New resting-state fMRI related studies at PubMed

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Individual differences in resting-state functional connectivity with the executive network: support for a cerebellar role in anxiety vulnerability.

Fri, 09/29/2017 - 13:00
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Individual differences in resting-state functional connectivity with the executive network: support for a cerebellar role in anxiety vulnerability.

Brain Struct Funct. 2016 Jul;221(6):3081-93

Authors: Caulfield MD, Zhu DC, McAuley JD, Servatius RJ

Abstract
This study characterized cerebellar connectivity with executive intrinsic functional connectivity networks. Using seed regions at the right and left dorsolateral prefrontal cortices (dlPFC) and right orbital frontoinsula, we measured resting-state brain connectivity in healthy college-aged participants. Based on the previous research demonstrating a relationship between the cerebellum and self-report measures of behavioral inhibition, we assessed individual differences in connectivity between groups. Overall, intrinsic activity in cerebellar lobule VIII was significantly correlated with the executive network and cerebellar Crus I with the salience network. Between-group comparisons indicated stronger cerebellar connectivity with the executive network in behaviorally inhibited individuals. Intrinsic activity in Crus I, a region previously implicated in non-motor cerebellar functions, significantly correlated with intrinsic activity in the right dlPFC seed region. These findings support a growing number of studies demonstrating cerebellar influence on higher cognitive processes, extending this relationship to individual differences in anxiety vulnerability.

PMID: 26231515 [PubMed - indexed for MEDLINE]

Cholinergic and serotonergic modulations differentially affect large-scale functional networks in the mouse brain.

Fri, 09/29/2017 - 13:00
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Cholinergic and serotonergic modulations differentially affect large-scale functional networks in the mouse brain.

Brain Struct Funct. 2016 Jul;221(6):3067-79

Authors: Shah D, Blockx I, Keliris GA, Kara F, Jonckers E, Verhoye M, Van der Linden A

Abstract
Resting-state functional MRI (rsfMRI) is a widely implemented technique used to investigate large-scale topology in the human brain during health and disease. Studies in mice provide additional advantages, including the possibility to flexibly modulate the brain by pharmacological or genetic manipulations in combination with high-throughput functional connectivity (FC) investigations. Pharmacological modulations that target specific neurotransmitter systems, partly mimicking the effect of pathological events, could allow discriminating the effect of specific systems on functional network disruptions. The current study investigated the effect of cholinergic and serotonergic antagonists on large-scale brain networks in mice. The cholinergic system is involved in cognitive functions and is impaired in, e.g., Alzheimer's disease, while the serotonergic system is involved in emotional and introspective functions and is impaired in, e.g., Alzheimer's disease, depression and autism. Specific interest goes to the default-mode-network (DMN), which is studied extensively in humans and is affected in many neurological disorders. The results show that both cholinergic and serotonergic antagonists impaired the mouse DMN-like network similarly, except that cholinergic modulation additionally affected the retrosplenial cortex. This suggests that both neurotransmitter systems are involved in maintaining integrity of FC within the DMN-like network in mice. Cholinergic and serotonergic modulations also affected other functional networks, however, serotonergic modulation impaired the frontal and thalamus networks more extensively. In conclusion, this study demonstrates the utility of pharmacological rsfMRI in animal models to provide insights into the role of specific neurotransmitter systems on functional networks in neurological disorders.

PMID: 26195064 [PubMed - indexed for MEDLINE]

Cortical thickness is associated with altered autonomic function in cognitively impaired and non-impaired older adults.

Thu, 09/28/2017 - 12:20
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Cortical thickness is associated with altered autonomic function in cognitively impaired and non-impaired older adults.

J Physiol. 2017 Sep 26;:

Authors: Lin F, Ren P, Wang X, Anthony M, Tadin D, Heffner KL

Abstract
BACKGROUND: Parasympathetic nervous system (PNS) is critical for adaptation to environment demands. PNS can reflect an individual's regulatory capacity of frontal brain regions and has been linked to cognitive capacity. Yet, the relationship of PNS function with cognitive decline and abnormal frontal function that characterize preclinical progression toward Alzheimer's disease (AD) is unclear. Here, we aimed to elucidate the relationship between PNS function and AD-associated neurodegeneration by testing two competing hypotheses involving frontal regions' activity (neurodegeneration vs. compensation).
METHODS: In 38 older human adults with amnestic mild cognitive impairment (aMCI) or normative cognition, we measured AD-associated neurodegeneration (AD signature cortical thickness; ADSCT), resting-state fMRI of frontal regions' spontaneous activation, and an electrocardiography measure of PNS (high frequency heart rate variability; HF-HRV). HF-HRV was assessed at rest and during a cognitive task protocol designed to capture HF-HRV reactivity.
RESULTS: Higher HF-HRV at rest was significantly related to both more severe AD-associated neurodegeneration (lower ADSCT scores) and worse cognitive ability. Cognitive impairments were also related to greater suppression of HF-HRV reactivity. High activities of the anterior cingulate cortex significantly mediated relationships between ADSCT and both HF-HRV at rest and HF-HRV reactivity. Notably, these relationships were not affected by the clinical phenotype.
CONCLUSIONS: We show that AD-associated neurodegeneration is associated with altered PNS regulation and that compensatory processes linked to frontal overactivation might be responsible for those alterations. This finding provides the first line of evidence in a new framework for understanding how early-stage AD-associated neurodegeneration affects autonomic regulation. This article is protected by copyright. All rights reserved.

