New resting-state fMRI related studies at PubMed

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Default Mode Network Subsystems are Differentially Disrupted in Posttraumatic Stress Disorder.

Tue, 04/25/2017 - 13:40
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Default Mode Network Subsystems are Differentially Disrupted in Posttraumatic Stress Disorder.

Biol Psychiatry Cogn Neurosci Neuroimaging. 2017 Jan 13;1:

Authors: Miller DR, Hayes SM, Hayes JP, Spielberg JM, Lafleche G, Verfaellie M

Abstract
BACKGROUND: Posttraumatic stress disorder (PTSD) is a psychiatric disorder characterized by debilitating re-experiencing, avoidance, and hyperarousal symptoms following trauma exposure. Recent evidence suggests that individuals with PTSD show disrupted functional connectivity in the default mode network, an intrinsic network that consists of a midline core, a medial temporal lobe (MTL) subsystem, and a dorsomedial prefrontal cortex (dMPFC) subsystem. The present study examined whether functional connectivity in these subsystems is differentially disrupted in PTSD.
METHODS: Sixty-nine returning war Veterans with PTSD and 44 trauma-exposed Veterans without PTSD underwent resting state functional MRI (rs-fMRI). To examine functional connectivity, seeds were placed in the core hubs of the default mode network, namely the posterior cingulate cortex (PCC) and anterior medial PFC (aMPFC), and in each subsystem.
RESULTS: Compared to controls, individuals with PTSD had reduced functional connectivity between the PCC and the hippocampus, a region of the MTL subsystem. Groups did not differ in connectivity between the PCC and dMPFC subsystem or between the aMPFC and any region within either subsystem. In the PTSD group, connectivity between the PCC and hippocampus was negatively associated with avoidance/numbing symptoms. Examination of the MTL and dMPFC subsystems revealed reduced anticorrelation between the ventromedial PFC (vMPFC) seed of the MTL subsystem and the dorsal anterior cingulate cortex in the PTSD group.
CONCLUSIONS: Our results suggest that selective alterations in functional connectivity in the MTL subsystem of the default mode network in PTSD may be an important factor in PTSD pathology and symptomatology.

PMID: 28435932 [PubMed - in process]

Improving automated multiple sclerosis lesion segmentation with a cascaded 3D convolutional neural network approach.

Tue, 04/25/2017 - 13:40
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Improving automated multiple sclerosis lesion segmentation with a cascaded 3D convolutional neural network approach.

Neuroimage. 2017 Apr 18;:

Authors: Valverde S, Cabezas M, Roura E, González-Villà S, Pareto D, Vilanova JC, Ramió-Torrentà L, Rovira À, Oliver A, Lladó X

Abstract
In this paper, we present a novel automated method for White Matter (WM) lesion segmentation of Multiple Sclerosis (MS) patient images. Our approach is based on a cascade of two 3D patch-wise convolutional neural networks (CNN). The first network is trained to be more sensitive revealing possible candidate lesion voxels while the second network is trained to reduce the number of misclassified voxels coming from the first network. This cascaded CNN architecture tends to learn well from a small (n≤35) set of labeled data of the same MRI contrast, which can be very interesting in practice, given the difficulty to obtain manual label annotations and the large amount of available unlabeled Magnetic Resonance Imaging (MRI) data. We evaluate the accuracy of the proposed method on the public MS lesion segmentation challenge MICCAI2008 dataset, comparing it with respect to other state-of-the-art MS lesion segmentation tools. Furthermore, the proposed method is also evaluated on two private MS clinical datasets, where the performance of our method is also compared with different recent public available state-of-the-art MS lesion segmentation methods. At the time of writing this paper, our method is the best ranked approach on the MICCAI2008 challenge, outperforming the rest of 60 participant methods when using all the available input modalities (T1-w, T2-w and FLAIR), while still in the top-rank (3rd position) when using only T1-w and FLAIR modalities. On clinical MS data, our approach exhibits a significant increase in the accuracy segmenting of WM lesions when compared with the rest of evaluated methods, highly correlating (r≥0.97) also with the expected lesion volume.

PMID: 28435096 [PubMed - as supplied by publisher]

Representation of Multiple Body Parts in the Missing-Hand Territory of Congenital One-Handers.

Tue, 04/25/2017 - 13:40
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Representation of Multiple Body Parts in the Missing-Hand Territory of Congenital One-Handers.

