Anesthesiol Clin. 2016 Jun;34(2):255-69
Authors: Martucci KT, Mackey SC
The challenges and understanding of acute and chronic pain have been illuminated through the advancement of central neuroimaging. Through neuroimaging research, new technology and findings have allowed us to identify and understand the neural mechanisms contributing to chronic pain. Several regions of the brain are known to be of particular importance for the maintenance and amplification of chronic pain, and this knowledge provides novel targets for future research and treatment. This article reviews neuroimaging for the study of chronic pain, and in particular, the rapidly advancing and popular research tools of structural and functional MRI.
PMID: 27208709 [PubMed - indexed for MEDLINE]
Identifying the presence of Parkinson's disease using low-frequency fluctuations in BOLD signals.
Neurosci Lett. 2017 Feb 26;:
Authors: Tang Y, Meng L, Wan CM, Liu ZH, Liao WH, Yan XX, Wang XY, Tang BS, Guo JF
Parkinson's disease (PD) is a chronic, progressive, and degenerative neurological disorder that is characterized by the degeneration of dopamine neurons in the substantia nigra and the formation of intracellular Lewy inclusion bodies. Resting-state functional magnetic resonance imaging (RS-fMRI) has demonstrated evidence of changes in metabolic patterns in individuals with PD. The purpose of this study was to determine whether the presence of PD could be "predicted" based on resting fluctuations in the blood oxygenation level dependent signal. We utilized RS-fMRI to measure the amplitude of low-frequency fluctuation (ALFF) and the fractional ALFF (fALFF) in 51 patients with PD and 50 age- and sex-matched healthy controls. Compared with the healthy controls, the individuals with PD exhibited altered ALFFs in the bilateral lingual gyrus and left putamen and an altered fALFF in the right cerebellum posterior lobe. Support vector machines (SVMs), which comprise a supervised pattern recognition method that enables predictions at the individual level, were trained to separate individuals with PD from healthy controls based on the ALFF and fALFF. Using the leave-one-out cross-validation method to analyze our sample, we reliably distinguished the participants with PD from the controls with 92% sensitivity and 87% specificity. Overall, these findings suggest that the SVM-neuroimaging approach may be of particular clinical value because it enables the accurate identification of PD at the individual level. RS-fMRI should be considered for development as a biomarker and an analytical tool for the evaluation of PD.
PMID: 28249785 [PubMed - as supplied by publisher]
Multiregional integration in the brain during resting-state fMRI activity.
PLoS Comput Biol. 2017 Mar 01;13(3):e1005410
Authors: Hay E, Ritter P, Lobaugh NJ, McIntosh AR
Data-driven models of functional magnetic resonance imaging (fMRI) activity can elucidate dependencies that involve the combination of multiple brain regions. Activity in some regions during resting-state fMRI can be predicted with high accuracy from the activities of other regions. However, it remains unclear in which regions activity depends on unique integration of multiple predictor regions. To address this question, sparse (parsimonious) models could serve to better determine key interregional dependencies by reducing false positives. We used resting-state fMRI data from 46 subjects, and for each region of interest (ROI) per subject we performed whole-brain recursive feature elimination (RFE) to select the minimal set of ROIs that best predicted activity in the modeled ROI. We quantified the dependence of activity on multiple predictor ROIs, by measuring the gain in prediction accuracy of models that incorporated multiple predictor ROIs compared to models that used a single predictor ROI. We identified regions that showed considerable evidence of multiregional integration and determined the key regions that contributed to their observed activity. Our models reveal fronto-parietal integration networks, little integration in primary sensory regions, as well as redundancy between some regions. Our study demonstrates the utility of whole-brain RFE to generate data-driven models with minimal sets of ROIs that predict activity with high accuracy. By determining the extent to which activity in each ROI depended on integration of signals from multiple ROIs, we find cortical integration networks during resting-state activity.
PMID: 28248957 [PubMed - as supplied by publisher]
Naltrexone ameliorates functional network abnormalities in alcohol-dependent individuals.