PMID: 28952161 [PubMed - as supplied by publisher]

Exploring the associations between intrinsic brain connectivity and creative ability using functional connectivity strength and connectome analysis.

Thu, 09/28/2017 - 12:20
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Exploring the associations between intrinsic brain connectivity and creative ability using functional connectivity strength and connectome analysis.

Brain Connect. 2017 Sep 26;:

Authors: Gao Z, Zhang D, Liang A, Liang B, Wang Z, Cai Y, Li J, Gao M, Liu X, Chang S, Jiao B, Huang R, Liu M

Abstract
The present study aimed to explore the association between resting-state functional connectivity and creativity ability. Toward this end, the figural Torrance Tests of Creative Thinking (TTCT) scores were collected from 180 participants. Based on the figural TTCT measures, we collected resting-state fMRI data for participants with two different levels of creativity ability (a high creativity group (HG, n = 22) and a low creativity group (LG, n = 20)). For the aspect of group difference, this study combined voxel-wise functional connectivity strength and seed-based functional connectivity to identify brain regions with group-change functional connectivity. Furthermore, the connectome properties of the identified regions and their associations with creativity were investigated using the permutation test, discriminative analysis, and brain-behavior correlation analysis. The results indicated that there were 4 regions with group differences in functional connectivity strength, and these regions were linked to 30 other regions, demonstrating different functional connectivity between the groups. Together, these regions form a creativity-related network, and we observed higher network efficiency in the HG compared with the LG. The regions involved in the creativity network were widely distributed across the modality-specific/supra-modality cerebral cortex, sub-cortex, and cerebellum. Notably, properties of regions in the supra-modality networks (i.e., the default mode network and attention network) carried creativity-level discriminative information and were significantly correlated with the creativity performance. Together, these findings demonstrate a link between intrinsic brain connectivity and creative ability, which should provide new insights into the neural basis of creativity.

PMID: 28950708 [PubMed - as supplied by publisher]

Altered intrinsic functional brain architecture in female patients with bulimia nervosa.

Thu, 09/28/2017 - 12:20
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Altered intrinsic functional brain architecture in female patients with bulimia nervosa.

J Psychiatry Neurosci. 2017 Sep 26;42(6):160183

Authors: Wang L, Kong QM, Li K, Li XN, Zeng YW, Chen C, Qian Y, Feng SJ, Li JT, Su Y, Correll CU, Mitchell PB, Yan CG, Zhang DR, Si TM

Abstract
BACKGROUND: Bulimia nervosa is a severe psychiatric syndrome with uncertain pathogenesis. Neural systems involved in sensorimotor and visual processing, reward and impulsive control may contribute to the binge eating and purging behaviours characterizing bulimia nervosa. However, little is known about the alterations of functional organization of whole brain networks in individuals with this disorder.
METHODS: We used resting-state functional MRI and graph theory to characterize functional brain networks of unmedicated women with bulimia nervosa and healthy women.
RESULTS: We included 44 unmedicated women with bulimia nervosa and 44 healthy women in our analyses. Women with bulimia nervosa showed increased clustering coefficient and path length compared with control women. The nodal strength in patients with the disorder was higher in the sensorimotor and visual regions as well as the precuneus, but lower in several subcortical regions, such as the hippocampus, parahippocampal gyrus and orbitofrontal cortex. Patients also showed hyperconnectivity primarily involving sensorimotor and unimodal visual association regions, but hypoconnectivity involving subcortical (striatum, thalamus), limbic (amygdala, hippocampus) and paralimbic (orbitofrontal cortex, parahippocampal gyrus) regions. The topological aberrations correlated significantly with scores of bulimia and drive for thinness and with body mass index.
LIMITATIONS: We reruited patients with only acute bulimia nervosa, so it is unclear whether the topological abnormalities comprise vulnerability markers for the disorder developing or the changes associated with illness state.
CONCLUSION: Our findings show altered intrinsic functional brain architecture, specifically abnormal global and local efficiency, as well as nodal- and network-level connectivity across sensorimotor, visual, subcortical and limbic systems in women with bulimia nervosa, suggesting that it is a disorder of dysfunctional integration among large-scale distributed brain regions. These abnormalities contribute to more comprehensive understanding of the neural mechanism underlying pathological eating and body perception in women with bulimia nervosa.