Curr Biol. 2017 Apr 19;:

Authors: Hahamy A, Macdonald SN, van den Heiligenberg F, Kieliba P, Emir U, Malach R, Johansen-Berg H, Brugger P, Culham JC, Makin TR

Abstract
Individuals born without one hand (congenital one-handers) provide a unique model for understanding the relationship between focal reorganization in the sensorimotor cortex and everyday behavior. We previously reported that the missing hand's territory of one-handers becomes utilized by its cortical neighbor (residual arm representation), depending on residual arm usage in daily life to substitute for the missing hand's function [1, 2]. However, the repertoire of compensatory behaviors may involve utilization of other body parts that do not cortically neighbor the hand territory. Accordingly, the pattern of brain reorganization may be more extensive [3]. Here we studied unconstrained compensatory strategies under ecological conditions in one-handers, as well as changes in activation, connectivity, and neurochemical profile in their missing hand's cortical territory. We found that compensatory behaviors in one-handers involved multiple body parts (residual arm, lips, and feet). This diversified compensatory profile was associated with large-scale cortical reorganization, regardless of cortical proximity to the hand territory. Representations of those body parts used to substitute hand function all mapped onto the cortical territory of the missing hand, as evidenced by task-based and resting-state fMRI. The missing-hand territory also exhibited reduced GABA levels, suggesting a reduction in connectional selectivity to enable the expression of diverse cortical inputs. Because the same body parts used for compensatory purposes are those showing increased representation in the missing hand's territory, we suggest that the typical hand territory may not necessarily represent the hand per se, but rather any other body part that shares the functionality of the missing hand [4].

PMID: 28434861 [PubMed - as supplied by publisher]

Decreased hemispheric connectivity and decreased intra- and inter- hemisphere asymmetry of resting state functional network connectivity in schizophrenia.

Mon, 04/24/2017 - 12:20

Decreased hemispheric connectivity and decreased intra- and inter- hemisphere asymmetry of resting state functional network connectivity in schizophrenia.

Brain Imaging Behav. 2017 Apr 22;:

Authors: Agcaoglu O, Miller R, Damaraju E, Rashid B, Bustillo J, Cetin MS, Van Erp TGM, McEwen S, Preda A, Ford JM, Lim KO, Manoach DS, Mathalon DH, Potkin SG, Calhoun VD

Abstract
Many studies have shown that schizophrenia patients have aberrant functional network connectivity (FNC) among brain regions, suggesting schizophrenia manifests with significantly diminished (in majority of the cases) connectivity. Schizophrenia is also associated with a lack of hemispheric lateralization. Hoptman et al. (2012) reported lower inter-hemispheric connectivity in schizophrenia patients compared to controls using voxel-mirrored homotopic connectivity. In this study, we merge these two points of views together using a group independent component analysis (gICA)-based approach to generate hemisphere-specific timecourses and calculate intra-hemisphere and inter-hemisphere FNC on a resting state fMRI dataset consisting of age- and gender-balanced 151 schizophrenia patients and 163 healthy controls. We analyzed the group differences between patients and healthy controls in each type of FNC measures along with age and gender effects. The results reveal that FNC in schizophrenia patients shows less hemispheric asymmetry compared to that of the healthy controls. We also found a decrease in connectivity in all FNC types such as intra-left (L_FNC), intra-right (R_FNC) and inter-hemisphere (Inter_FNC) in the schizophrenia patients relative to healthy controls, but general patterns of connectivity were preserved in patients. Analyses of age and gender effects yielded results similar to those reported in whole brain FNC studies.

PMID: 28434159 [PubMed - as supplied by publisher]

Combined fMRI-MRS acquires simultaneous glutamate and BOLD-fMRI signals in the human brain.

Mon, 04/24/2017 - 12:20

Combined fMRI-MRS acquires simultaneous glutamate and BOLD-fMRI signals in the human brain.

Neuroimage. 2017 Apr 18;:

Authors: Ip IB, Berrington A, Hess AT, Parker AJ, Emir UE, Bridge H

Abstract
Combined fMRI-MRS is a novel method to non-invasively investigate functional activation in the human brain using simultaneous acquisition of hemodynamic and neurochemical measures. The aim of the current study was to quantify neural activity using combined fMRI-MRS at 7 T. BOLD-fMRI and semi-LASER localization MRS data were acquired from the visual cortex of 13 participants during short blocks (64s) of flickering checkerboards. We demonstrate a correlation between glutamate and BOLD-fMRI time courses (R = 0.381, p =0.031). In addition, we show increases in BOLD-fMRI (1.43 ± 0.17%) and glutamate concentrations (0.15 ± 0.05 I.U., ~2%) during visual stimulation. In contrast, we observed no change in glutamate concentrations in resting state MRS data during sham stimulation periods. Spectral line width changes generated by the BOLD-response were corrected using line broadening. In summary, our results establish the feasibility of concurrent measurements of BOLD-fMRI and neurochemicals using a novel combined fMRI-MRS sequence. Our findings strengthen the link between glutamate and functional activity in the human brain by demonstrating a significant correlation of BOLD-fMRI and glutamate over time, and by showing ~2% glutamate increases during 64s of visual stimulation. Our tool may become useful for studies characterizing functional dynamics between neurochemicals and hemodynamics in health and disease.

