New resting-state fMRI related studies at PubMed

Subscribe to New resting-state fMRI related studies at PubMed feed New resting-state fMRI related studies at PubMed
NCBI: db=pubmed; Term=resting state fMRI
Updated: 1 hour 14 min ago

resting state fMRI; +17 new citations

Fri, 06/08/2018 - 13:07

17 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results:

resting state fMRI

These pubmed results were generated on 2018/06/08

PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

Corrigendum: Resting-State Functional Connectivity and Network Analysis of Cerebellum With Respect to IQ and Gender.

Thu, 06/07/2018 - 14:20
Related Articles

Corrigendum: Resting-State Functional Connectivity and Network Analysis of Cerebellum With Respect to IQ and Gender.

Front Hum Neurosci. 2018;12:216

Authors: Pezoulas VC, Zervakis M, Michelogiannis S, Klados MA

Abstract
[This corrects the article on p. 189 in vol. 11, PMID: 28491028.].

PMID: 29872387 [PubMed - in process]

Central Neural Correlates During Inhibitory Control in Lifelong Premature Ejaculation Patients.

Thu, 06/07/2018 - 14:20
Related Articles

Central Neural Correlates During Inhibitory Control in Lifelong Premature Ejaculation Patients.

Front Hum Neurosci. 2018;12:206

Authors: Yang X, Gao M, Zhang L, Liu L, Liu P, Sun J, Xi Y, Yin H, Qin W

Abstract
Lifelong premature ejaculation (LPE) is a common male sexual dysfunction. Lack of active control for rapid ejaculation brought great distress to sexual harmony and even fertility. Previous neurophysiology studies revealed an ejaculation-related control mechanism in the brain. However, it remains unclear whether this inhibitory network is altered in LPE patients. The present study investigated the central inhibitory network function of LPE patients by using stop signal task (SST)-related functional magnetic resonance imaging (fMRI) and resting-state functional connectivity (FC) analysis. The results showed no difference in task-related behavioral performance or neural activation during response inhibition between LPE patients and controls. However, LPE patients showed a significantly different correlation pattern between the stop signal reaction time (SSRT) and left inferior frontal gyrus (IFG) activation during successful inhibition, in which a typical negative correlation between SSRT and the activation was completely disappeared in patients. In addition, using the left IFG as a seed, patients showed weaker FC between the seed and two areas (left dentate nucleus (DN) and right frontal pole) compared with controls. These data suggest that LPE patients have an abnormal brain control network, which may contribute to the reduced central control of rapid ejaculation. This study provides new insights into the neural mechanism of LPE involving the central inhibitory network, which may offer an underlying intervention target for future treatment.

PMID: 29872385 [PubMed]

Functional networks reemerge during recovery of consciousness after acute severe traumatic brain injury.

Thu, 06/07/2018 - 14:20
Related Articles

Functional networks reemerge during recovery of consciousness after acute severe traumatic brain injury.

Cortex. 2018 May 12;:

Authors: Threlkeld ZD, Bodien YG, Rosenthal ES, Giacino JT, Nieto-Castanon A, Wu O, Whitfield-Gabrieli S, Edlow BL