PMID: 28949286 [PubMed - as supplied by publisher]

Dimensionality reduction impedes the extraction of dynamic functional connectivity states from fMRI recordings of resting wakefulness.

Thu, 09/28/2017 - 12:20
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Dimensionality reduction impedes the extraction of dynamic functional connectivity states from fMRI recordings of resting wakefulness.

J Neurosci Methods. 2017 Sep 22;:

Authors: Kafashan M, A Palanca BJ, Ching S

Abstract
BACKGROUND: Resting wakefulness is not a unitary state, with evidence accumulating that spontaneous reorganization of brain activity can be assayed through functional magnetic resonance imaging (fMRI). The dynamics of correlated fMRI signals among functionally-related brain regions, termed dynamic functional connectivity (dFC), may represent nonstationarity arising from underlying neural processes. However, given the dimensionality and noise inherent in such recordings, seeming fluctuations in dFC could be due to sampling variability or artifacts.
NEW METHOD: Here, we highlight key methodological considerations when evaluating dFC in resting-state fMRI data.
COMPARISON WITH EXISTING METHOD: In particular, we demonstrate how dimensionality reduction of fMRI data, a common practice often involving principal component analysis, may give rise to spurious dFC phenomenology due to its effect of decorrelating the underlying time-series.
CONCLUSION: We formalize a dFC assessment that avoids dimensionality reduction and use it to show the existence of at least two FC states in the resting-state.

PMID: 28947263 [PubMed - as supplied by publisher]

Functional imaging in Huntington disease.

Thu, 09/28/2017 - 12:20
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Functional imaging in Huntington disease.

Handb Clin Neurol. 2017;144:263-287

Authors: Niethammer M, Eidelberg D

Abstract
Functional imaging has been increasingly used in the study of neurodegenerative diseases as such techniques can elucidate neurochemical and functional changes that cannot be captured with structural imaging. Unlike other neurodegenerative diseases, in Huntington disease (HD) genetic testing allows for diagnostic certainty. Thus, the focus has been on understanding the pathophysiogic processes underlying the development of the disease, as well as the identification of potential biomarkers to monitor disease progression, particularly during the presymptomatic stage. These imaging methods have expanded our understanding of HD beyond dopaminergic deficits and striatal cell loss, and have described alteration in widespread networks relating to motor and cognitive symptoms. In this chapter, we review the current literature on radiotracer and functional magnetic resonance imaging relating to HD.

PMID: 28947122 [PubMed - in process]

A multi-variate blind source separation algorithm.

Thu, 09/28/2017 - 12:20
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A multi-variate blind source separation algorithm.

Comput Methods Programs Biomed. 2017 Nov;151:91-99

Authors: Goldhacker M, Keck P, Igel A, Lang EW, Tomé AM

Abstract
BACKGROUND AND OBJECTIVE: The study follows the proposal of decomposing a given data matrix into a product of independent spatial and temporal component matrices. A multi-variate decomposition approach is presented, based on an approximate diagonalization of a set of matrices computed using a latent space representation.
METHODS: The proposed methodology follows an algebraic approach, which is common to space, temporal or spatiotemporal blind source separation algorithms. More specifically, the algebraic approach relies on singular value decomposition techniques, which avoids computationally costly and numerically instable matrix inversion. The method is equally applicable to correlation matrices determined from second order correlations or by considering fourth order correlations.
RESULTS: The resulting algorithms are applied to fMRI data sets either to extract the underlying fMRI components or to extract connectivity maps from resting state fMRI data collected for a dynamic functional connectivity analysis. Intriguingly, our algorithm shows increased spatial specificity compared to common approaches, while temporal precision stays similar.
CONCLUSION: The study presents a novel spatiotemporal blind source separation algorithm, which is both robust and avoids parameters that are difficult to fine tune. Applied on experimental data sets, the new method yields highly confined and focused areas with least spatial extent in the retinotopy case, and similar results in the dynamic functional connectivity analyses compared to other blind source separation algorithms. Therefore, we conclude that our novel algorithm is highly competitive and yields results, which are superior or at least similar to existing approaches.

PMID: 28947009 [PubMed - in process]

Ventral Striatum Functional Connectivity as a Predictor of Adolescent Depressive Disorder in a Longitudinal Community-Based Sample.

Thu, 09/28/2017 - 12:20
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Ventral Striatum Functional Connectivity as a Predictor of Adolescent Depressive Disorder in a Longitudinal Community-Based Sample.