Addict Biol. 2017 Feb 28;:
Authors: Morris LS, Baek K, Tait R, Elliott R, Ersche KD, Flechais R, McGonigle J, Murphy A, Nestor LJ, Orban C, Passetti F, Paterson LM, Rabiner I, Reed L, Smith D, Suckling J, Taylor EM, Bullmore ET, Lingford-Hughes AR, Deakin B, Nutt DJ, Sahakian BJ, Robbins TW, Voon V, ICCAM Consortium
Naltrexone, an opioid receptor antagonist, is commonly used as a relapse prevention medication in alcohol and opiate addiction, but its efficacy and the mechanisms underpinning its clinical usefulness are not well characterized. In the current study, we examined the effects of 50-mg naltrexone compared with placebo on neural network changes associated with substance dependence in 21 alcohol and 36 poly-drug-dependent individuals compared with 36 healthy volunteers. Graph theoretic and network-based statistical analysis of resting-state functional magnetic resonance imaging (MRI) data revealed that alcohol-dependent subjects had reduced functional connectivity of a dispersed network compared with both poly-drug-dependent and healthy subjects. Higher local efficiency was observed in both patient groups, indicating clustered and segregated network topology and information processing. Naltrexone normalized heightened local efficiency of the neural network in alcohol-dependent individuals, to the same levels as healthy volunteers. Naltrexone failed to have an effect on the local efficiency in abstinent poly-substance-dependent individuals. Across groups, local efficiency was associated with substance, but no alcohol exposure implicating local efficiency as a potential premorbid risk factor in alcohol use disorders that can be ameliorated by naltrexone. These findings suggest one possible mechanism for the clinical effects of naltrexone, namely, the amelioration of disrupted network topology.
PMID: 28247526 [PubMed - as supplied by publisher]
Working memory capacity and the functional connectome - insights from resting-state fMRI and voxelwise centrality mapping.
Brain Imaging Behav. 2017 Feb 28;:
Authors: Markett S, Reuter M, Heeren B, Lachmann B, Weber B, Montag C
The functional connectome represents a comprehensive network map of functional connectivity throughout the human brain. To date, the relationship between the organization of functional connectivity and cognitive performance measures is still poorly understood. In the present study we use resting-state functional magnetic resonance imaging (fMRI) data to explore the link between the functional connectome and working memory capacity in an individual differences design. Working memory capacity, which refers to the maximum amount of context information that an individual can retain in the absence of external stimulation, was assessed outside the MRI scanner and estimated based on behavioral data from a change detection task. Resting-state time series were analyzed by means of voxelwise degree and eigenvector centrality mapping, which are data-driven network analytic approaches for the characterization of functional connectivity. We found working memory capacity to be inversely correlated with both centrality in the right intraparietal sulcus. Exploratory analyses revealed that this relationship was putatively driven by an increase in negative connectivity strength of the structure. This resting-state connectivity finding fits previous task based activation studies that have shown that this area responds to manipulations of working memory load.
PMID: 28247158 [PubMed - as supplied by publisher]
Longitudinal Intrinsic Brain Activity Changes in Cirrhotic Patients before and One Month after Liver Transplantation.
Korean J Radiol. 2017 Mar-Apr;18(2):370-377
Authors: Cheng Y, Huang LX, Zhang L, Ma M, Xie SS, Ji Q, Zhang XD, Zhang GY, Zhang XN, Ni HY, Shen W
OBJECTIVE: To evaluate the spontaneous brain activity alterations in liver transplantation (LT) recipients using resting-state functional MRI.
MATERIALS AND METHODS: Twenty cirrhotic patients as transplant candidates and 25 healthy controls (HCs) were included in this study. All patients repeated the MRI study one month after LT. Amplitude of low-frequency fluctuation (ALFF) values were compared between cirrhotic patients (both pre- and post-LT) and HCs as well as between the pre- and post-LT groups. The relationship between ALFF changes and venous blood ammonia levels and neuropsychological tests were investigated using Pearson's correlation analysis.