Abstract
Integrity of the default mode network (DMN) is believed to be essential for human consciousness. However, the effects of acute severe traumatic brain injury (TBI) on DMN functional connectivity are poorly understood. Furthermore, the temporal dynamics of DMN reemergence during recovery of consciousness have not been studied longitudinally in patients with acute severe TBI. We performed resting-state functional magnetic resonance imaging (rs-fMRI) to measure DMN connectivity in 17 patients admitted to the intensive care unit (ICU) with acute severe TBI and in 16 healthy control subjects. Eight patients returned for follow-up rs-fMRI and behavioral assessment six months post-injury. At each time point, we analyzed DMN connectivity by measuring intra-network correlations (i.e. positive correlations between DMN nodes) and inter-network anticorrelations (i.e. negative correlations between the DMN and other resting-state networks). All patients were comatose upon arrival to the ICU and had a disorder of consciousness (DoC) at the time of acute rs-fMRI (9.2 ± 4.6 days post-injury): 2 coma, 4 unresponsive wakefulness syndrome, 7 minimally conscious state, and 4 post-traumatic confusional state. We found that, while DMN anticorrelations were absent in patients with acute DoC, patients who recovered from coma to a minimally conscious or confusional state while in the ICU showed partially preserved DMN correlations. Patients who remained in coma or unresponsive wakefulness syndrome in the ICU showed no DMN correlations. All eight patients assessed longitudinally recovered beyond the confusional state by 6 months post-injury and showed normal DMN correlations and anticorrelations, indistinguishable from those of healthy subjects. Collectively, these findings suggest that recovery of consciousness after acute severe TBI is associated with partial preservation of DMN correlations in the ICU, followed by long-term normalization of DMN correlations and anticorrelations. Both intra-network DMN correlations and inter-network DMN anticorrelations may be necessary for full recovery of consciousness after acute severe TBI.

PMID: 29871771 [PubMed - as supplied by publisher]

Age-specific effects of structural and functional connectivity in prefrontal-amygdala circuitry in women with bipolar disorder.

Thu, 06/07/2018 - 14:20
Related Articles

Age-specific effects of structural and functional connectivity in prefrontal-amygdala circuitry in women with bipolar disorder.

BMC Psychiatry. 2018 Jun 05;18(1):177

Authors: Tang Y, Ma Y, Chen X, Fan X, Jiang X, Zhou Y, Wang F, Wei S

Abstract
BACKGROUND: Bipolar disorder (BD) is a serious mental illness. Several studies have shown that brain structure and function changes and the development of BD are associated with age and sex differences. Therefore, we hypothesized that the functional and structural neural circuitry of BD patients would differ according to age. The amygdala and prefrontal cortex (PFC) are play a key role in the emotional and cognitive processing of patients with BD. In this study, we used magnetic resonance imaging (MRI) to examine the structural and functional connectivity within amygdala-PFC neural circuitry in women with BD at different ages.
METHODS: Forty-nine female patients with BD who were aged 13-25 years and 60 age-matched healthy control (HC) individuals, as well as 43 female patients with BD who were aged 26-45 years and 60 age-matched HC individuals underwent resting-state functional MRI (rs-fMRI) and diffusion tensor imaging to examine the structural and functional connectivity within the amygdala-PFC neural circuitry.
RESULTS: We found abnormalities in the amygdala-PFC functional connectivity in patients aged 13-25 years and significantly different fractional anisotropy (FA) values in patients aged 26-45 compared with the age-matched HCs. The significance of these findings was indicated by corrected p values of less than 0.05 (uncorrected p values less than 0.001).
CONCLUSIONS: The findings in this cross-sectional study suggested that abnormalities in the functional connectivity of the amygdala-PFC neural circuitry are related to the pathophysiology of BD in women aged 13-25 years, while changes in the structural integrity of this neural circuitry are associated with the pathophysiology of BD in women aged 26-45 years. Therefore, functional and structural brain alterations may occur at different ages in female patients with BD.

PMID: 29871591 [PubMed - in process]

resting state fMRI; +21 new citations

Wed, 06/06/2018 - 14:23

21 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results:

resting state fMRI

These pubmed results were generated on 2018/06/06

PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

Altered regional homogeneity in patients with late monocular blindness: a resting-state functional MRI study.

Tue, 06/05/2018 - 12:20
Related Articles

Altered regional homogeneity in patients with late monocular blindness: a resting-state functional MRI study.

