scholarly journals Global and network functional connectivity of nucleus basalis of Meynert is strengthened in blind individuals

2021 ◽  
Author(s):  
Ji Won Bang ◽  
Russell W Chan ◽  
Carlos Parra ◽  
Joel S Schuman ◽  
Amy C Nau ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Brain Function ◽  
Vision Loss ◽  
Network Connectivity ◽  
Nucleus Basalis ◽  
Nucleus Basalis Of Meynert ◽  
Resting State Functional Connectivity ◽  
Global Signal ◽  
Principal Source ◽  
Blind Individuals

Vision loss causes dramatic changes in brain function which are thought to facilitate behavioral adaptation. One interesting prospect is that the cholinergic signals are involved in this blindness-induced plasticity. Critically, the nucleus basalis of Meynert is the principal source of the cholinergic signals, however, no studies have yet investigated whether the nucleus basalis of Meynert is altered in blindness. Therefore, here we examined its structure, cerebrovascular response, and the resting-state functional connectivity in blind individuals. We found that the global signal of the nucleus basalis of Meynert as well as its network connectivity with the visual, language, and default mode network is significantly enhanced in early blind individuals. On the other hand, its structure and cerebrovascular response remain unchanged in early blind individuals. Further, we observed that less visual experience predicts stronger global and network connectivity of the nucleus basalis of Meynert. These results suggest that the nucleus basalis of Meynert develops a stronger neuromodulatory influence on the cortex of blind individuals at both global and network levels.

scholarly journals Effects of Cigarette Smoking on Resting-State Functional Connectivity of the Nucleus Basalis of Meynert in Mild Cognitive Impairment

2021 ◽  
Vol 13 ◽  
Author(s):  
Tiantian Qiu ◽  
Qingze Zeng ◽  
Xiao Luo ◽  
Tongcheng Xu ◽  
Zhujing Shen ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Functional Connectivity ◽  
Cigarette Smoking ◽  
Resting State ◽  
Interaction Effects ◽  
Nucleus Basalis ◽  
Nucleus Basalis Of Meynert ◽  
Resting State Functional Connectivity ◽  
Mixed Effect

Background: Mild cognitive impairment (MCI) is the prodromal phase of Alzheimer’s disease (AD) and has a high risk of progression to AD. Cigarette smoking is one of the important modifiable risk factors in AD progression. Cholinergic dysfunction, especially the nucleus basalis of Meynert (NBM), is the converging target connecting smoking and AD. However, how cigarette smoking affects NBM connectivity in MCI remains unclear.Objective: This study aimed to evaluate the interaction effects of condition (non-smoking vs. smoking) and diagnosis [cognitively normal (CN) vs. MCI] based on the resting-state functional connectivity (rsFC) of the NBM.Methods: After propensity score matching, we included 86 non-smoking CN, 44 smoking CN, 62 non-smoking MCI, and 32 smoking MCI. All subjects underwent structural and functional magnetic resonance imaging scans and neuropsychological tests. The seed-based rsFC of the NBM with the whole-brain voxel was calculated. Furthermore, the mixed effect analysis was performed to explore the interaction effects between condition and diagnosis on rsFC of the NBM.Results: The interaction effects of condition × diagnosis on rsFC of the NBM were observed in the bilateral prefrontal cortex (PFC), bilateral supplementary motor area (SMA), and right precuneus/middle occipital gyrus (MOG). Specifically, the smoking CN showed decreased rsFC between left NBM and PFC and increased rsFC between left NBM and SMA compared with non-smoking CN and smoking MCI. The smoking MCI showed reduced rsFC between right NBM and precuneus/MOG compared with non-smoking MCI. Additionally, rsFC between the NBM and SMA showed a significant negative correlation with Wechsler Memory Scale-Logical Memory (WMS-LM) immediate recall in smoking CN (r = −0.321, p = 0.041).Conclusion: Our findings indicate that chronic nicotine exposure through smoking may lead to functional connectivity disruption between the NBM and precuneus in MCI patients. The distinct alteration patterns on NBM connectivity in CN smokers and MCI smokers suggest that cigarette smoking has different influences on normal and impaired cognition.

scholarly journals Functional connectivity of the nucleus basalis of Meynert in Lewy body dementia and Alzheimer’s disease

