scholarly journals High-amplitude co-fluctuations in cortical activity drive functional connectivity

2019 ◽  
Author(s):  
Farnaz Zamani Esfahlani ◽  
Youngheun Jo ◽  
Joshua Faskowitz ◽  
Lisa Byrge ◽  
Daniel P. Kennedy ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Resting State ◽  
Temporal Structure ◽  
High Amplitude ◽  
Network Activity ◽  
Connectivity Pattern ◽  
Future Research ◽  
Resting State Functional Connectivity ◽  
Brain Organization ◽  
Fluctuation Amplitude

Resting-state functional connectivity is used throughout neuroscience to study brain organization and to generate biomarkers of development, disease, and cognition. The processes that give rise to correlated activity are, however, poorly understood. Here, we decompose resting-state functional connectivity using a “temporal unwrapping” procedure to assess the contributions of moment-to-moment activity co-fluctuations to the overall connectivity pattern. This approach temporally resolves functional connectivity at a timescale of single frames, which enables us to make direct comparisons of co-fluctuations of network organization with fluctuations in the BOLD time series. We show that, surprisingly, only a small fraction of frames exhibiting the strongest co-fluctuation amplitude are required to explain a significant fraction of variance in the overall pattern of connection weights as well as the network’s modular structure. These frames coincide with frames of high BOLD activity amplitude, corresponding to activity patterns that are remarkably consistent across individuals and identify fluctuations in default mode and control network activity as the primary driver of resting-state functional connectivity. Finally, we demonstrate that co-fluctuation amplitude synchronizes across subjects during movie-watching and that high-amplitude frames carry detailed information about individual subjects (whereas low-amplitude frames carry little). Our approach reveals fine-scale temporal structure of resting-state functional connectivity, and discloses that frame-wise contributions vary across time. These observations illuminate the relation of brain activity to functional connectivity and open a number of new directions for future research.

scholarly journals High-amplitude cofluctuations in cortical activity drive functional connectivity

2020 ◽  
Vol 117 (45) ◽  
pp. 28393-28401
Author(s):  
Farnaz Zamani Esfahlani ◽  
Youngheun Jo ◽  
Joshua Faskowitz ◽  
Lisa Byrge ◽  
Daniel P. Kennedy ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Resting State ◽  
Temporal Structure ◽  
Activity Patterns ◽  
High Amplitude ◽  
Network Activity ◽  
Connectivity Pattern ◽  
Future Research ◽  
Resting State Functional Connectivity ◽  
Brain Organization

Resting-state functional connectivity is used throughout neuroscience to study brain organization and to generate biomarkers of development, disease, and cognition. The processes that give rise to correlated activity are, however, poorly understood. Here we decompose resting-state functional connectivity using a temporal unwrapping procedure to assess the contributions of moment-to-moment activity cofluctuations to the overall connectivity pattern. This approach temporally resolves functional connectivity at a timescale of single frames, which enables us to make direct comparisons of cofluctuations of network organization with fluctuations in the blood oxygen level-dependent (BOLD) time series. We show that surprisingly, only a small fraction of frames exhibiting the strongest cofluctuation amplitude are required to explain a significant fraction of variance in the overall pattern of connection weights as well as the network’s modular structure. These frames coincide with frames of high BOLD activity amplitude, corresponding to activity patterns that are remarkably consistent across individuals and identify fluctuations in default mode and control network activity as the primary driver of resting-state functional connectivity. Finally, we demonstrate that cofluctuation amplitude synchronizes across subjects during movie watching and that high-amplitude frames carry detailed information about individual subjects (whereas low-amplitude frames carry little). Our approach reveals fine-scale temporal structure of resting-state functional connectivity and discloses that frame-wise contributions vary across time. These observations illuminate the relation of brain activity to functional connectivity and open a number of directions for future research.

scholarly journals Prevalent and sex-biased breathing patterns modify functional connectivity MRI in young adults

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Charles J. Lynch ◽  
Benjamin M. Silver ◽  
Marc J. Dubin ◽  
Alex Martin ◽  
Henning U. Voss ◽  
...  
Keyword(s):  
Young Adults ◽  
Functional Connectivity ◽  
Resting State ◽  
Resting State Fmri ◽  
Resonance Imaging ◽  
Breathing Patterns ◽  
Resting State Functional Connectivity ◽  
Brain Organization ◽  
Normal Breathing ◽  
Functional Connectivity Mri

