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: 3 hours 39 min ago

Uncoupling protein 2 haplotype does not affect human brain structure and function in a sample of community-dwelling older adults.

Sat, 08/05/2017 - 15:00
Related Articles

Uncoupling protein 2 haplotype does not affect human brain structure and function in a sample of community-dwelling older adults.

PLoS One. 2017;12(8):e0181392

Authors: Heise V, Zsoldos E, Suri S, Sexton C, Topiwala A, Filippini N, Mahmood A, Allan CL, Singh-Manoux A, Kivimäki M, Mackay CE, Ebmeier KP

Abstract
Uncoupling protein 2 (UCP2) is a mitochondrial membrane protein that plays a role in uncoupling electron transport from adenosine triphosphate (ATP) formation. Polymorphisms of the UCP2 gene in humans affect protein expression and function and have been linked to survival into old age. Since UCP2 is expressed in several brain regions, we investigated in this study whether UCP2 polymorphisms might 1) affect occurrence of neurodegenerative or mental health disorders and 2) affect measures of brain structure and function. We used structural magnetic resonance imaging (MRI), diffusion-weighted MRI and resting-state functional MRI in the neuroimaging sub-study of the Whitehall II cohort. Data from 536 individuals aged 60 to 83 years were analyzed. No association of UCP2 polymorphisms with the occurrence of neurodegenerative disorders or grey and white matter structure or resting-state functional connectivity was observed. However, there was a significant effect on occurrence of mood disorders in men with the minor alleles of -866G>A (rs659366) and Ala55Val (rs660339)) being associated with increasing odds of lifetime occurrence of mood disorders in a dose dependent manner. This result was not accompanied by effects of UCP2 polymorphisms on brain structure and function, which might either indicate that the sample investigated here was too small and underpowered to find any significant effects, or that potential effects of UCP2 polymorphisms on the brain are too subtle to be picked up by any of the neuroimaging measures used.

PMID: 28771482 [PubMed - in process]

Globally weaker and topologically different: resting-state connectivity in youth with autism.

Sat, 08/05/2017 - 15:00
Related Articles

Globally weaker and topologically different: resting-state connectivity in youth with autism.

Mol Autism. 2017;8:39

Authors: Yerys BE, Herrington JD, Satterthwaite TD, Guy L, Schultz RT, Bassett DS

Abstract
BACKGROUND: There is a lack of agreement about functional connectivity differences in individuals with autism spectrum disorder (ASD). Studies using absolute strength have found reduced connectivity, while those using relative strength--a measure of system topology--reveal mostly enhanced connectivity. We hypothesized that mixed findings may be driven by the metric of functional connectivity.
METHODS: Resting-state echo planar 3 T functional magnetic resonance imaging scans were acquired on a Siemens Verio Scanner from 6 to 17-year-old youth with ASD (n = 81) and a matched typically developing control group (n = 82). All functional time series data were preprocessed using a confound regression procedure that has been previously validated in large-scale developmental datasets. It has also been shown to be highly effective at reducing the influence of motion artifact on connectivity data. We extracted time series data from a 333-node parcellation scheme, which was previously mapped to 13 functional systems. A Pearson's correlation was calculated and transformed to Fisher's z between every pair of nodes to create a weighted 333 × 333 adjacency matrix. Mean absolute functional connectivity strength was the mean Fisher's z of the matrix. Relative functional connectivity was corrected for individual differences in mean absolute functional connectivity (i.e., each connection in the matrix was divided by their mean z), and functional connectivity was evaluated within and across each of the functional networks in the parcellation scheme.
RESULTS: Absolute functional connectivity strength was lower in ASD, and lower functional connectivity was correlated with greater ASD symptom severity. Relative functional connectivity was higher for the ASD group in the ventral attention and retrosplenial-temporal systems, with lower cross-system functional connectivity between the ventral attention and somatomotor-mouth systems. Functional connectivity within the ventral attention and retro-splenial systems correlated significantly with ASD symptom severity.
CONCLUSIONS: Within a context of globally weaker functional connectivity, youth with ASD have an atypical topology of brain systems that support social perception and communication. This study clarifies the mixed results reported previously and demonstrates that the functional connectivity metric influences the observed direction of functional connectivity differences for individuals with ASD.

PMID: 28770039 [PubMed - in process]

Altered Coupling between Motion-Related Activation and Resting-State Brain Activity in the Ipsilesional Sensorimotor Cortex after Cerebral Stroke.

Sat, 08/05/2017 - 15:00
Related Articles

Altered Coupling between Motion-Related Activation and Resting-State Brain Activity in the Ipsilesional Sensorimotor Cortex after Cerebral Stroke.