2021 ◽  
pp. 1-6
Author(s):  
Julia Schumacher ◽  
Alan J. Thomas ◽  
Luis R. Peraza ◽  
Michael Firbank ◽  
John T. O’Brien ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Lewy Body ◽  
Cholinergic System ◽  
Structural Changes ◽  
Lewy Body Dementia ◽  
Occipital Cortex ◽  
Nucleus Basalis ◽  
Nucleus Basalis Of Meynert

ABSTRACT Cholinergic deficits are a hallmark of Alzheimer’s disease (AD) and Lewy body dementia (LBD). The nucleus basalis of Meynert (NBM) provides the major source of cortical cholinergic input; studying its functional connectivity might, therefore, provide a tool for probing the cholinergic system and its degeneration in neurodegenerative diseases. Forty-six LBD patients, 29 AD patients, and 31 healthy age-matched controls underwent resting-state functional magnetic resonance imaging (fMRI). A seed-based analysis was applied with seeds in the left and right NBM to assess functional connectivity between the NBM and the rest of the brain. We found a shift from anticorrelation in controls to positive correlations in LBD between the right/left NBM and clusters in right/left occipital cortex. Our results indicate that there is an imbalance in functional connectivity between the NBM and primary visual areas in LBD, which provides new insights into alterations within a part of the corticopetal cholinergic system that go beyond structural changes.

scholarly journals The effect of global signal regression on DCM estimates of noise and effective connectivity from resting state fMRI

2019 ◽  
Author(s):  
Hannes Almgren ◽  
Frederik Van de Steen ◽  
Adeel Razi ◽  
Karl Friston ◽  
Daniele Marinazzo
Keyword(s):  
Functional Connectivity ◽  
Resting State ◽  
Effective Connectivity ◽  
Network Connectivity ◽  
Resting State Fmri ◽  
Measurement Noise ◽  
Resting State Networks ◽  
Cross Sectional ◽  
Global Signal ◽  
Leibler Divergence

AbstractThe influence of the global BOLD signal on resting state functional connectivity in fMRI data remains a topic of debate, with little consensus. In this study, we assessed the effects of global signal regression (GSR) on effective connectivity within and between resting-state networks – as estimated with dynamic causal modelling (DCM) for resting state fMRI (rsfMRI). DCM incorporates a forward (generative) model that quantifies the contribution of different types of noise (including global measurement noise), effective connectivity, and (neuro)vascular processes to functional connectivity measurements. DCM analyses were applied to two different designs; namely, longitudinal and cross-sectional designs. In the modelling of longitudinal designs, we included four extensive longitudinal resting state fMRI datasets with a total number of 20 subjects. In the analysis of cross-sectional designs, we used rsfMRI data from 361 subjects from the Human Connectome Project. We hypothesized that (1) GSR would have no discernible impact on effective connectivity estimated with DCM, and (2) GSR would be reflected in the parameters representing global measurement noise. Additionally, we performed comparative analyses of the informative value of data with and without GSR. Our results showed negligible to small effects of GSR on connectivity within small (separately estimated) RSNs. For between-network connectivity, we found two important effects: the effect of GSR on between-network connectivity (averaged over all connections) was negligible to small, while the effect of GSR on individual connections was non-negligible. Contrary to our expectations, we found either no effect (in the longitudinal designs) or a non-specific (cross-sectional design) effect of GSR on parameters representing (global) measurement noise. Data without GSR were found to be more informative than data with GSR; however, in small resting state networks the precision of posterior estimates was greater using data after GSR. In conclusion, GSR is a minor concern in DCM studies; however, individual between-network connections (as opposed to average between-network connectivity) and noise parameters should be interpreted quantitatively with some caution. The Kullback-Leibler divergence of the posterior from the prior, together with the precision of posterior estimates, might offer a useful measure to assess the appropriateness of GSR, when nuancing data features in resting state fMRI.

scholarly journals Improvising at Rest: Differentiating Jazz and Classical Music Training with Resting State Functional Connectivity

2019 ◽  
Author(s):  
Alexander Belden ◽  
Tima Zeng ◽  
Emily Przysinda ◽  
Sheeba Arnold Anteraper ◽  
Susan Whitfield-Gabrieli ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Resting State ◽  
Divergent Thinking ◽  
Network Connectivity ◽  
Salience Network ◽  
Resting State Functional Connectivity ◽  
Cortical Networks ◽  
Music Training ◽  
Classical Musicians ◽  
Visual Network

