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Abnormal functional connectivity strength in first-episode, drug-naïve adult patients with major depressive disorder.

Tue, 09/10/2019 - 19:50
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Abnormal functional connectivity strength in first-episode, drug-naïve adult patients with major depressive disorder.

Prog Neuropsychopharmacol Biol Psychiatry. 2019 Sep 06;:109759

Authors: Shi Y, Li J, Feng Z, Xie H, Duan J, Chen F, Yang H

Abstract
BACKGROUND: The pathogenesis of major depressive disorder (MDD) is complicated and equivocal. Previous studies have found an incidence of abnormal changes of neural networks, with plentiful evidence pointing the finger of suspicion firmly at the default mode network (DMN) and cortico-limbic networks. The aim of the present study was to use the approach of functional connectivity strength (FCS) to directly investigate the features of spontaneous brain activity in the case of first-episode, drug-naïve adult patients with MDD at rest.
METHODS: Resting-state functional magnetic resonance imaging (MRI) scans were performed on 23 first-episode drug-naïve major depressive disorder (MDD) patients and 20 healthy controls (HCs). In this study, using graph-theory approaches(FCS), we computed the characteristics of brain connectivity. Simultaneously, we used a series of validated test procedures to evaluate the patients' cognitive function. Subsequently, the results were compared with the peak of FCS value and a correlation analysis was conducted.
RESULTS: Compared with the HCs group, MDD patients showed significantly decreased FCS in bilateral posterior cingulate cortex (PCC)/precuneus and bilateral prefrontal cortex(PFC) and increased FCS in right posterior central gyrus, left thalamus and left temporal lobe. These brain regions belongs to the default-mode network and cortico-limbic networks. Finally, the correlation analyses showed the negative correlation of the FCS values in the left posterior cingulate cortex (PCC)/precuneus and Hamilton Anxiety Rating Scale (HAMA, r = -0.472, p = .023), Stroop Color Word Test-A(SCWT-A, r = -0.451, p = .031), Stroop Color Word Test-B(SCWT-B, r = -0.588, p = .003).Meanwhile, there was negative correlation between the FCS values in the left thalamus and SCWT-A(r = -0.473, p = .023), SCWT-B(r = -0.465, p = .025), SCWTC(r = -0.524, p = .010).In addition, the FCS values in the right PCC has negative correlation with Montgomery Asberg Depression Rating Scale (MADRS) (r = -0.433, p = .039).
CONCLUSIONS: DMN is an important node of MDD. FCS within the default mode network and cortico-limbic networks in patients with major depressive disorder has been changed in the early stage of MDD. FCS can provide favourable and additional evidence in the investigation of brain pathophysiology and therapy in depression.

PMID: 31499128 [PubMed - as supplied by publisher]

Graph-theoretical analysis for energy landscape reveals the organization of state transitions in the resting-state human cerebral cortex.

Tue, 09/10/2019 - 19:50
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Graph-theoretical analysis for energy landscape reveals the organization of state transitions in the resting-state human cerebral cortex.

PLoS One. 2019;14(9):e0222161

Authors: Kang J, Pae C, Park HJ

Abstract
The resting-state brain is often considered a nonlinear dynamic system transitioning among multiple coexisting stable states. Despite the increasing number of studies on the multistability of the brain system, the processes of state transitions have rarely been systematically explored. Thus, we investigated the state transition processes of the human cerebral cortex system at rest by introducing a graph-theoretical analysis of the state transition network. The energy landscape analysis of brain state occurrences, estimated using the pairwise maximum entropy model for resting-state fMRI data, identified multiple local minima, some of which mediate multi-step transitions toward the global minimum. The state transition among local minima is clustered into two groups according to state transition rates and most inter-group state transitions were mediated by a hub transition state. The distance to the hub transition state determined the path length of the inter-group transition. The cortical system appeared to have redundancy in inter-group transitions when the hub transition state was removed. Such a hub-like organization of transition processes disappeared when the connectivity of the cortical system was altered from the resting-state configuration. In the state transition, the default mode network acts as a transition hub, while coactivation of the prefrontal cortex and default mode network is captured as the global minimum. In summary, the resting-state cerebral cortex has a well-organized architecture of state transitions among stable states, when evaluated by a graph-theoretical analysis of the nonlinear state transition network of the brain.

PMID: 31498822 [PubMed - in process]

Baseline Functional Connectivity Predicts Connectivity Changes Due to a Small Dose of Midazolam in Older Adults.

Tue, 09/10/2019 - 19:50
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Baseline Functional Connectivity Predicts Connectivity Changes Due to a Small Dose of Midazolam in Older Adults.