Am J Psychiatry. 2017 Sep 26;:appiajp201717040430

Authors: Pan PM, Sato JR, Salum GA, Rohde LA, Gadelha A, Zugman A, Mari J, Jackowski A, Picon F, Miguel EC, Pine DS, Leibenluft E, Bressan RA, Stringaris A

Abstract
OBJECTIVE: Previous studies have implicated aberrant reward processing in the pathogenesis of adolescent depression. However, no study has used functional connectivity within a distributed reward network, assessed using resting-state functional MRI (fMRI), to predict the onset of depression in adolescents. This study used reward network-based functional connectivity at baseline to predict depressive disorder at follow-up in a community sample of adolescents.
METHOD: A total of 637 children 6-12 years old underwent resting-state fMRI. Discovery and replication analyses tested intrinsic functional connectivity (iFC) among nodes of a putative reward network. Logistic regression tested whether striatal node strength, a measure of reward-related iFC, predicted onset of a depressive disorder at 3-year follow-up. Further analyses investigated the specificity of this prediction.
RESULTS: Increased left ventral striatum node strength predicted increased risk for future depressive disorder (odds ratio=1.54, 95% CI=1.09-2.18), even after excluding participants who had depressive disorders at baseline (odds ratio=1.52, 95% CI=1.05-2.20). Among 11 reward-network nodes, only the left ventral striatum significantly predicted depression. Striatal node strength did not predict other common adolescent psychopathology, such as anxiety, attention deficit hyperactivity disorder, and substance use.
CONCLUSIONS: Aberrant ventral striatum functional connectivity specifically predicts future risk for depressive disorder. This finding further emphasizes the need to understand how brain reward networks contribute to youth depression.

PMID: 28946760 [PubMed - as supplied by publisher]

Different Functional and Microstructural Changes Depending on Duration of Mild Cognitive Impairment in Parkinson Disease.

Thu, 09/28/2017 - 12:20
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Different Functional and Microstructural Changes Depending on Duration of Mild Cognitive Impairment in Parkinson Disease.

AJNR Am J Neuroradiol. 2016 May;37(5):897-903

Authors: Shin NY, Shin YS, Lee PH, Yoon U, Han S, Kim DJ, Lee SK

Abstract
BACKGROUND AND PURPOSE: The higher cortical burden of Lewy body and Alzheimer disease-type pathology has been reported to be associated with a faster onset of cognitive impairment of Parkinson disease. So far, there has been a few studies only about the changes of gray matter volume depending on duration of cognitive impairment in Parkinson disease. Therefore, our aim was to evaluate the different patterns of structural and functional changes in Parkinson disease with mild cognitive impairment according to the duration of parkinsonism before mild cognitive impairment.
MATERIALS AND METHODS: Fifty-nine patients with Parkinson disease with mild cognitive impairment were classified into 2 groups on the basis of shorter (<1 year, n = 16) and longer (≥1 year, n = 43) durations of parkinsonism before mild cognitive impairment. Fifteen drug-naïve patients with de novo Parkinson disease with intact cognition were included for comparison. Cortical thickness, Tract-Based Spatial Statistics, and seed-based resting-state functional connectivity analyses were performed. Age, sex, years of education, age at onset of parkinsonism, and levodopa-equivalent dose were included as covariates.
RESULTS: The group with shorter duration of parkinsonism before mild cognitive impairment showed decreased fractional anisotropy and increased mean and radial diffusivity values in the frontal areas compared with the group with longer duration of parkinsonism before mild cognitive impairment (corrected P < .05). The group with shorter duration of parkinsonism before mild cognitive impairment showed decreased resting-state functional connectivity in the default mode network area when the left or right posterior cingulate was used as a seed, and in the dorsolateral prefrontal areas when the left or right caudate was used as a seed (corrected P < .05). The group with longer duration of parkinsonism before mild cognitive impairment showed decreased resting-state functional connectivity mainly in the medial prefrontal cortex when the left or right posterior cingulate was used as a seed, and in the parieto-occipital areas when the left or right caudate was used as a seed (corrected P < .05). No differences in cortical thickness were found in all group contrasts.
CONCLUSIONS: Resting-state functional connectivity and WM alterations might be useful imaging biomarkers for identifying changes in patients with Parkinson disease with mild cognitive impairment according to the duration of parkinsonism before mild cognitive impairment. The functional and microstructural substrates may topographically differ depending on the rate of cognitive decline in these patients.

PMID: 26705323 [PubMed - indexed for MEDLINE]

Interactions Between Large-Scale Functional Brain Networks Are Captured by Sparse Coupled HMMs.

Tue, 09/26/2017 - 10:20

Interactions Between Large-Scale Functional Brain Networks Are Captured by Sparse Coupled HMMs.