Neuroreport. 2017 Nov 08;28(16):1085-1091

Authors: Huang X, Ye CL, Zhong YL, Ye L, Yang QC, Li HJ, Jiang N, Peng DC, Shao Y

Abstract
Many previous studies have demonstrated that the blindness patients have has functional and anatomical abnormalities in the visual and other vision-related cortex. However, changes in the brain function in late monocular blindness (MB) at rest are largely unknown. In this study, we investigated the underlying regional homogeneity (ReHo) of brain-activity abnormalities in patients with late MB and their relationship with clinical features. A total of 32 patients with MB (25 male and seven female) and 32 healthy controls (HCs) (25 male and seven female) closely matched in age, sex, and education underwent resting-state functional MRI scans. The ReHo method was used to assess local features of spontaneous brain activities. Patients with MB were distinguishable from HCs using the receiver operating characteristic curve. The relationship between the mean ReHo in brain regions and the behavioral performance was calculated using correlation analysis. Compared with HCs, patients with MB showed significantly decreased ReHo values in the right rectal gyrus, right cuneus, right anterior cingulate, and right lateral occipital cortex and increased ReHo values in the right inferior temporal gyrus, right frontal middle orbital, left posterior cingulate/precuneus, and left middle frontal gyrus. However, there was no significant relationship between the different mean ReHo values in the brain regions and the clinical features. Late MB involves abnormalities of the visual cortex and other vision-related brain regions, which may reflect brain dysfunction in these regions.

PMID: 28858036 [PubMed - indexed for MEDLINE]

Interaction effect between 5-HTTLPR and HTR1A rs6295 polymorphisms on the frontoparietal network.

Tue, 06/05/2018 - 12:20
Related Articles

Interaction effect between 5-HTTLPR and HTR1A rs6295 polymorphisms on the frontoparietal network.

Neuroscience. 2017 Oct 24;362:239-247

Authors: Long H, Liu B, Wang C, Zhang X, Li J, Yu C, Jiang T

Abstract
Previous studies have shown a close relationship between the serotonin system and working memory (WM), but the neural mechanism for the role of the serotonin system on the WM is unclear. The frontoparietal network is involved in WM and is associated with the serotonin system. Therefore, this study investigated the interaction effect of the serotonin transporter-linked polymorphic region (5-HTTLPR) and the polymorphism in the serotonin 1A receptor gene (rs6295) on the frontoparietal network obtained from the independent component analysis in a large, young Chinese sample population. The current study found a significant interaction effect of 5-HTTLPR and rs6295 on the connectivity within the right frontoparietal network, specifically in the middle frontal gyrus and inferior parietal lobule. Moreover, the mean connectivity in the right inferior parietal lobule was positively correlated with WM performance. These brain network analysis findings could provide a new perspective on the neural mechanisms of gene-gene interactions and on individual differences in cognitive functions.

PMID: 28793232 [PubMed - indexed for MEDLINE]

Altered Intranetwork and Internetwork Functional Connectivity in Type 2 Diabetes Mellitus With and Without Cognitive Impairment.

Tue, 06/05/2018 - 12:20
Related Articles

Altered Intranetwork and Internetwork Functional Connectivity in Type 2 Diabetes Mellitus With and Without Cognitive Impairment.

Sci Rep. 2016 09 13;6:32980

Authors: Yang SQ, Xu ZP, Xiong Y, Zhan YF, Guo LY, Zhang S, Jiang RF, Yao YH, Qin YY, Wang JZ, Liu Y, Zhu WZ

Abstract
Type 2 diabetes mellitus (T2DM) is associated with cognitive impairment. We investigated whether alterations of intranetwork and internetwork functional connectivity with T2DM progression exist, by using resting-state functional MRI. MRI data were analysed from 19 T2DM patients with normal cognition (DMCN) and 19 T2DM patients with cognitive impairment (DMCI), 19 healthy controls (HC). Functional connectivity among 36 previously well-defined brain regions which consisted of 5 resting-state network (RSN) systems [default mode network (DMN), dorsal attention network (DAN), control network (CON), salience network (SAL) and sensorimotor network (SMN)] was investigated at 3 levels (integrity, network and connectivity). Impaired intranetwork and internetwork connectivity were found in T2DM, especially in DMCI, on the basis of the three levels of analysis. The bilateral posterior cerebellum, the right insula, the DMN and the CON were mainly involved in these changes. The functional connectivity strength of specific brain architectures in T2DM was found to be associated with haemoglobin A1c (HbA1c), cognitive score and illness duration. These network alterations in intergroup differences, which were associated with brain functional impairment due to T2DM, indicate that network organizations might be potential biomarkers for predicting the clinical progression, evaluating the cognitive impairment, and further understanding the pathophysiology of T2DM.