RESULTS: In the cirrhotic patients, decreased ALFF in the vision-related regions (left lingual gyrus and calcarine), sensorimotor-related regions (left postcentral gyrus and middle cingulate cortex), and the default-mode network (bilateral precuneus and left inferior parietal lobule) were restored, and the increased ALFF in the temporal and frontal lobe improved in the early period after LT. The ALFF decreases persisted in the right supplementary motor area, inferior parietal lobule, and calcarine. The ALFF changes in the right precuneus were negatively correlated with changes in number connection test-A scores (r = 0.507, p < 0.05).
CONCLUSION: LT improved spontaneous brain activity and the results for associated cognition tests. However, decreased ALFF in some areas persisted, and new-onset abnormal ALFF were possible, indicating that complete cognitive function recovery may need more time.
PMID: 28246517 [PubMed - in process]
Motion sickness increases functional connectivity between visual motion and nausea-associated brain regions.
Auton Neurosci. 2017 Jan;202:108-113
Authors: Toschi N, Kim J, Sclocco R, Duggento A, Barbieri R, Kuo B, Napadow V
The brain networks supporting nausea not yet understood. We previously found that while visual stimulation activated primary (V1) and extrastriate visual cortices (MT+/V5, coding for visual motion), increasing nausea was associated with increasing sustained activation in several brain areas, with significant co-activation for anterior insula (aIns) and mid-cingulate (MCC) cortices. Here, we hypothesized that motion sickness also alters functional connectivity between visual motion and previously identified nausea-processing brain regions. Subjects prone to motion sickness and controls completed a motion sickness provocation task during fMRI/ECG acquisition. We studied changes in connectivity between visual processing areas activated by the stimulus (MT+/V5, V1), right aIns and MCC when comparing rest (BASELINE) to peak nausea state (NAUSEA). Compared to BASELINE, NAUSEA reduced connectivity between right and left V1 and increased connectivity between right MT+/V5 and aIns and between left MT+/V5 and MCC. Additionally, the change in MT+/V5 to insula connectivity was significantly associated with a change in sympathovagal balance, assessed by heart rate variability analysis. No state-related connectivity changes were noted for the control group. Increased connectivity between a visual motion processing region and nausea/salience brain regions may reflect increased transfer of visual/vestibular mismatch information to brain regions supporting nausea perception and autonomic processing. We conclude that vection-induced nausea increases connectivity between nausea-processing regions and those activated by the nauseogenic stimulus. This enhanced low-frequency coupling may support continual, slowly evolving nausea perception and shifts toward sympathetic dominance. Disengaging this coupling may be a target for biobehavioral interventions aimed at reducing motion sickness severity.
PMID: 28245927 [PubMed - in process]
Cortical plasticity after brachial plexus injury and repair: a resting-state functional MRI study.
Neurosurg Focus. 2017 Mar;42(3):E14
Authors: Bhat DI, Indira Devi B, Bharti K, Panda R
OBJECTIVE The authors aimed to understand the alterations of brain resting-state networks (RSNs) in patients with pan-brachial plexus injury (BPI) before and after surgery, which might provide insight into cortical plasticity after peripheral nerve injury and regeneration. METHODS Thirty-five patients with left pan-BPI before surgery, 30 patients after surgery, and 25 healthy controls underwent resting-state functional MRI (rs-fMRI). The 30 postoperative patients were subdivided into 2 groups: 14 patients with improvement in muscle power and 16 patients with no improvement in muscle power after surgery. RSNs were extracted using independent component analysis to evaluate connectivity at a significance level of p < 0.05 (familywise error corrected). RESULTS The patients with BPI had lower connectivity in their sensorimotor network (SMN) and salience network (SN) and greater connectivity in their default mode network (DMN) before surgery than the controls. Connectivity of the left supplementary motor cortex in the SMN and medial frontal gyrus and in the anterior cingulate cortex in the SN increased in patients whose muscle power had improved after surgery, whereas no significant changes were noted in the unimproved patients. There was a trend toward reduction in DMN connectivity in all the patients after surgery compared with that in the preoperative patients; however, this result was not statistically significant. CONCLUSIONS The results of this study highlight the fact that peripheral nerve injury, its management, and successful treatment cause dynamic changes within the brain's RSNs, which includes not only the obvious SMN but also the higher cognitive networks such as the SN and DMN, which indicates brain plasticity and compensatory mechanisms at work.