IEEE Trans Med Imaging. 2017 Sep 21;:

Authors: Bolton TA, Tarun A, Sterpenich V, Schwartz S, Van De Ville D

Abstract
Functional magnetic resonance imaging (fMRI) provides a window on the human brain at work. Spontaneous brain activity measured during resting-state has already provided many insights into brain function. In particular, recent interest in dynamic interactions between brain regions has increased the need for more advanced modeling tools. Here, we deploy a recent fMRI deconvolution technique to express resting-state temporal fluctuations as a combination of large-scale functional network activity profiles. Then, building upon a novel sparse coupled hidden Markov model (SCHMM) framework, we parameterised their temporal evolution as a mix between intrinsic dynamics, and a restricted set of cross-network modulatory couplings extracted in data-driven manner. We demonstrate and validate the method on simulated data, for which we observed that the SCHMM could accurately estimate network dynamics, revealing more precise insights about direct network-to-network modulatory influences than with conventional correlational methods. On experimental resting-state fMRI data, we unraveled a set of reproducible cross-network couplings across two independent datasets. Our framework opens new perspectives for capturing complex temporal dynamics and their changes in health and disease.

PMID: 28945590 [PubMed - as supplied by publisher]

Obesity is associated with altered mid-insula functional connectivity to limbic regions underlying appetitive responses to foods.

Tue, 09/26/2017 - 10:20

Obesity is associated with altered mid-insula functional connectivity to limbic regions underlying appetitive responses to foods.

J Psychopharmacol. 2017 Sep 01;:269881117728429

Authors: Avery JA, Powell JN, Breslin FJ, Lepping RJ, Martin LE, Patrician TM, Donnelly JE, Savage CR, Simmons WK

Abstract
Obesity is fundamentally a disorder of energy balance. In obese individuals, more energy is consumed than is expended, leading to excessive weight gain through the accumulation of adipose tissue. Complications arising from obesity, including cardiovascular disease, elevated peripheral inflammation, and the development of Type II diabetes, make obesity one of the leading preventable causes of morbidity and mortality. Thus, it is of paramount importance to both individual and public health that we understand the neural circuitry underlying the behavioral regulation of energy balance. To this end, we sought to examine obesity-related differences in the resting state functional connectivity of the dorsal mid-insula, a region of gustatory and interoceptive cortex associated with homeostatically sensitive responses to food stimuli. Within the present study, obese and healthy weight individuals completed resting fMRI scans during varying interoceptive states, both while fasting and after a standardized meal. We examined group differences in the pre- versus post-meal functional connectivity of the mid-insula, and how those differences were related to differences in self-reported hunger ratings and ratings of meal pleasantness. Obese and healthy weight individuals exhibited opposing patterns of eating-related functional connectivity between the dorsal mid-insula and multiple brain regions involved in reward, valuation, and satiety, including the medial orbitofrontal cortex, the dorsal striatum, and the ventral striatum. In particular, healthy weight participants exhibited a significant positive relationship between changes in hunger and changes in medial orbitofrontal functional connectivity, while obese participants exhibited a complementary negative relationship between hunger and ventral striatum connectivity to the mid-insula. These obesity-related alterations in dorsal mid-insula functional connectivity patterns may signify a fundamental difference in the experience of food motivation in obese individuals, wherein approach behavior toward food is guided more by reward-seeking than by homeostatically relevant interoceptive information from the body.

PMID: 28944718 [PubMed - as supplied by publisher]

Multimodal Discrimination of Schizophrenia Using Hybrid Weighted Feature Concatenation of Brain Functional Connectivity and Anatomical Features with an Extreme Learning Machine.

Tue, 09/26/2017 - 10:20

Multimodal Discrimination of Schizophrenia Using Hybrid Weighted Feature Concatenation of Brain Functional Connectivity and Anatomical Features with an Extreme Learning Machine.

Front Neuroinform. 2017;11:59

Authors: Qureshi MNI, Oh J, Cho D, Jo HJ, Lee B

Abstract
Multimodal features of structural and functional magnetic resonance imaging (MRI) of the human brain can assist in the diagnosis of schizophrenia. We performed a classification study on age, sex, and handedness-matched subjects. The dataset we used is publicly available from the Center for Biomedical Research Excellence (COBRE) and it consists of two groups: patients with schizophrenia and healthy controls. We performed an independent component analysis and calculated global averaged functional connectivity-based features from the resting-state functional MRI data for all the cortical and subcortical anatomical parcellation. Cortical thickness along with standard deviation, surface area, volume, curvature, white matter volume, and intensity measures from the cortical parcellation, as well as volume and intensity from sub-cortical parcellation and overall volume of cortex features were extracted from the structural MRI data. A novel hybrid weighted feature concatenation method was used to acquire maximal 99.29% (P < 0.0001) accuracy which preserves high discriminatory power through the weight of the individual feature type. The classification was performed by an extreme learning machine, and its efficiency was compared to linear and non-linear (radial basis function) support vector machines, linear discriminant analysis, and random forest bagged tree ensemble algorithms. This article reports the predictive accuracy of both unimodal and multimodal features after 10-by-10-fold nested cross-validation. A permutation test followed the classification experiment to assess the statistical significance of the classification results. It was concluded that, from a clinical perspective, this feature concatenation approach may assist the clinicians in schizophrenia diagnosis.