PMID: 28433623 [PubMed - as supplied by publisher]

Altered eigenvector centrality is related to local resting-state network functional connectivity in patients with longstanding type 1 diabetes mellitus.

Sat, 04/22/2017 - 10:20
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Altered eigenvector centrality is related to local resting-state network functional connectivity in patients with longstanding type 1 diabetes mellitus.

Hum Brain Mapp. 2017 Apr 21;:

Authors: van Duinkerken E, Schoonheim MM, IJzerman RG, Moll AC, Landeira-Fernandez J, Klein M, Diamant M, Snoek FJ, Barkhof F, Wink AM

Abstract
INTRODUCTION: Longstanding type 1 diabetes (T1DM) is associated with microangiopathy and poorer cognition. In the brain, T1DM is related to increased functional resting-state network (RSN) connectivity in patients without, which was decreased in patients with clinically evident microangiopathy. Subcortical structure seems affected in both patient groups. How these localized alterations affect the hierarchy of the functional network in T1DM is unknown. Eigenvector centrality mapping (ECM) and degree centrality are graph theoretical methods that allow determining the relative importance (ECM) and connectedness (degree centrality) of regions within the whole-brain network hierarchy.
METHODS: Therefore, ECM and degree centrality of resting-state functional MRI-scans were compared between 51 patients with, 53 patients without proliferative retinopathy, and 49 controls, and associated with RSN connectivity, subcortical gray matter volume, and cognition.
RESULTS: In all patients versus controls, ECM and degree centrality were lower in the bilateral thalamus and the dorsal striatum, with lowest values in patients without proliferative retinopathy (PFWE  < 0.05). Increased ECM in this group versus patients with proliferative retinopathy was seen in the bilateral lateral occipital cortex, and in the right cuneus and occipital fusiform gyrus versus controls (PFWE  < 0.05). In all patients, ECM and degree centrality were related to altered visual, sensorimotor, and auditory and language RSN connectivity (PFWE  < 0.05), but not to subcortical gray matter volume or cognition (PFDR  > 0.05).
CONCLUSION: The findings suggested reorganization of the hierarchy of the cortical connectivity network in patients without proliferative retinopathy, which is lost with disease progression. Centrality seems sensitive to capture early T1DM-related functional connectivity alterations, but not disease progression. Hum Brain Mapp, 2017. © 2017 Wiley Periodicals, Inc.

PMID: 28429383 [PubMed - as supplied by publisher]

Resting-State Neuroimaging and Neuropsychological Findings in Opioid Use Disorder during Abstinence: A Review.

Sat, 04/22/2017 - 10:20
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Resting-State Neuroimaging and Neuropsychological Findings in Opioid Use Disorder during Abstinence: A Review.

Front Hum Neurosci. 2017;11:169

Authors: Ieong HF, Yuan Z

Abstract
Dependence to opiates, including illicit heroin and prescription pain killers, and treatment of the opioid use disorder (OUD) have been longstanding problems over the world. Despite intense efforts to scientific investigation and public health care, treatment outcomes have not significantly improved for the past 50 years. One reason behind the continuing use of heroin worldwide despite such efforts is its highly addictive nature. Brain imaging studies over the past two decades have made significant contribution to the understanding of the addictive properties as to be due in part to biological processes, specifically those in the brain structure and function. Moreover, traditional clinical neuropsychology studies also contribute to the account in part for the treatment-refractory nature of the drug abuse. However, there is a gap between those studies, and the rates of relapse are still high. Thus, a multidisciplinary approach is needed to understand the fundamental neural mechanism of OUD. How does the brain of an OUD patient functionally and cognitively differ from others? This brief review is to compare and contrast the current literature on non-invasive resting state neuroimaging and clinical neuropsychological studies with the focus on the abstinence stage in OUD. The results show as follow: Brain connectivity strength in the reward system, dysregulation of circuits associated with emotion and stress, enhanced beta and alpha power activity, and high impulsivity are induced by OUD.Some recovery signs in cognition are demonstrated in OUD subjects after prolonged abstinence, but not in the subjects undergoing methadone treatment.Normalization in the composition of brain oscillations especially in the temporal region is induced and restored by methadone treatment in roughly 6 months in mean duration for OUDs having a mean opioid-use history of 10 years. We hope that the review provides valuable implications for clinical research and practice and paves a new insight into the future path to the identification of potential biomarkers and clinical outcome predictors in OUD in the domains of brain regions, functions, and behaviors.

