scholarly journals BOLD signal and functional connectivity associated with loving kindness meditation

2014 ◽  
Vol 4 (3) ◽  
pp. 337-347 ◽  
Author(s):  
Kathleen A. Garrison ◽  
Dustin Scheinost ◽  
R. Todd Constable ◽  
Judson A. Brewer
Keyword(s):  
Functional Connectivity ◽  
Bold Signal ◽  
Loving Kindness

scholarly journals Dissociated mean and functional connectivity BOLD signals in visual cortex during eyes closed and fixation

2012 ◽  
Vol 108 (9) ◽  
pp. 2363-2372 ◽  
Author(s):  
Mark McAvoy ◽  
Linda Larson-Prior ◽  
Marek Ludwikow ◽  
Dongyang Zhang ◽  
Abraham Z. Snyder ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Functional Connectivity ◽  
Primary Visual Cortex ◽  
Blood Oxygen Level Dependent ◽  
Extrastriate Cortex ◽  
Connected Components ◽  
Bold Signal ◽  
Thalamic Nuclei ◽  
Eyes Closed ◽  
Visual Areas

We investigated the effects of resting state type on blood oxygen level-dependent (BOLD) signal and functional connectivity in two paradigms: participants either alternated between fixation and eyes closed or maintained fixation or eyes closed throughout each scan. The BOLD signal and functional connectivity of lower and higher tiers of the visual cortical hierarchy were found to be differentially modulated during eyes closed versus fixation. Fixation was associated with greater mean BOLD signals in primary visual cortex and lower mean BOLD signals in extrastriate visual areas than periods of eyes closed. In addition, analysis of thalamocortical functional connectivity during scans in which participants maintained fixation showed synchronized BOLD fluctuations between those thalamic nuclei whose mean BOLD signal was systematically modulated during alternating epochs of eyes closed and fixation, primary visual cortex and the attention network, while during eyes closed negatively correlated fluctuations were seen between the same thalamic nuclei and extrastriate visual areas. Finally, in all visual areas the amplitude of spontaneous BOLD fluctuations was greater during eyes closed than during fixation. The dissociation between early and late tiers of visual cortex, which characterizes both mean and functionally connected components of the BOLD signal, may depend on the reorganization of thalamocortical networks. Since dissociated changes in local blood flow also characterize transitions between different stages of sleep and wakefulness (Braun AR, Balkin TJ, Wesenten NJ, Gwadry F, Carson RE, Varga M, Baldwin P, Belenky G, Herscovitch P. Science 279: 91–95, 1998), our results suggest that dissociated endogenous neural activity in primary and extrastriate cortex may represent a general aspect of brain function.

scholarly journals Subcortical connectivity in dementia with Lewy bodies and Alzheimer's disease

2013 ◽  
Vol 203 (3) ◽  
pp. 209-214 ◽  
Author(s):  
Eva R. Kenny ◽  
John T. O'Brien ◽  
Michael J. Firbank ◽  
Andrew M. Blamire
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Resting State ◽  
Dementia With Lewy Bodies ◽  
Lewy Bodies ◽  
Low Frequency ◽  
Blood Oxygen Level Dependent ◽  
Bold Signal ◽  
Blood Oxygen Level

BackgroundResting-state functional magnetic resonance imaging (fMRI) can be used to measure correlations in spontaneous low-frequency fluctuations in the blood oxygen level-dependent (BOLD) signal which represent functional connectivity between key brain areas.AimsTo investigate functional connectivity with regions hypothesised to be differentially affected in dementia with Lewy bodies (DLB) compared with Alzheimer's disease and controls.MethodFifteen participants with probable DLB, 16 with probable Alzheimer's disease and 16 controls were scanned in the resting-state using a 3T scanner. The BOLD signal time-series of fluctuations in seed regions were correlated with all other voxels to measure functional connectivity.ResultsParticipants with DLB and Alzheimer's disease showed greater caudate and thalamic connectivity compared with controls. Those with DLB showed greater putamen connectivity compared with those with Alzheimer's disease and the controls. No regions showed less connectivity in DLB or Alzheimer's disease v. controls, or in DLB v. Alzheimer's disease.ConclusionsAltered connectivity in DLB and Alzheimer's disease provides new insights into the neurobiology of these disorders and may aid in earlier diagnosis.

scholarly journals Interictal Functional Connectivity of Human Epileptic Networks Assessed by Intracerebral EEG and BOLD Signal Fluctuations

PLoS ONE ◽  
2011 ◽  
Vol 6 (5) ◽  
pp. e20071 ◽  
Author(s):  
Gaelle Bettus ◽  
Jean-Philippe Ranjeva ◽  
Fabrice Wendling ◽  
Christian G. Bénar ◽  
Sylviane Confort-Gouny ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Bold Signal ◽  
Intracerebral Eeg ◽  
Epileptic Networks

scholarly journals Cortical and subcortical hemodynamic changes during human sleep slow waves

2020 ◽  
Author(s):  
Monica Betta ◽  
Giacomo Handjaras ◽  
Andrea Leo ◽  
Alessandra Federici ◽  
Valentina Farinelli ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Electrical Coupling ◽  
Nrem Sleep ◽  
Slow Waves ◽  
Bold Signal ◽  
Hemodynamic Changes ◽  
Regional Patterns ◽  
Cortical Level ◽  
Function Of Sleep ◽  
Cortical Distribution