PMID: 28943848 [PubMed]

Investigating Brain Connectomic Alterations in Autism Using the Reproducibility of Independent Components Derived from Resting State Functional MRI Data.

Tue, 09/26/2017 - 10:20

Investigating Brain Connectomic Alterations in Autism Using the Reproducibility of Independent Components Derived from Resting State Functional MRI Data.

Front Neurosci. 2017;11:459

Authors: Syed MA, Yang Z, Hu XP, Deshpande G

Abstract
Significance: Autism is a developmental disorder that is currently diagnosed using behavioral tests which can be subjective. Consequently, objective non-invasive imaging biomarkers of Autism are being actively researched. The common theme emerging from previous functional magnetic resonance imaging (fMRI) studies is that Autism is characterized by alterations of fMRI-derived functional connections in certain brain networks which may provide a biomarker for objective diagnosis. However, identification of individuals with Autism solely based on these measures has not been reliable, especially when larger sample sizes are taken into consideration. Objective: We surmise that metrics derived from Autism subjects may not be highly reproducible within this group leading to poor generalizability. We hypothesize that functional brain networks that are most reproducible within Autism and healthy Control groups separately, but not when the two groups are merged, may possess the ability to distinguish effectively between the groups. Methods: In this study, we propose a "discover-confirm" scheme based upon the assessment of reproducibility of independent components obtained from resting state fMRI (discover) followed by a clustering analysis of these components to evaluate their ability to discriminate between groups in an unsupervised way (confirm). Results: We obtained cluster purity ranging from 0.695 to 0.971 in a data set of 799 subjects acquired from multiple sites, depending on how reproducible the corresponding components were in each group. Conclusion: The proposed method was able to characterize reproducibility of brain networks in Autism and could potentially be deployed in other mental disorders as well.

PMID: 28943835 [PubMed]

Childhood stress, grown-up brain networks: corticolimbic correlates of threat-related early life stress and adult stress response.

Tue, 09/26/2017 - 10:20

Childhood stress, grown-up brain networks: corticolimbic correlates of threat-related early life stress and adult stress response.

Psychol Med. 2017 Sep 25;:1-13

Authors: Kaiser RH, Clegg R, Goer F, Pechtel P, Beltzer M, Vitaliano G, Olson DP, Teicher MH, Pizzagalli DA

Abstract
BACKGROUND: Exposure to threat-related early life stress (ELS) has been related to vulnerability for stress-related disorders in adulthood, putatively via disrupted corticolimbic circuits involved in stress response and regulation. However, previous research on ELS has not examined both the intrinsic strength and flexibility of corticolimbic circuits, which may be particularly important for adaptive stress responding, or associations between these dimensions of corticolimbic dysfunction and acute stress response in adulthood.
METHODS: Seventy unmedicated women varying in history of threat-related ELS completed a functional magnetic resonance imaging scan to evaluate voxelwise static (overall) and dynamic (variability over a series of sliding windows) resting-state functional connectivity (RSFC) of bilateral amygdala. In a separate session and subset of participants (n = 42), measures of salivary cortisol and affect were collected during a social-evaluative stress challenge.
RESULTS: Higher severity of threat-related ELS was related to more strongly negative static RSFC between amygdala and left dorsolateral prefrontal cortex (DLPFC), and elevated dynamic RSFC between amygdala and rostral anterior cingulate cortex (rACC). Static amygdala-DLPFC antagonism mediated the relationship between higher severity of threat-related ELS and blunted cortisol response to stress, but increased dynamic amygdala-rACC connectivity weakened this mediated effect and was related to more positive post-stress mood.
CONCLUSIONS: Threat-related ELS was associated with RSFC within lateral corticolimbic circuits, which in turn was related to blunted physiological response to acute stress. Notably, increased flexibility between the amygdala and rACC compensated for this static disruption, suggesting that more dynamic medial corticolimbic circuits might be key to restoring healthy stress response.

PMID: 28942738 [PubMed - as supplied by publisher]

Integration and Segregation of Default Mode Network Resting-state Functional Connectivity in Transition-age Males with High-functioning Autism Spectrum Disorder: A Proof of Concept Study.

Tue, 09/26/2017 - 10:20

Integration and Segregation of Default Mode Network Resting-state Functional Connectivity in Transition-age Males with High-functioning Autism Spectrum Disorder: A Proof of Concept Study.