Anesth Analg. 2019 Sep 06;:

Authors: Frölich MA, White DM, Kraguljac NV, Lahti AC

Abstract
BACKGROUND: In the perioperative context, benzodiazepines are widely used as anxiolytics. They affect cognition in general, but it is unclear whether the effects of a small dose of the short-acting benzodiazepine midazolam can be assessed objectively. To address this scientific question, we conducted a prospective observational study in adults 55-73 years of age. Using both validated psychometric and functional imaging techniques, we determined whether a 2-mg intravenous (IV) dose of midazolam affects cognitive function.
METHODS: We measured the effect of 2 mg IV of midazolam with both the well-established Repeatable Battery for the Assessment of Neuropsychological Status test and resting-state functional magnetic imaging (rs-fMRI) in older adults.
RESULTS: Midazolam reduces immediate and delayed memory and has a profound and robust effect on rs-fMRI. Baseline resting-state connectivity predicts memory decline after midazolam administration.
CONCLUSIONS: Observed effects of midazolam on brain networks were statistically significant even in a small group of volunteers. If validated by other investigators, resting-state brain connectivity may have utility as a measure to predict sensitivity to midazolam in older adults.

PMID: 31498189 [PubMed - as supplied by publisher]

Locally Linear Embedding and fMRI Feature Selection in Psychiatric Classification.

Tue, 09/10/2019 - 19:50
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Locally Linear Embedding and fMRI Feature Selection in Psychiatric Classification.

IEEE J Transl Eng Health Med. 2019;7:2200211

Authors: Sidhu G

Abstract
BACKGROUND: Functional magnetic resonance imaging (fMRI) provides non-invasive measures of neuronal activity using an endogenous Blood Oxygenation-Level Dependent (BOLD) contrast. This article introduces a nonlinear dimensionality reduction (Locally Linear Embedding) to extract informative measures of the underlying neuronal activity from BOLD time-series. The method is validated using the Leave-One-Out-Cross-Validation (LOOCV) accuracy of classifying psychiatric diagnoses using resting-state and task-related fMRI.
METHODS: Locally Linear Embedding of BOLD time-series (into each voxel's respective tensor) was used to optimise feature selection. This uses Gauß' Principle of Least Constraint to conserve quantities over both space and time. This conservation was assessed using LOOCV to greedily select time points in an incremental fashion on training data that was categorised in terms of psychiatric diagnoses.
FINDINGS: The embedded fMRI gave highly diagnostic performances (> 80%) on eleven publicly-available datasets containing healthy controls and patients with either Schizophrenia, Attention-Deficit Hyperactivity Disorder (ADHD), or Autism Spectrum Disorder (ASD). Furthermore, unlike the original fMRI data before or after using Principal Component Analysis (PCA) for artefact reduction, the embedded fMRI furnished significantly better than chance classification (defined as the majority class proportion) on ten of eleven datasets.
INTERPRETATION: Locally Linear Embedding appears to be a useful feature extraction procedure that retains important information about patterns of brain activity distinguishing among psychiatric cohorts.

PMID: 31497410 [PubMed]

The dorsolateral prefrontal cortex is selectively involved in chemotherapy-related cognitive impairment in breast cancer patients with different hormone receptor expression.

Tue, 09/10/2019 - 19:50
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The dorsolateral prefrontal cortex is selectively involved in chemotherapy-related cognitive impairment in breast cancer patients with different hormone receptor expression.

Am J Cancer Res. 2019;9(8):1776-1785

Authors: Chen H, Ding K, Zhao J, Chao HH, Li CR, Cheng H

Abstract
To investigate chemotherapy-related cognitive impairment (CRCI) in breast cancer patients with different hormone receptor (HR) expression and its neural mechanisms, forty BC patient were enrolled in this study and were divided into two groups. HR+ group was composed of twenty-one patients with Estrogen Receptor (ER)+/Progesterone Receptor (PR) +, HR- group included nineteen patients with ER-/PR-. A battery of neuropsychological tests and resting-state functional magnetic resonance imaging (rs-fMRI) examinations were administered to all subjects. The functional connectivity of the dorsolateral prefrontal cortex (DLPFC) of the patients was calculated from the resting-state fMRI data, and the correlation between the DLPFC's connectivity and the neuropsychological test was analyzed. The functional connectivity (FC) of the left dorsolateral prefrontal cortex (DLPFC) with the left precuneus (PCU), the right DLPFC with the right precuneus and the right superior frontal gyrus (SFG) of the HR- group were significantly increased compared to the HR+ group. Meanwhile, a significant positive correlation was found between the post-chemotherapy prospective memory (PM) score and the functional connectivity of the left DLPFC with the left precuneus in the HR- group. These findings suggest that different hormone receptor expression in patients with breast cancer may be associated with CRCI and provide evidence that the DLPFC functional connectivity (FC) strength may be selectively involved in CRCI in HR- group breast cancer patients, especially in regard to the subjective prospective memory.

