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LittleBrain: A gradient-based tool for the topographical interpretation of cerebellar neuroimaging findings.

Fri, 01/18/2019 - 04:51

LittleBrain: A gradient-based tool for the topographical interpretation of cerebellar neuroimaging findings.

PLoS One. 2019;14(1):e0210028

Authors: Guell X, Goncalves M, Kaczmarzyk JR, Gabrieli JDE, Schmahmann JD, Ghosh SS

Abstract
Gradient-based approaches to brain function have recently unmasked fundamental properties of brain organization. Diffusion map embedding analysis of resting-state fMRI data revealed a primary-to-transmodal axis of cerebral cortical macroscale functional organization. The same method was recently used to analyze resting-state data within the cerebellum, revealing for the first time a sensorimotor-fugal macroscale organization principle of cerebellar function. Cerebellar gradient 1 extended from motor to non-motor task-unfocused (default-mode network) areas, and cerebellar gradient 2 isolated task-focused processing regions. Here we present a freely available and easily accessible tool that applies this new knowledge to the topographical interpretation of cerebellar neuroimaging findings. LittleBrain illustrates the relationship between cerebellar data (e.g., volumetric patient study clusters, task activation maps, etc.) and cerebellar gradients 1 and 2. Specifically, LittleBrain plots all voxels of the cerebellum in a two-dimensional scatterplot, with each axis corresponding to one of the two principal functional gradients of the cerebellum, and indicates the position of cerebellar neuroimaging data within these two dimensions. This novel method of data mapping provides alternative, gradual visualizations that complement discrete parcellation maps of cerebellar functional neuroanatomy. We present application examples to show that LittleBrain can also capture subtle, progressive aspects of cerebellar functional neuroanatomy that would be difficult to visualize using conventional mapping techniques. Download and use instructions can be found at https://xaviergp.github.io/littlebrain.

PMID: 30650101 [PubMed - in process]

Frontostriatal network dysfunction as a domain-general mechanism underlying phantom perception.

Fri, 01/18/2019 - 04:51
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Frontostriatal network dysfunction as a domain-general mechanism underlying phantom perception.

Hum Brain Mapp. 2019 Jan 15;:

Authors: Hullfish J, Abenes I, Yoo HB, De Ridder D, Vanneste S

Abstract
In the present study, we use resting state fMRI to investigate whether nucleus accumbens (NAc) and extended frontostriatal networks are involved in the pathology of auditory phantom perception, i.e., tinnitus, through a study of functional connectivity. We hypothesize that resting state functional connectivity involving NAc will be increased relative to what is observed in healthy subjects and that this connectivity will correlate with clinical measures of tinnitus such as percept loudness, duration of symptoms, etc. We show that a large sample of patients with chronic tinnitus (n = 90) features extensive functional connectivity involving NAc that is largely absent in healthy subjects (n = 94). We further show that connectivity involving NAc correlates significantly with tinnitus percept loudness and the duration of tinnitus symptoms, even after controlling for the effects of age and hearing loss. The loudness correlation, which involves NAc and parahippocampal cortex, is consistent with existing literature identifying the parahippocampus as a tinnitus generator. Our results further suggest that frontostriatal connectivity may predict the transition from acute to chronic tinnitus, analogous to what is seen in the pain literature. We discuss these ideas and suggest fruitful avenues for future research.

PMID: 30648324 [PubMed - as supplied by publisher]

Dynamic changes of functional segregation and integration in vulnerability and resilience to schizophrenia.

Fri, 01/18/2019 - 04:51
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Dynamic changes of functional segregation and integration in vulnerability and resilience to schizophrenia.

Hum Brain Mapp. 2019 Jan 15;:

Authors: Duan J, Xia M, Womer FY, Chang M, Yin Z, Zhou Q, Zhu Y, Liu Z, Jiang X, Wei S, Anthony O'Neill F, He Y, Tang Y, Wang F

Abstract
Schizophrenia (SZ) is a highly heritable disease with neurodevelopmental origins and significant functional brain network dysfunction. Functional network is heavily influenced by neurodevelopment processes and can be characterized by the degree of segregation and integration. This study examines functional segregation and integration in SZ and their first-degree relatives (high risk [HR]) to better understand the dynamic changes in vulnerability and resiliency, and disease markers. Resting-state functional magnetic resonance imaging data acquired from 137 SZ, 89 HR, and 210 healthy controls (HCs). Small-worldness σ was computed at voxel level to quantify balance between segregation and integration. Interregional functional associations were examined based on Euclidean distance between regions and reflect degree of segregation and integration. Distance strength maps were used to localize regions of altered distance-based functional connectivity. σ was significantly decreased in SZ compared to HC, with no differences in high risk (HR). In three-group comparison, significant differences were noted in short-range connectivity (primarily in the primary sensory, motor and their association cortices, and the thalamus) and medium/long-range connectivity (in the prefrontal cortices [PFCs]). Decreased short- and increased medium/long-range connectivity was found in SZ. Decreased short-range connectivity was seen in SZ and HR, while HR had decreased medium/long-range connectivity. We observed disrupted balance between segregation and integration in SZ, whereas relatively preserved in HR. Similarities and differences between SZ and HR, specific changes of SZ were found. These might reflect dynamic changes of segregation in primary cortices and integration in PFCs in vulnerability and resilience, and disease markers in SZ.