PMID: 27622870 [PubMed - indexed for MEDLINE]

On testing for spatial correspondence between maps of human brain structure and function.

Mon, 06/04/2018 - 11:20
Related Articles

On testing for spatial correspondence between maps of human brain structure and function.

Neuroimage. 2018 May 31;:

Authors: Alexander-Bloch A, Shou H, Liu S, Satterthwaite TD, Glahn DC, Shinohara RT, Vandekar SN, Raznahan A

Abstract
A critical issue in many neuroimaging studies is the comparison between brain maps. Nonetheless, it remains unclear how one should test hypotheses focused on the overlap or spatial correspondence between two or more brain maps. This "correspondence problem" affects, for example, the interpretation of comparisons between task-based patterns of functional activation, resting-state networks or modules, and neuroanatomical landmarks. To date, this problem has been addressed with remarkable variability in terms of methodological approaches and statistical rigor. In this paper, we address the correspondence problem using a spatial permutation framework to generate null models of overlap, by applying random rotations to spherical representations of the cortical surface, an approach for which we also provide a theoretical statistical foundation. We use this method to derive clusters of cognitive functions that are correlated in terms of their functional neuroatomical substrates. In addition, using publicly available data, we formally demonstrate the correspondence between maps of task-based functional activity, resting-state fMRI networks and gyral-based anatomical landmarks. We provide open-access code to implement the methods presented for two commonly-used tools for surface based cortical analysis. This spatial permutation approach constitutes a useful advance over widely-used methods for the comparison of cortical maps, thereby opening new possibilities for the integration of diverse neuroimaging data.

PMID: 29860082 [PubMed - as supplied by publisher]

Consistency of Regions of Interest as nodes of fMRI functional brain networks.

Sat, 06/02/2018 - 15:00
Related Articles

Consistency of Regions of Interest as nodes of fMRI functional brain networks.

Netw Neurosci. 2017 Oct 01;1(3):254-274

Authors: Korhonen O, Saarimäki H, Glerean E, Sams M, Saramäki J

Abstract
The functional network approach, where fMRI BOLD time series are mapped to networks depicting functional relationships between brain areas, has opened new insights into the function of the human brain. In this approach, the choice of network nodes is of crucial importance. One option is to consider fMRI voxels as nodes. This results in a large number of nodes, making network analysis and interpretation of results challenging. A common alternative is to use predefined clusters of anatomically close voxels, Regions of Interest (ROIs). This approach assumes that voxels within ROIs are functionally similar. Because these two approaches result in different network structures, it is crucial to understand what happens to network connectivity when moving from the voxel level to the ROI level. We show that the consistency of ROIs, defined as the mean Pearson correlation coefficient between the time series of their voxels, varies widely in resting-state experimental data. Therefore the assumption of similar voxel dynamics within each ROI does not generally hold. Further, the time series of low-consistency ROIs may be highly correlated, resulting in spurious links in ROI-level networks. Based on these results, we recommend that averaging BOLD signals over anatomically defined ROIs should be carefully considered.

PMID: 29855622 [PubMed]

Altered functional connectivity of the default mode network by glucose loading in young, healthy participants.

Sat, 06/02/2018 - 15:00
Related Articles

Altered functional connectivity of the default mode network by glucose loading in young, healthy participants.

