New resting-state fMRI related studies at PubMed

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

Sun, 09/08/2019 - 15:40
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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 - 15:40
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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 - 14:20
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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 - 14:20
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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]

Altered amygdala subregion-related circuits in treatment-naïve post-traumatic stress disorder comorbid with major depressive disorder.

Sat, 09/07/2019 - 14:20
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Altered amygdala subregion-related circuits in treatment-naïve post-traumatic stress disorder comorbid with major depressive disorder.

Eur Neuropsychopharmacol. 2019 Sep 02;:

Authors: Yuan M, Pantazatos SP, Zhu H, Li Y, Miller JM, Rubin-Falcone H, Zanderigo F, Ren Z, Yuan C, Lui S, Gong Q, Qiu C, Zhang W, John Mann J

Abstract
Individuals with both post-traumatic stress disorder and major depressive disorder (PTSD+MDD) often show greater social and occupational impairment and poorer treatment response than individuals with PTSD alone. Increasing evidence reveals that the amygdala, a brain region implicated in the pathophysiology of both of these conditions, is a complex of structurally and functionally heterogeneous nuclei. Quantifying the functional connectivity of two key amygdala subregions, the basolateral (BLA) and centromedial (CMA), in PTSD+MDD and PTSD-alone could advance our understanding of the neurocircuitry of these conditions. 18 patients with PTSD+MDD, 28 with PTSD-alone, and 50 trauma exposed healthy controls (TEHC), all from a cohort who survived the same large earthquake in China, underwent resting-state functional magnetic resonance imaging. Bilateral BLA and CMA functional connectivity (FC) maps were created using a seed-based approach for each participant. The analysis of covariance of FC was used to determine between-group differences. A significant interaction between amygdala subregion and diagnostic group suggested that differences in connectivity patterns between the two seeds were mediated by diagnosis. Post-hoc analyses revealed that PTSD+MDD patients showed weaker connectivity between right BLA and (a) left anterior cingulate cortex/supplementary motor area, and (b) bilateral putamen/pallidum, compared with PTSD-alone patients. Higher CMA connectivities left ACC/SMA were also observed in PTSD+MDD compared with PTSD-alone. An inverse relationship between the connectivity of right BLA with right putamen/pallidum and MDD symptoms was found in PTSD+MDD. These findings indicate a relationship between the neural pathophysiology of PTSD+MDD compared with PTSD-alone and TEHC and may inform future clinical interventions.

PMID: 31488341 [PubMed - as supplied by publisher]

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

Fri, 09/06/2019 - 19:20
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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.

Fri, 09/06/2019 - 19:20
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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.

Fri, 09/06/2019 - 19:20
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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 - 18:20
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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 - 18:20
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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]

Noninvasive optical assessment of resting-state cerebral blood flow in children with sickle cell disease.

Thu, 09/05/2019 - 18:20
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Noninvasive optical assessment of resting-state cerebral blood flow in children with sickle cell disease.

Neurophotonics. 2019 Jul;6(3):035006

Authors: Lee SY, Cowdrick KR, Sanders B, Sathialingam E, McCracken CE, Lam WA, Joiner CH, Buckley EM