PMID: 30648317 [PubMed - as supplied by publisher]

Altered functional connectivity of the marginal division in Parkinson's disease with mild cognitive impairment: A pilot resting-state fMRI study.

Wed, 01/16/2019 - 19:48

Altered functional connectivity of the marginal division in Parkinson's disease with mild cognitive impairment: A pilot resting-state fMRI study.

J Magn Reson Imaging. 2019 Jan 15;:

Authors: Li MG, Chen YY, Chen ZY, Feng J, Liu MY, Lou X, Shu SY, Wang ZF, Ma L

Abstract
BACKGROUND: The marginal division (MrD) is an important subcortical center involved in learning and memory. Mild cognitive impairment (MCI) is commonly seen in patients with Parkinson's disease (PD), but the neurobiological basis is yet to be elucidated.
PURPOSE: To use resting-state functional magnetic resonance imaging (rs-fMRI) to explore the altered functional connectivity (FC) of the MrD in patients with PD-MCI.
STUDY TYPE: Prospective pilot study.
POPULATION: Twenty-five patients with PD-MCI; 25 PD patients and no cognitive impairment (PD-NCI); and 25 healthy control (HC) participants.
SEQUENCE: 3.0 T GE Healthcare MRI scanner; three-dimensional T1 -weighted fast spoiled gradient recalled echo (3D T1 -FSPGR); rs-fMRI.
ASSESSMENT: The MrD was defined using manual delineation, which was the seed point to compute the FC to examine correlations between low-frequency fMRI signal fluctuations in MrD and the whole brain.
STATISTICAL TESTS: Between-group comparisons of the rs-fMRI data were computed using two-sample t-tests in a voxelwise manner after controlling for age and sex, to determine the brain regions that showed significant differences in FC with the bilateral MrDs. Correlation analyses were performed for FC values and cognitive abilities in patients with PD.
RESULTS: In the PD-MCI group, compared with the PD-NCI group, we observed lesser FC between the MrD bilaterally and right putamen, left insula, left cerebellum, and left thalamus; greater FC between the MrD bilaterally and left middle cingulate cortex, left middle frontal gyrus, left superior frontal gyrus, left supplementary motor area, and left middle/inferior occipital gyrus. Moreover, the strength of FC between the MrD and regions that showed differences between the PD-MCI and PD-NCI groups was significantly correlated with neuropsychological scores in patients with PD.
DATA CONCLUSION: The current study suggests that MrD dysfunction may contribute to MCI in PD. However, the mechanisms underlying this process require further investigation. Level of Evidence 1. Technical Efficacy Stage 2. J. Magn. Reson. Imaging 2019.

PMID: 30644620 [PubMed - as supplied by publisher]

Altered functional connectivity in binge eating disorder and bulimia nervosa: A resting-state fMRI study.

Wed, 01/16/2019 - 19:48
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Altered functional connectivity in binge eating disorder and bulimia nervosa: A resting-state fMRI study.

Brain Behav. 2019 Jan 15;:e01207

Authors: Stopyra MA, Simon JJ, Skunde M, Walther S, Bendszus M, Herzog W, Friederich HC

Abstract
INTRODUCTION: The etiology of bulimic-type eating (BTE) disorders such as binge eating disorder (BED) and bulimia nervosa (BN) is still largely unknown. Brain networks subserving the processing of rewards, emotions, and cognitive control seem to play a crucial role in the development and maintenance of eating disorders. Therefore, further investigations into the neurobiological underpinnings are needed to discern abnormal connectivity patterns in BTE disorders.
METHODS: The present study aimed to investigate functional as well as seed-based connectivity within well-defined brain networks. Twenty-seven individuals with BED, 29 individuals with BN, 28 overweight, and 30 normal-weight control participants matched by age, gender, and education underwent resting-state functional magnetic resonance imaging. Functional connectivity was assessed by spatial group independent component analysis and a seed-based correlation approach by examining the default mode network (DMN), salience network (SN), and executive network (EN).
RESULTS: Group comparisons revealed that BTE disorder patients exhibit aberrant functional connectivity in the dorsal anterior cingulate cortex (dACC) within the SN, as well as in the medial prefrontal cortex within the DMN. Furthermore, BED and BN groups differed from each other in functional connectivity within each network. Seed-based correlational analysis revealed stronger synchronous dACC-retrosplenial cortex activity in the BN group.
CONCLUSION: Our findings demonstrate abnormalities in brain networks involved in salience attribution, self-referential processing, and cognitive control in bulimic-type eating disorders. Together with our observation of functional connectivity differences between BED and BN, this study offers a differentiated account of both similarities and differences regarding brain connectivity in BED and BN.

