scholarly journals Dynamics of multiple interacting excitatory and inhibitory populations with delays

2018 ◽  
Author(s):  
Christopher M. Kim ◽  
Ulrich Egert ◽  
Arvind Kumar
Keyword(s):  
Stationary State ◽  
Network Model ◽  
Transmission Delay ◽  
Network Activity ◽  
Oscillatory Activity ◽  
Bifurcation Structure ◽  
Transmission Delays ◽  
Spiking Network ◽  
Frequency Coupling ◽  
Cross Frequency Coupling

A network consisting of excitatory and inhibitory (EI) neurons is a canonical model for understanding cortical network activity. In this study, we extend the EI network model and investigate how its dynamical landscape can be enriched when it interacts with another excitatory (E) population with transmission delays. Through analysis and simulations of a rate model and a spiking network model, we study the transition from stationary to oscillatory states by analyzing the Hopf bifurcation structure in terms of two network parameters: 1) transmission delay between the EI subnetwork and the E population and 2) inhibitory couplings that induce oscillatory activity in the EI subnetwork. We find that the critical coupling strength can strongly modulate as a function of transmission delay, and consequently the stationary state is interwoven intricately with oscillatory states generating different frequency modes. This leads to the emergence of an isolated stationary state surrounded by multiple oscillatory states and cross-frequency coupling develops at the bifurcation points. We identify the possible network motifs that induce oscillations and examine how multiple oscillatory states come together to enrich the dynamical landscape.

scholarly journals Delta-mediated cross-frequency coupling organizes oscillatory activity across the rat cortico-basal ganglia network

2013 ◽  
Vol 7 ◽  
Author(s):  
Jon López-Azcárate ◽  
María Jesús Nicolás ◽  
Ivan Cordon ◽  
Manuel Alegre ◽  
Miguel Valencia ◽  
...  
Keyword(s):  
Basal Ganglia ◽  
Oscillatory Activity ◽  
Frequency Coupling ◽  
Cross Frequency Coupling

scholarly journals Gamma Entrainment Improves Synchronization Deficits in Dementia Patients

2021 ◽  
Author(s):  
Mojtaba Lahijanian ◽  
Hamid Aghajan ◽  
Zahra Vahabi ◽  
Arshia Afzal
Keyword(s):  
Oscillatory Activity ◽  
Therapeutic Effects ◽  
Phase Coupling ◽  
Non Invasive ◽  
Temporal Phase ◽  
Dementia Patients ◽  
Frequency Coupling ◽  
Phase Amplitude ◽  
Cross Frequency Coupling

AbstractNon-invasive gamma entrainment has shown promising results in alleviating cognitive symptoms of Alzheimer’s disease in mice and humans. In this study, we examine improvements in the synchronization characteristics of the brain’s oscillations induced by 40Hz auditory stimulation based on electroencephalography data recorded from a group of dementia patients. We observed that when the quality of entrainment surpasses a certain level, several indicators of brain synchronization significantly improve. Specifically, the entrained oscillatory activity maintains temporal phase stability in the frontal, parietal, and occipital regions, and persistent spatial phase coupling between them. In addition, notable theta-gamma phase-amplitude coupling is observed in these areas. Interestingly, a high theta power at rest predicts the quality of entrainment. We identify differentiating attributes of temporal/spatial synchronization and cross-frequency coupling in the data of two groups with entrained and non-entrained responses which point to enhanced network synchronization caused by entrainment and can explain its potential therapeutic effects.

scholarly journals Nasal respiration entrains neocortical long-range gamma coherence during wakefulness

2018 ◽  
Author(s):  
Matías Cavelli ◽  
Santiago Castro-Zaballa ◽  
Joaquín Gonzalez ◽  
Daniel Rojas-Líbano ◽  
Nicolas Rubido ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Long Range ◽  
Cognitive Functions ◽  
Muscular Activity ◽  
Gamma Activity ◽  
Oscillatory Activity ◽  
Respiratory Phase ◽  
Gamma Coherence ◽  
Frequency Coupling ◽  
Cross Frequency Coupling

AbstractRecent studies have shown that slow cortical potentials in archi-, paleo- and neocortex, can phase-lock with nasal respiration. In some of these areas, gamma activity (γ: 30-100 Hz) is also coupled to the animal’s respiration. It has been hypothesized that this interaction plays a role in coordinating distributed neural activity. In a similar way, inter-cortical interactions at γ frequency has been also associated as a binding mechanism by which the brain generates temporary opportunities necessary for implementing cognitive functions. The aim of the present study is to explore if nasal respiration entrains inter-cortical interactions at γ frequency.Six adult cats chronically prepared for electrographic recordings were employed in this study. Our results show that slow cortical respiratory potentials are present in several areas of the neocortex and olfactory bulb during wakefulness. Also, we found cross-frequency coupling between the respiratory phase and the amplitude of γ activity in all recorded areas. These oscillatory entrainments are independent of muscular activity, because are maintained during cataplexy induced by carbachol microinjection into the nucleus pontis oralis. Importantly, we observed that respiratory phase modulates the inter-cortical gamma coherence between neocortical pairs of electrodes during wakefulness. However, during NREM and REM sleep, breathing was unable to entrain the oscillatory activity, neither in the olfactory bulb nor in the neocortex. These results suggest a single unified phenomenon involving cross frequency coupling and long-range γ coherence across the neocortex. This fact could be related to a temporal binding process necessary for cognitive functions during wakefulness.