PMID: 28428748 [PubMed - in process]

Resting-State Seed-Based Analysis: An Alternative to Task-Based Language fMRI and Its Laterality Index.

Sat, 04/22/2017 - 10:20
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Resting-State Seed-Based Analysis: An Alternative to Task-Based Language fMRI and Its Laterality Index.

AJNR Am J Neuroradiol. 2017 Apr 20;:

Authors: Smitha KA, Arun KM, Rajesh PG, Thomas B, Kesavadas C

Abstract
BACKGROUND AND PURPOSE: Language is a cardinal function that makes human unique. Preservation of language function poses a great challenge for surgeons during resection. The aim of the study was to assess the efficacy of resting-state fMRI in the lateralization of language function in healthy subjects to permit its further testing in patients who are unable to perform task-based fMRI.
MATERIALS AND METHODS: Eighteen healthy right-handed volunteers were prospectively evaluated with resting-state fMRI and task-based fMRI to assess language networks. The laterality indices of Broca and Wernicke areas were calculated by using task-based fMRI via a voxel-value approach. We adopted seed-based resting-state fMRI connectivity analysis together with parameters such as amplitude of low-frequency fluctuation and fractional amplitude of low-frequency fluctuation (fALFF). Resting-state fMRI connectivity maps for language networks were obtained from Broca and Wernicke areas in both hemispheres. We performed correlation analysis between the laterality index and the z scores of functional connectivity, amplitude of low-frequency fluctuation, and fALFF.
RESULTS: Pearson correlation analysis between signals obtained from the z score of fALFF and the laterality index yielded a correlation coefficient of 0.849 (P < .05). Regression analysis of the fALFF with the laterality index yielded an R(2) value of 0.721, indicating that 72.1% of the variance in the laterality index of task-based fMRI could be predicted from the fALFF of resting-state fMRI.
CONCLUSIONS: The present study demonstrates that fALFF can be used as an alternative to task-based fMRI for assessing language laterality. There was a strong positive correlation between the fALFF of the Broca area of resting-state fMRI with the laterality index of task-based fMRI. Furthermore, we demonstrated the efficacy of fALFF for predicting the laterality of task-based fMRI.

PMID: 28428208 [PubMed - as supplied by publisher]

The correlation between mood states and functional connectivity within the default mode network can differentiate Internet gaming disorder from healthy controls.

Sat, 04/22/2017 - 10:20
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The correlation between mood states and functional connectivity within the default mode network can differentiate Internet gaming disorder from healthy controls.

Prog Neuropsychopharmacol Biol Psychiatry. 2017 Apr 18;:

Authors: Dong G, Li H, Wang L, Potenza MN

Abstract
The default-mode network (DMN) has been suggested to support a baseline state of brain activity. However, whether connectivity within the DMN is associated with mood states remains incompletely understood. The current study examined the correlation between mood state and the functional connectivity (FC) among DMN regions, and examined if the FC can differentiate Internet gaming disorder (IGD) from healthy controls (HC). Resting state data were collected within 108 college students (IGD,41; HC,67). Negative correlations were observed between measures of: (1) Depression and FCs among ventral DMN regions; (2) Anger and FCs among dorsal DMN regions; and, (3) Anger and Depression and FCs of both the ventral and dorsal DMN. The results suggest that negative mood states of Depression and Anger might reflect poorer, or might impair, FCs among DMN regions. In addition, the FC among DMNs could be useful indexes in differencing IGD from HC. Future studies should examine the extent to which the findings may extend to clinical populations and whether increased connectivity of DMN regions may represent a mechanism for reducing negative mood states.

PMID: 28428146 [PubMed - as supplied by publisher]

Differences in interregional brain connectivity in children with unilateral hearing loss.

Fri, 04/21/2017 - 15:20
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Differences in interregional brain connectivity in children with unilateral hearing loss.

Laryngoscope. 2017 Apr 20;:

Authors: Jung ME, Colletta M, Coalson R, Schlaggar BL, Lieu JEC

Abstract
OBJECTIVES: To identify functional network architecture differences in the brains of children with unilateral hearing loss (UHL) using resting-state functional-connectivity magnetic resonance imaging (rs-fcMRI).
STUDY DESIGN: Prospective observational study.
METHODS: Children (7 to 17 years of age) with severe to profound hearing loss in one ear, along with their normal hearing (NH) siblings, were recruited and imaged using rs-fcMRI. Eleven children had right UHL; nine had left UHL; and 13 had normal hearing. Forty-one brain regions of interest culled from established brain networks such as the default mode (DMN); cingulo-opercular (CON); and frontoparietal networks (FPN); as well as regions for language, phonological, and visual processing, were analyzed using regionwise correlations and conjunction analysis to determine differences in functional connectivity between the UHL and normal hearing children.
RESULTS: When compared to the NH group, children with UHL showed increased connectivity patterns between multiple networks, such as between the CON and visual processing centers. However, there were decreased, as well as aberrant connectivity patterns with the coactivation of the DMN and FPN, a relationship that usually is negatively correlated.
CONCLUSION: Children with UHL demonstrate multiple functional connectivity differences between brain networks involved with executive function, cognition, and language comprehension that may represent adaptive as well as maladaptive changes. These findings suggest that possible interventions or habilitation, beyond amplification, might be able to affect some children's requirement for additional help at school.
LEVEL OF EVIDENCE: 3b. Laryngoscope, 2017.