Front Neurol. 2017;8:339

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

Abstract
Functional connectivity maps using resting-state functional magnetic resonance imaging (rs-fMRI) can closely resemble task fMRI activation patterns, suggesting that resting-state brain activity may predict task-evoked activation or behavioral performance. However, this conclusion was mostly drawn upon a healthy population. It remains unclear whether the predictive ability of resting-state brain activity for task-evoked activation would change under different pathological conditions. This study investigated dynamic changes of coupling between patterns of resting-state functional connectivity (RSFC) and motion-related activation in different stages of cerebral stroke. Twenty stroke patients with hand motor function impairment were involved. rs-fMRI and hand motion-related fMRI data were acquired in the acute, subacute, and early chronic stages of cerebral stroke on a 3-T magnetic resonance (MR) scanner. Sixteen healthy participants were enrolled as controls. For each subject, an activation map of the affected hand was first created using general linear model analysis on task fMRI data, and then an RSFC map was determined by seeding at the peak region of hand motion activation during the intact hand task. We then measured the extent of coupling between the RSFC maps and motion-related activation maps. Dynamic changes of the coupling between the two fMRI maps were estimated using one-way repeated measures analysis of variance across the three stages. Moreover, imaging parameters were correlated with motor performances. Data analysis showed that there were different coupling patterns between motion-related activation and RSFC maps associating with the affected motor regions during the acute, subacute, and early chronic stages of stroke. Coupling strengths increased as the recovery from stroke progressed. Coupling strengths were correlated with hand motion performance in the acute stage, while coupling recovery was negatively correlated with the recovery outcome of hand motion performance in the early chronic stages. Couplings between RSFC and motion-related activation were dynamically changed with stroke progression, which suggested changes in the prediction of resting-state brain activity for task-evoked brain activity in different pathological states. The changes in coupling strength between these two types of brain activity implicate a reparative mechanism of brain injury and may represent a biomarker for predicting motor recovery in cerebral stroke.

PMID: 28769870 [PubMed]

Correlation between Dopamine Transporter Degradation and Striatocortical Network Alteration in Parkinson's Disease.

Sat, 08/05/2017 - 15:00
Related Articles

Correlation between Dopamine Transporter Degradation and Striatocortical Network Alteration in Parkinson's Disease.

Front Neurol. 2017;8:323

Authors: Lin WC, Chen HL, Hsu TW, Hsu CC, Huang YC, Tsai NW, Lu CH

Abstract
The association between dopamine neuron loss and functional change in the striatocortical network was analyzed in 31 patients with Parkinson's disease (PD) [mean disease duration 4.03 ± 4.20 years; Hoehn and Yahr (HY) stage 2.2 ± 1.2] and 37 age-matched normal control subjects. We performed (99m)Tc-TRODAT-1 SPECT/CT imaging to detect neuron losses and resting-state functional magnetic resonance imaging to detect functional changes. Mean striatal dopamine transporter binding ratios were determined by region of interest analysis. The functional connectivity correlation coefficient (fc-cc) was determined in six striatal subregions, and interactions between these binding ratios and the striatocortical fc-cc values were analyzed. The PD patients had significant functional network alterations in all striatal subregions. Lower striatal dopamine transporter binding correlated significantly with lower fc-cc values in the superior medial frontal (SMF) lobe and superior frontal lobe and higher fc-cc values in the cerebellum and parahippocampus. The difference in fc-cc between the ventral inferior striatum and SMF lobe was significantly correlated with increased disease duration (r = -0.533, P = 0.004), higher HY stage (r = -0.431, P = 0.020), and lower activities of daily living score (r = 0.369, P = 0.049). The correlation of frontostriatal network changes with clinical manifestations suggests that fc-cc may serve as a surrogate marker of disease progression.

PMID: 28769862 [PubMed]

Neuronal Correlates of Individual Differences in the Big Five Personality Traits: Evidences from Cortical Morphology and Functional Homogeneity.

Sat, 08/05/2017 - 15:00
Related Articles

Neuronal Correlates of Individual Differences in the Big Five Personality Traits: Evidences from Cortical Morphology and Functional Homogeneity.