PMID: 31497358 [PubMed]

Central Nervous System Mechanisms of Nausea in Gastroparesis: An fMRI-Based Case-Control Study.

Mon, 09/09/2019 - 19:49
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Central Nervous System Mechanisms of Nausea in Gastroparesis: An fMRI-Based Case-Control Study.

Dig Dis Sci. 2019 Sep 07;:

Authors: Snodgrass P, Sandoval H, Calhoun VD, Ramos-Duran L, Song G, Sun Y, Alvarado B, Bashashati M, Sarosiek I, McCallum RW

Abstract
BACKGROUND/AIMS: Nausea is a major complaint of gastroparesis (GP), and the pathophysiology of this condition is poorly understood. Therefore, this study utilized fMRI to investigate the possible central nervous system (CNS) mechanisms of nausea in 10 GP patients versus 8 healthy controls (HCs).
METHODS: Nausea severity was assessed on a 0-10 scale and presented as mean ± SD. Nausea was increased from baseline utilizing up to 30 min of visual stimulation (VS). Functional network connectivity was measured with fMRI at baseline and after 30 min of VS. fMRI data were preprocessed using statistical parametric mapping software. Thirty-four independent components were identified as meaningful resting-state networks (RSNs) by group independent component analysis. The Functional Network Connectivity (FNC) among 5 RSNs considered important in CNS nausea mechanisms was calculated as the Pearson's pairwise correlation.
RESULTS: Baseline nausea score in GP patients was 2.7 ± 2.0 and increased to 7.0 ± 1.5 after stimulation (P < 0.01). In HCs nausea scores did not increase from baseline after stimulus (0.3 ± 0.5). When comparing GP patients to HCs after VS, a significant reduction (P < 0.001) in bilateral insula network connectivity compared to the right insula network was detected. No significant differences in connectivity were noted among the other RSNs. Additionally, the average gray matter volume was non-significantly reduced in the insula in GP patients compared to HC.
CONCLUSIONS: The insula connectivity network is impaired in nauseated GP patients. This phenomenon could explain the susceptibility of GP patients to nausea or may have resulted from a state of chronic nausea.

PMID: 31494751 [PubMed - as supplied by publisher]

Large-scale plurimodal networks common to listening to, producing and reading word lists: an fMRI study combining task-induced activation and intrinsic connectivity in 144 right-handers.

Mon, 09/09/2019 - 19:49
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Large-scale plurimodal networks common to listening to, producing and reading word lists: an fMRI study combining task-induced activation and intrinsic connectivity in 144 right-handers.

Brain Struct Funct. 2019 Sep 07;:

Authors: Hesling I, Labache L, Joliot M, Tzourio-Mazoyer N

Abstract
We aimed at identifying plurimodal large-scale networks for producing, listening to and reading word lists based on the combined analyses of task-induced activation and resting-state intrinsic connectivity in 144 healthy right-handers. In the first step, we identified the regions in each hemisphere showing joint activation and joint asymmetry during the three tasks. In the left hemisphere, 14 homotopic regions of interest (hROIs) located in the left Rolandic sulcus, precentral gyrus, cingulate gyrus, cuneus and inferior supramarginal gyrus (SMG) met this criterion, and 7 hROIs located in the right hemisphere were located in the preSMA, medial superior frontal gyrus, precuneus and superior temporal sulcus (STS). In a second step, we calculated the BOLD temporal correlations across these 21 hROIs at rest and conducted a hierarchical clustering analysis to unravel their network organization. Two networks were identified, including the WORD-LIST_CORE network that aggregated 14 motor, premotor and phonemic areas in the left hemisphere plus the right STS that corresponded to the posterior human voice area (pHVA). The present results revealed that word-list processing is based on left articulatory and storage areas supporting the action-perception cycle common not only to production and listening but also to reading. The inclusion of the right pHVA acting as a prosodic integrative area highlights the importance of prosody in the three modalities and reveals an intertwining across hemispheres between prosodic (pHVA) and phonemic (left SMG) processing. These results are consistent with the motor theory of speech postulating that articulatory gestures are the central motor units on which word perception, production, and reading develop and act together.

PMID: 31494717 [PubMed - as supplied by publisher]

Cerebello-striatal interaction mediates effects of subthalamic nucleus deep brain stimulation in Parkinson's disease.

Mon, 09/09/2019 - 19:49
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Cerebello-striatal interaction mediates effects of subthalamic nucleus deep brain stimulation in Parkinson's disease.

