scholarly journals Alteration of phase–phase coupling between theta and gamma rhythms in a depression-model of rats

2012 ◽  
Vol 7 (2) ◽  
pp. 167-172 ◽  
Author(s):  
Chenguang Zheng ◽  
Tao Zhang
Keyword(s):  
Phase Coupling ◽  
Gamma Rhythms ◽  
Phase Phase

scholarly journals Coexistence of fast and slow gamma oscillations in one population of inhibitory spiking neurons

2019 ◽  
Author(s):  
Hongjie Bi ◽  
Marco Segneri ◽  
Matteo di Volo ◽  
Alessandro Torcini
Keyword(s):  
Gamma Oscillations ◽  
Brain Regions ◽  
Neural Population ◽  
Neural Firing ◽  
Phase Coupling ◽  
Population Activity ◽  
Brain Functions ◽  
Wide Range ◽  
Gamma Rhythms ◽  
Phase Phase

Oscillations are a hallmark of neural population activity in various brain regions with a spectrum covering a wide range of frequencies. Within this spectrum gamma oscillations have received particular attention due to their ubiquitous nature and to their correlation with higher brain functions. Recently, it has been reported that gamma oscillations in the hippocampus of behaving rodents are segregated in two distinct frequency bands: slow and fast. These two gamma rhythms correspond to different states of the network, but their origin has been not yet clarified. Here, we show theoretically and numerically that a single inhibitory population can give rise to coexisting slow and fast gamma rhythms corresponding to collective oscillations of a balanced spiking network. The slow and fast gamma rhythms are generated via two different mechanisms: the fast one being driven by the coordinated tonic neural firing and the slow one by endogenous fluctuations due to irregular neural activity. We show that almost instantaneous stimulations can switch the collective gamma oscillations from slow to fast and vice versa. Furthermore, to make a closer contact with the experimental observations, we consider the modulation of the gamma rhythms induced by a slower (theta) rhythm driving the network dynamics. In this context, depending on the strength of the forcing and the noise amplitude, we observe phase-amplitude and phase-phase coupling between the fast and slow gamma oscillations and the theta forcing. Phase-phase coupling reveals on average different theta-phases preferences for the two coexisting gamma rhythms joined to a wide cycle-to-cycle variability.

scholarly journals Periodic Forcing of Inhibition-Stabilized Networks: Nonlinear Resonances and Phase-Amplitude Coupling

2015 ◽  
Vol 27 (12) ◽  
pp. 2477-2509 ◽  
Author(s):  
Romain Veltz ◽  
Terrence J. Sejnowski
Keyword(s):  
Pyramidal Neurons ◽  
Phase Coupling ◽  
Periodic Forcing ◽  
Circuit Element ◽  
Damped Oscillations ◽  
Inhibitory Population ◽  
Multiple Frequencies ◽  
Phase Amplitude ◽  
Periodic Inputs ◽  
Phase Phase

Inhibition-stabilized networks (ISNs) are neural architectures with strong positive feedback among pyramidal neurons balanced by strong negative feedback from inhibitory interneurons, a circuit element found in the hippocampus and the primary visual cortex. In their working regime, ISNs produce damped oscillations in the [Formula: see text]-range in response to inputs to the inhibitory population. In order to understand the properties of interconnected ISNs, we investigated periodic forcing of ISNs. We show that ISNs can be excited over a range of frequencies and derive properties of the resonance peaks. In particular, we studied the phase-locked solutions, the torus solutions, and the resonance peaks. Periodically forced ISNs respond with (possibly multistable) phase-locked activity, whereas networks with sustained intrinsic oscillations respond more dynamically to periodic inputs with tori. Hence, the dynamics are surprisingly rich, and phase effects alone do not adequately describe the network response. This strengthens the importance of phase-amplitude coupling as opposed to phase-phase coupling in providing multiple frequencies for multiplexing and routing information.

scholarly journals On cross-frequency phase-phase coupling between theta and gamma oscillations in the hippocampus