Front Neurosci. 2017;11:414

Authors: Li T, Yan X, Li Y, Wang J, Li Q, Li H, Li J

Abstract
There have been many neuroimaging studies of human personality traits, and it have already provided glimpse into the neurobiology of complex traits. And most of previous studies adopt voxel-based morphology (VBM) analysis to explore the brain-personality mechanism from two levels (vertex and regional based), the findings are mixed with great inconsistencies and the brain-personality relations are far from a full understanding. Here, we used a new method of surface-based morphology (SBM) analysis, which provides better alignment of cortical landmarks to generate about the associations between cortical morphology and the personality traits across 120 healthy individuals at both vertex and regional levels. While to further reveal local functional correlates of the morphology-personality relationships, we related surface-based functional homogeneity measures to the regions identified in the regional-based SBM correlation. Vertex-wise analysis revealed that people with high agreeableness exhibited larger areas in the left superior temporal gyrus. Based on regional parcellation we found that extroversion was negatively related with the volume of the left lateral occipito-temporal gyrus and agreeableness was negatively associated with the sulcus depth of the left superior parietal lobule. Moreover, increased regional homogeneity in the left lateral occipito-temporal gyrus is related to the scores of extroversion, and increased regional homogeneity in the left superior parietal lobule is related to the scores of agreeableness. These findings provide supporting evidence of a link between personality and brain structural mysteries with a method of SBM, and further suggest that local functional homogeneity of personality traits has neurobiological relevance that is likely based on anatomical substrates.

PMID: 28769751 [PubMed]

Commentary: BRAIN NETWORKS. Correlated Gene Expression Supports Synchronous Activity in Brain Networks. Science 348, 1241-4.

Sat, 08/05/2017 - 15:00
Related Articles

Commentary: BRAIN NETWORKS. Correlated Gene Expression Supports Synchronous Activity in Brain Networks. Science 348, 1241-4.

Front Neurosci. 2017;11:412

Authors: Pantazatos SP, Li X

Abstract
A recent report claims that functional brain networks defined with resting-state functional magnetic resonance imaging (fMRI) can be recapitulated with correlated gene expression (i.e., high within-network tissue-tissue "strength fraction," SF) (Richiardi et al., 2015). However, the authors do not adequately control for spatial proximity. We replicated their main analysis, performed a more effective adjustment for spatial proximity, and tested whether "null networks" (i.e., clusters with center coordinates randomly placed throughout cortex) also exhibit high SF. Removing proximal tissue-tissue correlations by Euclidean distance, as opposed to removing correlations within arbitrary tissue labels as in Richiardi et al. (2015), reduces within-network SF to no greater than null. Moreover, randomly placed clusters also have significantly high SF, indicating that high within-network SF is entirely attributable to proximity and is unrelated to functional brain networks defined by resting-state fMRI. We discuss why additional validations in the original article are invalid and/or misleading and suggest future directions.

PMID: 28769750 [PubMed]

Mechanism of Cerebralcare Granule® for Improving Cognitive Function in Resting-State Brain Functional Networks of Sub-healthy Subjects.

Sat, 08/05/2017 - 15:00
Related Articles

Mechanism of Cerebralcare Granule® for Improving Cognitive Function in Resting-State Brain Functional Networks of Sub-healthy Subjects.

Front Neurosci. 2017;11:410

Authors: Li J, Guo H, Ge L, Cheng L, Wang J, Li H, Zhang K, Xiang J, Chen J, Zhang H, Xu Y

Abstract
Cerebralcare Granule® (CG), a Chinese herbal medicine, has been used to ameliorate cognitive impairment induced by ischemia or mental disorders. The ability of CG to improve health status and cognitive function has drawn researchers' attention, but the relevant brain circuits that underlie the ameliorative effects of CG remain unclear. The present study aimed to explore the underlying neurobiological mechanisms of CG in ameliorating cognitive function in sub-healthy subjects using resting-state functional magnetic resonance imaging (fMRI). Thirty sub-healthy participants were instructed to take one 2.5-g package of CG three times a day for 3 months. Clinical cognitive functions were assessed with the Chinese Revised Wechsler Adult Intelligence Scale (WAIS-RC) and Wechsler Memory Scale (WMS), and fMRI scans were performed at baseline and the end of intervention. Functional brain network data were analyzed by conventional network metrics (CNM) and frequent subgraph mining (FSM). Then 21 other sub-healthy participants were enrolled as a blank control group of cognitive functional. We found that administrating CG can improve the full scale of intelligence quotient (FIQ) and Memory Quotient (MQ) scores. At the same time, following CG treatment, in CG group, the topological properties of functional brain networks were altered in various frontal, temporal, occipital cortex regions, and several subcortical brain regions, including essential components of the executive attention network, the salience network, and the sensory-motor network. The nodes involved in the FSM results were largely consistent with the CNM findings, and the changes in nodal metrics correlated with improved cognitive function. These findings indicate that CG can improve sub-healthy subjects' cognitive function through altering brain functional networks. These results provide a foundation for future studies of the potential physiological mechanism of CG.

PMID: 28769748 [PubMed]

Brain imaging in myotonic dystrophy type 1: A systematic review.

Sat, 08/05/2017 - 15:00
Related Articles

Brain imaging in myotonic dystrophy type 1: A systematic review.