PMID: 28245732 [PubMed - in process]
Abnormal Spontaneous Brain Activity in Women with Premenstrual Syndrome Revealed by Regional Homogeneity.
Front Hum Neurosci. 2017;11:62
Authors: Liao H, Pang Y, Liu P, Liu H, Duan G, Liu Y, Tang L, Tao J, Wen D, Li S, Liang L, Deng D
Background: Previous studies have revealed that the etiologies of premenstrual syndrome (PMS) refer to menstrual cycle related brain changes. However, its intrinsic neural mechanism is still unclear. The aim of the present study was to assess abnormal spontaneous brain activity and to explicate the intricate neural mechanism of PMS using resting state functional magnetic resonance imaging (RS-fMRI). Materials and Methods: The data of 20 PMS patients (PMS group) and 21 healthy controls (HC group) were analyzed by regional homogeneity (ReHo) method during the late luteal phase of menstrual cycle. In addition, all the participants were asked to complete a daily record of severity of problems (DRSP) questionnaire. Results: Compared with HC group, the results showed that PMS group had increased ReHo mainly in the bilateral precuneus, left inferior temporal cortex (ITC), right inferior frontal cortex (IFC) and left middle frontal cortex (MFC) and decreased ReHo in the right anterior cingulate cortex (ACC) at the luteal phase. Moreover, the PMS group had higher DRSP scores, and the DRSP scores positively correlated with ReHo in left MFC and negatively correlated with ReHo in the right ACC. Conclusion: Our results suggest that abnormal spontaneous brain activity is found in PMS patients and the severity of symptom is specifically related to the left MFC and right ACC. The present findings may be beneficial to explicate the intricate neural mechanism of PMS.
PMID: 28243196 [PubMed - in process]
Abnormal resting-state brain activities in patients with first-episode obsessive-compulsive disorder.
Neuropsychiatr Dis Treat. 2017;13:507-513
Authors: Niu Q, Yang L, Song X, Chu C, Liu H, Zhang L, Li Y, Zhang X, Cheng J, Li Y
OBJECTIVE: This paper attempts to explore the brain activity of patients with obsessive-compulsive disorder (OCD) and its correlation with the disease at resting duration in patients with first-episode OCD, providing a forceful imaging basis for clinic diagnosis and pathogenesis of OCD.
METHODS: Twenty-six patients with first-episode OCD and 25 healthy controls (HC group; matched for age, sex, and education level) underwent functional magnetic resonance imaging (fMRI) scanning at resting state. Statistical parametric mapping 8, data processing assistant for resting-state fMRI analysis toolkit, and resting state fMRI data analysis toolkit packages were used to process the fMRI data on Matlab 2012a platform, and the difference of regional homogeneity (ReHo) values between the OCD group and HC group was detected with independent two-sample t-test. With age as a concomitant variable, the Pearson correlation analysis was adopted to study the correlation between the disease duration and ReHo value of whole brain.
RESULTS: Compared with HC group, the ReHo values in OCD group were decreased in brain regions, including left thalamus, right thalamus, right paracentral lobule, right postcentral gyrus, and the ReHo value was increased in the left angular gyrus region. There was a negative correlation between disease duration and ReHo value in the bilateral orbitofrontal cortex (OFC).
CONCLUSION: OCD is a multifactorial disease generally caused by abnormal activities of many brain regions at resting state. Worse brain activity of the OFC is related to the OCD duration, which provides a new insight to the pathogenesis of OCD.
PMID: 28243104 [PubMed - in process]
Abnormalities of localized connectivity in schizophrenia patients and their unaffected relatives: a meta-analysis of resting-state functional magnetic resonance imaging studies.
