scholarly journals Brain dynamics: Synchronous peaks, functional connectivity, and its temporal variability

2021 ◽  
Author(s):  
Edmund T. Rolls ◽  
Wei Cheng ◽  
Jianfeng Feng
Keyword(s):  
Functional Connectivity ◽  
Temporal Variability ◽  
Brain Dynamics

scholarly journals Brain dynamics: the temporal variability of connectivity, and differences in schizophrenia and ADHD

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Edmund T. Rolls ◽  
Wei Cheng ◽  
Jianfeng Feng
Keyword(s):  
Functional Connectivity ◽  
Mental Disorders ◽  
Temporal Variability ◽  
Temporal Cortex ◽  
Brain Dynamics ◽  
First Episode ◽  
Thalamic Nuclei ◽  
Attractor Networks ◽  
Human Connectome Project ◽  
Health And Disease

AbstractWe describe advances in the understanding of brain dynamics that are important for understanding the operation of the cerebral cortex in health and disease. In data from 1017 participants from the Human Connectome Project, we show that early visual and connected areas have low temporal variability of their functional connectivity. We show that a low temporal variability of the connectivity of cortical areas is related to high mean functional connectivity between those areas, and provide an account of how these dynamics arise. We then investigate how these concepts help to understand brain dynamics in mental disorders. We find that in both first episode and long-term schizophrenia, reduced functional connectivity of early visual and related temporal cortex areas is associated with increased temporal variability of the functional connectivity, consistent with decreased stability of attractor networks related to sensory processing. In ADHD, we find these functional connectivities are increased and their temporal variability is decreased, and relate this to increased engagement with visual sensory input as manifest in high screen time usage in ADHD. We further show that these differences in the dynamics of the cortex in schizophrenia, and ADHD can be related to differences in the functional connectivity of the specific sensory vs. association thalamic nuclei. These discoveries help to advance our understanding of cortical operation in health, and in some mental disorders.

scholarly journals Modular origins of high-amplitude cofluctuations in fine-scale functional connectivity dynamics

2021 ◽  
Vol 118 (46) ◽  
pp. e2109380118
Author(s):  
Maria Pope ◽  
Makoto Fukushima ◽  
Richard F. Betzel ◽  
Olaf Sporns
Keyword(s):  
Functional Connectivity ◽  
Functional Neuroimaging ◽  
Empirical Studies ◽  
Structural Connectivity ◽  
Spatial Arrangement ◽  
High Amplitude ◽  
Brain Regions ◽  
Brain Dynamics ◽  
Modular Organization ◽  
Fine Scale

The topology of structural brain networks shapes brain dynamics, including the correlation structure of brain activity (functional connectivity) as estimated from functional neuroimaging data. Empirical studies have shown that functional connectivity fluctuates over time, exhibiting patterns that vary in the spatial arrangement of correlations among segregated functional systems. Recently, an exact decomposition of functional connectivity into frame-wise contributions has revealed fine-scale dynamics that are punctuated by brief and intermittent episodes (events) of high-amplitude cofluctuations involving large sets of brain regions. Their origin is currently unclear. Here, we demonstrate that similar episodes readily appear in silico using computational simulations of whole-brain dynamics. As in empirical data, simulated events contribute disproportionately to long-time functional connectivity, involve recurrence of patterned cofluctuations, and can be clustered into distinct families. Importantly, comparison of event-related patterns of cofluctuations to underlying patterns of structural connectivity reveals that modular organization present in the coupling matrix shapes patterns of event-related cofluctuations. Our work suggests that brief, intermittent events in functional dynamics are partly shaped by modular organization of structural connectivity.

scholarly journals Asthma-Specific Temporal Variability Reveals the Effect of Group Cognitive Behavior Therapy in Asthmatic Patients

2021 ◽  
Vol 12 ◽  
Author(s):  
Yuqun Zhang ◽  
Youyong Kong ◽  
Yuan Yang ◽  
Yingyin Yin ◽  
Zhenghua Hou ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Asthma Control ◽  
Behavior Therapy ◽  
Cognitive Behavior Therapy ◽  
Temporal Variability ◽  
Control Level ◽  
Post Treatment ◽  
Cognitive Behavior ◽  
Dynamic Functional Connectivity ◽  
Asthmatic Patients