Neurology. 2017 Aug 02;:

Authors: Okkersen K, Monckton DG, Le N, Tuladhar AM, Raaphorst J, van Engelen BGM

Abstract
OBJECTIVE: To systematically review brain imaging studies in myotonic dystrophy type 1 (DM1).
METHODS: We searched Embase (index period 1974-2016) and MEDLINE (index period 1946-2016) for studies in patients with DM1 using MRI, magnetic resonance spectroscopy (MRS), functional MRI (fMRI), CT, ultrasound, PET, or SPECT. From 81 studies, we extracted clinical characteristics, primary outcomes, clinical-genetic correlations, and information on potential risk of bias. Results were summarized and pooled prevalence of imaging abnormalities was calculated, where possible.
RESULTS: In DM1, various imaging changes are widely dispersed throughout the brain, with apparently little anatomical specificity. We found general atrophy and widespread gray matter volume reductions in all 4 cortical lobes, the basal ganglia, and cerebellum. The pooled prevalence of white matter hyperintensities is 70% (95% CI 64-77), compared with 6% (95% CI 3-12) in unaffected controls. DTI shows increased mean diffusivity in all 4 lobes and reduced fractional anisotropy in virtually all major association, projection, and commissural white matter tracts. Functional studies demonstrate reduced glucose uptake and cerebral perfusion in frontal, parietal, and temporal lobes, and abnormal fMRI connectivity patterns that correlate with personality traits. There is significant between-study heterogeneity in terms of imaging methods, which together with the established clinical variability of DM1 may explain divergent results. Longitudinal studies are remarkably scarce.
CONCLUSIONS: DM1 brains show widespread white and gray matter involvement throughout the brain, which is supported by abnormal resting-state network, PET/SPECT, and MRS parameters. Longitudinal studies evaluating spatiotemporal imaging changes are essential.

PMID: 28768849 [PubMed - as supplied by publisher]

Resting-state fMRI and social cognition: An opportunity to connect.

Thu, 08/03/2017 - 13:00
Related Articles

Resting-state fMRI and social cognition: An opportunity to connect.

Hum Psychopharmacol. 2017 Aug 01;:

Authors: Doruyter A, Groenewold NA, Dupont P, Stein DJ, Warwick JM

Abstract
Many psychiatric disorders are characterized by altered social cognition. The importance of social cognition has previously been recognized by the National Institute of Mental Health Research Domain Criteria project, in which it features as a core domain. Social task-based functional magnetic resonance imaging (fMRI) currently offers the most direct insight into how the brain processes social information; however, resting-state fMRI may be just as important in understanding the biology and network nature of social processing. Resting-state fMRI allows researchers to investigate the functional relationships between brain regions in a neutral state: so-called resting functional connectivity (RFC). There is evidence that RFC is predictive of how the brain processes information during social tasks. This is important because it shifts the focus from possibly context-dependent aberrations to context-independent aberrations in functional network architecture. Rather than being analysed in isolation, the study of resting-state brain networks shows promise in linking results of task-based fMRI results, structural connectivity, molecular imaging findings, and performance measures of social cognition-which may prove crucial in furthering our understanding of the social brain.

PMID: 28766324 [PubMed - as supplied by publisher]

[Study of fraction amplitude of low frequency fluctuation on resting-state functional magnetic resonance imaging in adultperipheral facial paralysis].

Thu, 08/03/2017 - 13:00
Related Articles

[Study of fraction amplitude of low frequency fluctuation on resting-state functional magnetic resonance imaging in adultperipheral facial paralysis].

Zhonghua Yi Xue Za Zhi. 2017 Jul 18;97(27):2081-2086

Authors: Zhu YJ, Ma GL, Song TB, Du L, Guo RC, Sun SL, Li H, Sun LG

Abstract
Objective: To analysis the change of brain functional activity in the left and right peripheral facial paralysis by using resting-state functional magnetic resonance imaging (R-fMRI) of fraction amplitude of low frequency fluctuation(fALFF) measurement technique, and research the abnormal brain region with different side patients whether there are differences. Methods: A total of 43 patients with peripheral facial paralysis patients (patient groups, divided into left / right two subgroups) and 21 healthy volunteers (control group) in this study.Resting-state fMRI were acquired for each volunteer and patient. The fALFF approach was used to compare the peripheral facial paralysis groups to healthy group.Functional analysis was performed with brain function analysis software REST and DPARSFA , and then analysis the difference of two groups of patients and control group in two sample t test.At the same time, the correlation analysis between fALFF parameters map of the left and right side of two groups of patients and corresponding facial nerve grading TFGS score.Ultimately obtain a statistically significant brain regions. Results: Compared to healthy group, the decreased fALFF areas in the left side facial paralysis were showed in the right superior temporal gyrus , the pole of the right temporal, right middle temporal gyrus, the left occipital gyrus, and left medial cingulate gyrus, left paracentral lobule, and the left supplementary motor area; while the increased brain regions have the right superior frontal gyrus, right middle frontal gyrus, the right precentral gyrus, bilateral inferior temporal gyrus and middle temporal gyrus.Compared to healthy group, the decreased fALFF areas in the right side facial paralysis were showed in the right inferior temporal gyrus and fusiform gyrus, the left inferior occipital gyrus, the left superior parietalgyrus, the left inferior parietalgyrus, left precuneus, left paracentral lobule, the left supplementary motor area; while the increased brain regions have the left Calcarine, right lingual gyrus, corpus callosum, right medial cingulum gyrus.In the left facial paralysis group TFGS score was positively correlated with brain regions have left middle frontal gyrus, left precuneus and left cuneus, while the negatively related brain area on the right lingual gyrus.In the right facial paralysis groups TFGS score was positively correlated with brain areas have right inferior temporal gyrus and middle temporal gyrus, left inferior parietalgyrus; while the negatively correlated brain area on the left superior temporal gyrus, the right medial frontal gyrus. Conclusion: The left and right side facial paralysis patient's mood and motor function integration mechanism may be different, and the patient's emotional and psychological changes may be associated with disease severity.