Abstract
Sickle cell disease (SCD) is a genetic blood disorder that has profound effects on the brain. Chronic anemia combined with both macro- and microvascular perfusion abnormalities that arise from stenosis or occlusion of blood vessels increased blood viscosity, adherence of red blood cells to the vascular endothelium, and impaired autoregulatory mechanisms in SCD patients all culminate in susceptibility to cerebral infarction. Indeed, the risk of stroke is 250 times higher in children with SCD than in the general population. Unfortunately, while transcranial Doppler ultrasound (TCD) has been widely clinically adopted to longitudinally monitor macrovascular perfusion in these patients, routine clinical screening of microvascular perfusion abnormalities is challenging with current modalities (e.g., positron emission tomography and magnetic resonance imaging) given their high-cost, requirement for sedation in children < 6 year, and need for trained personnel. We assess the feasibility of a low-cost, noninvasive optical technique known as diffuse correlation spectroscopy (DCS) to quantify an index of resting-state cortical cerebral blood flow (BFI) in 11 children with SCD along with 11 sex- and age-matched healthy controls. As expected, BFI was significantly higher in SCD subjects compared to healthy controls ( p < 0.001 ). Within SCD subjects, BFI was inversely proportional to resting-state arterial hemoglobin levels ( p = 0.012 ), consistent with expected anemia-induced compensatory vasodilation that aims to maintain adequate oxygen delivery to the tissue. Further, in a subset of patients measured with TCD ( n = 7 ), DCS-measured blood flow was correlated with TCD-measured blood flow velocity in middle cerebral artery ( R s = 0.68 ), although the trend was not statistically significant ( p = 0.11 ). These results are consistent with those of several previous studies using traditional neuroimaging techniques, suggesting that DCS may be a promising low-cost tool for assessment of tissue-level CBF in pediatric SCD.

PMID: 31482101 [PubMed]

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

Thu, 09/05/2019 - 18:20
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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]

Changes in Resting-State Functional Connectivity Related to Freezing of Gait in Parkinson's Disease.

Wed, 09/04/2019 - 11:20

Changes in Resting-State Functional Connectivity Related to Freezing of Gait in Parkinson's Disease.

Neuroscience. 2019 Aug 31;:

Authors: Potvin-Desrochers A, Mitchell T, Gisiger T, Paquette C

Abstract
Freezing of gait (FOG) is a common motor symptom in Parkinson's disease (PD) thought to arise from the dysfunctional cortico-basal ganglia-thalamic circuity. The purpose of this study was to assess the changes in brain resting-state functional connectivity (rs-FC) of subcortical structures comprising the cortico-basal ganglia-thalamic circuity in individuals with PD with and without FOG. Resting-state functional magnetic resonance imaging was acquired in 27 individuals with idiopathic PD (14 with FOG and 13 without FOG). A seed-to-voxel analysis was performed with the seeds in the bilateral basal ganglia nuclei, thalamus, and pedunculopontine nucleus. Between-group differences in rs-FC revealed that the bilateral thalamus and globus pallidus external were significantly more connected with visual areas in PD with FOG compared to PD without FOG. In addition, PD with FOG had increased connectivity between the left putamen and retrosplenial cortex as well as with the cerebellum. Our findings suggest an increased connectivity at rest of subcortical and cortical regions involved in sensory and visuospatial processing that may be compensating for sensorimotor deficits in FOG. This increased connectivity may contribute to the hypothesized overload in the cortico-basal ganglia-thalamic circuity processing capacity, which may ultimately result in FOG occurrence.

PMID: 31479699 [PubMed - as supplied by publisher]

In vivo 13 C and 1 H-[13 C] MRS studies of neuroenergetics and neurotransmitter cycling, applications to neurological and psychiatric disease and brain cancer.

Wed, 09/04/2019 - 11:20

In vivo 13 C and 1 H-[13 C] MRS studies of neuroenergetics and neurotransmitter cycling, applications to neurological and psychiatric disease and brain cancer.

NMR Biomed. 2019 Sep 02;:e4172

Authors: Rothman DL, de Graaf RA, Hyder F, Mason GF, Behar KL, De Feyter HM

Abstract
In the last 25 years 13 C MRS has been established as the only noninvasive method for measuring glutamate neurotransmission and cell specific neuroenergetics. Although technically and experimentally challenging 13 C MRS has already provided important new information on the relationship between neuroenergetics and neuronal function, the high energy cost of brain function in the resting state and the role of altered neuroenergetics and neurotransmitter cycling in disease. In this paper we review the metabolic and neurotransmitter pathways that can be measured by 13 C MRS and key findings on the linkage between neuroenergetics, neurotransmitter cycling, and brain function. Applications of 13 C MRS to neurological and psychiatric disease as well as brain cancer are reviewed. Recent technological developments that may help to overcome spatial resolution and brain coverage limitations of 13 C MRS are discussed.

