat. Rev. Neurosci. 8, 393-402) put forward a seminal model of speech processes. The ventral stream (mostly bilateral) would be involved in speech recognition and phonological-lexical processing, whereas the dorsal stream (largely lateralized to the left hemisphere) would map phonological representations onto articulatory motor patterns. In this study we analyzed repetition errors for single words and spontaneous speech ratings on the Italian version of the Aachen Aphasia Test. Through a VLSM procedure we aimed at discriminating the neuroanatomical substrates of the phonological and articulatory impairment (and of their normal functional processing). We also estimated functional connectivity networks related to articulation and phonology using seed-to-voxel connectivity analysis with resting state fMRI data. Results indicate that repetition deficit of single words is associated with lesions in a network of left perisylvian areas including the central operculum, the Heschl's gyrus, the angular gyrus, and the supramarginal gyrus (posterior part). Articulatory impairment is associated with lesions in a number of areas in the left dorsal stream, such as the insula (anterior portion), the pars opercularis of the inferior frontal gyrus, the central operculum and the precentral gyrus. On the contrary, phonological impairment is underpinned by lesions of the Heschl's gyrus, and of the posterior portion of the superior temporal and supramarginal gyri. Anatomo-clinical correlative results partly support Hickok and Poeppel's functional model of phonological and articulatory processing.

PMID: 30367847 [PubMed - as supplied by publisher]

Partially impaired functional connectivity states between right anterior insula and default mode network in autism spectrum disorder.

Sun, 10/28/2018 - 10:20

Partially impaired functional connectivity states between right anterior insula and default mode network in autism spectrum disorder.

Hum Brain Mapp. 2018 Oct 27;:

Authors: Guo X, Duan X, Suckling J, Chen H, Liao W, Cui Q, Chen H

Abstract
Time-invariant resting-state functional connectivity studies have illuminated the crucial role of the right anterior insula (rAI) in prominent social impairments of autism spectrum disorder (ASD). However, a recent dynamic connectivity study demonstrated that rather than being stationary, functional connectivity patterns of the rAI vary significantly across time. The present study aimed to explore the differences in functional connectivity in dynamic states of the rAI between individuals with ASD and typically developing controls (TD). Resting-state functional magnetic resonance imaging data obtained from a publicly available database were analyzed in 209 individuals with ASD and 298 demographically matched controls. A k-means clustering algorithm was utilized to obtain five dynamic states of functional connectivity of the rAI. The temporal properties, frequency properties, and meta-analytic decoding were first identified in TD group to obtain the characteristics of each rAI dynamic state. Multivariate analysis of variance was then performed to compare the functional connectivity patterns of the rAI between ASD and TD groups in obtained states. Significantly impaired connectivity was observed in ASD in the ventral medial prefrontal cortex and posterior cingulate cortex, which are two critical hubs of the default mode network (DMN). States in which ASD showed decreased connectivity between the rAI and these regions were those more relevant to socio-cognitive processing. From a dynamic perspective, these findings demonstrate partially impaired resting-state functional connectivity patterns between the rAI and DMN across states in ASD, and provide novel insights into the neural mechanisms underlying social impairments in individuals with ASD.

PMID: 30367744 [PubMed - as supplied by publisher]

Opposing patterns of neuronal variability in the sensorimotor network mediate cyclothymic and depressive temperaments.

Sun, 10/28/2018 - 10:20

Opposing patterns of neuronal variability in the sensorimotor network mediate cyclothymic and depressive temperaments.

Hum Brain Mapp. 2018 Oct 27;:

Authors: Conio B, Magioncalda P, Martino M, Tumati S, Capobianco L, Escelsior A, Adavastro G, Russo D, Amore M, Inglese M, Northoff G

Abstract
Affective temperaments have been described since the early 20th century and may play a central role in psychiatric illnesses, such as bipolar disorder (BD). However, the neuronal basis of temperament is still unclear. We investigated the relationship of temperament with neuronal variability in the resting state signal-measured by fractional standard deviation (fSD) of Blood-Oxygen-Level Dependent signal-of the different large-scale networks, that is, sensorimotor network (SMN), along with default-mode, salience and central executive networks, in standard frequency band (SFB) and its sub-frequencies slow4 and slow5, in a large sample of healthy subject (HC, n = 109), as well as in the various temperamental subgroups (i.e., cyclothymic, hyperthymic, depressive, and irritable). A replication study on an independent dataset of 121 HC was then performed. SMN fSD positively correlated with cyclothymic z-score and was significantly increased in the cyclothymic temperament compared to the depressive temperament subgroups, in both SFB and slow4. We replicated our findings in the independent dataset. A relationship between cyclothymic temperament and neuronal variability, an index of intrinsic neuronal activity, in the SMN was found. Cyclothymic and depressive temperaments were associated with opposite changes in the SMN variability, resembling changes previously described in manic and depressive phases of BD. These findings shed a novel light on the neural basis of affective temperament and also carry important implications for the understanding of a potential dimensional continuum between affective temperaments and BD, on both psychological and neuronal levels.