PMID: 28763879 [PubMed - in process]

BRAPH: A graph theory software for the analysis of brain connectivity.

Wed, 08/02/2017 - 12:00
Related Articles

BRAPH: A graph theory software for the analysis of brain connectivity.

PLoS One. 2017;12(8):e0178798

Authors: Mijalkov M, Kakaei E, Pereira JB, Westman E, Volpe G, Alzheimer's Disease Neuroimaging Initiative

Abstract
The brain is a large-scale complex network whose workings rely on the interaction between its various regions. In the past few years, the organization of the human brain network has been studied extensively using concepts from graph theory, where the brain is represented as a set of nodes connected by edges. This representation of the brain as a connectome can be used to assess important measures that reflect its topological architecture. We have developed a freeware MatLab-based software (BRAPH-BRain Analysis using graPH theory) for connectivity analysis of brain networks derived from structural magnetic resonance imaging (MRI), functional MRI (fMRI), positron emission tomography (PET) and electroencephalogram (EEG) data. BRAPH allows building connectivity matrices, calculating global and local network measures, performing non-parametric permutations for group comparisons, assessing the modules in the network, and comparing the results to random networks. By contrast to other toolboxes, it allows performing longitudinal comparisons of the same patients across different points in time. Furthermore, even though a user-friendly interface is provided, the architecture of the program is modular (object-oriented) so that it can be easily expanded and customized. To demonstrate the abilities of BRAPH, we performed structural and functional graph theory analyses in two separate studies. In the first study, using MRI data, we assessed the differences in global and nodal network topology in healthy controls, patients with amnestic mild cognitive impairment, and patients with Alzheimer's disease. In the second study, using resting-state fMRI data, we compared healthy controls and Parkinson's patients with mild cognitive impairment.

PMID: 28763447 [PubMed - in process]

Intranasal Oxytocin Selectively Modulates Large-Scale Brain Networks in Humans.

Wed, 08/02/2017 - 12:00
Related Articles

Intranasal Oxytocin Selectively Modulates Large-Scale Brain Networks in Humans.

Brain Connect. 2017 Aug 01;:

Authors: Brodmann K, Gruber O, Goya-Maldonado R

Abstract
A growing body of evidence indicates that the neuropeptide oxytocin (OT) alters the neural correlates of socio-emotional and salience processing. Yet the effects of OT over important large-scale networks involved in these processes, such as the default mode (DM), ventral attention (VA) and cingulo-opercular (CO) networks, remain unknown. Therefore, we conducted a placebo-controlled crossover study with intranasal 24IU OT in 38 healthy male subjects using a resting-state fMRI (rs-fMRI) paradigm to investigate its impact over these three candidate networks. To understand the underlying mechanisms of the neuropeptide, we compared the intra-network connectivity for each network candidate and also the inter-network connectivity across all networks between both treatment conditions. Based on the relevance of inter-individual factors for OT effects, we correlated individual network changes with behavioral performance in a decision-making task and with impulsivity scores. Our results show that OT mainly alters connectivity in the VA, on one side reducing the coupling to regions that typically form the nodes of the DM, an introspective and self-referential network, and on the other side increasing the coupling to the edges of the CO, which is involved in salience processing. The results of the inter-network analyses confirmed the specificity of the OT effects. Indeed, we observed significant correlations with erroneous performance during decision-making but not with the obtained impulsivity scores. Overall, our data supports that the modulation of functional connectivity within the VA is a basic mechanism by which OT directs attentional resources from internal to external cues, preparing the brain for context-dependent salience processing.

PMID: 28762756 [PubMed - as supplied by publisher]

Low-frequency hippocampal-cortical activity drives brain-wide resting-state functional MRI connectivity.