Parkinsonism Relat Disord. 2019 Sep 03;:

Authors: Hanssen H, Steinhardt J, Münchau A, Al-Zubaidi A, Tzvi E, Heldmann M, Schramm P, Neumann A, Rasche D, Saryyeva A, Voges J, Galazky I, Büntjen L, Heinze HJ, Krauss JK, Tronnier V, Münte TF, Brüggemann N

Abstract
BACKGROUND: In Parkinson's disease (PD), dopamine replacement therapy (DRT) enhances the effective connectivity of the prefrontal cortex (PFC) and supplementary motor area (SMA). The clinical effects of deep brain stimulation (DBS) of the subthalamic nucleus (STN) go beyond DRT effects including highly beneficial tremor suppression.
OBJECTIVES: Here, we aimed to determine DBS-related changes of a motor network using resting state fMRI in PD patients with chronic STN DBS.
METHODS: In a repeated-measurement design, 26 medicated PD patients (60.9 years (SD 8.9)) were investigated using resting state fMRI while bipolar STN stimulation was (i) active or (ii) switched off, and dynamic causal modelling was subsequently performed.
RESULTS: DBS improved the MDS-UPDRS-III score by 26.4% (DBS ON/Med ON vs. DBS OFF/Med ON). Active stimulation resulted in an increased effective connectivity from cerebellum to putamen (p = 0.00118). In addition, there was a stronger coupling from PFC to cerebellum (p = 0.021), as well as from cerebellum to SMA (p = 0.043) on an uncorrected level. Coupling strength from PFC to cerebellum correlated with the DBS-related change of the resting tremor subscore (r = 0.54, p = 0.031). Self-connections increased as a function of DBS in the right PFC, PMC, SMA, M1, thalamus and left cerebellum.
CONCLUSIONS: DBS-related improvement of Parkinsonian signs appears to be driven by an interaction between the cerebellum and the putamen. Resting tremor suppression may be related to an enhanced prefronto-cerebellar network. Activation of the mesial premotor loop (PFC-SMA) as seen in DRT may thus be secondary due to the primary modulation of cerebellar networks.

PMID: 31494048 [PubMed - as supplied by publisher]

Abnormal topology of brain functional networks in unipolar depression and bipolar disorder using optimal graph thresholding.

Sun, 09/08/2019 - 22:47
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Abnormal topology of brain functional networks in unipolar depression and bipolar disorder using optimal graph thresholding.

Prog Neuropsychopharmacol Biol Psychiatry. 2019 Sep 04;:109758

Authors: Yu Z, Qin J, Xiong X, Xu F, Wang J, Hou F, Yang A

Abstract
Two popular debilitating illness, unipolar depression (UD) and bipolar disorder (BD), have the similar symptoms and tight association on the psychopathological level, leading to a clinical challenge to distinguish them. In order to figure out the underlying common and different mechanism of both mood disorders, resting-state functional magnetic resonance imaging (rs-fMRI) data derived from 36 UD patients, 42 BD patients (specially type I, BD-I) and 45 healthy controls (HC) were analyzed retrospectively in this study. Functional brain networks were firstly constructed on both group and individual levels with a density 0.2, which was determined by a network thresholding approach based on modular similarity. Then we investigated the alterations of modular structure and other topological properties of the functional brain network, including global network characteristics and nodal network measures. The results demonstrated that the functional brain networks of UD and BD-I groups preserved the modularity and small-worldness property. However, compared with HC, reduced number of modules was observed in both patients' groups with shared alterations occurring in hippocampus, para hippocampal gyrus, amygdala and superior parietal gyrus and distinct changes of modular composition mainly in the caudate regions of basal ganglia. Additionally, for the network characteristics, compared to HC, significantly decreased global efficiency and small-worldness were observed in BD-I. For the nodal metrics, significant decrease of local efficiency was found in several regions in both UD and BD-I, while a UD-specified increase of participant coefficient was found in the right paracentral lobule and the right thalamus. These findings may contribute to throw light on the neuropathological mechanisms underlying the two disorders and further help to explore objective biomarkers for the correct diagnosis of UD and BD.

PMID: 31493423 [PubMed - as supplied by publisher]

A study of neural activity and functional connectivity within the olfactory brain network in Parkinson's disease.

Sun, 09/08/2019 - 22:47
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A study of neural activity and functional connectivity within the olfactory brain network in Parkinson's disease.

Neuroimage Clin. 2019;23:101946

Authors: Georgiopoulos C, Witt ST, Haller S, Dizdar N, Zachrisson H, Engström M, Larsson EM