PMID: 30644179 [PubMed - as supplied by publisher]

Association of functional dorsal attention network alterations with breast cancer and chemotherapy.

Wed, 01/16/2019 - 19:48
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Association of functional dorsal attention network alterations with breast cancer and chemotherapy.

Sci Rep. 2019 Jan 14;9(1):104

Authors: Shen CY, Chen VC, Yeh DC, Huang SL, Zhang XR, Chai JW, Huang YH, Chou MC, Weng JC

Abstract
Breast cancer is the most common cancer among women worldwide. Adjuvant chemotherapy has significantly reduced mortality but increased cognitive impairments, including attention function, making quality of life issues a crucial concern. This study enrolled nineteen breast cancer patients who were treated with standard chemotherapy within 6 months and 20 sex-matched healthy controls to investigate the brain effects of chemotherapy. All participants underwent resting-state functional magnetic resonance imaging (rs-fMRI) with mean fractional amplitude of low-frequency fluctuation (mfALFF) analysis and were correlated with neuropsychological tests, including the Mini-Mental State Examination (MMSE), the Cognitive and Affective Mindfulness Scale-Revised (CAMS-R), and the Impact of Event Scale-Revised (IES-R), to explore the possible underlying mechanism of cognitive alternations. We found increased mfALFF over the frontoparietal lobe and decreased mfALFF over the occipital lobe in the cancer patients compared with the healthy controls; the altered brain regions may be associated with the dorsal attention network (DAN) and may be explained by a compensatory mechanism. Both MMSE and CAMS-R scores showed a positive correlation with mfALFF in the occipital lobe but a negative correlation in the frontoparietal lobe. By contrast, IES-R scores showed a positive correlation with mfALFF in the frontoparietal lobe but a negative correlation in the occipital lobe. These alterations are potentially related to the effects of both chemotherapy and psychological distress. Future research involving a larger sample size of patients with breast cancer is recommended.

PMID: 30643203 [PubMed - in process]

Altered Central Autonomic Network in Baseball Players: A Resting-state fMRI Study.

Wed, 01/16/2019 - 19:48
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Altered Central Autonomic Network in Baseball Players: A Resting-state fMRI Study.

Sci Rep. 2019 Jan 14;9(1):110

Authors: Sie JH, Chen YH, Chang CY, Yen NS, Chu WC, Shiau YH

Abstract
The physiological adaptive regulation of healthy population with a high fitness level is associated with enhanced cognitive control in brain. This study further investigated the effects of different levels of sporting experience on intrinsic brain networks involved in central autonomic processing using resting-state functional magnetic resonance imaging. We explored functional connectivity of four core regions within central autonomic network (CAN), namely posterior midcingulate cortex (pMCC), left amygdala (AMYG), and right anterior (aINS) and left posterior insular cortices, in advanced and intermediate baseball players, and compared their strength of connectivity with individuals without baseball-playing experience. Functional connectivity maps across three groups confirmed a close relationship between CAN and large-scale brain networks in sensory, motor and cognitive domains. Crucially, both advanced and intermediate batters demonstrated enhanced connectivity between pMCC and sensorimotor network, between right aINS and dorsal anterior cingulate cortex, and between left AMYG and right putamen, than controls. These results reflected a stronger interregional coupling in sensorimotor and cognitive control, and in motor skill consolidation. In conclusion, we provided evidence that different levels of sporting experience could reorganize/enhance intrinsic functional connectivity for central autonomic processing.

PMID: 30643162 [PubMed - in process]

Nuclei-specific thalamic connectivity predicts seizure frequency in drug-resistant medial temporal lobe epilepsy.

Wed, 01/16/2019 - 19:48
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Nuclei-specific thalamic connectivity predicts seizure frequency in drug-resistant medial temporal lobe epilepsy.