AbstractJazz improvisation offers a model for creative cognition, as it involves the real-time creation of a novel, information-rich product. Previous research has shown that when musicians improvise, they recruit regions in the Default Mode Network (DMN) and Executive Control Network (ECN). Here, we ask whether these findings from task-fMRI studies might extend to intrinsic differences in resting state functional connectivity. We compared Improvising musicians, Classical musicians, and Minimally Musically Trained (MMT) controls in seed-based functional connectivity and network analyses in resting state functional MRI. We also examined the functional correlates of behavioral performance in musical improvisation and divergent thinking. Seed-based analysis consistently showed higher connectivity in ventral DMN (vDMN) and bilateral ECN in both groups of musically trained individuals as compared to MMT controls, with additional group differences in primary visual network, precuneus network, and posterior salience network. In particular, primary visual network connectivity to DMN and ECN was highest in Improvisational musicians, whereas within-network connectivity of vDMN and precuneus network was higher in both Improvisational and Classical musicians than in MMT controls; in contrast, connectivity between posterior salience network and superior parietal lobule was highest in Classical musicians. Furthermore, graph-theoretical analysis indicated heightened betweenness centrality, clustering, and local efficiency in Classical musicians. Taken together, results suggest that heightened functional connectivity among musicians can be explained by higher within-network connectivity (more tight-knit cortical networks) in Classical musicians, as opposed to more disperse, globally-connected cortical networks in Improvisational musicians.HighlightsMusic training is associated with higher resting state connectivityHigher connectivity in Improvisational musicians from visual network to ECN and DMNClassical musicians show higher vDMN and Precuneus within-network connectivityImprovisation and divergent thinking performance correlate with similar connectivity patterns

scholarly journals Evaluation of confound regression strategies for the mitigation of micromovement artifact in studies of dynamic resting-state functional connectivity and multilayer network modularity

2019 ◽  
Vol 3 (2) ◽  
pp. 427-454 ◽  
Author(s):  
David M. Lydon-Staley ◽  
Rastko Ciric ◽  
Theodore D. Satterthwaite ◽  
Danielle S. Bassett
Keyword(s):  
Functional Connectivity ◽  
Brain Activity ◽  
Systematic Evaluation ◽  
Resting State Functional Connectivity ◽  
Multilayer Network ◽  
Dynamic Functional Connectivity ◽  
Spontaneous Brain Activity ◽  
Global Signal ◽  
Health And Disease ◽  
Modularity Maximization

Dynamic functional connectivity reflects the spatiotemporal organization of spontaneous brain activity in health and disease. Dynamic functional connectivity may be susceptible to artifacts induced by participant motion. This report provides a systematic evaluation of 12 commonly used participant-level confound regression strategies designed to mitigate the effects of micromovements in a sample of 393 youths (ages 8–22 years). Each strategy was evaluated according to a number of benchmarks, including (a) the residual association between participant motion and edge dispersion, (b) distance-dependent effects of motion on edge dispersion, (c) the degree to which functional subnetworks could be identified by multilayer modularity maximization, and (d) measures of module reconfiguration, including node flexibility and node promiscuity. Results indicate variability in the effectiveness of the evaluated pipelines across benchmarks. Methods that included global signal regression were the most consistently effective de-noising strategies.

scholarly journals A distinctive neural nexus in blind individuals supports Braille reading

2021 ◽  
Author(s):  
Ruxue WANG ◽  
Jiangtao GONG ◽  
Chenying ZHAO ◽  
Yingqing XU ◽  
Bo HONG
Keyword(s):  
Visual Cortex ◽  
Functional Connectivity ◽  
Frontal Cortex ◽  
Reading Proficiency ◽  
Occipital Cortex ◽  
Resting State Functional Connectivity ◽  
Crossmodal Plasticity ◽  
Blind Individuals ◽  
Language Areas