Abstract
Olfactory dysfunction is an early manifestation of Parkinson's disease (PD). The present study aimed to illustrate potential differences between PD patients and healthy controls in terms of neural activity and functional connectivity within the olfactory brain network. Twenty PD patients and twenty healthy controls were examined with olfactory fMRI and resting-state fMRI. Data analysis of olfactory fMRI included data-driven tensorial independent component (ICA) and task-driven general linear model (GLM) analyses. Data analysis of resting-state fMRI included probabilistic ICA based on temporal concatenation and functional connectivity analysis within the olfactory network. ICA of olfactory fMRI identified an olfactory network consisting of the posterior piriform cortex, insula, right orbitofrontal cortex and thalamus. Recruitment of this network was less significant for PD patients. GLM analysis revealed significantly lower activity in the insula bilaterally and the right orbitofrontal cortex in PD compared to healthy controls but no significant differences in the olfactory cortex itself. Analysis of resting-state fMRI did not reveal any differences in the functional connectivity within the olfactory, default mode, salience or central executive networks between the two groups. In conclusion, olfactory dysfunction in PD is associated with less significant recruitment of the olfactory brain network. ICA could demonstrate differences in both the olfactory cortex and its main projections, compared to GLM that revealed differences only on the latter. Resting-state fMRI did not reveal any significant differences in functional connectivity within the olfactory, default mode, salience and central executive networks in this cohort.

PMID: 31491835 [PubMed - in process]

Somatic symptoms disorders in Parkinson's disease are related to default mode and salience network dysfunction.

Sun, 09/08/2019 - 22:47
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Somatic symptoms disorders in Parkinson's disease are related to default mode and salience network dysfunction.

Neuroimage Clin. 2019;23:101932

Authors: Franciotti R, Delli Pizzi S, Russo M, Carrarini C, Carrozzino D, Perfetti B, Onofrj M, Bonanni L

Abstract
BACKGROUND: Somatic Symptoms Disorder (SSD) has been shown to have a clinically very high prevalence in Parkinson's Disease (PD) with frequencies ranging from 7.0% to 66.7%, higher than in the general population (10%- 25%). SSD has been associated with dysfunction in Default Mode and Salience network.
AIM: With the present study we aim to verify by means of resting state functional MRI whether possible specific abnormalities in the activation and functional connectivity of the default mode network (DMN) and salience network in cognitively intact PD patients may be more prominent in PD patients with somatic symptoms (SSD-PD) as compared with patients without SSD (PD).
METHODS: Eighteen SSD-PD patients (61% male), 18 PD patients (83% male) and 22 healthy age-matched subjects (59% male) were enrolled in the study and underwent resting state functional MRI.
RESULTS: fractional amplitude of low-frequency fluctuation (fALFF) showed reduced activity in bilateral lateral parietal cortex and in left anterior insula in both SSD-PD and PD compared to control group. Functional connectivity (FC) values in the DMN areas and between DMN and salience network areas were found to be lower in SSD-PD than in control group and PD. No significant correlation was found between fMRI results and demographic and clinical variables, excluding the effect of possible confounders on fMRI results. The present study, showing reduced activity in bilateral parietal areas and in the left anterior insula as compared to healthy controls, suggests a dysfunction of the DMN and salience network in PD, either with or without SSD. The FC reduction within DMN areas and between DMN and salience network areas in SSD-PD patients suggests a role of dysfunctional connectivity in the resting state network of patients with SSD.

PMID: 31491814 [PubMed - in process]

Intraoperative resting state functional connectivity and resting state networks in patients with intracerebral lesions: detectability and variations between sessions.

Sat, 09/07/2019 - 22:45
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Intraoperative resting state functional connectivity and resting state networks in patients with intracerebral lesions: detectability and variations between sessions.

World Neurosurg. 2019 Sep 03;:

Authors: Metwali H, Raemaekers M, Kniese K, Samii A

Abstract
OBJECTIVE: Evaluation of the functional connectivity (FC) and resting state networks (RSN) in patients under anesthesia operated for resection of intracerebral lesions.
METHODS: we performed intraoperative resting state fMRI (irs-fMRI) in 24 patients under anesthesia before and after lesion resection. Correlation matrices were established for each session (total 48 sessions). The change in the overall FC, and FC of the healthy and operated hemispheres between the first and second session was analyzed. We tested the correlation between changes in the FC and the clinical outcome, the duration, rate and total dosage of anesthesia. Furthermore, we performed a group analysis to detect topographic changes in RSNs in patients under anesthesia. A single subject analysis was performed to detect clinically relevant RSNs in each patient.
RESULTS: The FC decreased significantly in the second session. The interhemispheric connectivity decreased significantly in the second session. The decrease in the pathological hemisphere was significant, and was significantly more than the decrease in the intrahemispheric connectivity of the healthy hemisphere. The change of the FC was not correlated to the clinical outcome, duration, rate and dosage of anesthesia. Group analysis showed topographic changes in RSN, especially the high level networks like default mode and salience networks. Identification of clinically relevant networks was also possible.
CONCLUSION: FC and resting state networks could be identified under anesthesia and used for extended brain mapping. Further studies are required for optimization of the depth of hypnosis to stabilize the FC between sessions.

PMID: 31491572 [PubMed - as supplied by publisher]

Current Understanding of Religion, Spirituality, and Their Neurobiological Correlates.

Sat, 09/07/2019 - 22:45
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Current Understanding of Religion, Spirituality, and Their Neurobiological Correlates.