PMID: 31478594 [PubMed - as supplied by publisher]

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

Wed, 09/04/2019 - 11:20
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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]

Altered Nucleus Basalis Connectivity Predicts Treatment Response in Mild Cognitive Impairment.

Wed, 09/04/2019 - 11:20
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Altered Nucleus Basalis Connectivity Predicts Treatment Response in Mild Cognitive Impairment.

Radiology. 2018 12;289(3):775-785

Authors: Meng D, Li X, Bauer M, Taylor JP, Auer DP, Alzheimer's Disease Neuroimaging Initiative

Abstract
Purpose To determine whether functional connectivity (FC) mapping of nucleus basalis of Meynert (NBM) cholinergic network (hereafter, NBM FC) could provide a biomarker of central cholinergic deficits with predictive potential for response to cholinesterase inhibitor (ChEI) treatment. Materials and Methods The Alzheimer's Disease Neuroimaging Initiative (ADNI) was approved by the institutional review boards of all participating sites. All participants and their representatives gave written informed consent prior to data collection. NBM FC was examined in 33 healthy control participants, 102 patients with mild cognitive impairment (MCI), and 33 patients with AD by using resting-state functional MRI data from the ADNI database. NBM FC was compared between groups before and after 6 months of ChEI treatment in MCI. Associations between baseline NBM FC and baseline cognitive performance as well as cognitive outcomes after treatment were investigated. Results Compared with the healthy control group, NBM FC was decreased in patients with untreated MCI and increased in patients with AD treated with ChEI (corrected P ˂ .05). Global cognition (Alzheimer's Disease Assessment Scale-Cognitive subscale score) was associated with NBM FC (r = -0.349; P ˂ .001). NBM FC was higher 6 months after ChEI compared with before ChEI in treated MCI (corrected P ˂ .05), but did not change at 6 months in patients with untreated MCI (corrected P ˂ .05). Baseline NBM FC in MCI strongly predicted cognitive outcomes 6 months after ChEI (R2 = 0.458; P = .001). Conclusion Functional dissociation of the nucleus basalis of Meynert from a cortical network may explain the cognitive deficits in dementia and allow for the selection of individuals who are more likely to respond to cholinesterase inhibitors at early disease stages. © RSNA, 2018 Online supplemental material is available for this article.

PMID: 30204076 [PubMed - indexed for MEDLINE]

Cortical tau deposition follows patterns of entorhinal functional connectivity in aging.

Tue, 09/03/2019 - 16:20
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Cortical tau deposition follows patterns of entorhinal functional connectivity in aging.

Elife. 2019 Sep 02;8:

Authors: Adams JN, Maass A, Harrison TM, Baker SL, Jagust WJ

Abstract
Tau pathology first appears in the transentorhinal and anterolateral entorhinal cortex (alEC) in the aging brain. The transition to Alzheimer's disease (AD) is hypothesized to involve amyloid-b (Ab) facilitated tau spread through neural connections. We contrasted functional connectivity (FC) of alEC and posteromedial EC (pmEC), subregions of EC that differ in functional specialization and cortical connectivity, with the hypothesis that alEC-connected cortex would show greater tau deposition than pmEC-connected cortex. We used resting state fMRI to measure FC, and PET to measure tau and Aβ in cognitively normal older adults. Tau preferentially deposited in alEC-connected cortex compared to pmEC-connected or non-connected cortex, and stronger connectivity was associated with increased tau deposition. FC-tau relationships were present regardless of Aβ, though strengthened with Aβ. These results provide an explanation for the anatomic specificity of neocortical tau deposition in the aging brain and reveal relationships between normal aging and the evolution of AD.