Neuroimage Clin. 2019 Jan 09;:101671

Authors: Jo HJ, Kenny-Jung DL, Balzekas I, Benarroch EE, Jones DT, Brinkmann BH, Matt Stead S, Van Gompel JJ, Welker KM, Worrell GA

Abstract
BACKGROUND AND OBJECTIVES: We assessed correlations between the resting state functional connectivity (RSFC) of different thalamic nuclei and seizure frequency in patients with drug-resistant medial temporal lobe epilepsy (mTLE).
METHODS: Seventeen patients with mTLE and 17 sex-/age-/handedness-matched controls participated. A seed-based correlation method for the resting-state FMRI data was implemented to get RSFC maps of 70 thalamic nuclei seed masks. Group statistics for individual RSFC for subjects and seed masks were performed to obtain within-group characteristics and between-group differences with age covariates. A linear regression was applied to test whether seizure frequency correlated with thalamic nuclear RSFC with the whole brain in mTLE patients.
RESULTS: RSFC of thalamic nuclei showed spatially distinguishable connectivity patterns that reflected principal inputs and outputs that were derived from priori anatomical knowledge. We found group differences between normal control and mTLE groups in RSFC for nuclei seeds located in various subdivisions of thalamus. The RSFCs in some of those nuclei were strongly correlated with seizure frequency.
CONCLUSIONS: Mediodorsal thalamic nuclei may play important roles in seizure activity or in the regulation of neuronal activity in the limbic system. The RSFC of motor- and sensory-relay nuclei may help elucidate sensory-motor deficits associated with chronic seizure activity. RSFC of the pulvinar nuclei of the thalamus could also be a key reflection of symptom-related functional deficits in mTLE.

PMID: 30642762 [PubMed - as supplied by publisher]

Subjective memory complaints are associated with altered resting-state functional connectivity but not structural atrophy.

Wed, 01/16/2019 - 19:48
Related Articles

Subjective memory complaints are associated with altered resting-state functional connectivity but not structural atrophy.

Neuroimage Clin. 2019 Jan 11;:101675

Authors: Kawagoe T, Onoda K, Yamaguchi S

Abstract
Research indicates that a subtle cognitive decline, accompanied by pathological changes, occurs in individuals with subjective memory complaints (SMC). However, there is less evidence regarding the measurement of resting-state functional connectivity to detect subtle brain network alterations in neurodegenerative illnesses before cognitive change manifestation. We investigated the correlation between SMC and cognitive performance and explored functional and structural brain changes underlying SMC severity, using behavioral and brain imaging data-driven approaches. We observed that SMC was associated with depression but not with cognitive test scores, implying that SMC represent the "worried-well"; however, this model explains only 15% of the target variance. Using a conservative threshold, we observed connectivity related to SMC severity in the lingual gyrus, cuneus, anterior insula, and superior parietal lobule. Post-hoc analysis indicated that occipital and parietal functional connectivity increased with SMC severity. In contrast, volumetric alterations were not associated with SMC, even after applying a liberal threshold. Our findings suggest that altered resting-state functional connectivity in regions associated with SMC might reflect early compensatory changes that occur before cognitive and structural abnormalities develop.

PMID: 30642761 [PubMed - as supplied by publisher]

Brain connectivity tracks effects of chemotherapy separately from behavioral measures.

Wed, 01/16/2019 - 19:48
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Brain connectivity tracks effects of chemotherapy separately from behavioral measures.

Neuroimage Clin. 2019 Jan 06;:101654

Authors: Kardan O, Reuter-Lorenz PA, Peltier S, Churchill NW, Misic B, Askren MK, Jung MS, Cimprich B, Berman MG

Abstract
Several studies in cancer research have suggested that cognitive dysfunction following chemotherapy, referred to in lay terms as "chemobrain", is a serious problem. At present, the changes in integrative brain function that underlie such dysfunction remain poorly understood. Recent developments in neuroimaging suggest that patterns of functional connectivity can provide a broadly applicable neuromarker of cognitive performance and other psychometric measures. The current study used multivariate analysis methods to identify patterns of disruption in resting state functional connectivity of the brain due to chemotherapy and the degree to which the disruptions can be linked to behavioral measures of distress and cognitive performance. Sixty two women (22 healthy control, 18 patients treated with adjuvant chemotherapy, and 22 treated without chemotherapy) were evaluated with neurocognitive measures followed by self-report questionnaires and open eyes resting-state fMRI scanning at three time points: diagnosis (M0, pre-adjuvant treatment), 1 month (M1), and 7 months (M7) after treatment. The results indicated deficits in cognitive health of breast cancer patients immediately after chemotherapy that improved over time. This psychological trajectory was paralleled by a disruption and later recovery of resting-state functional connectivity, mostly in the parietal and frontal brain regions. Mediation analysis showed that the functional connectivity alteration pattern is a separable treatment symptom from the decreased cognitive health. Current study indicates that more targeted support for patients should be developed to ameliorate these multi-faceted side effects of chemotherapy treatment on neural functioning and cognitive health.