Harv Rev Psychiatry. 2019 Sep/Oct;27(5):303-316

Authors: Rim JI, Ojeda JC, Svob C, Kayser J, Drews E, Kim Y, Tenke CE, Skipper J, Weissman MM

Abstract
Religion and spirituality (R/S) have been prominent aspects of most human cultures through the ages; however, scientific inquiry into this phenomenon has been limited. We conducted a systematic literature review of research on the neurobiological correlates of R/S, which resulted in 25 reports studying primarily R/S with electroencephalography, structural neuroimaging (MRI), and functional neuroimaging (fMRI, PET). These studies investigated a wide range of religions (e.g., Christianity, Buddhism, Islam) and R/S states and behaviors (e.g., resting state, prayer, judgments) and employed a wide range of methodologies, some of which (e.g., no control group, varying measures of religiosity, small sample sizes) raise concerns about the validity of the results. Despite these limitations, the findings of these studies collectively suggest that the experience of R/S has specific neurobiological correlates and that these correlates are distinct from non-R/S counterparts. The findings implicate several brain regions potentially associated with R/S development and behavior, including the medial frontal cortex, orbitofrontal cortex, precuneus, posterior cingulate cortex, default mode network, and caudate. This research may suggest future clinical applications and interventions related to R/S and various disorders, including mood, anxiety, psychotic, pain, and vertiginous disorders. Further studies with more rigorous study designs are warranted to elucidate the neurobiological mechanisms of R/S and their potential clinical applications.

PMID: 31490186 [PubMed - in process]

Functional and structural connectivity of the executive control network in college binge drinkers.

Sat, 09/07/2019 - 01:42
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Functional and structural connectivity of the executive control network in college binge drinkers.

Addict Behav. 2019 Jun 03;99:106009

Authors: Sousa SS, Sampaio A, Marques P, López-Caneda E, Gonçalves ÓF, Crego A

Abstract
Binge Drinking (BD) is a pattern of excessive alcohol consumption highly prevalent among college students, and has been associated with structural and functional alterations of brain networks. Recent advances in the resting-state connectivity analysis have boosted the research of the network-level connectivity disturbances associated with many psychiatric and neurological disorders, including addiction. Accordingly, atypical functional connectivity patterns in resting-state networks such as the Executive Control Network (ECN) have been found in substance users and alcohol-dependent individuals. In this study, we assessed for the first time the ECN functional and structural connectivity in a group of 34 college students, 20 (10 women) binge drinkers (BDs) in comparison with a group of 14 (8 women) alcohol abstinent controls (AACs). Overall, our findings documented increased resting-state functional connectivity (rsFC) in the BDs left middle frontal cortex of the left ECN in comparison to the AACs, while no structural connectivity differences were observed between groups. Pearson correlations revealed a positive association between the left middle frontal gyrus rsFC and the frequency of BD episodes per month, in the BD group. These findings suggest that maintaining a pattern of acute and intermittent alcohol consumption during important stages of brain development, as the transition from adolescence to adulthood, is associated with impaired ECN rsFC despite no group differences being yet noticed in the ECN structural connectivity.

PMID: 31487578 [PubMed - as supplied by publisher]

Identification of physiological response functions to correct for fluctuations in resting-state fMRI related to heart rate and respiration.

Sat, 09/07/2019 - 01:42
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Identification of physiological response functions to correct for fluctuations in resting-state fMRI related to heart rate and respiration.

Neuroimage. 2019 Sep 02;:116150

Authors: Kassinopoulos M, Mitsis GD

Abstract
Functional magnetic resonance imaging (fMRI) is widely viewed as the gold standard for studying brain function due to its high spatial resolution and non-invasive nature. However, it is well established that changes in breathing patterns and heart rate strongly influence the blood oxygen-level dependent (BOLD) fMRI signal and this, in turn, can have considerable effects on fMRI studies, particularly resting-state studies. The dynamic effects of physiological processes are often quantified by using convolution models along with simultaneously recorded physiological data. In this context, physiological response function (PRF) curves (cardiac and respiratory response functions), which are convolved with the corresponding physiological fluctuations, are commonly employed. While it has often been suggested that the PRF curves may be region- or subject-specific, it is still an open question whether this is the case. In the present study, we propose a novel framework for the robust estimation of PRF curves and use this framework to rigorously examine the implications of using population-, subject-, session- and scan-specific PRF curves. The proposed framework was tested on resting-state fMRI and physiological data from the Human Connectome Project. Our results suggest that PRF curves vary significantly across subjects and, to a lesser extent, across sessions from the same subject. These differences can be partly attributed to physiological variables such as the mean and variance of the heart rate during the scan. The proposed methodological framework can be used to obtain robust scan-specific PRF curves from data records with duration longer than 5 min, exhibiting significantly improved performance compared to previously defined canonical cardiac and respiration response functions. Besides removing physiological confounds from the BOLD signal, accurate modeling of subject- (or session-/scan-) specific PRF curves is of importance in studies that involve populations with altered vascular responses, such as aging subjects.