BMC Neurosci. 2018 May 31;19(1):33

Authors: Ishibashi K, Sakurai K, Shimoji K, Tokumaru AM, Ishii K

Abstract
BACKGROUND: The functional connectivity of the default mode network (DMN) decreases in patients with Alzheimer's disease (AD) as well as in patients with type 2 diabetes mellitus (T2DM). Altered functional connectivity of the DMN is associated with cognitive impairment. T2DM is a known cause of cognitive dysfunction and dementia in the elderly, and studies have established that T2DM is a risk factor for AD. In addition, recent studies with positron emission tomography demonstrated that increased plasma glucose levels decrease neuronal activity, especially in the precuneus/posterior cingulate cortex (PC/PCC), which is the functional core of the DMN. These findings prompt the question of how increased plasma glucose levels decrease neuronal activity in the PC/PCC. Given the association among DMN, AD, and T2DM, we hypothesized that increased plasma glucose levels decrease the DMN functional connectivity, thus possibly reducing PC/PCC neuronal activity. We conducted this study to test this hypothesis.
RESULTS: Twelve young, healthy participants without T2DM and insulin resistance were enrolled in this study. Each participant underwent resting-state functional magnetic resonance imaging in both fasting and glucose loading conditions to evaluate the DMN functional connectivity. The results showed that the DMN functional connectivity in the PC/PCC was significantly lower in the glucose loading condition than in the fasting condition (P = 0.014).
CONCLUSIONS: Together with previous findings, the present results suggest that decreased functional connectivity of the DMN is possibly responsible for reduced PC/PCC neuronal activity in healthy individuals with increased plasma glucose levels.

PMID: 29855257 [PubMed - in process]

Alterations of parenchymal microstructure, neuronal connectivity and cerebrovascular resistance at adolescence following mild to moderate traumatic brain injury in early development.

Sat, 06/02/2018 - 15:00
Related Articles

Alterations of parenchymal microstructure, neuronal connectivity and cerebrovascular resistance at adolescence following mild to moderate traumatic brain injury in early development.

J Neurotrauma. 2018 Jun 01;:

Authors: Parent M, Li Y, Santhakumar V, Hyder F, Sanganahalli BG, Kannurpatti S

Abstract
TBI is a leading cause of morbidity in children. To investigate outcome of early developmental TBI during adolescence, a rat model of fluid percussion injury was developed, where previous work reported deficits in sensorimotor behavior and cortical blood flow at adolescence. 1 Based on the non-localized outcome, we hypothesized that multiple neurophysiological components of brain function, namely neuronal connectivity, synapse/axonal microstructural integrity and neurovascular function are altered and magnetic resonance imaging (MRI) methods could be used to determine regional alterations. Adolescent outcomes of developmental TBI were studied 2-months after injury, using functional MRI (fMRI) and Diffusion Tensor Imaging (DTI). fMRI based resting state functional connectivity (RSFC), representing neural connectivity, was significantly altered between sham and TBI. RSFC strength decreased in the cortex, hippocampus and thalamus accompanied by decrease in the spatial extent of their corresponding RSFC networks and inter-hemispheric asymmetry. Cerebrovascular reactivity to arterial CO2 changes diminished after TBI across both hemispheres, with a more pronounced decrease in the ipsilateral hippocampus, thalamus and motor cortex. DTI measures of fractional anisotropy (FA) and apparent diffusion coefficient (ADC), reporting on axonal and microstructural integrity of the brain, indicated similar inter-hemispheric asymmetry, with highest change in the ipsilateral hippocampus and regions adjoining the ipsilateral thalamus, hypothalamus and amygdala. TBI-induced corpus callosal microstructural alterations indicated measurable changes in inter-hemispheric structural connectivity. Hippocampus, thalamus and select cortical regions were most consistently affected in multiple imaging markers. The multi-modal MRI results demonstrate cortical and subcortical alterations in neural connectivity, cerebrovascular resistance and parenchymal microstructure in the adolescent brain, indicating the highly diffuse and persistent nature of the lateral fluid percussion TBI early in development.

PMID: 29855211 [PubMed - as supplied by publisher]

Transient patterns of functional dysconnectivity in clinical high risk and early-illness schizophrenia individuals compared to healthy controls.