Background: Group cognitive behavior therapy (GCBT) is a successful therapy for asthma. However, the neural biomarker of GCBT which could be used in clinic remains unclear. The temporal variability is a novel concept to characterize the dynamic functional connectivity (FC), which has many advantages as biomarker. Therefore, the aim of this study is to explore the potential difference of temporal variability between asthmatic patients and healthy controls, then determine the different patterns of temporal variability between pre- and post-treatment group and reveal the relationship between the variability and the symptoms improvement reduced by GCBT.Methods: At baseline, 40 asthmatic patients and 40 matched controls received resting-state functional magnetic resonance imaging (fMRI) scans and clinical assessments. After 8 weeks of GCBT treatment, 17 patients received fMRI scans, and assessments again. Temporal variability at baseline and post-treatment were calculated for further analysis.Results: Compared with controls, asthmatic patients showed widespread decreases in temporal variability. Moreover, the variability in both right caudate and left putamen were positively correlated with asthma control level. After GCBT, asthma control level and depression of patients were improved. Meanwhile, compared with pre-GCBT, patients after treatment showed lower variability in left opercular of Rolandic, right parahippocampal gyrus and right lingual gyrus, as well as higher variability in left temporal pole. Variability in regions which were found abnormal at baseline did not exhibit significant differences between post-GCBT and controls.Conclusions: Asthma-specific changes of dynamic functional connectivity may serve as promising underpinnings of GCBT for asthma.Clinical Trial Registration:http://www.chictr.org.cn/index.aspx, identifier: Chi-CTR-15007442.

scholarly journals Whole-Brain Dynamics in Aging: Disruptions in Functional Connectivity and the Role of the Rich Club

2020 ◽  
Author(s):  
Anira Escrichs ◽  
Carles Biarnes ◽  
Josep Garre-Olmo ◽  
José Manuel Fernández-Real ◽  
Rafel Ramos ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Resting State ◽  
Functional Network ◽  
Brain Dynamics ◽  
Whole Brain ◽  
Rich Club ◽  
Brain Functional Network ◽  
Age Related ◽  
Age Range ◽  
The Brain

Abstract Normal aging causes disruptions in the brain that can lead to cognitive decline. Resting-state functional magnetic resonance imaging studies have found significant age-related alterations in functional connectivity across various networks. Nevertheless, most of the studies have focused mainly on static functional connectivity. Studying the dynamics of resting-state brain activity across the whole-brain functional network can provide a better characterization of age-related changes. Here, we employed two data-driven whole-brain approaches based on the phase synchronization of blood-oxygen-level-dependent signals to analyze resting-state fMRI data from 620 subjects divided into two groups (middle-age group (n = 310); age range, 50–64 years versus older group (n = 310); age range, 65–91 years). Applying the intrinsic-ignition framework to assess the effect of spontaneous local activation events on local–global integration, we found that the older group showed higher intrinsic ignition across the whole-brain functional network, but lower metastability. Using Leading Eigenvector Dynamics Analysis, we found that the older group showed reduced ability to access a metastable substate that closely overlaps with the so-called rich club. These findings suggest that functional whole-brain dynamics are altered in aging, probably due to a deficiency in a metastable substate that is key for efficient global communication in the brain.

scholarly journals Changes in the temporal variability of the EEG functional connectivity during aging

2015 ◽  
Vol 7 (1) ◽  
pp. 5-15
Author(s):  
Almudena González ◽  
Guzmán Alba ◽  
Julián González
Keyword(s):  
Functional Connectivity ◽  
Cognitive Performance ◽  
Temporal Variability ◽  
Healthy Subjects ◽  
Generalized Synchronization ◽  
Performance Deficits ◽  
Cortical Areas ◽  
Eyes Closed ◽  
Eeg Recordings ◽  
Eeg Functional Connectivity

This work is aimed at investigating changes in the temporal variability of EEG functional connectivity (FC) during agin. The variability in the FC has been linked to cognitive performance. The study was carried out in two groups of healthy subjects: one of 10 adults between 50-65 years old and another of 15 subjects ranging 66-85 years. EEG recordings were made at rest using 16 monopolar channels: under eyes closed (EC) and under hyperventilation (HV). The cortical FC between all EEG channel pairs was estimated from an index (L) of nonlinear generalized synchronization. For each subject and condition, the global connectivity (GC) of each area/channel with the rest of them was calculated, then the GC average and the GC temporal variability (TVC) of such connectivities was computed from the GC mean and standard deviation of successive EEG recordings respectively. The changes with age and condition of GC and TVC of each cortical area were estimated via a MANOVA. We found that the GC does not change with age during OC or HV, but the TVC of all cortical areas is significantly higher (p<0.01) for subjects under 65 and mainly for the central, temporal and parietal areas (p<0.01). It is concluded that TVC decreasing with aging may be related to cognitive performance deficits.

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