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 ◽  
...  

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.

Author(s):  
Jon López-Azcárate ◽  
María Jesús Nicolás ◽  
Ivan Cordon ◽  
Manuel Alegre ◽  
Miguel Valencia ◽  
...  

2021 ◽  
Author(s):  
Mojtaba Lahijanian ◽  
Hamid Aghajan ◽  
Zahra Vahabi ◽  
Arshia Afzal

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.


2018 ◽  
Author(s):  
Matías Cavelli ◽  
Santiago Castro-Zaballa ◽  
Joaquín Gonzalez ◽  
Daniel Rojas-Líbano ◽  
Nicolas Rubido ◽  
...  

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.


2017 ◽  
Author(s):  
Elliot Murphy ◽  
Antonio Benítez-Burraco

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.


2018 ◽  
Author(s):  
Christopher M. Kim ◽  
Ulrich Egert ◽  
Arvind Kumar

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.


2021 ◽  
Vol 09 ◽  
Author(s):  
Kenneth Blum ◽  
Mark S Gold ◽  
Jean L. Cadet ◽  
David Baron ◽  
Abdalla Bowirrat ◽  
...  

Background: Repeated cocaine administration changes histone acetylation and methylation on Lys residues and Deoxyribonucleic acid (DNA) within the nucleus accumbens (NAc). Recently Nestler’s group explored histone Arg (R) methylation in reward processing models. Damez-Werno et al. (2016) reported that during investigator and selfadministration experiments, the histone mark protein-R-methyltransferase-6 (PRMT6) and asymmetric dimethylation of R2 on histone H3 (H3R2me2a) decreased in the rodent and cocaine-dependent human NAc. Overexpression of PRMT6 in D2-MSNs in all NAc neurons increased cocaine seeking, whereas PRMT6 overexpression in D1-MSNs protects against cocaine-seeking. Hypothesis: Hypothesizing that dopaminylation (H3R2me2a binding) occurs in psychostimulant use disorder (PSU), and the binding inhibitor Srcin1, like the major DRD2 A2 allelic polymorphism, protects against psychostimulant seeking behavior by normalizing nucleus accumbens (NAc) dopamine expression. Discussion: Numerous publications confirmed the association between the DRD2 Taq A1 allele (30-40 lower D2 receptor numbers) and severe cocaine dependence. Lepack et al. (2020) found that acute cocaine increases dopamine in NAc synapses, results in histone H3 glutamine 5 dopaminylation (H3Q5dop), and consequent inhibition of D2 expression. The inhibition increases with chronic cocaine use and accompanies cocaine withdrawal. They also found that the Src kinase sig-naling inhibitor 1 (Srcin1 or p140CAP) during cocaine withdrawal reduced H3R2me2a binding. Consequently, this inhibited dopaminylation induced a “homeostatic brake.” Conclusion: The decrease in Src signaling in NAc D2-MSNs, like the DRD2 Taq A2 allele, a well-known genetic mechanism protective against SUD normalized nucleus accumbens (NAc) dopamine expression and decreased cocaine reward and motivation to self-administer cocaine. The Srcin1 may be an important therapeutic target.


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