scholarly journals Resonant waves drive long-range correlations in fMRI signals

2022 ◽  
Author(s):  
Joana Cabral ◽  
Francisca F Fernandes ◽  
Noam Shemesh
Keyword(s):  
Functional Connectivity ◽  
Long Range ◽  
Phase Synchronization ◽  
Spatial Configuration ◽  
Activity Patterns ◽  
Standing Waves ◽  
Subcortical Structures ◽  
Complex Activity ◽  
Long Range Correlations ◽  
Intrinsic Functional Connectivity

The fundamental principles driving spontaneous long-range correlations between distant brain areas - known as intrinsic functional connectivity - remain unclear. To investigate this, we develop an ultrafast functional Magnetic Resonance Imaging (fMRI) approach with unprecedented temporal resolution (38 milliseconds) in the rat brain. We detect a repertoire of principal components exhibiting standing wave properties, i.e., with phase relationships varying gradually across space and oscillating in time, driving in- and anti-phase synchronization across distinct cortical and subcortical structures. The spatial configuration, stability and peak frequency of these standing waves is found to depend on the sedation/anaesthesia state, with medetomidine sedation revealing the most stable (i.e., less damped) standing waves, resonating at frequencies extending up to 0.25 Hz. Our findings show that the complex activity patterns observed in resting-state fMRI signals result from the superposition of standing waves, supporting the hypothesis that intrinsic functional connectivity is inherently associated to resonance phenomena.

scholarly journals Tightly-coupled inhibitory and excitatory functional networks in the early visual cortex

2021 ◽  
Author(s):  
Haleigh N. Mulholland ◽  
Bettina Hein ◽  
Matthias Kaschube ◽  
Gordon B. Smith
Keyword(s):  
Visual Cortex ◽  
Spontaneous Activity ◽  
Long Range ◽  
Computational Models ◽  
Activity Patterns ◽  
Critical Role ◽  
Inhibitory Neurons ◽  
Functional Networks ◽  
Long Range Correlations ◽  
Inhibitory Networks

AbstractIntracortical inhibition plays a critical role in shaping activity patterns in the mature cortex. However, little is known about the structure of inhibition in early development prior to the onset of sensory experience, a time when spontaneous activity exhibits long-range correlations predictive of mature functional networks. Here, using calcium imaging of GABAergic neurons in the early ferret visual cortex, we show that spontaneous activity in inhibitory neurons is already highly organized into distributed modular networks before visual experience. Inhibitory neurons exhibit spatially modular activity with long-range correlations and precise local organization that is in quantitative agreement with excitatory networks. Furthermore, excitatory and inhibitory networks are strongly co-aligned at both millimeter and cellular scales. These results demonstrate a remarkable degree of organization in inhibitory networks early in the developing cortex, providing support for computational models of self-organizing networks and suggesting a mechanism for the emergence of distributed functional networks during development.

scholarly journals Tightly coupled inhibitory and excitatory functional networks in the developing primary visual cortex

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Haleigh N Mulholland ◽  
Bettina Hein ◽  
Matthias Kaschube ◽  
Gordon B Smith
Keyword(s):  
Visual Cortex ◽  
Spontaneous Activity ◽  
Long Range ◽  
Computational Models ◽  
Activity Patterns ◽  
Critical Role ◽  
Inhibitory Neurons ◽  
Functional Networks ◽  
Long Range Correlations ◽  
Inhibitory Networks

Intracortical inhibition plays a critical role in shaping activity patterns in the mature cortex. However, little is known about the structure of inhibition in early development prior to the onset of sensory experience, a time when spontaneous activity exhibits long-range correlations predictive of mature functional networks. Here, using calcium imaging of GABAergic neurons in the ferret visual cortex, we show that spontaneous activity in inhibitory neurons is already highly organized into distributed modular networks before visual experience. Inhibitory neurons exhibit spatially modular activity with long-range correlations and precise local organization that is in quantitative agreement with excitatory networks. Furthermore, excitatory and inhibitory networks are strongly co-aligned at both millimeter and cellular scales. These results demonstrate a remarkable degree of organization in inhibitory networks early in the developing cortex, providing support for computational models of self-organizing networks and suggesting a mechanism for the emergence of distributed functional networks during development.

scholarly journals Studies of charm and beauty hadron long-range correlations in pp and pPb collisions at LHC energies

2021 ◽  
Vol 813 ◽  
pp. 136036
Author(s):  
A.M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Long Range ◽  
Long Range Correlations

scholarly journals Long-range correlations in pinned athermal networks

2021 ◽  
Vol 104 (1) ◽  
Author(s):  
Debankur Das ◽  
Pappu Acharya ◽  
Kabir Ramola
Keyword(s):  
Long Range ◽  
Long Range Correlations

scholarly journals Strengthened Corticosubcortical Functional Connectivity during Muscle Fatigue

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Zhiguo Jiang ◽  
Xiao-Feng Wang ◽  
Guang H. Yue
Keyword(s):  
Motor Control ◽  
Functional Connectivity ◽  
Quantile Regression ◽  
Muscle Fatigue ◽  
Motor Performance ◽  
Primary Motor Cortex ◽  
Motor Task ◽  
Voluntary Contraction ◽  
Control Network ◽  
Subcortical Structures

The present study examined functional connectivity (FC) between functional MRI (fMRI) signals of the primary motor cortex (M1) and each of the three subcortical neural structures, cerebellum (CB), basal ganglia (BG), and thalamus (TL), during muscle fatigue using the quantile regression technique. Understanding activation relation between the subcortical structures and the M1 during prolonged motor performance should help delineate how central motor control network modulates acute perturbations at peripheral sensorimotor system such as muscle fatigue. Ten healthy subjects participated in the study and completed a 20-minute intermittent handgrip motor task at 50% of their maximal voluntary contraction (MVC) level. Quantile regression analyses were carried out to compare the FC between the contralateral (left) M1 and CB, BG, and TL in the minimal (beginning 100 s) versus significant (ending 100 s) fatigue stages. Widespread, statistically significant increases in FC were found in bilateral BG, CB, and TL with the left M1 during significant versus minimal fatigue stages. Our results imply that these subcortical nuclei are critical components in the motor control network and actively involved in modulating voluntary muscle fatigue, possibly, by working together with the M1 to strengthen the descending central command to prolong the motor performance.

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