scholarly journals Paleo-oscillomics: inferring aspects of Neanderthal language abilities from gene regulation of neural oscillations

2017 ◽  
Author(s):  
Elliot Murphy ◽  
Antonio Benítez-Burraco
Keyword(s):  
Language Evolution ◽  
Oscillatory Activity ◽  
Neural Oscillations ◽  
Brain Anatomy ◽  
Language Abilities ◽  
Frequency Coupling ◽  
Methylation Patterns ◽  
Cross Frequency Coupling ◽  
The Brain ◽  
Core Features

AbstractLanguage seemingly evolved from changes in brain anatomy and wiring. We argue that language evolution can be better understood if particular changes in phasal and cross-frequency coupling properties of neural oscillations, resulting in core features of language, are considered. Because we cannot track the oscillatory activity of the brain from extinct hominins, we used our current understanding of the language oscillogenome (that is, the set of genes responsible for basic aspects of the oscillatory activity relevant for language) to infer some properties of the Neanderthal oscillome. We have found that several candidates for the language oscillogenome show differences in their methylation patterns between Neanderthals and humans. We argue that differences in their expression levels could be informative of differences in cognitive functions important for language.

Good Vibrations: Cross-frequency Coupling in the Human Nucleus Accumbens during Reward Processing

2009 ◽  
Vol 21 (5) ◽  
pp. 875-889 ◽  
Author(s):  
Michael X Cohen ◽  
Nikolai Axmacher ◽  
Doris Lenartz ◽  
Christian E. Elger ◽  
Volker Sturm ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Reward Processing ◽  
Oscillatory Activity ◽  
Diverse Range ◽  
Information Encoding ◽  
Gating Mechanism ◽  
Power Prior ◽  
Frequency Coupling ◽  
Reward Information ◽  
Cross Frequency Coupling

The nucleus accumbens is critical for reward-guided learning and decision-making. It is thought to “gate” the flow of a diverse range of information (e.g., rewarding, aversive, and novel events) from limbic afferents to basal ganglia outputs. Gating and information encoding may be achieved via cross-frequency coupling, in which bursts of high-frequency activity occur preferentially during specific phases of slower oscillations. We examined whether the human nucleus accumbens engages such a mechanism by recording electrophysiological activity directly from the accumbens of human patients undergoing deep brain stimulation surgery. Oscillatory activity in the gamma (40–80 Hz) frequency range was synchronized with the phase of simultaneous alpha (8–12 Hz) waves. Further, losing and winning small amounts of money elicited relatively increased gamma oscillation power prior to and following alpha troughs, respectively. Gamma–alpha synchronization may reflect an electrophysiological gating mechanism in the human nucleus accumbens, and the phase differences in gamma–alpha coupling may reflect a reward information coding scheme similar to phase coding.

scholarly journals Neuromodulation of Astrocytic K+ Clearance

2021 ◽  
Vol 22 (5) ◽  
pp. 2520
Author(s):  
Alba Bellot-Saez ◽  
Rebecca Stevenson ◽  
Orsolya Kékesi ◽  
Evgeniia Samokhina ◽  
Yuval Ben-Abu ◽  
...  
Keyword(s):  
Oscillatory Behavior ◽  
Network Activity ◽  
Oscillatory Activity ◽  
Extracellular Potassium ◽  
Uptake Mechanism ◽  
Kir Channels ◽  
Neuronal Network Activity ◽  
Clearance Process ◽  
Spatial Buffering ◽  
The Impact

Potassium homeostasis is fundamental for brain function. Therefore, effective removal of excessive K+ from the synaptic cleft during neuronal activity is paramount. Astrocytes play a key role in K+ clearance from the extracellular milieu using various mechanisms, including uptake via Kir channels and the Na+-K+ ATPase, and spatial buffering through the astrocytic gap-junction coupled network. Recently we showed that alterations in the concentrations of extracellular potassium ([K+]o) or impairments of the astrocytic clearance mechanism affect the resonance and oscillatory behavior of both the individual and networks of neurons. These results indicate that astrocytes have the potential to modulate neuronal network activity, however, the cellular effectors that may affect the astrocytic K+ clearance process are still unknown. In this study, we have investigated the impact of neuromodulators, which are known to mediate changes in network oscillatory behavior, on the astrocytic clearance process. Our results suggest that while some neuromodulators (5-HT; NA) might affect astrocytic spatial buffering via gap-junctions, others (DA; Histamine) primarily affect the uptake mechanism via Kir channels. These results suggest that neuromodulators can affect network oscillatory activity through parallel activation of both neurons and astrocytes, establishing a synergistic mechanism to maximize the synchronous network activity.

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