PMID: 28425563 [PubMed - as supplied by publisher]

Modafinil-Induced Changes in Functional Connectivity in the Cortex and Cerebellum of Healthy Elderly Subjects.

Fri, 04/21/2017 - 15:20
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Modafinil-Induced Changes in Functional Connectivity in the Cortex and Cerebellum of Healthy Elderly Subjects.

Front Aging Neurosci. 2017;9:85

Authors: Punzi M, Gili T, Petrosini L, Caltagirone C, Spalletta G, Sensi SL

Abstract
In the past few years, cognitive enhancing drugs (CEDs) have gained growing interest and the focus of investigations aimed at exploring their use to potentiate the cognitive performances of healthy individuals. Most of this exploratory CED-related research has been performed on young adults. However, CEDs may also help to maintain optimal brain functioning or compensate for subtle and or subclinical deficits associated with brain aging or early-stage dementia. In this study, we assessed effects on resting state brain activity in a group of healthy elderly subjects undergoing acute administration of modafinil, a wakefulness-promoting agent. To that aim, participants (n = 24) were investigated with resting state functional Magnetic Resonance Imaging (rs-fMRI) before and after the administration of a single dose (100 mg) of modafinil. Effects were compared to age and size-matched placebo group. Rs-fMRI effects were assessed, employing a graph-based approach and Eigenvector Centrality (EC) analysis, by taking in account topological changes occurring in functional brain networks. The main finding of the study is that modafinil promotes enhanced centrality, a measure of the importance of nodes within functional networks, of the bilateral primary visual (V1) cortex. EC analysis also revealed that modafinil-treated subjects show increased functional connectivity between the V1 and specific cerebellar (Crus I, Crus II, VIIIa lobule) and frontal (right inferior frontal sulcus and left middle frontal gyrus) regions. Present findings provide functional data supporting the hypothesis that modafinil can modulate the cortico-cerebellar connectivity of the aging brain.

PMID: 28424611 [PubMed - in process]

Longitudinal recovery of local neuronal activity and consciousness level in acquired brain injury.

Fri, 04/21/2017 - 02:40

Longitudinal recovery of local neuronal activity and consciousness level in acquired brain injury.

Hum Brain Mapp. 2017 Apr 19;:

Authors: Zou Q, Wu X, Hu J, Tang W, Mao Y, Zhu J, Lu L, Zhang Y, Gao JH

Abstract
Decreased brain activity in the default mode network, particularly in the precuneus (PCU), has been consistently shown in acquired brain injury (ABI) patients. However, it is unclear whether resting-state brain activity recovers longitudinally in ABI patients and whether functional activity restoration is associated with improvements in consciousness level. Here, resting-state fMRI data were acquired from 23 ABI patients and 30 age- and gender-matched controls with two longitudinal observations for each participant. The fMRI data were analyzed using amplitude of low-frequency fluctuation (ALFF) to measure the fluctuation strength of local spontaneous activity, and seed-based functional connectivity was used to measure functional relationship with the seed region in the whole brain. The level of consciousness was assessed using the Glasgow Coma Scale (GCS) and Coma Recovery Scale-Revised (CRS-R) on both scanning days of the patients. Interaction effect between the two groups and two scans in ALFF was observed in the PCU, which was driven by restored ALFF in the ABI, while a stable ALFF in the control group. Moreover, restoration of ALFF in the PCU correlated with improvements in both the CRS-R and GCS. Specifically, recovery of ALFF in the PCU primarily reflected the signals of the slow-4 frequency band (0.027-0.073 Hz). Based on the functional connectivity maps of the PCU, we observed a nonsignificant interaction effect or correlation with consciousness level. These findings suggest local activity in the PCU but possibly not its functional connectivity, is related to the longitudinal changes in behavioral responsiveness in ABI. Hum Brain Mapp, 2017. © 2017 Wiley Periodicals, Inc.

PMID: 28422373 [PubMed - as supplied by publisher]

Mapping Dorsal and Ventral Caudate in Older Adults: Method and Validation.