AbstractEEG slow waves, the hallmarks of NREM sleep, are closely linked to the restorative function of sleep and their regional cortical distribution reflects plasticity- and learning-related processes. Here we took advantage of simultaneous EEG-fMRI recordings to map cortical and subcortical hemodynamic (BOLD) fluctuations time-locked to sleep slow waves. Recordings were performed in twenty healthy adults during an afternoon nap. Slow waves were associated with BOLD-signal increases in the brainstem and in portions of thalamus and cerebellum characterized by preferential functional connectivity with limbic and somatomotor areas, respectively. At the cortical level, significant BOLD-signal decreases were found in several areas, including insula and somatomotor cortex, and were preceded by slow signal increases that peaked around slow-wave onset. EEG slow waves and BOLD fluctuations showed similar cortical propagation patterns, from centro-frontal to temporo-occipital cortices. These regional patterns of hemodynamic-electrical coupling are consistent with theoretical accounts of the functions of sleep slow waves.

scholarly journals Surgically disconnected temporal pole exhibits resting functional connectivity with remote brain regions

2017 ◽  
Author(s):  
David E. Warren ◽  
Matthew J. Sutterer ◽  
Joel Bruss ◽  
Taylor J. Abel ◽  
Andrew Jones ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Structural Connectivity ◽  
Low Frequency ◽  
Resting State Fmri ◽  
Brain Regions ◽  
Bold Signal ◽  
Disease States ◽  
Behavior Development ◽  
Temporal Pole ◽  
Relationship Of

AbstractFunctional connectivity, as measured by resting-state fMRI, has proven a powerful method for studying brain systems in the context of behavior, development, and disease states. However, the relationship of functional connectivity to structural connectivity remains unclear. If functional connectivity relies on structural connectivity, then anatomical isolation of a brain region should eliminate functional connectivity with other brain regions. We tested this by measuring functional connectivity of the surgically disconnected temporal pole in resection patients (N=5; mean age 37; 2F, 3M). Functional connectivity was evaluated based on coactivation of whole-brain fMRI data with the average low-frequency BOLD signal from disconnected tissue in each patient. In sharp contrast to our prediction, we observed significant functional connectivity between the disconnected temporal pole and remote brain regions in each disconnection case. These findings raise important questions about the neural bases of functional connectivity measures derived from the fMRI BOLD signal.

scholarly journals The Role of the Human Brain Neuron-Glia-Synaptic Composition in Forming Resting State Functional Connectivity Networks

2021 ◽  
Author(s):  
Sayan Kahali ◽  
Marcus E Raichle ◽  
Dmitriy A Yablonskiy
Keyword(s):  
Functional Connectivity ◽  
Human Brain ◽  
Resting State ◽  
Functional Networks ◽  
Bold Signal ◽  
Neuronal Density ◽  
Functional Relationships ◽  
Wide Range ◽  
Functional Units ◽  
The Brain

While significant progress has been achieved in studying resting state functional networks in a healthy human brain and in a wide range of clinical conditions, many questions related to their relationship to the brain's cellular constituents remain open. In this paper we use quantitative Gradient Recalled Echo (qGRE) MRI for in vivo quantitative mapping of human brain cellular composition, and BOLD (blood oxygen level dependent) MRI resting state data from the Human Connectome Project to explore how the brain cellular constituents relate to resting state functional networks. Our results show that the BOLD-signal-defined synchrony of connections between cellular circuits in network-defined individual functional units is mainly associated with the regional neuronal density, while the strength of the functional connectivity between functional units is influenced not only by the neuronal but also glia and synaptic components of brain tissue cellular constituents. Data show that these cellular-functional relationships are most evident in the infra-slow frequency range (0.01-0.16 Hz) of brain activity, which is known to be linked with fluctuations of the BOLD signal. These mechanisms lead to a rather broad distribution of resting state functional network properties. We found that visual networks with the highest neuronal density (but lowest density of glial cells and synapses) exhibit the strongest coherence of BOLD signal in individual functional units, as well as the strongest intra-network connectivity. The Default Mode Network (DMN) is positioned near the opposite part of the spectrum with relatively low coherence of the BOLD signal but a remarkably balanced cellular content enabling DMN prominent role in the overall organization of the brain and the hierarchy of functional networks in health and disease.

scholarly journals Nuisance effects in inter-scan functional connectivity estimates before and after nuisance regression

2019 ◽  
Author(s):  
Alican Nalci ◽  
Wenjing Luo ◽  
Thomas T. Liu
Keyword(s):  
Functional Connectivity ◽  
Brain Regions ◽  
Blood Oxygenation ◽  
Bold Signal ◽  
Global Signal ◽  
Before And After ◽  
Oxygenation Level ◽  
Motion Measurements ◽  
The Brain

AbstractIn resting-state functional MRI, the correlation between blood-oxygenation-level-dependent (BOLD) signals across brain regions is used to estimate the functional connectivity (FC) of the brain. FC estimates are prone to the influence of nuisance factors including scanner-related artifacts and physiological modulations of the BOLD signal. Nuisance regression is widely performed to reduce the effect of nuisance factors on FC estimates on a per-scan basis. However, a dedicated analysis of nuisance effects on the variability of FC metrics across a collection of scans has been lacking. This work investigates the effects of nuisance factors on the variability of FC estimates across a collection of scans both before and after nuisance regression. Inter-scan variations in FC estimates are shown to be significantly correlated with the geometric norms of various nuisance terms, including head motion measurements, signals derived from white-matter and cerebrospinal regions, and the whole-brain global signal (GS) both before and after nuisance regression. In addition, it is shown that GS regression (GSR) can introduce GS norm-related fluctuations that are negatively correlated with inter-scan FC estimates. The empirical results are shown to be largely consistent with the predictions of a theoretical framework previously developed for the characterization of dynamic FC measures. This work shows that caution must be exercised when interpreting inter-scan FC measures across scans both before and after nuisance regression.

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