In the absence of visual input, occipital 'visual' cortex of blind people has been found to be engaged in non-visual higher cognitive tasks. Although the increased functional connectivity between 'visual' cortex and frontal cortex in the blind has been observed, the specific organization and functional role of this connectivity change remain to be elucidated. Here, we tested resting-state functional connectivity for primary 'visual' cortex (V1) and higher-tier lateral occipital cortex (LOC) in people with acquired blindness, and found an enhanced connectivity between the LOC but not V1 and typical frontal language areas - the inferior frontal cortex (IFC). In fact, the left-lateralized LOC-IFC connectivity strength predicted blind individuals' natural Braille reading proficiency. Furthermore, an increased bidirectional information flow between the left LOC and IFC was observed during a natural Braille reading task. In particular, the task-relevant modulation of the top-down communication from left IFC to LOC was significantly stronger than that of the bottom-up communication. Altogether, our study identified a distinctive neural nexus, LOC-IFC connection, and its behavioral significance in the acquired blind, revealing the neural correlates of the crossmodal plasticity in their 'visual' cortex underlying natural Braille reading.

scholarly journals Advanced Meditation Alters Resting-State Brain Network Connectivity Correlating With Improved Mindfulness

2021 ◽  
Vol 12 ◽  
Author(s):  
Ramana V. Vishnubhotla ◽  
Rupa Radhakrishnan ◽  
Kestas Kveraga ◽  
Rachael Deardorff ◽  
Chithra Ram ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Resting State ◽  
Network Connectivity ◽  
Blood Oxygen Level Dependent ◽  
Brain Network ◽  
Resting State Functional Connectivity ◽  
Blood Oxygen Level ◽  
Default Mode ◽  
Before And After ◽  
Brain Network Connectivity

Purpose: The purpose of this study was to investigate the effect of an intensive 8-day Samyama meditation program on the brain functional connectivity using resting-state functional MRI (rs-fMRI).Methods: Thirteen Samyama program participants (meditators) and 4 controls underwent fMRI brain scans before and after the 8-day residential meditation program. Subjects underwent fMRI with a blood oxygen level dependent (BOLD) contrast at rest and during focused breathing. Changes in network connectivity before and after Samyama program were evaluated. In addition, validated psychological metrics were correlated with changes in functional connectivity.Results: Meditators showed significantly increased network connectivity between the salience network (SN) and default mode network (DMN) after the Samyama program (p < 0.01). Increased connectivity within the SN correlated with an improvement in self-reported mindfulness scores (p < 0.01).Conclusion: Samyama, an intensive silent meditation program, favorably increased the resting-state functional connectivity between the salience and default mode networks. During focused breath watching, meditators had lower intra-network connectivity in specific networks. Furthermore, increased intra-network connectivity correlated with improved self-reported mindfulness after Samyama.Clinical Trials Registration: [https://clinicaltrials.gov], Identifier: [NCT04366544]. Registered on 4/17/2020.

scholarly journals Sex differences in the relationship between cardiorespiratory fitness and brain function in older adulthood

2019 ◽  
Vol 126 (4) ◽  
pp. 1032-1041 ◽  
Author(s):  
Christina J. Dimech ◽  
John A. E. Anderson ◽  
Amber W. Lockrow ◽  
R. Nathan Spreng ◽  
Gary R. Turner
Keyword(s):  
Older Adults ◽  
Sex Differences ◽  
Functional Connectivity ◽  
Cardiorespiratory Fitness ◽  
Resting State ◽  
Brain Function ◽  
Network Integration ◽  
Resting State Functional Connectivity ◽  
Older Adulthood ◽  
Fitness Level

We investigated sex differences in the association between a measure of physical health, cardiorespiratory fitness (CRF), and brain function using resting-state functional connectivity fMRI. We examined these sex differences in the default, frontoparietal control, and cingulo-opercular networks, assemblies of functionally connected brain regions known to be impacted by both age and fitness level. Healthy older adults ( n = 49; 29 women) were scanned to obtain measures of intrinsic connectivity within and across these 3 networks. We calculated global efficiency (a measure of network integration) and local efficiency (a measure of network specialization) using graph theoretical methods. Across all three networks combined, local efficiency was positively associated with CRF, and this was more robust in male versus female older adults. Furthermore, global efficiency was negatively associated with CRF, but only in males. Our findings suggest that in older adults, associations between brain network integrity and physical health are sex-dependent. These results underscore the importance of considering sex differences when examining associations between fitness and brain function in older adulthood. NEW & NOTEWORTHY We examined the association between cardiorespiratory fitness and resting state functional connectivity in several brain networks known to be impacted by age and fitness level. We found significant associations between fitness and measures of network integration and network specialization, but in a sex-dependent manner, highlighting the interplay between sex differences, fitness, and aging brain health. Our findings underscore the importance of considering sex differences when examining associations between fitness and brain function in older adulthood.

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