Fri, 04/21/2017 - 02:40
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Mapping Dorsal and Ventral Caudate in Older Adults: Method and Validation.

Front Aging Neurosci. 2017;9:91

Authors: Huang H, Nguyen PT, Schwab NA, Tanner JJ, Price CC, Ding M

Abstract
The caudate nucleus plays important roles in cognition and affect. Depending on associated connectivity and function, the caudate can be further divided into dorsal and ventral aspects. Dorsal caudate, highly connected to dorsolateral prefrontal cortex (DLPFC), is implicated in executive function and working memory; ventral caudate, more interconnected with the limbic system, is implicated in affective functions such as pain processing. Clinically, certain brain disorders are known to differentially impact dorsal and ventral caudate. Thus, precise parcellation of caudate has both basic and clinical neuroscience significance. In young adults, past work has combined resting-state fMRI functional connectivity with clustering algorithms to define dorsal and ventral caudate. Whether the same approach is effective in older adults and how to validate the parcellation results have not been considered. We addressed these problems by obtaining resting-state fMRI data from 56 older non-demented adults (age: 69.07 ± 5.92 years and MOCA: 25.71 ± 2.46) along with a battery of cognitive and clinical assessments. Connectivity from each voxel of caudate to the rest of the brain was computed using cross correlation. Applying the K-means clustering algorithm to the connectivity patterns with K = 2 yielded two substructures within caudate, which agree well with previously reported dorsal and ventral divisions of caudate. Furthermore, dorsal-caudate-seeded functional connectivity was shown to be more strongly associated with working memory and fluid reasoning composite scores, whereas ventral-caudate-seeded functional connectivity more strongly associated with pain and fatigue severity. These results demonstrate that dorsal and ventral caudate can be reliably identified by combining resting-state fMRI and clustering algorithms in older adults.

PMID: 28420985 [PubMed - in process]

Age-Related Difference in Functional Brain Connectivity of Mastication.

Fri, 04/21/2017 - 02:40
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Age-Related Difference in Functional Brain Connectivity of Mastication.

Front Aging Neurosci. 2017;9:82

Authors: Lin CS, Wu CY, Wu SY, Lin HH, Cheng DH, Lo WL

Abstract
The age-related decline in motor function is associated with changes in intrinsic brain signatures. Here, we investigated the functional connectivity (FC) associated with masticatory performance, a clinical index evaluating general masticatory function. Twenty-six older adults (OA) and 26 younger (YA) healthy adults were recruited and assessed using the masticatory performance index (MPI) and resting-state functional magnetic resonance imaging (rs-fMRI). We analyzed the rs-fMRI FC network related to mastication, which was constructed based on 12 bilateral mastication-related brain regions according to the literature. For the OA and the YA group, we identified the mastication-related hubs, i.e., the nodes for which the degree centrality (DC) was positively correlated with the MPI. For each pair of nodes, we identified the inter-nodal link for which the FC was positively correlated with the MPI. The network analysis revealed that, in the YA group, the FC between the sensorimotor cortex, the thalamus (THA) and the cerebellum was positively correlated with the MPI. Consistently, the cerebellum nodes were defined as the mastication-related hubs. In contrast, in the OA group, we found a sparser connection within the sensorimotor regions and cerebellum and a denser connection across distributed regions, including the FC between the superior parietal lobe (SPL), the anterior insula (aINS) and the dorsal anterior cingulate cortex (dACC). Compared to the YA group, the network of the OA group also comprised more mastication-related hubs, which were spatially distributed outside the sensorimotor regions, including the right SPL, the right aINS, and the bilateral dACC. In general, the findings supported the hypothesis that in OA, higher masticatory performance is associated with a widespread pattern of mastication-related hubs. Such a widespread engagement of multiple brain regions associated with the MPI may reflect an increased demand in sensorimotor integration, attentional control and monitoring for OA to maintain good mastication.

PMID: 28420981 [PubMed - in process]

Resting State fMRI Reveals Increased Subthalamic Nucleus and Sensorimotor Cortex Connectivity in Patients with Parkinson's Disease under Medication.

Fri, 04/21/2017 - 02:40
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Resting State fMRI Reveals Increased Subthalamic Nucleus and Sensorimotor Cortex Connectivity in Patients with Parkinson's Disease under Medication.