Sat, 06/02/2018 - 15:00
Related Articles

Transient patterns of functional dysconnectivity in clinical high risk and early-illness schizophrenia individuals compared to healthy controls.

Brain Connect. 2018 Jun 01;:

Authors: Mennigen E, Fryer SL, Rashid B, Damaraju E, Du Y, Loewy RL, Stuart BK, Calhoun VD, Mathalon DH

Abstract
Schizophrenia shows abnormal dynamic functional network connectivity (dFNC), but it is unclear whether these abnormalities are present early in the illness course or precede illness onset in individuals at clinical high risk for psychosis (CHR). We examined dFNC from resting state functional magnetic resonance imaging data in CHR (n=53), early illness schizophrenia (ESZ; n=58), and healthy control (HC; n=70) individuals. We applied a sliding temporal window approach capturing 5 distinct dFNC states. In ESZ patients, the likelihood of transitioning from state 4, a state that exhibited greater cortical-subcortical hyperconnectivity and also lacked typically observed anti-correlation between the DMN and other functional networks, to a hypoconnected state was increased compared to HC and CHR groups. Further, we investigated the interaction of group and state on dFNC. Overall, HC individuals showed significant changes of connectivity between states that were absent or altered in ESZ patients and CHR individuals. Connectivity differences between groups were identified primarily in two out of the five states in particular between HC and ESZ groups. In summary, it appears that the interaction effect was mostly driven by i) dynamic connectivity changes in HC that were abnormal in CHR and ESZ individuals and ii) the fact that dysconnectivity between groups was only present in some states. These findings underscore the likelihood that abnormalities are present not only in static FNC, but also in dFNC, in individuals at clinical high risk for schizophrenia.

PMID: 29855202 [PubMed - as supplied by publisher]

The Effects of Music Intervention on Functional Connectivity Strength of the Brain in Schizophrenia.

Sat, 06/02/2018 - 15:00
Related Articles

The Effects of Music Intervention on Functional Connectivity Strength of the Brain in Schizophrenia.

Neural Plast. 2018;2018:2821832

Authors: Yang M, He H, Duan M, Chen X, Chang X, Lai Y, Li J, Liu T, Luo C, Yao D

Abstract
Schizophrenia is often associated with behavior abnormality in the cognitive and affective domain. Music intervention is used as a complementary treatment for improving symptoms in patients with schizophrenia. However, the neurophysiological correlates of these remissions remain poorly understood. Here, we investigated the effects of music intervention in neural circuits through functional magnetic resonance imaging (fMRI) study in schizophrenic subjects. Under the standard care, patients were randomly assigned to music and non-music interventions (MTSZ, UMTSZ) for 1 month. Resting-state fMRI were acquired over three time points (baseline, 1 month, and 6 months later) in patients and analyzed using functional connectivity strength (FCS) and seed-based functional connection (FC) approaches. At baseline, compared with healthy controls, decreased FCS in the right middle temporal gyrus (MTG) was observed in patients. However, after music intervention, the functional circuitry of the right MTG, which was related with the function of emotion and sensorimotor, was improved in MTSZ. Furthermore, the FC increments were significantly correlated with the improvement of symptoms, while vanishing 6 months later. Together, these findings provided evidence that music intervention might positively modulate the functional connectivity of MTG in patients with schizophrenia; such changes might be associated with the observed therapeutic effects of music intervention on neurocognitive function. This trial is registered with ChiCTR-OPC-14005339.

PMID: 29853841 [PubMed - in process]

Ballroom Dancing Promotes Neural Activity in the Sensorimotor System: A Resting-State fMRI Study.

Sat, 06/02/2018 - 15:00
Related Articles

Ballroom Dancing Promotes Neural Activity in the Sensorimotor System: A Resting-State fMRI Study.