PMID: 31487547 [PubMed - as supplied by publisher]

Neonatal functional brain maturation in the context of perioperative critical care and pain management: A case report.

Sat, 09/07/2019 - 01:42
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Neonatal functional brain maturation in the context of perioperative critical care and pain management: A case report.

Heliyon. 2019 Aug;5(8):e02350

Authors: Hodkinson DJ, Mongerson CRL, Jennings RW, Bajic D

Abstract
Introduction: Remarkable plasticity during the first year of life imparts heighted vulnerability of the developing infant brain. Application of resting-state functional magnetic resonance imaging (rs-fMRI) in infants may contribute to our understanding of neuroplastic changes associated with therapeutic interventions and/or brain insults. In addition to showing clinically relevant incidental brain MRI findings, the objective of our pilot study was to test feasibility of rs-fMRI methods at this early age in the context of pediatric perioperative critical care.
Methods: We report the case of a former 33-week premature infant born with long-gap esophageal atresia that underwent complex perioperative critical care (Foker process) requiring prolonged post-operative sedation and whom presented with incidental subdural hematoma. Rs-fMRI data was acquired before (at 1-month corrected age) and after (at 2.25-months corrected age) complex perioperative care. We evaluated resting-state functional connectivity (RSFC) using graph theory to explore the complex structure of brain networks.
Results: A transient increase in head circumference coincided temporally with lifting of sedation and initiation of sedation drugs weaning, and qualified for hydrocephalus (93%) but not macrocephaly (>95%). RSFC analysis identified networks spatially consistent with those previously described in the literature, with notable pre-post-treatment qualitative differences in correlated and anticorrelated spontaneous brain activity.
Discussion: Current definitions of macrocephaly may require lower threshold criteria for monitoring of critically ill infants. Although we demonstrate that available rs-fMRI could be effectively applied in a critically ill infant in the setting of brain pathology, future group-level studies should investigate RSFC to evaluate maintenance of network homeostasis during development of both healthy and critically ill infants.

PMID: 31485532 [PubMed]

Color Categorization Independent of Color Naming.

Thu, 09/05/2019 - 22:39
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Color Categorization Independent of Color Naming.

Cell Rep. 2019 Sep 03;28(10):2471-2479.e5

Authors: Siuda-Krzywicka K, Witzel C, Chabani E, Taga M, Coste C, Cools N, Ferrieux S, Cohen L, Seidel Malkinson T, Bartolomeo P

Abstract
Color is continuous, yet we group colors into discrete categories associated with color names (e.g., yellow, blue). Color categorization is a case in point in the debate on how language shapes human cognition. Evidence suggests that color categorization depends on top-down input from the language system to the visual cortex. We directly tested this hypothesis by assessing color categorization in a stroke patient, RDS, with a rare, selective deficit in naming visually presented chromatic colors, and relatively preserved achromatic color naming. Multimodal MRI revealed a left occipito-temporal lesion that directly damaged left color-biased regions, and functionally disconnected their right-hemisphere homologs from the language system. The lesion had a greater effect on RDS's chromatic color naming than on color categorization, which was relatively preserved on a nonverbal task. Color categorization and naming can thus be independent in the human brain, challenging the mandatory involvement of language in adult human cognition.

PMID: 31484060 [PubMed - in process]

Test-retest reproducibility of a multi-atlas automated segmentation tool on multimodality brain MRI.

Thu, 09/05/2019 - 22:39
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Test-retest reproducibility of a multi-atlas automated segmentation tool on multimodality brain MRI.

Brain Behav. 2019 Sep 04;:e01363

Authors: Rezende TJR, Campos BM, Hsu J, Li Y, Ceritoglu C, Kutten K, França Junior MC, Mori S, Miller MI, Faria AV

Abstract
INTRODUCTION: The increasing use of large sample sizes for population and personalized medicine requires high-throughput tools for imaging processing that can handle large amounts of data with diverse image modalities, perform a biologically meaningful information reduction, and result in comprehensive quantification. Exploring the reproducibility of these tools reveals the specific strengths and weaknesses that heavily influence the interpretation of results, contributing to transparence in science.
METHODS: We tested-retested the reproducibility of MRICloud, a free automated method for whole-brain, multimodal MRI segmentation and quantification, on two public, independent datasets of healthy adults.
RESULTS: The reproducibility was extremely high for T1-volumetric analysis, high for diffusion tensor images (DTI) (however, regionally variable), and low for resting-state fMRI.
CONCLUSION: In general, the reproducibility of the different modalities was slightly superior to that of widely used software. This analysis serves as a normative reference for planning samples and for the interpretation of structure-based MRI studies.