Front Aging Neurosci. 2017;9:74

Authors: Shen B, Gao Y, Zhang W, Lu L, Zhu J, Pan Y, Lan W, Xiao C, Zhang L

Abstract
Functional connectivity (FC) between the subthalamic nucleus (STN) and the sensorimotor cortex is increased in off-medication patients with Parkinson's disease (PD). However, the status of FC between STN and sensorimotor cortex in on-medication PD patients remains unclear. In this study, resting state functional magnetic resonance imaging was employed on 31 patients with PD under medication and 31 healthy controls. Two-sample t-test was used to study the change in FC pattern of the STN, the FC strength of the bilateral STN was correlated with overall motor symptoms, while unilateral STN was correlated with offside motor symptoms. Both bilateral and right STN showed increased FC with the right sensorimotor cortex, whereas only right STN FC was correlated with left-body rigidity scores in all PD patients. An additional subgroup analysis was performed according to the ratio of mean tremor scores and mean postural instability and gait difficulty (PIGD) scores, only the PIGD subgroup showed the increased FC between right STN and sensorimotor cortex under medication. Increased FC between the STN and the sensorimotor cortex was found, which was related to motor symptom severity in on-medication PD patients. Anti-PD drugs may influence the hyperdirect pathway to alleviate motor symptoms with the more effect on the tremor subtype.

PMID: 28420978 [PubMed - in process]

Multi-modal, Multi-measure, and Multi-class Discrimination of ADHD with Hierarchical Feature Extraction and Extreme Learning Machine Using Structural and Functional Brain MRI.

Fri, 04/21/2017 - 02:40
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Multi-modal, Multi-measure, and Multi-class Discrimination of ADHD with Hierarchical Feature Extraction and Extreme Learning Machine Using Structural and Functional Brain MRI.

Front Hum Neurosci. 2017;11:157

Authors: Qureshi MNI, Oh J, Min B, Jo HJ, Lee B

Abstract
Structural and functional MRI unveil many hidden properties of the human brain. We performed this multi-class classification study on selected subjects from the publically available attention deficit hyperactivity disorder ADHD-200 dataset of patients and healthy children. The dataset has three groups, namely, ADHD inattentive, ADHD combined, and typically developing. We calculated the global averaged functional connectivity maps across the whole cortex to extract anatomical atlas parcellation based features from the resting-state fMRI (rs-fMRI) data and cortical parcellation based features from the structural MRI (sMRI) data. In addition, the preprocessed image volumes from both of these modalities followed an ANOVA analysis separately using all the voxels. This study utilized the average measure from the most significant regions acquired from ANOVA as features for classification in addition to the multi-modal and multi-measure features of structural and functional MRI data. We extracted most discriminative features by hierarchical sparse feature elimination and selection algorithm. These features include cortical thickness, image intensity, volume, cortical thickness standard deviation, surface area, and ANOVA based features respectively. An extreme learning machine performed both the binary and multi-class classifications in comparison with support vector machines. This article reports prediction accuracy of both unimodal and multi-modal features from test data. We achieved 76.190% (p < 0.0001) classification accuracy in multi-class settings as well as 92.857% (p < 0.0001) classification accuracy in binary settings. In addition, we found ANOVA-based significant regions of the brain that also play a vital role in the classification of ADHD. Thus, from a clinical perspective, this multi-modal group analysis approach with multi-measure features may improve the accuracy of the ADHD differential diagnosis.

PMID: 28420972 [PubMed - in process]

A Fall in the Workplace Leads to a Diagnosis of Parkinson's Disease.

Fri, 04/21/2017 - 02:40
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A Fall in the Workplace Leads to a Diagnosis of Parkinson's Disease.

Workplace Health Saf. 2016 Aug;64(8):348-9

Authors: Lurati AR

Abstract
A 62 year old male worker sustained a head contusion from a fall in the workplace. When assessing the mechanism of the fall, it was noted that the worker stated that his feet became "stuck" and would not move. He also stated that he could not move fast enough to break his fall. Upon physical examination, a resting tremor was noted as well as upper and lower body rigidity, and a festinating gait. The worker was evaluated by a neurologist and diagnosed with early Parkinson's disease.

PMID: 27026277 [PubMed - indexed for MEDLINE]

Intranasal oxytocin enhances intrinsic corticostriatal functional connectivity in women.

Wed, 04/19/2017 - 13:20

Intranasal oxytocin enhances intrinsic corticostriatal functional connectivity in women.

Transl Psychiatry. 2017 Apr 18;7(4):e1099

Authors: Bethlehem RAI, Lombardo MV, Lai MC, Auyeung B, Crockford SK, Deakin J, Soubramanian S, Sule A, Kundu P, Voon V, Baron-Cohen S