Abstract Resting state functional connectivity magnetic resonance imaging (fMRI) is a tool for investigating human brain organization. Here we identify, visually and algorithmically, two prevalent influences on fMRI signals during 440 h of resting state scans in 440 healthy young adults, both caused by deviations from normal breathing which we term deep breaths and bursts. The two respiratory patterns have distinct influences on fMRI signals and signal covariance, distinct timescales, distinct cardiovascular correlates, and distinct tendencies to manifest by sex. Deep breaths are not sex-biased. Bursts, which are serial taperings of respiratory depth typically spanning minutes at a time, are more common in males. Bursts share features of chemoreflex-driven clinical breathing patterns that also occur primarily in males, with notable neurological, psychiatric, medical, and lifespan associations. These results identify common breathing patterns in healthy young adults with distinct influences on functional connectivity and an ability to differentially influence resting state fMRI studies.

scholarly journals Resting State Functional Connectivity Is Associated With Motor Pathway Integrity and Upper-Limb Behavior in Chronic Stroke

2020 ◽  
Vol 34 (6) ◽  
pp. 547-557 ◽  
Author(s):  
Brenton Hordacre ◽  
Mitchell R. Goldsworthy ◽  
Ellana Welsby ◽  
Lynton Graetz ◽  
Sophie Ballinger ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Upper Limb ◽  
Resting State ◽  
Motor Evoked Potential ◽  
Chronic Stroke ◽  
Network Activity ◽  
Stroke Survivors ◽  
Resting State Functional Connectivity ◽  
Motor Pathway ◽  
Motor Pathways

Background. Resting state functional connectivity (RSFC) is a developmental priority for stroke recovery. Objective. To determine whether (1) RSFC differs between stroke survivors based on integrity of descending motor pathways; (2) RSFC is associated with upper-limb behavior in chronic stroke; and (3) the relationship between interhemispheric RSFC and upper-limb behavior differs based on descending motor pathway integrity. Methods. A total of 36 people with stroke (aged 64.4 ± 11.1 years, time since stroke 4.0 ± 2.8 years) and 25 healthy adults (aged 67.3 ± 6.7 years) participated in this study. RSFC was estimated from electroencephalography (EEG) recordings. Integrity of descending motor pathways was ascertained using transcranial magnetic stimulation to determine motor-evoked potential (MEP) status and magnetic resonance imaging to determine lesion overlap and fractional anisotropy of the corticospinal tract (CST). For stroke participants, upper-limb motor behavior was assessed using the Fugl-Meyer test, Action Research Arm Test and grip strength. Results. β-Frequency interhemispheric sensorimotor RSFC was greater for MEP+ stroke participants compared with MEP− ( P = .020). There was a significant positive correlation between β RSFC and upper-limb behavior ( P = .004) that appeared to be primarily driven by the MEP+ group. A hierarchical regression identified that the addition of β RSFC to measures of CST integrity explained greater variance in upper-limb behavior ( R2 change = 0.13; P = .01). Conclusions. This study provides insight to understand the role of EEG-based measures of interhemispheric network activity in chronic stroke. Resting state interhemispheric connectivity was positively associated with upper-limb behavior for stroke survivors where residual integrity of descending motor pathways was maintained.

scholarly journals Differential Alterations in Resting State Functional Connectivity Associated with Depressive Symptoms and Early Life Adversity

2021 ◽  
Vol 11 (5) ◽  
pp. 591
Author(s):  
Eleonora Fadel ◽  
Heinz Boeker ◽  
Matti Gaertner ◽  
Andre Richter ◽  
Birgit Kleim ◽  
...  
Keyword(s):  
Depressive Symptoms ◽  
Functional Connectivity ◽  
Childhood Abuse ◽  
Resting State ◽  
Early Life ◽  
Clinical Symptoms ◽  
Future Research ◽  
Resting State Functional Connectivity ◽  
Early Life Adversity ◽  
Depression Subtypes