PMID: 30642760 [PubMed - as supplied by publisher]

Sensory-motor network functional connectivity in children with unilateral cerebral palsy secondary to perinatal stroke.

Wed, 01/16/2019 - 19:48
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Sensory-motor network functional connectivity in children with unilateral cerebral palsy secondary to perinatal stroke.

Neuroimage Clin. 2019 Jan 09;:101670

Authors: Woodward KE, Carlson HL, Kuczynski A, Saunders J, Hodge J, Kirton A

Abstract
BACKGROUND: Perinatal stroke is the most common cause of unilateral cerebral palsy. Mechanisms of post-stroke developmental plasticity in children are poorly understood. To better understand the relationship between functional connectivity and disability, we used resting-state fMRI to compare sensorimotor connectivity with clinical dysfunction.
METHODS: School-aged children with periventricular venous infarction (PVI) and unilateral cerebral palsy were compared to controls. Resting-state BOLD signal was acquired on 3 T MRI and analyzed using CONN in SPM12. Functional connectivity was computed between S1, M1, supplementary motor area (SMA), and thalamus of the left/non-lesioned and right/lesioned hemisphere. Primary outcome was connectivity expressed as a Fisher-transformed correlation coefficient. Motor function was measured using the Assisting Hand Assessment (AHA), and Melbourne Assessment (MA). Proprioceptive function was measured using a robotic position matching task (VarXY).
RESULTS: Participants included 15 PVI and 21 controls. AHA and MA in stroke patients were negatively correlated with connectivity (increased connectivity = poorer performance). Position sense was inversely correlated with connectivity (increased connectivity = improved performance) between the non-lesioned S1 and thalamus/SMA. In controls, VarXY was positively correlated with connectivity between the thalamus and bilateral sensorimotor regions.
CONCLUSIONS: Resting state fMRI measures of sensorimotor connectivity are associated with clinical sensorimotor function in children with unilateral cerebral palsy secondary to PVI. Greater insight into understanding reorganization of brain networks following perinatal stroke may facilitate personalized rehabilitation.

PMID: 30642756 [PubMed - as supplied by publisher]

Customized head molds reduce motion during resting state fMRI scans.

Wed, 01/16/2019 - 01:47

Customized head molds reduce motion during resting state fMRI scans.

Neuroimage. 2019 Jan 08;:

Authors: Power JD, Silver BM, Silverman MR, Ajodan EL, Bos DJ, Jones RM

Abstract
Head motion causes artifacts in functional magnetic resonance imaging (fMRI) scans, a problem especially relevant for task-free resting state paradigms and for developmental, aging, and clinical populations. In a cohort spanning 7-28 years old (mean age 15) we produced customized head-anatomy-specific Styrofoam molds for each subject that inserted into an MRI head coil. We scanned these subjects under two conditions: using our standard procedure of packing the head coil with foam padding about the head to reduce head motion, and using the customized molds to reduce head motion. Here we report the effects found in our first 13 subjects. In 12 of 13 subjects, the molds reduced head motion throughout the scan, and reduced the fraction of a scan with substantial motion (i.e., volumes with motion notably above baseline levels of motion). Motion was reduced in all 6 head position estimates, especially in rotational, left-right, and superior-inferior directions. Motion was reduced throughout the full age range studied, including children, adolescents, and young adults. In terms of the fMRI data itself, quality indices improved with the head mold on, scrubbing analyses detected less distance-dependent artifact in scans with the head mold on, and distant-dependent artifact was less evident in both the entire scan and also during only low-motion volumes. Subjects found the molds comfortable. Head molds are thus effective tools for reducing head motion, and motion artifacts, during fMRI scans.

PMID: 30639840 [PubMed - as supplied by publisher]

Univariate and multivariate analyses of functional networks in absolute pitch.

Wed, 01/16/2019 - 01:47

Univariate and multivariate analyses of functional networks in absolute pitch.