Abstract
Oxytocin may influence various human behaviors and the connectivity across subcortical and cortical networks. Previous oxytocin studies are male biased and often constrained by task-based inferences. Here, we investigate the impact of oxytocin on resting-state connectivity between subcortical and cortical networks in women. We collected resting-state functional magnetic resonance imaging (fMRI) data on 26 typically developing women 40 min following intranasal oxytocin administration using a double-blind placebo-controlled crossover design. Independent components analysis (ICA) was applied to examine connectivity between networks. An independent analysis of oxytocin receptor (OXTR) gene expression in human subcortical and cortical areas was carried out to determine plausibility of direct oxytocin effects on OXTR. In women, OXTR was highly expressed in striatal and other subcortical regions, but showed modest expression in cortical areas. Oxytocin increased connectivity between corticostriatal circuitry typically involved in reward, emotion, social communication, language and pain processing. This effect was 1.39 standard deviations above the null effect of no difference between oxytocin and placebo. This oxytocin-related effect on corticostriatal connectivity covaried with autistic traits, such that oxytocin-related increase in connectivity was stronger in individuals with higher autistic traits. In sum, oxytocin strengthened corticostriatal connectivity in women, particularly with cortical networks that are involved in social-communicative, motivational and affective processes. This effect may be important for future work on neurological and psychiatric conditions (for example, autism), particularly through highlighting how oxytocin may operate differently for subsets of individuals.

PMID: 28418398 [PubMed - in process]

S100A10 identified in a genome-wide gene × cannabis dependence interaction analysis of risky sexual behaviours.

Wed, 04/19/2017 - 13:20

S100A10 identified in a genome-wide gene × cannabis dependence interaction analysis of risky sexual behaviours.

J Psychiatry Neurosci. 2017 Apr 13;42(4):160189

Authors: Polimanti R, Meda SA, Pearlson GD, Zhao H, Sherva R, Farrer LA, Kranzler HR, Gelernter J

Abstract
BACKGROUND: We conducted a genome-wide gene × environment interaction analysis to identify genetic variants that interact with cannabis dependence (CaD) in influencing risky sexual behaviours (RSB).
METHODS: Our sample included cannabis-exposed and sexually experienced African-American and European-American participants. A DSM-IV CaD diagnosis and RSB were evaluated using the Semi-Structured Assessment for Drug Dependence and Alcoholism. We analyzed RSBs as a score that takes into account experiences of unprotected sex and multiple sexual partners.
RESULTS: A total of 3350 people participated in our study; 43% had a CaD diagnosis, 56% were African-American and 33% were women. We identified a genome-wide significant locus in African-American participants (S100A10 rs72993629, p = 2.73 × 10(-8)) and a potential transpopulation signal in women (CLTC rs12944716, p = 5.27 × 10(-8)). A resting-state fMRI follow-up analysis of S100A10 rs72993629 conducted in an independent cohort showed 2 significant associations: reduced power of the left paracentral lobule in amplitude of low frequency fluctuations (ALFF) analysis (p = 7.8 × 10(-3)) and reduced power of the right pallidum in fractional ALFF analysis (p = 4.6 × 10(-3)). The activity of these brain regions is known to be involved in sexual functions and behaviours. The S100A10 result functionally recapitulated our S100B finding observed in our previous genome-wide association study of CaD. The probability of identifying 2 S100 genes in 2 independent genome-wide investigations by chance is approximately 1 in 1.1 million.
LIMITATIONS: We were not able to identify any African-American cohort with appropriate sample size, and phenotypic assessment is available to replicate our findings.
CONCLUSION: The S100A10 and S100B genes, which are located on different chromosomes, encode specialized calcium-binding proteins. These data support a role for calcium homeostasis in individuals with CaD and its induced behaviours.

PMID: 28418321 [PubMed - as supplied by publisher]

A posterior-to-anterior shift of brain functional dynamics in aging.

Wed, 04/19/2017 - 13:20
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A posterior-to-anterior shift of brain functional dynamics in aging.

Brain Struct Funct. 2017 Apr 17;:

Authors: Zhang H, Lee A, Qiu A

Abstract
Convergent evidence from task-based functional magnetic resonance imaging (fMRI) studies suggests a posterior-to-anterior shift as an adaptive compensatory scaffolding mechanism for aging. This study aimed to investigate whether brain functional dynamics at rest follow the same scaffolding mechanism for aging using a large Chinese sample aged from 22 to 79 years (n = 277). We defined a probability of brain regions being hubs over a period of time to characterize functional hub dynamic, and defined variability of the functional connectivity to characterize dynamic functional connectivity using resting-state fMRI. Our results revealed that both functional hub dynamics and dynamic functional connectivity posited an age-related posterior-to-anterior shift. Specifically, the posterior brain region showed attenuated dynamics, while the anterior brain regions showed augmented dynamics in aging. Interestingly, our analysis further indicated that the age-related episodic memory decline was associated with the age-related decrease in the brain functional dynamics of the posterior regions. Hence, these findings provided a new dimension to view the scaffolding mechanism for aging based on the brain functional dynamics.

PMID: 28417233 [PubMed - as supplied by publisher]

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