PMID: 31483562 [PubMed - as supplied by publisher]

Sex Moderates Amyloid and Apolipoprotein ε4 Effects on Default Mode Network Connectivity at Rest.

Thu, 09/05/2019 - 22:39
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Sex Moderates Amyloid and Apolipoprotein ε4 Effects on Default Mode Network Connectivity at Rest.

Front Neurol. 2019;10:900

Authors: Caldwell JZK, Zhuang X, Leavitt MJ, Banks SJ, Cummings J, Cordes D, Alzheimer's Disease Neuroimaging Initiative

Abstract
Women are more likely to have Alzheimer's disease (AD) and decline more rapidly once diagnosed despite greater verbal memory early in the disease compared to men-an advantage that has been termed "memory reserve." Resting state functional MRI (fMRI) investigations demonstrate interactions between sex and AD risk factors in default mode network (DMN) connectivity, a network of brain regions showing progressive dysfunction in AD. Separate work suggests connectivity of left prefrontal cortex (PFC) may correlate with more general cognitive reserve in healthy aging. It is unknown whether left prefrontal functional connectivity with anterior and posterior default mode network (aDMN, pDMN) might differ by sex in AD. This study employed group independent component analysis (ICA) to analyze resting state fMRI data from 158 participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI) with baseline diagnoses of normal cognition or early mild cognitive impairment (eMCI). pDMN and aDMN were defined on a subject-specific basis; prefrontal areas were selected from the Brodmann atlas (BA 6, 44, 8, and 9). Moderation regression analyses examined whether sex and amyloid PET positivity (A+/-) moderated effects of apolipoprotein ε4 (APOE ε4) on connectivity between left PFC, aDMN, and pDMN; and between aDMN and pDMN. Significant analyses were followed up with partial correlations assessing relationship of connectivity to verbal memory on the Rey Auditory Verbal Learning Test (RAVLT), and with preliminary analyses within NC and eMCI groups separately. Results showed no sex moderation of effects of A+ and APOE ε4 on left prefrontal/DMN connectivity in the full sample. However, sex significantly moderated impact of A+ and APOE ε4 on connectivity between aDMN and pDMN (p < 0.01). Women with an APOE allele (ε4+) and A+ showed greater aDMN/pDMN connectivity than their ε4- counterparts. No significant results were observed in men. Subgroup analyses suggested the aDMN/pDMN finding was true for those with NC, not eMCI. Partial correlations controlling for age and education showed increased aDMN/pDMN connectivity related to better verbal learning in women (p < 0.01) and not men (p = 0.18). In women at risk for AD or in early symptomatic stages who also have evidence of amyloid burden, stronger aDMN/pDMN connectivity may support verbal learning.

PMID: 31481928 [PubMed]

Frequency-dependent changes in fractional amplitude of low-frequency oscillations in Alzheimer's disease: a resting-state fMRI study.

Wed, 09/04/2019 - 22:36
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Frequency-dependent changes in fractional amplitude of low-frequency oscillations in Alzheimer's disease: a resting-state fMRI study.

Brain Imaging Behav. 2019 Sep 02;:

Authors: Yang L, Yan Y, Li Y, Hu X, Lu J, Chan P, Yan T, Han Y

Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disease in elderly individuals. We conducted this study to examine whether alterations in the fractional amplitudes of low-frequency fluctuations (fALFF) in the AD spectrum were frequency-dependent and symptom-relevant. A total of 43 patients with subjective cognitive decline (SCD), 52 with amnestic mild cognitive impairment (aMCI), 44 with Alzheimer's dementia (d-AD) and 55 well-matched controls participated in resting-state functional magnetic resonance imaging (rs-fMRI) scans. The amplitudes were measured using fALFF within the slow-4 (0.027-0.073 Hz) and slow-5 (0.01-0.027 Hz) bands. Repeated-measures analysis of variance was performed on fALFF within two bands and correlated with neuropsychological test scores. The significant main effects of frequency and group on fALFF differed widely across brain regions. There were more varied areas in the slow-5 band than the slow-4 band. The fALFF associated with primary disease effects was mainly distributed in the parietal lobe. Obvious frequency band and group interaction effects were observed in the left angular gyrus, left calcarine fissure and surrounding cortex, left superior cerebellum, left cuneus and right lingual gyrus. Neuropsychological tests scores were significantly correlated with the fALFF magnitude of the left cuneus and right lingual in the slow-5 band. Our results suggested that the AD continuum had abnormal amplitudes in intrinsic brain activity, and these abnormalities were frequency-dependent and mainly associated with the slow-5 band rather than the slow-4 band. This may guide the frequency choice of future rs-fMRI studies and provide new insights into the neuropathophysiology of AD.

PMID: 31478145 [PubMed - as supplied by publisher]