Neuroimage. 2019 Jan 10;:

Authors: Brauchli C, Leipold S, Jäncke L

Abstract
Absolute pitch (AP) refers to the rare ability to identify the pitch of any given tone without an external reference tone. Previous studies have shown that during auditory processing, AP musicians activate the auditory cortex (AC), the prefrontal cortex (PFC), and parietal areas of the brain. Therefore, it has been hypothesized that AP is sustained by a widespread functional network. In the present functional magnetic resonance imaging (fMRI) study, we tested this hypothesis by employing a mass-univariate analysis of resting-state functional connectivity within the AC, the PFC, and parietal areas in a large sample of musicians with and without AP (N = 100). AP musicians showed increased functional connectivity in the left middle frontal gyrus (MFG), left intraparietal sulcus (IPS), and right superior parietal lobule (SPL). These results provide the first evidence for an AP-specific network characterized by increased functional connections in higher-order cognitive areas. Interestingly, AP was not associated with increases in functional connectivity of the AC, but AP was successfully decoded from functional connectivity patterns in the left AC using multi-voxel pattern analysis (MVPA), with group classification accuracy being highest for the left Heschl's gyrus (HG). MVPA can capture fine-grained patterns in the brain connectivity profile of AP musicians, whilst a mass-univariate analysis is sensitive to macroscopic trends in the data. The successful differentiation of AP musicians by MVPA but not by a mass-univariate analysis of connectivity in the AC thus indicates that AP musicians differ in the fine-grained rather than the macroscopic AC function. Based on our findings, and in light of current literature, we propose pitch-label associations, tonal working memory, pitch categorization, and multimodal integration as potential mechanisms underlying the AP ability. This set of psychological functions is controlled by a distributed functional network and a particular AC connectivity pattern only present in AP musicians.

PMID: 30639332 [PubMed - as supplied by publisher]

Structural and Functional Magnetic Resonance Imaging of Dementia With Lewy Bodies.

Wed, 01/16/2019 - 01:47

Structural and Functional Magnetic Resonance Imaging of Dementia With Lewy Bodies.

Int Rev Neurobiol. 2019;144:95-141

Authors: Balážová Z, Nováková M, Minsterová A, Rektorová I

Abstract
Dementia with Lewy bodies (DLB) is the second most common cause of neurodegenerative dementia after Alzheimer's disease (AD). Although diagnosis may be challenging, there is increasing evidence that the use of biomarkers according to 2017 revised criteria for diagnosis and management of dementia with Lewy bodies can increase diagnostic accuracy. Apart from nuclear medicine techniques, various magnetic resonance imaging (MRI) techniques have been utilized in attempt to enhance diagnostic accuracy. This chapter reviews structural, functional and diffusion MRI studies in DLB cohorts being compared to healthy controls, AD or dementia in Parkinson's disease (PDD). We also included relatively new MRI methods that may have potential to identify early DLB subjects and aim at examining brain iron and neuromelanin.

PMID: 30638458 [PubMed - in process]

Functional MRI in Parkinson's Disease Cognitive Impairment.

Wed, 01/16/2019 - 01:47

Functional MRI in Parkinson's Disease Cognitive Impairment.

Int Rev Neurobiol. 2019;144:29-58

Authors: Baggio HC, Junqué C

Abstract
Functional magnetic resonance imaging (fMRI) has been used to study the neural bases of cognitive deficits in Parkinson's disease for several years. Traditionally, task-based fMRI has been applied to study specific cognitive functions, providing information on disease-related alterations and regarding the physiological bases of normal cognition, the dopaminergic system, and the frontostriatal circuits. More recently, functional connectivity techniques using resting-state fMRI data have been developed. Unconstrained by specific cognitive tasks, these techniques allow assessing whole-brain patterns of connectivity believed to be useful proxies for the underlying functional architecture of the brain. These methods have shown that different types of Parkinson's disease-related cognitive deficits are associated with patterns of altered connectivity within and between resting-state intrinsic connectivity networks. Although methodological standardization and the vulnerability of fMRI techniques to artifacts mandate further technical refinement, early studies provide encouraging results regarding the potential of fMRI-derived parameters for the ultimate goal of individual-subject classification.

PMID: 30638456 [PubMed - in process]

Abnormal amplitude of low frequency fluctuation and functional connectivity in non-neuropsychiatric systemic lupus erythematosus: a resting-state fMRI study.

Wed, 01/16/2019 - 01:47
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Abnormal amplitude of low frequency fluctuation and functional connectivity in non-neuropsychiatric systemic lupus erythematosus: a resting-state fMRI study.