Depression and early life adversity (ELA) are associated with aberrant resting state functional connectivity (FC) of the default mode (DMN), salience (SN), and central executive networks (CEN). However, the specific and differential associations of depression and ELA with FC of these networks remain unclear. Applying a dimensional approach, here we analyzed associations of FC between major nodes of the DMN, SN, and CEN with severity of depressive symptoms and ELA defined as childhood abuse and neglect in a sample of 83 healthy and depressed subjects. Depressive symptoms were linked to increased FC within the SN and decreased FC of the SN with the DMN and CEN. Childhood abuse was associated with increased FC within the SN, whereas childhood neglect was associated with decreased FC within the SN and increased FC between the SN and the DMN. Our study thus provides evidence for differential associations of depressive symptoms and ELA with resting state FC and contributes to a clarification of previously contradictory findings. Specific FC abnormalities may underlie specific cognitive and emotional impairments. Future research should link specific clinical symptoms resulting from ELA to FC patterns thereby characterizing depression subtypes with specific neurobiological signatures.

Eyes closed or Eyes open? Exploring the alpha desynchronization hypothesis in resting state functional connectivity networks with intracranial EEG

2017 ◽  
Author(s):  
Jaime Gómez-Ramírez ◽  
Shelagh Freedman ◽  
Diego Mateos ◽  
José Luis Pérez-Velázquez ◽  
Taufik Valiante
Keyword(s):  
Functional Connectivity ◽  
Resting State ◽  
Connectivity Pattern ◽  
Cost Calculation ◽  
Resting State Functional Connectivity ◽  
Eyes Closed ◽  
Regional Specificity ◽  
Eyes Open ◽  
First Time ◽  
Intracranial Recordings

AbstractThis paper addresses a fundamental question, are eyes closed and eyes open resting states equivalent baseline conditions, or do they have consistently different electrophysiological signatures? We compare the functional connectivity patterns in an eyes closed resting state with an eyes open resting state, and show that functional connectivity in the alpha band decreases in the eyes open condition compared to eyes closed. This "alpha desynchronization " or reduction in the number of connections from eyes closed to eyes open, is here, for the first time, studied with intracranial recordings. We provide two calculations of the wiring cost, local and mesoscopic, defined in terms of the distance between the electrodes and the likelihood that they are functionally connected. We find that, in agreement with the "alpha desynchronization" hypothesis, the local wiring cost decreases going from eyes closed to eyes open. However, when the wiring cost calculation takes into account the connectivity pattern, the wiring cost variation from eyes closed to eyes open is not as consistent and shows regional specificity. The wiring cost measure defined here, provides a new avenue for understanding the electrophysiology of resting state.

scholarly journals A-189 Exploring the Effects of EEG Neurofeedback Training on Verbal Episodic Memory in a TBI Sample

2020 ◽  
Vol 35 (6) ◽  
pp. 984-984
Author(s):  
Kaser A ◽  
Gordon E ◽  
May G ◽  
Dolan S ◽  
Zambrano-Vazquez L
Keyword(s):  
Functional Connectivity ◽  
Episodic Memory ◽  
Cognitive Functioning ◽  
Resting State ◽  
Verbal Learning ◽  
Future Research ◽  
Neurofeedback Training ◽  
Resting State Functional Connectivity ◽  
Eeg Neurofeedback ◽  
Verbal Episodic Memory

Abstract Objective Traumatic brain injuries (TBI) are commonly characterized by neural changes that impair physical, behavioral, and cognitive functioning across diverse ages and demographics. Cognitive complaints frequently include memory difficulties, with deficits in episodic memory greatly impairing daily functioning and future planning. Although various interventions and rehabilitation techniques have been implemented for TBI, limited treatment options are available for TBI-driven memory complaints. Recent research has explored the use of neurofeedback training (NFT) to improve cognitive functioning in TBI patients, yet it remains unclear whether this intervention may be successful in improving these memory deficits. Method In this double-blind, placebo-controlled pilot study, the use of EEG neurofeedback training (NFT) on verbal episodic memory was explored in 12 veterans with TBI. Participants were randomized to active treatment or sham treatment, and they completed 20 sessions of NFT. Clinical assessments and functional magnetic resonance imaging (fMRI) data were collected pre and post treatment to measure any changes in resting-state functional connectivity or cognitive functioning. Results Findings suggest that immediate recall scores improved following active NFT, as measured by the California Verbal Learning Task-II. We also observed increased resting-state functional connectivity between the ventromedial prefrontal cortex and the inferior temporal lobe following NFT (Fig. 1), which may represent an underlying mechanism of memory improvement. Conclusions These exploratory findings may hold promise for future research on the use of NFT for memory enhancement in various populations.

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