Neural Plast. 2018;2018:2024835

Authors: Lu Y, Zhao Q, Wang Y, Zhou C

Abstract
Objective: This study aims at investigating differences in the spontaneous brain activity and functional connectivity in the sensorimotor system between ballroom dancers and nondancers, to further support the functional alteration in people with expertise.
Materials and Methods: Twenty-three ballroom dancers and twenty-one matched novices with no dance experience were recruited in this study. Amplitude of low-frequency fluctuation (ALFF) and seed-based functional connectivity, as methods for assessing resting-state functional magnetic resonance imaging (rs-fMRI) data, were used to reveal the resting-state brain function in these participants.
Results: Compared to the novices, ballroom dancers showed increased ALFF in the left middle temporal gyrus, bilateral precentral gyrus, bilateral inferior frontal gyrus, left postcentral gyrus, left inferior temporal gyrus, right middle occipital gyrus, right superior temporal gyrus, and left middle frontal gyrus. The ballroom dancers also demonstrated lower ALFF in the left lingual gyrus and altered functional connectivity between the inferior frontal gyrus and temporal, parietal regions.
Conclusions: Our results indicated that ballroom dancers showed elevated neural activity in sensorimotor regions relative to novices and functional alterations in frontal-temporal and frontal-parietal connectivity, which may reflect specific training experience related to ballroom dancing, including high-capacity action perception, attentional control, and movement adjustment.

PMID: 29853838 [PubMed - in process]

Functional complexity emerging from anatomical constraints in the brain: the significance of network modularity and rich-clubs.

Sat, 06/02/2018 - 15:00
Related Articles

Functional complexity emerging from anatomical constraints in the brain: the significance of network modularity and rich-clubs.

Sci Rep. 2016 12 05;6:38424

Authors: Zamora-López G, Chen Y, Deco G, Kringelbach ML, Zhou C

Abstract
The large-scale structural ingredients of the brain and neural connectomes have been identified in recent years. These are, similar to the features found in many other real networks: the arrangement of brain regions into modules and the presence of highly connected regions (hubs) forming rich-clubs. Here, we examine how modules and hubs shape the collective dynamics on networks and we find that both ingredients lead to the emergence of complex dynamics. Comparing the connectomes of C. elegans, cats, macaques and humans to surrogate networks in which either modules or hubs are destroyed, we find that functional complexity always decreases in the perturbed networks. A comparison between simulated and empirically obtained resting-state functional connectivity indicates that the human brain, at rest, lies in a dynamical state that reflects the largest complexity its anatomical connectome can host. Last, we generalise the topology of neural connectomes into a new hierarchical network model that successfully combines modular organisation with rich-club forming hubs. This is achieved by centralising the cross-modular connections through a preferential attachment rule. Our network model hosts more complex dynamics than other hierarchical models widely used as benchmarks.

PMID: 27917958 [PubMed - indexed for MEDLINE]

Focused ultrasound induced opening of the blood-brain barrier disrupts inter-hemispheric resting state functional connectivity in the rat brain.

Fri, 06/01/2018 - 13:40

Focused ultrasound induced opening of the blood-brain barrier disrupts inter-hemispheric resting state functional connectivity in the rat brain.

Neuroimage. 2018 May 28;:

Authors: Todd N, Zhang Y, Arcaro M, Becerra L, Borsook D, Livingstone M, McDannold N

Abstract
Focused ultrasound (FUS) is a technology capable of delivering therapeutic levels of energy through the intact skull to a tightly localized brain region. Combining the FUS pressure wave with intravenously injected microbubbles creates forces on blood vessel walls that open the blood-brain barrier (BBB). This noninvasive and localized opening of the BBB allows for targeted delivery of pharmacological agents into the brain for use in therapeutic development. It is possible to use FUS power levels such that the BBB is opened without damaging local tissues. However, open questions remain related to the effects that FUS-induced BBB opening has on brain function including local physiology and vascular hemodynamics. We evaluated the effects that FUS-induced BBB opening has on resting state functional magnetic resonance imaging (rs-fMRI) metrics. Data from rs-fMRI was acquired in rats that underwent sham FUS BBB vs. FUS BBB opening targeted to the right primary somatosensory cortex hindlimb region (S1HL). FUS BBB opening reduced the functional connectivity between the right S1HL and other sensorimotor regions, including statistically significant reduction of connectivity to the homologous region in the left hemisphere (left S1HL). The effect was observed in all three metrics analyzed: functional connectivity between anatomically defined regions, whole brain voxel-wise correlation maps based on anatomical seeds, and spatial patterns from independent component analysis. Connectivity metrics for other regions where the BBB was not perturbed were not affected. While it is not clear whether the effect is vascular or neuronal in origin, these results suggest that even safe levels of FUS BBB opening have an effect on the physiological processes that drive the signals measured by BOLD fMRI. As such these effects must be accounted for when carrying out studies using fMRI to evaluate the effects of pharmacological agents delivered via FUS-induced BBB opening.