Neuroradiology. 2019 Jan 12;:

Authors: Yu H, Qiu X, Zhang YQ, Deng Y, He MY, Zhao YT, Zhai ZH

Abstract
PURPOSE: To explore the amplitude of low frequency fluctuation (ALFF) and functional connectivity (FC) disorders in non-neuropsychiatric systemic lupus erythematosus (non-NPSLE) patients by resting-state functional magnetic resonance imaging (rs-fMRI) and to study whether there are some clinical biomarkers that can be used to monitor the brain dysfunction.
METHODS: Based on the rs-fMRI data of 36 non-NPSLE patients and 30 normal controls, we first obtained the regions with abnormal ALFF signals in non-NPSLE patients. Then, by taking these areas as seed regions of interest (ROIs), we calculated the FC between ROIs and the whole brain to assess the network-level alterations. Finally, we correlated the altered values of ALFF and FC in non-NPSLE patients to some clinical data.
RESULTS: Compared with the controls, non-NPSLE patients showed decreased ALFF in bilateral precuneus and increased ALFF in right cuneus and right calcarine fissure surrounding cortex (CAL). At network level, non-NPSLE patients exhibited higher FC between left precuneus and left middle occipital gyrus (MOG)/left superior occipital gyrus (SOG)/right middle frontal gyrus (MFG)/right dorsolateral superior frontal gyrus (SFGdor), and higher FC between right cuneus and bilateral precuneus/left posterior cingulate gyrus (PCG). The abnormal ALFF in right CAL and abnormal FC in right cuneus-left precuneus, right cuneus-right precuneus, and right cuneus-left PCG were correlated with the patients' certain clinical data (p < 0.05).
CONCLUSION: Rs-fMRI is a promising tool for detecting the brain function disorders in non-NPSLE patients and to help understand the neurophysiological mechanisms. C4 and Systemic Lupus Erythematosus Disease Activity Index may be biomarkers of brain dysfunction in non-NPSLE patients.

PMID: 30637462 [PubMed - as supplied by publisher]

The Role of Disturbed Small-World Networks in Patients with White Matter Lesions and Cognitive Impairment Revealed by Resting State Function Magnetic Resonance Images (rs-fMRI).

Sat, 01/12/2019 - 22:39

The Role of Disturbed Small-World Networks in Patients with White Matter Lesions and Cognitive Impairment Revealed by Resting State Function Magnetic Resonance Images (rs-fMRI).

Med Sci Monit. 2019 Jan 11;25:341-356

Authors: Wang J, Chen Y, Liang H, Niedermayer G, Chen H, Li Y, Wu M, Wang Y, Zhang Y

Abstract
BACKGROUND Leukoaraiosis is characterized by white matter lesions (WMLs) on magnetic resonance imaging (MRI) and is associated with cognitive impairment. The small-world network is viewed as the optimal brain network with maximal efficiency in information processing. Patients with cognitive impairment are thought to have disrupted small-world networks. In this study, we compared the small-world network attributes between controls (study participants without memory complaints) and patients with WMLs with cognitive impairment. MATERIAL AND METHODS All study participants were prescreened using MRI and neuropsychological tests. Patients with WMLs were further divided into 2 groups according to the result of Montreal Cognitive Assessment (MoCA), i.e., WMLs with non-dementia vascular cognitive impairment (WMLs-VCIND) and WMLs with vascular dementia (WMLs-VaD). Resting-state functional MRI data were collected and applied with graph theoretical analysis to compare small-world properties between the 3 groups. RESULTS We found that the overall functional connectivity strength was lowest in the WMLs-VaD patients but highest in the normal control study participants. Patients in both the WMLs-VCIND and the WMLs-VaD groups had decreased small-world properties compared with the group of normal control study participants. Moreover, the small-world properties significantly correlated with MoCA scores. CONCLUSIONS These findings suggest potential constructive reorganization of brain networks secondary to WMLs, and provides novel insights into the role of small-world properties in cognitive dysfunction in WMLs.

PMID: 30634184 [PubMed - in process]

Connectome-based model predicts individual differences in propensity to trust.

Sat, 01/12/2019 - 22:39

Connectome-based model predicts individual differences in propensity to trust.

Hum Brain Mapp. 2019 Jan 11;:

Authors: Lu X, Li T, Xia Z, Zhu R, Wang L, Luo YJ, Feng C, Krueger F

Abstract
Trust constitutes a fundamental basis of human society and plays a pivotal role in almost every aspect of human relationships. Although enormous interest exists in determining the neuropsychological underpinnings of a person's propensity to trust utilizing task-based fMRI; however, little progress has been made in predicting its variations by task-free fMRI based on whole-brain resting-state functional connectivity (RSFC). Here, we combined a one-shot trust game with a connectome-based predictive modeling approach to predict propensity to trust from whole-brain RSFC. We demonstrated that individual variations in the propensity to trust were primarily predicted by RSFC rooted in the functional integration of distributed key nodes-caudate, amygdala, lateral prefrontal cortex, temporal-parietal junction, and the temporal pole-which are part of domain-general large-scale networks essential for the motivational, affective, and cognitive aspects of trust. We showed, further, that the identified brain-behavior associations were only evident for trust but not altruistic preferences and that propensity to trust (and its underlying neural underpinnings) were modulated according to the extent to which a person emphasizes general social preferences (i.e., horizontal collectivism) rather than general risk preferences (i.e., trait impulsiveness). In conclusion, the employed data-driven approach enables to predict propensity to trust from RSFC and highlights its potential use as an objective neuromarker of trust impairment in mental disorders.