Wed, 08/02/2017 - 12:00
Related Articles

Low-frequency hippocampal-cortical activity drives brain-wide resting-state functional MRI connectivity.

Proc Natl Acad Sci U S A. 2017 Jul 31;:

Authors: Chan RW, Leong ATL, Ho LC, Gao PP, Wong EC, Dong CM, Wang X, He J, Chan YS, Lim LW, Wu EX

Abstract
The hippocampus, including the dorsal dentate gyrus (dDG), and cortex engage in bidirectional communication. We propose that low-frequency activity in hippocampal-cortical pathways contributes to brain-wide resting-state connectivity to integrate sensory information. Using optogenetic stimulation and brain-wide fMRI and resting-state fMRI (rsfMRI), we determined the large-scale effects of spatiotemporal-specific downstream propagation of hippocampal activity. Low-frequency (1 Hz), but not high-frequency (40 Hz), stimulation of dDG excitatory neurons evoked robust cortical and subcortical brain-wide fMRI responses. More importantly, it enhanced interhemispheric rsfMRI connectivity in various cortices and hippocampus. Subsequent local field potential recordings revealed an increase in slow oscillations in dorsal hippocampus and visual cortex, interhemispheric visual cortical connectivity, and hippocampal-cortical connectivity. Meanwhile, pharmacological inactivation of dDG neurons decreased interhemispheric rsfMRI connectivity. Functionally, visually evoked fMRI responses in visual regions also increased during and after low-frequency dDG stimulation. Together, our results indicate that low-frequency activity robustly propagates in the dorsal hippocampal-cortical pathway, drives interhemispheric cortical rsfMRI connectivity, and mediates visual processing.

PMID: 28760982 [PubMed - as supplied by publisher]

Reconfiguration of brain network architectures between resting state and complexity-dependent cognitive reasoning.

Wed, 08/02/2017 - 12:00
Related Articles

Reconfiguration of brain network architectures between resting state and complexity-dependent cognitive reasoning.

J Neurosci. 2017 Jul 31;:

Authors: Hearne LJ, Cocchi L, Zalesky A, Mattingley JB

Abstract
Our capacity for higher cognitive reasoning has a measureable limit. This limit is thought to arise from the brain's capacity to flexibly reconfigure interactions between spatially distributed networks. Recent work, however, has suggested that reconfigurations of task-related networks are modest when compared with intrinsic 'resting state' network architecture. Here we combined resting state and task-driven functional magnetic resonance imaging to examine how flexible, task-specific reconfigurations associated with increasing reasoning demands are integrated within a stable intrinsic brain topology. Human participants (21 males and 28 females) underwent an initial resting state scan, followed by a cognitive reasoning task involving different levels of complexity, followed by a second resting state scan. The reasoning task required participants to deduce the identity of a missing element in a 4 x 4 matrix, and item difficulty was scaled parametrically as determined by relational complexity theory. Analyses revealed that external task engagement was characterized by a significant change in functional brain modules. Specifically, resting state and null-task demand conditions were associated with more segregated brain network topology, whereas increases in reasoning complexity resulted in merging of resting state modules. Further increments in task complexity did not change the established modular architecture, but impacted selective patterns of connectivity between fronto-parietal, subcortical, cingulo-opercular and default-mode networks. Larger increases in network efficiency within the newly established task modules were associated with higher reasoning accuracy. Our results shed light on the network architectures that underlie external task engagement, and highlight selective changes in brain connectivity supporting increases in task complexity.SIGNIFICANCE STATEMENTHumans have clear limits in their ability to solve complex reasoning problems. It is thought that such limitations arise from flexible, moment-to-moment reconfigurations of functional brain networks. It is less clear how such task-driven adaptive changes in connectivity relate to stable, intrinsic networks of the brain and behavioral performance. We found that increased reasoning demands rely on selective patterns of connectivity within cortical networks that emerged in addition to a more general, task-induced modular architecture. This task-driven architecture reverted to a more segregated resting state architecture both immediately before and after the task. These findings reveal how flexibility in human brain networks is integral to achieving successful reasoning performance across different levels of cognitive demand.

PMID: 28760864 [PubMed - as supplied by publisher]

Elucidating Functional Differences between Cortical Gyri and Sulci via Sparse Representation HCP Grayordinate fMRI Data.

Wed, 08/02/2017 - 12:00
Related Articles

Elucidating Functional Differences between Cortical Gyri and Sulci via Sparse Representation HCP Grayordinate fMRI Data.