PMID: 29852281 [PubMed - as supplied by publisher]

Resting State fMRI: A Valuable Tool for Studying Cognitive Dysfunction in PD.

Fri, 06/01/2018 - 13:40

Resting State fMRI: A Valuable Tool for Studying Cognitive Dysfunction in PD.

Parkinsons Dis. 2018;2018:6278649

Authors: Li K, Su W, Li SH, Jin Y, Chen HB

Abstract
Cognitive impairment is a common disabling symptom in PD. Unlike motor symptoms, the mechanism underlying cognitive dysfunction in Parkinson's disease (PD) remains unclear and may involve multiple pathophysiological processes. Resting state functional magnetic resonance imaging (rs-fMRI) is a fast-developing research field, and its application in cognitive impairments in PD is rapidly growing. In this review, we summarize rs-fMRI studies on cognitive function in PD and discuss the strong potential of rs-fMRI in this area. rs-fMRI can help reveal the pathophysiology of cognitive symptoms in PD, facilitate early identification of PD patients with cognitive impairment, distinguish PD dementia from dementia with Lewy bodies, and monitor and guide treatment for cognitive impairment in PD. In particular, ongoing and future longitudinal studies would enhance the ability of rs-fMRI in predicting PD dementia. In combination with other modalities such as positron emission tomography, rs-fMRI could give us more information on the underlying mechanism of cognitive deficits in PD.

PMID: 29850015 [PubMed]

Dynamic Network Analysis Reveals Altered Temporal Variability in Brain Regions after Stroke: A Longitudinal Resting-State fMRI Study.

Fri, 06/01/2018 - 13:40

Dynamic Network Analysis Reveals Altered Temporal Variability in Brain Regions after Stroke: A Longitudinal Resting-State fMRI Study.

Neural Plast. 2018;2018:9394156

Authors: Hu J, Du J, Xu Q, Yang F, Zeng F, Weng Y, Dai XJ, Qi R, Liu X, Lu G, Zhang Z

Abstract
Recent fMRI studies have demonstrated that resting-state functional connectivity (FC) is of nonstationarity. Temporal variability of FC reflects the dynamic nature of brain activity. Exploring temporal variability of FC offers a new approach to investigate reorganization and integration of brain networks after stroke. Here, we examined longitudinal alterations of FC temporal variability in brain networks after stroke. Nineteen stroke patients underwent resting fMRI scans across the acute stage (within-one-week after stroke), subacute stage (within-two-weeks after stroke), and early chronic stage (3-4 months after stroke). Nineteen age- and sex-matched healthy individuals were enrolled. Compared with the controls, stroke patients exhibited reduced regional temporal variability during the acute stages, which was recovered at the following two stages. Compared with the acute stage, the subacute stage exhibited increased temporal variability in the primary motor, auditory, and visual cortices. Across the three stages, the temporal variability in the ipsilesional precentral gyrus (PreCG) was increased first and then reduced. Increased temporal variability in the ipsilesional PreCG from the acute stage to the subacute stage was correlated with motor recovery from the acute stage to the early chronic stage. Our results demonstrated that temporal variability of brain network might be a potential tool for evaluating and predicting motor recovery after stroke.

PMID: 29849574 [PubMed - in process]

Pages