Neuropsychiatr Dis Treat. 2017;13:467-475
Authors: Xiao B, Wang S, Liu J, Meng T, He Y, Luo X
OBJECTIVE: The localized dysfunction of specialized brain regions in schizophrenia patients and their unaffected relatives has been identified in a large-scale brain network; however, evidence is inconsistent. We aimed to identify abnormalities in the localized connectivity in schizophrenia patients and their relatives by conducting a meta-analysis of regional homogeneity (ReHo) studies.
METHODS: Fourteen studies on resting-state functional magnetic resonance imaging, with 316 schizophrenia patients, 342 healthy controls, and 66 unaffected relatives, were included in the meta-analysis. This analysis was performed using anisotropic effect-size-based signed differential mapping software.
RESULTS: Schizophrenia patients showed increased ReHo in right superior frontal gyrus and right superior temporal gyrus, as well as decreased ReHo in left fusiform gyrus, left superior temporal gyrus, left postcentral gyrus, and right precentral gyrus. Unaffected relatives showed decreased ReHo in right insula and right superior temporal gyrus. These results remained widely unchanged in both sensitivity and subgroup analyses.
CONCLUSION: Schizophrenia patients and their unaffected relatives had extensive abnormal localized connectivity in cerebrum, especially in superior temporal gyrus, which were the potential diagnostic markers and expounded the pathophysiological hypothesis for the disorder.
PMID: 28243099 [PubMed - in process]
Abnormal whole-brain functional connectivity in patients with primary insomnia.
Neuropsychiatr Dis Treat. 2017;13:427-435
Authors: Li C, Dong M, Yin Y, Hua K, Fu S, Jiang G
The investigation of the mechanism of insomnia could provide the basis for improved understanding and treatment of insomnia. The aim of this study is to investigate the abnormal functional connectivity throughout the entire brain of insomnia patients, and analyze the global distribution of these abnormalities. Whole brains of 50 patients with insomnia and 40 healthy controls were divided into 116 regions and abnormal connectivities were identified by comparing the Pearson's correlation coefficients of each pair using general linear model analyses with covariates of age, sex, and duration of education. In patients with insomnia, regions that relate to wakefulness, emotion, worry/rumination, saliency/attention, and sensory-motor showed increased positive connectivity with each other; however, regions that often restrain each other, such as regions in salience network with regions in default mode network, showed decreased positive connectivity. Correlation analysis indicated that some increased positive functional connectivity was associated with the Self-Rating Depression Scale, Insomnia Severity Index, and Pittsburgh Sleep Quality Index scores. According to our findings, increased and decreased positive connectivities suggest function strengthening and function disinhibition, respectively, which offers a parsimonious explanation for the hyperarousal hypothesis in the level of the whole-brain functional connectivity in patients with insomnia.
PMID: 28243094 [PubMed - in process]
Increased intrinsic brain connectivity between pons and somatosensory cortex during attacks of migraine with aura.
Hum Brain Mapp. 2017 Feb 27;:
Authors: Hougaard A, Amin FM, Larsson HB, Rostrup E, Ashina M
The neurological disturbances of migraine aura are caused by transient cortical dysfunction due to waves of spreading depolarization that disrupt neuronal signaling. The effects of these cortical events on intrinsic brain connectivity during attacks of migraine aura have not previously been investigated. Studies of spontaneous migraine attacks are notoriously challenging due to their unpredictable nature and patient discomfort. We investigated 16 migraine patients with visual aura during attacks and in the attack-free state using resting state fMRI. We applied a hypothesis-driven seed-based approach focusing on cortical visual areas and areas involved in migraine pain, and a data-driven independent component analysis approach to detect changes in intrinsic brain signaling during attacks. In addition, we performed the analyses after mirroring the MRI data according to the side of perceived aura symptoms. We found a marked increase in connectivity during attacks between the left pons and the left primary somatosensory cortex including the head and face somatotopic areas (peak voxel: P = 0.0096, (x, y, z) = (-54, -32, 32), corresponding well with the majority of patients reporting right-sided pain. For aura-side normalized data, we found increased connectivity during attacks between visual area V5 and the lower middle frontal gyrus in the symptomatic hemisphere (peak voxel: P = 0.0194, (x, y, z) = (40, 40, 12). The present study provides evidence of altered intrinsic brain connectivity during attacks of migraine with aura, which may reflect consequences of cortical spreading depression, suggesting a link between aura and headache mechanisms. Hum Brain Mapp, 2017. © 2017 Wiley Periodicals, Inc.