Brain Connect. 2017 Sep 24;:

Authors: Joshi G, Arnold Anteraper S, Patil K, Semwal M, Goldin R, Furtak S, Chai XJ, Saygin Z, Gabrieli JD, Biederman J, Whitfield-Gabrieli S

Abstract
OBJECTIVES: To assess the resting-state functional connectivity (RsFc) profile of the default mode network (DMN) in transition-age males with autism spectrum disorder (ASD).
METHODS: Resting-state blood oxygen level dependent functional MRI (fMRI) data were acquired from adolescent and young adult males with high-functioning ASD (N=15) and from age-, sex-, and IQ-matched healthy controls (HC; N=16). The DMN was examined by assessing the positive and negative RsFc correlations of an average of the literature-based conceptualized major DMN nodes (medial prefrontal cortex [mPFC], posterior cingulate cortex, bilateral angular and inferior temporal gyrii regions). RsFc data analysis was performed using a seed driven approach.
RESULTS: ASD was characterized by an altered pattern of RsFc in the DMN. The ASD group exhibited a weaker pattern of intra- and extra- DMN positive and negative RsFc correlations respectively. In ASD the strength of intra-DMN coupling was significantly reduced with the mPFC and the bilateral angular gyrii regions. In addition, the polarity of the extra-DMN correlation with the right hemispheric task-positive regions of fusiform gyrus and supramarginal gyrus was reversed from typically negative to positive in the ASD group. A wide variability was observed in the presentation of the RsFc profile of the DMN in both HC and ASD groups that revealed a distinct pattern of sub-grouping using pattern recognition analyses.
CONCLUSIONS: These findings imply that the functional architecture profile of the DMN is altered in ASD with weaker than expected integration and segregation of the DMN RsFc. Future studies with larger sample sizes are warranted. Key Words: autism spectrum disorder, resting-state fMRI, default mode network.

PMID: 28942672 [PubMed - as supplied by publisher]

Dimensional depression severity in women with major depression and post-traumatic stress disorder correlates with fronto-amygdalar hypoconnectivty.

Tue, 09/26/2017 - 10:20
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Dimensional depression severity in women with major depression and post-traumatic stress disorder correlates with fronto-amygdalar hypoconnectivty.

Mol Psychiatry. 2016 Jul;21(7):894-902

Authors: Satterthwaite TD, Cook PA, Bruce SE, Conway C, Mikkelsen E, Satchell E, Vandekar SN, Durbin T, Shinohara RT, Sheline YI

Abstract
Depressive symptoms are common in multiple psychiatric disorders and are frequent sequelae of trauma. A dimensional conceptualization of depression suggests that symptoms should be associated with a continuum of deficits in specific neural circuits. However, most prior investigations of abnormalities in functional connectivity have typically focused on a single diagnostic category using hypothesis-driven seed-based analyses. Here, using a sample of 105 adult female participants from three diagnostic groups (healthy controls, n=17; major depression, n=38; and post-traumatic stress disorder, n=50), we examine the dimensional relationship between resting-state functional dysconnectivity and severity of depressive symptoms across diagnostic categories using a data-driven analysis (multivariate distance-based matrix regression). This connectome-wide analysis identified foci of dysconnectivity associated with depression severity in the bilateral amygdala. Follow-up seed analyses using subject-specific amygdala segmentations revealed that depression severity was associated with amygdalo-frontal hypo-connectivity in a network of regions including bilateral dorsolateral prefrontal cortex, anterior cingulate and anterior insula. In contrast, anxiety was associated with elevated connectivity between the amygdala and the ventromedial prefrontal cortex. Taken together, these results emphasize the centrality of the amygdala in the pathophysiology of depressive symptoms, and suggest that dissociable patterns of amygdalo-frontal dysconnectivity are a critical neurobiological feature across clinical diagnostic categories.

PMID: 26416545 [PubMed - indexed for MEDLINE]

Lateralization effects on functional connectivity of the auditory network in patients with unilateral pulsatile tinnitus as detected by functional MRI.

Mon, 09/25/2017 - 15:40

Lateralization effects on functional connectivity of the auditory network in patients with unilateral pulsatile tinnitus as detected by functional MRI.

Prog Neuropsychopharmacol Biol Psychiatry. 2017 Sep 20;:

Authors: Lv H, Zhao P, Liu Z, Liu X, Ding H, Liu L, Wang G, Xie J, Zeng R, Chen Y, Yang Z, Gong S, Wang Z

Abstract
Unilateral pulsatile tinnitus (PT) was proved to be a kind of disease with brain functional abnormalities within and beyond the auditory network (AN). However, changes in patterns of the lateralization effects of PT are yet to be established. Relationship between the AN and other brain networks in PT patients is also a scientific question need to be answered. In this study, we recruited 23 left-sided, 23 right-sided PT (LSPT, RSPT) patients and 23 normal controls (NC). We combined applied independent component analysis and seed-based functional connectivity (FC) analysis to investigate alteration feature of the FC of the AN by using resting-state functional magnetic resonance imaging (rs-fMRI). Compared with NC, LSPT patients demonstrated disconnected FC within the AN on both sides. Disrupted network integrity between AN and several brain functional networks, including executive control network, self-perceptual network and the limbic network, was also demonstrated in LSPT patient group bilaterally. In contrast, compared with NC, RSPT demonstrated decreased FC within the AN on the left side, but significant increased FC within the AN on the right side (symptomatic side). Enhanced FC between AN and executive control network, self-perceptual network and limbic network was also found mainly on the right side in patients with RSPT. Positive FC between the auditory network and the limbic network may be a reason to explain why RSPT patients are willing to be in the clinic. Briefly, LSPT exhibit disrupted network integrity in brain functional networks. But RSPT is featured by enhanced FC within AN and between networks, especially on the right (symptomatic) side. Corroboration of featured FC helps to reveal the pathophysiological changing process of the brain in patients with PT, providing imaging-based biomarker to distinguish PT from other kind of tinnitus.