Brain Res. 2017 Jul 28;:

Authors: Liu H, Jiang X, Zhang T, Ren Y, Hu X, Guo L, Han J, Liu T

Abstract
The highly convoluted cerebral cortex is characterized by two different topographic structures: convex gyri and concave sulci. Increasing studies have demonstrated that cortical gyri and sulci exhibit different structural connectivity patterns. Inspired by the intrinsic structural differences between gyri and sulci, in this paper, we present a data-driven framework based on sparse representation of fMRI data for functional network inferences, then examine the interactions within and across gyral and sulcal functional networks and finally elucidate possible functional differences using graph theory based properties. We apply the proposed framework to the high-resolution Human Connectome Project (HCP) grayordinate fMRI data. Extensive experimental results on both resting state fMRI data and task-based fMRI data consistently suggested that gyri are more functionally integrated, while sulci are more functionally segregated in the organizational architecture of cerebral cortex, offering novel understanding of the byzantine cerebral cortex.

PMID: 28760438 [PubMed - as supplied by publisher]

Functional integrity in children with anoxic brain injury from drowning.

Tue, 08/01/2017 - 23:20
Related Articles

Functional integrity in children with anoxic brain injury from drowning.

Hum Brain Mapp. 2017 Jul 31;:

Authors: Ishaque M, Manning JH, Woolsey MD, Franklin CG, Tullis EW, Beckmann CF, Fox PT

Abstract
Drowning is a leading cause of accidental injury and death in young children. Anoxic brain injury (ABI) is a common consequence of drowning and can cause severe neurological morbidity in survivors. Assessment of functional status and prognostication in drowning victims can be extremely challenging, both acutely and chronically. Structural neuroimaging modalities (CT and MRI) have been of limited clinical value. Here, we tested the utility of resting-state functional MRI (rs-fMRI) for assessing brain functional integrity in this population. Eleven children with chronic, spastic quadriplegia due to drowning-induced ABI were investigated. All were comatose immediately after the injury and gradually regained consciousness, but with varying ability to communicate their cognitive state. Eleven neurotypical children matched for age and gender formed the control group. Resting-state fMRI and co-registered T1-weighted anatomical MRI were acquired at night during drug-aided sleep. Network integrity was quantified by independent components analysis (ICA), at both group- and per-subject levels. Functional-status assessments based on in-home observations were provided by families and caregivers. Motor ICNs were grossly compromised in ABI patients both group-wise and individually, concordant with their prominent motor deficits. Striking preservations of perceptual and cognitive ICNs were observed, and the degree of network preservation correlated (ρ = 0.74) with the per-subject functional status assessments. Collectively, our findings indicate that rs-fMRI has promise for assessing brain functional integrity in ABI and, potentially, in other disorders. Furthermore, our observations suggest that the severe motor deficits observed in this population can mask relatively intact perceptual and cognitive capabilities. Hum Brain Mapp, 2017. © 2017 Wiley Periodicals, Inc.

PMID: 28759710 [PubMed - as supplied by publisher]

Functional neural circuits that underlie developmental stuttering.

Tue, 08/01/2017 - 23:20
Related Articles

Functional neural circuits that underlie developmental stuttering.

PLoS One. 2017;12(7):e0179255

Authors: Qiao J, Wang Z, Zhao G, Huo Y, Herder CL, Sikora CO, Peterson BS

Abstract
The aim of this study was to identify differences in functional and effective brain connectivity between persons who stutter (PWS) and typically developing (TD) fluent speakers, and to assess whether those differences can serve as biomarkers to distinguish PWS from TD controls. We acquired resting-state functional magnetic resonance imaging data in 44 PWS and 50 TD controls. We then used Independent Component Analysis (ICA) together with Hierarchical Partner Matching (HPM) to identify networks of robust, functionally connected brain regions that were highly reproducible across participants, and we assessed whether connectivity differed significantly across diagnostic groups. We then used Granger Causality (GC) to study the causal interactions (effective connectivity) between the regions that ICA and HPM identified. Finally, we used a kernel support vector machine to assess how well these measures of functional connectivity and granger causality discriminate PWS from TD controls. Functional connectivity was stronger in PWS compared with TD controls in the supplementary motor area (SMA) and primary motor cortices, but weaker in inferior frontal cortex (IFG, Broca's area), caudate, putamen, and thalamus. Additionally, causal influences were significantly weaker in PWS from the IFG to SMA, and from the basal ganglia to IFG through the thalamus, compared to TD controls. ICA and GC indices together yielded an accuracy of 92.7% in classifying PWS from TD controls. Our findings suggest the presence of dysfunctional circuits that support speech planning and timing cues for the initiation and execution of motor sequences in PWS. Our high accuracy of classification further suggests that these aberrant brain features may serve as robust biomarkers for PWS.

PMID: 28759567 [PubMed - in process]

Visually stressful striped patterns alter human visual cortical functional connectivity.

Tue, 08/01/2017 - 23:20
Related Articles

Visually stressful striped patterns alter human visual cortical functional connectivity.