PMID: 31475904 [PubMed - as supplied by publisher]

Frequency-specific oscillations synchronization in primary angle-closure glaucoma.

Tue, 09/03/2019 - 16:20
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Frequency-specific oscillations synchronization in primary angle-closure glaucoma.

Acta Radiol. 2019 Aug 31;:284185119870975

Authors: Jiang F, Ye YQ, Zuo JM, Huang X, Yu C, Zeng XJ

PMID: 31475845 [PubMed - as supplied by publisher]

Increased Nucleus Accumbens Connectivity in Resting-State Patients With Drug-Naive, First-Episode Somatization Disorder.

Tue, 09/03/2019 - 16:20
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Increased Nucleus Accumbens Connectivity in Resting-State Patients With Drug-Naive, First-Episode Somatization Disorder.

Front Psychiatry. 2019;10:585

Authors: Ou Y, Su Q, Liu F, Ding Y, Chen J, Zhang Z, Zhao J, Guo W

Abstract
The nucleus accumbens (NAc) plays an important role in the reward circuit, and abnormal regional activities of the reward circuit have been reported in various psychiatric disorders including somatization disorder (SD). However, few researches are designed to analyze the NAc connectivity in SD. This study was designed to explore the NAc connectivity in first-episode, drug-naive patients with SD using the bilateral NAc as seeds. Twenty-five first-episode, drug-naive patients with SD and 28 healthy controls were recruited. Functional connectivity (FC) was designed to analyze the images. LIBSVM (a library for support vector machines) was used to identify whether abnormal FC could be utilized to discriminate the patients from the controls. The patients showed significantly increased FC between the left NAc and the right gyrus rectus and left medial prefrontal cortex/anterior cingulate cortex (MPFC/ACC), and between the right NAc and the left gyrus rectus and left MPFC/ACC compared with the controls. The patients could be separated from the controls through increased FC between the left NAc and the right gyrus rectus with a sensitivity of 88.00% and a specificity of 82.14%. The findings reveal that patients with SD have increased NAc connectivity with the frontal regions of the reward circuit. Increased left NAc-right gyrus rectus connectivity can be used as a potential marker to discriminate patients with SD from healthy controls. The study thus highlights the importance of the reward circuit in the neuropathology of SD.

PMID: 31474890 [PubMed]

Prolonged Bedtime Smartphone Use is Associated With Altered Resting-State Functional Connectivity of the Insula in Adult Smartphone Users.

Tue, 09/03/2019 - 16:20
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Prolonged Bedtime Smartphone Use is Associated With Altered Resting-State Functional Connectivity of the Insula in Adult Smartphone Users.

Front Psychiatry. 2019;10:516

Authors: Paik SH, Park CH, Kim JY, Chun JW, Choi JS, Kim DJ

Abstract
Prolonged bedtime smartphone use is often associated with poor sleep quality and daytime dysfunction. In addition, the unstructured nature of smartphones may lead to excessive and uncontrolled use, which can be a cardinal feature of problematic smartphone use. This study was designed to investigate functional connectivity of insula, which is implicated in salience processing, interoceptive processing, and cognitive control, in association with prolonged bedtime smartphone use. We examined resting-state functional connectivity (rsFC) of insula in 90 adults who used smartphones by functional magnetic resonance imaging (fMRI). Smartphone time in bed was measured by self-report. Prolonged bedtime smartphone use was associated with higher smartphone addiction proneness scale (SAPS) scores, but not with sleep quality. The strength of the rsFC between the left insula and right putamen, and between the right insula and left superior frontal, middle temporal, fusiform, inferior orbitofrontal gyrus and right superior temporal gyrus was positively correlated with smartphone time in bed. The findings imply that prolonged bedtime smartphone use can be an important behavioral measure of problematic smartphone use and altered insula-centered functional connectivity may be associated with it.

PMID: 31474880 [PubMed]

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