PMID: 30367740 [PubMed - as supplied by publisher]

Comparison of EEG microstates with resting state fMRI and FDG-PET measures in the default mode network via simultaneously recorded trimodal (PET/MR/EEG) data.

Sun, 10/28/2018 - 10:20

Comparison of EEG microstates with resting state fMRI and FDG-PET measures in the default mode network via simultaneously recorded trimodal (PET/MR/EEG) data.

Hum Brain Mapp. 2018 Oct 27;:

Authors: Rajkumar R, Farrher E, Mauler J, Sripad P, Régio Brambilla C, Rota Kops E, Scheins J, Dammers J, Lerche C, Langen KJ, Herzog H, Biswal B, Shah NJ, Neuner I

Abstract
Simultaneous trimodal positron emission tomography/magnetic resonance imaging/electroencephalography (PET/MRI/EEG) resting state (rs) brain data were acquired from 10 healthy male volunteers. The rs-functional MRI (fMRI) metrics, such as regional homogeneity (ReHo), degree centrality (DC) and fractional amplitude of low-frequency fluctuations (fALFFs), as well as 2-[18F]fluoro-2-desoxy-d-glucose (FDG)-PET standardised uptake value (SUV), were calculated and the measures were extracted from the default mode network (DMN) regions of the brain. Similarly, four microstates for each subject, showing the diverse functional states of the whole brain via topographical variations due to global field power (GFP), were estimated from artefact-corrected EEG signals. In this exploratory analysis, the GFP of microstates was nonparametrically compared to rs-fMRI metrics and FDG-PET SUV measured in the DMN of the brain. The rs-fMRI metrics (ReHO, fALFF) and FDG-PET SUV did not show any significant correlations with any of the microstates. The DC metric showed a significant positive correlation with microstate C (r s = 0.73, p = .01). FDG-PET SUVs indicate a trend for a negative correlation with microstates A, B and C. The positive correlation of microstate C with DC metrics suggests a functional relationship between cortical hubs in the frontal and occipital lobes. The results of this study suggest further exploration of this method in a larger sample and in patients with neuropsychiatric disorders. The aim of this exploratory pilot study is to lay the foundation for the development of such multimodal measures to be applied as biomarkers for diagnosis, disease staging, treatment response and monitoring of neuropsychiatric disorders.

PMID: 30367727 [PubMed - as supplied by publisher]

Mapping Internet gaming disorder using effective connectivity: A spectral dynamic causal modeling study.

Sat, 10/27/2018 - 15:40

Mapping Internet gaming disorder using effective connectivity: A spectral dynamic causal modeling study.

Addict Behav. 2018 Oct 16;90:62-70

Authors: Wang M, Zheng H, Du X, Dong G

Abstract
OBJECTS: Understanding the neural basis underlying Internet gaming disorder (IGD) is essential for the diagnosis and treatment of this type of behavioural addiction. Aberrant resting-state functional connectivity (rsFC) of the default mode network (DMN) has been reported in individuals with IGD. Since rsFC is not a directional analysis, the effective connectivity within the DMN in IGD remains unclear. Here, we employed spectral dynamic causal modeling (spDCM) to explore this issue.
METHODS: Resting state fMRI data were collected from 64 IGD (age: 22.6 ± 2.2) and 63 well-matched recreational Internet game users (RGU, age: 23.1 ± 2.5). Voxel-based mean time series data extracted from the 4 brain regions within the DMN (medial prefrontal cortex, mPFC; posterior cingulate cortex, PCC; bilateral inferior parietal lobule, left IPL/right IPL) of two groups during the resting state were used for the spDCM analysis.
RESULTS: Compared with RGU, IGD showed reduced effective connectivity from the mPFC to the PCC and from the left IPL to the mPFC, with reduced self-connection in the PCC and the left IPL.
CONCLUSIONS: The spDCM could distinguish the changes in the functional architecture between two groups more precisely than rsFC. Our findings suggest that the decreased excitatory connectivity from the mPFC to the PCC may be a crucial biomarker for IGD. Future brain-based intervention should pay attention to dysregulation in the IPL-mPFC-PCC circuits.

PMID: 30366150 [PubMed - as supplied by publisher]

Habenula-prefrontal resting-state connectivity in reactive aggressive men - A pilot study.

Sat, 10/27/2018 - 15:40

Habenula-prefrontal resting-state connectivity in reactive aggressive men - A pilot study.