Hum Brain Mapp. 2017 Jul 31;:

Authors: Huang J, Zhu DC

Abstract
Visually stressful striped patterns with a spatial frequency (SF) of around 3 cycles per degree (cpd) can induce perceptual illusions/distortions and visual discomfort in most people, headaches in patients with migraine, and seizures in patients with photosensitive epilepsy. Patterns with SF ∼0.3 cpd have no such effects and are not uncomfortable to look at (non-stressful). The effects of the striped patterns on visual cortical activation have been investigated, but their effects on the visual cortical network remain to be studied. A prolonged visual stimulation with stressful patterns may alter the functional connections within the visual system, and their relationship with other networks. Using resting-state fMRI, this study revealed that the functional connections within the visual system were significantly enhanced by visually stressful stimulation. The functional connectivity between V1 and other brain regions was also significantly modified. Non-stressful stimulation produced no such significant effects. More importantly, the effects outlasted the stimulation, and this applied both to those effects within and those beyond the visual cortex, suggesting that repeated prolonged visual stimulation with stressful patterns may alter functional connections of the brain and this might be utilized as a visual neuromodulation approach for treatments of visually triggered headaches in migraine patients and visually induced seizures in patients with photosensitive epilepsy. Hum Brain Mapp, 2017. © 2017 Wiley Periodicals, Inc.

PMID: 28758271 [PubMed - as supplied by publisher]

Precision Functional Mapping of Individual Human Brains.

Tue, 08/01/2017 - 23:20
Related Articles

Precision Functional Mapping of Individual Human Brains.

Neuron. 2017 Jul 25;:

Authors: Gordon EM, Laumann TO, Gilmore AW, Newbold DJ, Greene DJ, Berg JJ, Ortega M, Hoyt-Drazen C, Gratton C, Sun H, Hampton JM, Coalson RS, Nguyen AL, McDermott KB, Shimony JS, Snyder AZ, Schlaggar BL, Petersen SE, Nelson SM, Dosenbach NUF

Abstract
Human functional MRI (fMRI) research primarily focuses on analyzing data averaged across groups, which limits the detail, specificity, and clinical utility of fMRI resting-state functional connectivity (RSFC) and task-activation maps. To push our understanding of functional brain organization to the level of individual humans, we assembled a novel MRI dataset containing 5 hr of RSFC data, 6 hr of task fMRI, multiple structural MRIs, and neuropsychological tests from each of ten adults. Using these data, we generated ten high-fidelity, individual-specific functional connectomes. This individual-connectome approach revealed several new types of spatial and organizational variability in brain networks, including unique network features and topologies that corresponded with structural and task-derived brain features. We are releasing this highly sampled, individual-focused dataset as a resource for neuroscientists, and we propose precision individual connectomics as a model for future work examining the organization of healthy and diseased individual human brains.

PMID: 28757305 [PubMed - as supplied by publisher]

Measuring alterations in oscillatory brain networks in schizophrenia with resting-state MEG: State-of-the-art and methodological challenges.

Tue, 08/01/2017 - 23:20
Related Articles

Measuring alterations in oscillatory brain networks in schizophrenia with resting-state MEG: State-of-the-art and methodological challenges.

Clin Neurophysiol. 2017 Jul 08;128(9):1719-1736

Authors: Alamian G, Hincapié AS, Pascarella A, Thiery T, Combrisson E, Saive AL, Martel V, Althukov D, Haesebaert F, Jerbi K

Abstract
OBJECTIVE: Neuroimaging studies provide evidence of disturbed resting-state brain networks in Schizophrenia (SZ). However, untangling the neuronal mechanisms that subserve these baseline alterations requires measurement of their electrophysiological underpinnings. This systematic review specifically investigates the contributions of resting-state Magnetoencephalography (MEG) in elucidating abnormal neural organization in SZ patients.
METHOD: A systematic literature review of resting-state MEG studies in SZ was conducted. This literature is discussed in relation to findings from resting-state fMRI and EEG, as well as to task-based MEG research in SZ population. Importantly, methodological limitations are considered and recommendations to overcome current limitations are proposed.
RESULTS: Resting-state MEG literature in SZ points towards altered local and long-range oscillatory network dynamics in various frequency bands. Critical methodological challenges with respect to experiment design, and data collection and analysis need to be taken into consideration.
CONCLUSION: Spontaneous MEG data show that local and global neural organization is altered in SZ patients. MEG is a highly promising tool to fill in knowledge gaps about the neurophysiology of SZ. However, to reach its fullest potential, basic methodological challenges need to be overcome.
SIGNIFICANCE: MEG-based resting-state power and connectivity findings could be great assets to clinical and translational research in psychiatry, and SZ in particular.

PMID: 28756348 [PubMed - as supplied by publisher]

Pages