PMID: 28240389 [PubMed - as supplied by publisher]
Early adverse life events are associated with altered brain network architecture in a sex- dependent manner.
Neurobiol Stress. 2017 Dec;7:16-26
Authors: Gupta A, Mayer EA, Acosta JR, Hamadani K, Torgerson C, van Horn JD, Chang L, Naliboff B, Tillisch K, Labus JS
INTRODUCTION: Early adverse life events (EALs) increase the risk for chronic medical and psychiatric disorders by altering early neurodevelopment. The aim of this study was to examine associations between EALs and network properties of core brain regions in the emotion regulation and salience networks, and to test the influence of sex on these associations.
METHODS: Resting-state functional and diffusion tensor magnetic resonance imaging were obtained in healthy individuals (61 men, 63 women). Functional and anatomical network properties of centrality and segregation were calculated for the core regions of the two networks using graph theory. Moderator analyses were applied to test hypotheses.
RESULTS: The type of adversity experienced influences brain wiring differently, as higher general EALs were associated with decreased functional and anatomical centrality in salience and emotion regulation regions, while physical and emotional EALs were associated with increased anatomical centrality and segregation in emotion regulation regions. Sex moderated the associations between EALs and measures of centrality; with decreased centrality of salience and emotion regulation regions with increased general EALs in females, and increased centrality in salience regions with higher physical and emotional EALs in males. Increased segregation of salience regions was associated with increased general EALs in males. Centrality of the amygdala was associated with physical symptoms, and segregation of salience regions was correlated with higher somatization in men only.
CONCLUSIONS: Emotion regulation and salience regions are susceptible to topological brain restructuring associated with EALs. The male and female brains appear to be differently affected by specific types of EALs.
PMID: 28239631 [PubMed - in process]
Cortical interactions during the resolution of information processing demands in autism spectrum disorders.
Brain Behav. 2017 Feb;7(2):e00596
Authors: Denisova K, Zhao G, Wang Z, Goh S, Huo Y, Peterson BS
INTRODUCTION: Our flexible and adaptive interactions with the environment are guided by our individual representation of the physical world, estimated through sensation and evaluation of available information against prior knowledge. When linking sensory evidence with higher-level expectations for action, the central nervous system (CNS) in typically developing (TD) individuals relies in part on distributed and interacting cortical regions to communicate neuronal signals flexibly across the brain. Increasing evidence suggests that the balance between levels of signal and noise during information processing may be disrupted in individuals with Autism Spectrum Disorders (ASD).
METHODS: Participants with and without ASD performed a visuospatial interference task while undergoing functional Magnetic Resonance Imaging (fMRI). We empirically estimated parameters characterizing participants' latencies and their subtle fluctuations (noise accumulation) over the 16-min scan. We modeled hemodynamic activation and used seed-based analyses of neural coupling to study dysfunction in interference-specific connectivity in a subset of ASD participants who were nonparametrically matched to TD participants on age, male-to-female ratio, and magnitude of movement during the scan.
RESULTS: Stochastic patterns of response fluctuations reveal significantly higher noise-to-signal levels and a more random and noisy structure in ASD versus TD participants, and in particular ASD adults who have the greatest clinical autistic deficits. While individuals with ASD show an overall weaker modulation of interference-specific functional connectivity relative to TD individuals, in particular between the seeds of Anterior Cingulate Cortex (ACC) and Inferior Parietal Sulcus (IPS) and the rest of the brain, we found that in ASD, higher uncertainty during the task is linked to increased interference-specific coupling between bilateral anterior insula and prefrontal cortex.