Neuropharmacology. 2018 Oct 23;:

Authors: Gan G, Zilverstand A, Parvaz MA, Preston-Campbell RN, d'Oleire Uquillas F, Moeller SJ, Tomasi D, Goldstein RZ, Alia-Klein N

Abstract
Disproportionate anger and reactive aggression in response to provocation are core symptoms of intermittent-explosive disorder (IED). Previous research shows a link between the propensity for aggression in healthy individuals and altered functioning of prefrontal-limbic and default-mode networks (DMN) at rest when no provocation is present. In a pilot study, we used resting-state functional magnetic resonance imaging to investigate the effects of pronounced reactive aggression in men, exemplified by IED, on the functional organization of resting-state brain networks including subcortical nodes such as the habenula previously implicated in aggression in preclinical models. Graph theory was applied to resting-state networks to determine alterations in global efficiency and clustering in high reactive aggressive men compared to low reactive aggressive men (controls). Further, we computed within-group correlations between trait aggression and graph measures, as well as within-group whole-brain seed-to-voxel regression analyses between trait aggression and habenula resting-state functional connectivity (rsFC). Reactive aggressive men compared to controls showed higher global efficiency in the left habenula, the left pulvinar in the thalamus, the left dorso-lateral prefrontal cortex, and the right temporal pole, as well as a trend for decreased clustering in DMN nodes. In the reactive aggressive group, high levels of trait aggression were linked to lower global efficiency of the left habenula, and to lower rsFC between the left habenula and the left ventro-lateral prefrontal cortex, a core region involved in inhibitory control. Together with preclinical evidence, our findings in men underline the relevance of aberrant habenula-prefrontal connectivity for the severity of aggressive behavior.

PMID: 30366001 [PubMed - as supplied by publisher]

Whole-Brain Network Connectivity Underlying the Human Speech Articulation as Emerged Integrating Direct Electric Stimulation, Resting State fMRI and Tractography.

Sat, 10/27/2018 - 15:40

Whole-Brain Network Connectivity Underlying the Human Speech Articulation as Emerged Integrating Direct Electric Stimulation, Resting State fMRI and Tractography.

Front Hum Neurosci. 2018;12:405

Authors: Zacà D, Corsini F, Rozzanigo U, Dallabona M, Avesani P, Annicchiarico L, Zigiotto L, Faraca G, Chioffi F, Jovicich J, Sarubbo S

Abstract
Production of fluent speech in humans is based on a precise and coordinated articulation of sounds. A speech articulation network (SAN) has been observed in multiple brain studies typically using either neuroimaging or direct electrical stimulation (DES), thus giving limited knowledge about the whole brain structural and functional organization of this network. In this study, seven right-handed patients underwent awake surgery resection of low-grade gliomas (4) and cavernous angiomas. We combined pre-surgical resting state fMRI (rs-fMRI) and diffusion MRI together with speech arrest sites obtained intra-operatively with DES to address the following goals: (i) determine the cortical areas contributing to the intrinsic functional SAN using the speech arrest sites as functional seeds for rs-fMRI; (ii) evaluate the relative contribution of gray matter terminations from the two major language dorsal stream bundles, the superior longitudinal fasciculus (SLF III) and the arcuate fasciculus (AF); and (iii) evaluate the possible pre-surgical prediction of SAN with rs-fMRI. In all these right-handed patients the intrinsic functional SAN included frontal, inferior parietal, temporal, and insular regions symmetrically and bilaterally distributed across the two hemispheres regardless of the side (four right) of speech arrest evocation. The SLF III provided a much higher density of terminations in the cortical regions of SAN in respect to AF. Pre-surgical rs-fMRI data demonstrated moderate ability to predict the SAN. The set of functional and structural data provided in this multimodal study characterized, at a whole-brain level, a distributed and bi-hemispherical network subserving speech articulation.

PMID: 30364298 [PubMed]

Structural and Functional Brain Connectivity Changes Between People With Abdominal and Non-abdominal Obesity and Their Association With Behaviors of Eating Disorders.

Sat, 10/27/2018 - 15:40

Structural and Functional Brain Connectivity Changes Between People With Abdominal and Non-abdominal Obesity and Their Association With Behaviors of Eating Disorders.

Front Neurosci. 2018;12:741

Authors: Park BY, Lee MJ, Kim M, Kim SH, Park H

Abstract
Abdominal obesity is important for understanding obesity, which is a worldwide medical problem. We explored structural and functional brain differences in people with abdominal and non-abdominal obesity by using multimodal neuroimaging and up-to-date analysis methods. A total of 274 overweight people, whose body mass index exceeded 25, were enrolled in this study. Participants were divided into abdominal and non-abdominal obesity groups using a waist-hip ratio threshold of 0.9 for males and 0.85 for females. Structural and functional brain differences were assessed with diffusion tensor imaging and resting-state functional magnetic resonance imaging. Centrality measures were computed from structural fiber tractography, and static and dynamic functional connectivity matrices. Significant inter-group differences in structural and functional connectivity were found using degree centrality (DC) values. The associations between the DC values of the identified regions/networks and behaviors of eating disorder scores were explored. The highest association was achieved by combining DC values of the cerebral peduncle, anterior corona radiata, posterior corona radiata (from structural connectivity), frontoparietal network (from static connectivity), and executive control network (from dynamic connectivity) compared to the use of structural or functional connectivity only. Our results demonstrated the effectiveness of multimodal imaging data and found brain regions or networks that may be responsible for behaviors of eating disorders in people with abdominal obesity.

PMID: 30364290 [PubMed]

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