PMID: 28941768 [PubMed - as supplied by publisher]

Long-term effects of cognitive rehabilitation on brain, functional outcome and cognition in Parkinson's disease.

Sun, 09/24/2017 - 14:20

Long-term effects of cognitive rehabilitation on brain, functional outcome and cognition in Parkinson's disease.

Eur J Neurol. 2017 Sep 23;:

Authors: Díez-Cirarda M, Ojeda N, Peña J, Cabrera-Zubizarreta A, Lucas-Jiménez O, Gómez-Esteban JC, Gómez-Beldarrain MÁ, Ibarretxe-Bilbao N

Abstract
BACKGROUND: Cognitive rehabilitation has demonstrated efficacy in producing short-term cognitive and brain changes in Parkinson's disease (PD) patients. To date, no study has assessed the long-term effects of cognitive rehabilitation using neuroimaging techniques in PD. The aim was to assess the longitudinal effects of a 3-month cognitive rehabilitation program evaluating the cognitive, behavioural and neuroimaging changes after 18 months.
METHODS: Fifteen PD patients underwent a cognitive, behavioural and neuroimaging assessment at pre-treatment (T0 ), post-treatment (T1 ) and after 18-months (T2 ). This study examined the long-term effects (from T0 to T2 ) and the maintenance of the changes (from T1 to T2 ). T1-weighted, diffusion-weighted, functional magnetic resonance imaging (fMRI) during both a resting-state and a memory paradigm were acquired. Voxel-based-morphometry and tract-based-spatial-statistics were used for grey and white matter analyses. A ROI-to-ROI approach was used for resting-state functional connectivity (FC), and model-based for brain activation during the memory paradigm.
RESULTS: PD patients showed increased cognitive performance, decreased functional disability, increased brain FC and activation at T2 compared with T0 (p<.05-FDR). Moreover, patients showed the maintenance of the improvements in cognition and functionality and the maintenance of the increased brain FC and activation at T2 compared with T1 . However, significant grey matter reduction and alterations of white matter integrity were found at T2 (p<.05-FWE).
CONCLUSIONS: Findings suggest that the improved cognitive performance and the increased brain FC and activation after cognitive rehabilitation were significantly maintained after 18 months in PD patients, despite the structural brain changes, consistent with a progression of neurodegenerative processes. This article is protected by copyright. All rights reserved.

PMID: 28940855 [PubMed - as supplied by publisher]

Increased thalamic resting-state connectivity as a core driver of LSD-induced hallucinations.

Sun, 09/24/2017 - 14:20

Increased thalamic resting-state connectivity as a core driver of LSD-induced hallucinations.

Acta Psychiatr Scand. 2017 Sep 21;:

Authors: Müller F, Lenz C, Dolder P, Lang U, Schmidt A, Liechti M, Borgwardt S

Abstract
OBJECTIVE: It has been proposed that the thalamocortical system is an important site of action of hallucinogenic drugs and an essential component of the neural correlates of consciousness. Hallucinogenic drugs such as LSD can be used to induce profoundly altered states of consciousness, and it is thus of interest to test the effects of these drugs on this system.
METHOD: 100 μg LSD was administrated orally to 20 healthy participants prior to fMRI assessment. Whole brain thalamic functional connectivity was measured using ROI-to-ROI and ROI-to-voxel approaches. Correlation analyses were used to explore relationships between thalamic connectivity to regions involved in auditory and visual hallucinations and subjective ratings on auditory and visual drug effects.
RESULTS: LSD caused significant alterations in all dimensions of the 5D-ASC scale and significantly increased thalamic functional connectivity to various cortical regions. Furthermore, LSD-induced functional connectivity measures between the thalamus and the right fusiform gyrus and insula correlated significantly with subjective auditory and visual drug effects.
CONCLUSION: Hallucinogenic drug effects might be provoked by facilitations of cortical excitability via thalamocortical interactions. Our findings have implications for the understanding of the mechanism of action of hallucinogenic drugs and provide further insight into the role of the 5-HT2A -receptor in altered states of consciousness.

PMID: 28940312 [PubMed - as supplied by publisher]

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