CONCLUSIONS: Subtle and informative differences in the structure of experiencing information exist between ASD and TD individuals. Our findings reveal in ASD an atypical capacity to apply previously perceived information in a manner optimal for adaptive functioning, plausibly revealing suboptimal message-passing across the CNS.
PMID: 28239517 [PubMed - in process]
Cognitive Pragmatic Rehabilitation Program in Schizophrenia: A Single Case fMRI Study.
Neural Plast. 2017;2017:1612078
Authors: Gabbatore I, Bosco FM, Geda E, Gastaldo L, Duca S, Costa T, Bara BG, Sacco K
Introduction. The present study was intended to evaluate the effects of a rehabilitative training, the Cognitive Pragmatic Treatment (CPT), aimed at improving communicative-pragmatic abilities and the related cognitive components, on the cerebral modifications of a single case patient diagnosed with schizophrenia. Methods. The patient underwent two functional magnetic resonance imaging (fMRI) sessions, before and after the treatment. In order to assess brain changes, we calculated the Amplitude of Low Frequency Fluctuation (ALFF) index of the resting-state fMRI signal, which is interpreted as reflecting the intensity of the spontaneous regional activity of the brain. Behavioural measures of the patient's communicative performance were also gathered before and after training and at follow-up. Results. The patient improved his communicative performance in almost all tests. Posttraining stronger ALFF signal emerged in the superior, inferior, and medial frontal gyri, as well as the superior temporal gyri. Conclusions. Even if based on a single case study, these preliminary results show functional changes at the cerebral level that seem to support the patient's behavioural improvements.
PMID: 28239498 [PubMed - in process]
Altered Resting-State Signals in Patients with Acute Stroke In or Under the Thalamus.
Neurosci Bull. 2016 Dec;32(6):585-590
Authors: Chen L, Li C, Zhai J, Wang A, Song Q, Liu Y, Ma R, Han L, Ndasauka Y, Li X, Li H, Zhang X
Previous studies have suggested that cortical functional reorganization is associated with motor recovery after stroke and that normal afferent sensory information is very important in that process. In this study, we selected patients who had a stroke in or under the thalamus, with potentially impaired afferent sensory information and analyzed the differences between these patients and healthy controls at three levels: brain regions, the functional connectivity between brain areas, and the whole-brain functional network. Compared with healthy controls, regional homogeneities in the left middle temporal gyrus decreased and functional connectivity between the left middle temporal gyrus and the stroke area increased in the patients. However, there was no significant change in the whole-brain functional network. By focusing on stroke located in or under the thalamus, our study contributes to wider inquiries into understanding and treating stroke.
PMID: 27664033 [PubMed - indexed for MEDLINE]
Alteration of regional homogeneity and white matter hyperintensities in amnestic mild cognitive impairment subtypes are related to cognition and CSF biomarkers.
Brain Imaging Behav. 2017 Feb 24;:
Authors: Luo X, Jiaerken Y, Huang P, Xu XJ, Qiu T, Jia Y, Shen Z, Guan X, Zhou J, Zhang M, Alzheimer’s Disease Neuroimaging Initiative (ADNI)
Amnestic mild cognitive impairment can be further classified as single-domain aMCI (SD-aMCI) with isolated memory deficit, or multi-domain aMCI (MD-aMCI) if memory deficit is combined with impairment in other cognitive domains. Prior studies reported these clinical subtypes presumably differ in etiology. Thus, we aimed to explore the possible mechanisms between different aMCI subtypes by assessing alteration in brain activity and brain vasculature, and their relations with CSF AD biomarkers. 49 healthy controls, 32 SD-aMCI, and 32 MD-aMCI, who had undergone structural scans, resting-state functional MRI (rsfMRI) scans and neuropsychological evaluations, were identified. Regional homogeneity (ReHo) was employed to analyze regional synchronization. Periventricular white matter hyperintensities (PWMH) and deep WMH (DWMH) volume of each participant was quantitatively assessed. AD biomarkers from CSF were also measured. SD-aMCI showed decreased ReHo in medial temporal gyrus (MTG), and increased ReHo in lingual gyrus (LG) and superior temporal gyrus (STG) relative to controls. MD-aMCI showed decreased ReHo, mostly located in precuneus (PCu), LG and postcentral gyrus (PCG), relative to SD-aMCI and controls. As for microvascular disease, MD-aMCI patients had more PWMH burden than SD-aMCI and controls. Correlation analyses indicated mean ReHo in differenced regions were related with memory, language, and executive function in aMCI patients. However, no significant associations between PWMH and behavioral data were found. The Aβ level was related with the ReHo value of STG in SD-aMCI. MD-aMCI displayed different patterns of abnormal regional synchronization and more severe PWMH burden compared with SD-aMCI. Therefore aMCI is not a uniform disease entity, and MD-aMCI group may show more complicated pathologies than SD-aMCI group.