PMID: 30633429 [PubMed - as supplied by publisher]

Regional cerebral hypoperfusion after acute sleep deprivation: A STROBE-compliant study of arterial spin labeling fMRI.

Sat, 01/12/2019 - 22:39

Regional cerebral hypoperfusion after acute sleep deprivation: A STROBE-compliant study of arterial spin labeling fMRI.

Medicine (Baltimore). 2019 Jan;98(2):e14008

Authors: Zhou F, Huang M, Gu L, Hong S, Jiang J, Zeng X, Gong H

Abstract
Previous neuroimaging studies have shown that functional changes occur after acute sleep deprivation, which suggest detrimental effects of a lack of sleep on the intrinsic functional architecture of the brain. We aimed to identify regional resting perfusion changes in subjects with acute sleep deprivation.Thirty-three healthy subjects with habitual good sleep participated in 36 hours (2 days and 1 night) of sleep deprivation and then underwent the attention network test and pseudo-continuous arterial spin labeling scanning. Regional cerebral blood flow was used to compare cerebral perfusion before and after sleep deprivation. Correlation analyses of regional perfusion changes and scores on the attention network test were performed.Compared with the baseline (n = 20) scans, the scans of subjects after sleep deprivation (n = 26) revealed a slower response time (549.99 milliseconds vs 603.36 milliseconds; t = -2.301; P = .028) and a significantly higher lapse rate (0.88% vs 22.85%; t = -2.977; P = .006). The sleep deprivation subjects showed lower cerebral blood flow (CBF) in the left parahippocampal gyrus/fusiform cortex (pHipp/Fus), right pHipp/Fus, and right prefrontal cortex (PFC) relative to the baseline subjects (Gaussian random field correction, voxel level P < .01, and cluster level P < .05). Although no significant relationships were observed between the altered regional CBF (rCBF) values and the attention network test scores, the receiver-operating characteristic and leave-one-out cross-validation analyses revealed that significant decreases in rCBF in the bilateral pHipp/Fus and right PFC could discriminate between sleep deprivation and good sleep status.We observed that rCBF was reduced after 36 hours (2 days and 1 night) of sleep deprivation. Our preliminary findings suggest an acute vulnerability to hypoperfusion due to lack of sleep.

PMID: 30633191 [PubMed - in process]

Dynamic Functional Network Connectivity In Schizophrenia With MEG And fMRI, Do Different Time Scales Tell A Different Story?

Sat, 01/12/2019 - 22:39

Dynamic Functional Network Connectivity In Schizophrenia With MEG And fMRI, Do Different Time Scales Tell A Different Story?

Brain Connect. 2019 Jan 11;:

Authors: Sanfratello L, Houck J, Calhoun VD

Abstract
The importance of how brain networks function together to create brain states has become increasingly recognized. Therefore, an investigation of eyes-open resting state dynamic functional network connectivity (dFNC) of healthy controls (HC) versus that of schizophrenia patients (SP) via both fMRI and a novel MEG pipeline was completed. The fMRI analysis used a spatial independent component analysis (ICA) to determine the networks on which the dFNC was based. The MEG analysis utilized a source-space activity estimate (MNE/dSPM) whose result was the input to a spatial ICA, on which the networks of the MEG dFNC was based. We found that dFNC measures reveal significant differences between HC and SP, which depended upon the imaging modality. Consistent with previous findings, a dFNC analysis predicated on fMRI data revealed HC and SP remain in different overall brain states (defined by a k-means clustering of network correlations) for significantly different periods of time, with SP spending less time in a highly-connected state. The MEG dFNC, in contrast, revealed group differences in more global statistics: SP changed between meta-states (k-means cluster states that are allowed to overlap in time) significantly more often and to states which were more different, relative to HC. MEG dFNC also revealed a highly connected state where a significant difference was observed in inter-individual variability, with greater variability among SP. Overall, our results show that fMRI and MEG reveal between-group functional connectivity differences in distinct ways, highlighting the utility of using each of the modalities individually, or potentially a combination of modalities, to better inform our understanding of disorders such as schizophrenia.

PMID: 30632385 [PubMed - as supplied by publisher]