PMID: 28236166 [PubMed - as supplied by publisher]
Functional connectivity of motor cortical network in patients with brachial plexus avulsion injury after contralateral cervical nerve transfer: a resting-state fMRI study.
Neuroradiology. 2017 Feb 24;:
Authors: Yu A, Wang S, Cheng X, Liang W, Bai R, Xue Y, Li W
INTRODUCTION: The purpose of this study is to assess the functional connectivity of the motor cortical network in patients with brachial plexus avulsion injury (BPAI) after contralateral C7 nerve transfer, using resting-state functional magnetic resonance imaging (RS-fMRI).
METHODS: Twelve patients with total brachial plexus root avulsion underwent RS-fMRI after contralateral C7 nerve transfer. Seventeen healthy volunteers were also included in this fMRI study as controls. The hand motor seed regions were defined as region of interests in the bilateral hemispheres. The seed-based functional connectivity was calculated in all the subjects. Differences in functional connectivity of the motor cortical network between patients and healthy controls were compared.
RESULTS: The inter-hemispheric functional connectivity of the M1 areas was increased in patients with BPAI compared with the controls. The inter-hemispheric functional connectivity between the supplementary motor areas was reduced bilaterally.
CONCLUSIONS: The resting-state inter-hemispheric functional connectivity of the bilateral M1 areas is altered in patients after contralateral C7 nerve transfer, suggesting a functional reorganization of cerebral cortex.
PMID: 28236051 [PubMed - as supplied by publisher]
Shared effects of the clusterin gene on the default mode network among individuals at risk for Alzheimer's disease.
CNS Neurosci Ther. 2017 Feb 23;:
Authors: Ye Q, Su F, Shu H, Gong L, Xie CM, Zhou H, Zhang ZJ, Bai F
AIMS: To explore the common effects of the clusterin (CLU) rs11136000 variant on the default mode network (DMN) in amnestic mild cognitive impairment (aMCI) subjects and remitted geriatric depression (RGD) subjects.
METHODS: Fifty-one aMCI subjects, 38 RGD subjects, and 64 cognitively normal elderly subjects underwent resting-state fMRI scans and neuropsychological tests at both baseline and a 35-month follow-up. Posterior cingulate cortex seed-based functional connectivity (FC) analysis was used to obtain the DMN patterns.
RESULTS: A CLU gene×disease×time interaction for aMCI subjects was mainly detected in the core cortical midline structures of the DMN, and the interaction for RGD subjects was mainly detected in the limbic system. However, they overlapped in two frontal regions, where consistent effects of the CLU gene on FC alterations were found between aMCI and RGD groups. Furthermore, the alterations of FC with frontal, parietal, and limbic regions compensated for episodic memory impairments in CLU-CT/TT carriers, while no such compensation was found in CLU-CC carriers.
CONCLUSION: The CLU gene could consistently affect the DMN FC with frontal regions among individuals at risk for Alzheimer's disease, and the CLU-T allele was associated with more compensatory neural processes in DMN changes.
PMID: 28233427 [PubMed - as supplied by publisher]