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Robson Scheffer-Teixeira ◽  
Adriano BL Tort
Keyword(s):  
Phase Locking ◽  
Gamma Oscillations ◽  
Linear Phase ◽  
Phase Coupling ◽  
Neuronal Coding ◽  
Theoretical Support ◽  
Hippocampal Activity ◽  
Phase Amplitude ◽  
Phase Phase ◽  
Frequency Phase

Phase-amplitude coupling between theta and multiple gamma sub-bands is a hallmark of hippocampal activity and believed to take part in information routing. More recently, theta and gamma oscillations were also reported to exhibit phase-phase coupling, or n:m phase-locking, suggesting an important mechanism of neuronal coding that has long received theoretical support. However, by analyzing simulated and actual LFPs, here we question the existence of theta-gamma phase-phase coupling in the rat hippocampus. We show that the quasi-linear phase shifts introduced by filtering lead to spurious coupling levels in both white noise and hippocampal LFPs, which highly depend on epoch length, and that significant coupling may be falsely detected when employing improper surrogate methods. We also show that waveform asymmetry and frequency harmonics may generate artifactual n:m phase-locking. Studies investigating phase-phase coupling should rely on appropriate statistical controls and be aware of confounding factors; otherwise, they could easily fall into analysis pitfalls.

scholarly journals Lack of evidence for cross-frequency phase-phase coupling between theta and gamma oscillations in the hippocampus

2016 ◽  
Author(s):  
Robson Scheffer-Teixeira ◽  
Adriano BL Tort
Keyword(s):  
Phase Locking ◽  
Gamma Oscillations ◽  
Actual Data ◽  
Gamma Phase ◽  
Phase Coupling ◽  
Neuronal Coding ◽  
Theoretical Support ◽  
Hippocampal Activity ◽  
Phase Amplitude ◽  
Phase Phase

AbstractPhase-amplitude coupling between theta and multiple gamma sub-bands hallmarks hippocampal activity and is believed to take part in information routing. More recently, theta and gamma oscillations were also reported to exhibit reliable phase-phase coupling, or n:m phase-locking. The existence of n:m phase-locking suggests an important mechanism of neuronal coding that has long received theoretical support. However, here we show that n:m phase-locking (1) is much lower than previously reported, (2) highly depends on epoch length, (3) does not statistically differ from chance (when employing proper surrogate methods), and that (4) filtered white noise has similar n:m scores as actual data. Moreover, (5) the diagonal stripes in theta-gamma phase-phase histograms of actual data can be explained by theta harmonics. These results point to lack of theta-gamma phase-phase coupling in the hippocampus, and suggest that studies investigating n:m phase-locking should rely on appropriate statistical controls, otherwise they could easily fall into analysis pitfalls.

scholarly journals Top–Down Activation of Spatiotopic Sensory Codes in Perceptual and Working Memory Search

2016 ◽  
Vol 28 (7) ◽  
pp. 996-1009 ◽  
Author(s):  
Bo-Cheng Kuo ◽  
Anna Christina Nobre ◽  
Gaia Scerif ◽  
Duncan E. Astle
Keyword(s):  
Working Memory ◽  
Temporal Dynamics ◽  
Memory Search ◽  
Relevant Information ◽  
Search Display ◽  
Phase Coupling ◽  
Functional Connections ◽  
Frontoparietal Network ◽  
Visual Areas ◽  
Phase Phase

A critical requirement of an efficient cognitive system is the selection and prioritization of relevant information. This occurs when selecting specific items from our sensory inputs, which then receive preferential status at subsequent levels of processing. Many everyday tasks also require us to select internal representations, such as a relevant item from memory. We show that both of these types of search are underpinned by the spatiotopic activation of sensory codes, using both fMRI and MEG data. When individuals searched for perceived and remembered targets, the MEG data highlighted a sensor level electrophysiological effect that reflects the contralateral organization of the visual system—namely, the N2pc. The fMRI data were used to identify a network of frontoparietal areas common to both types of search, as well as the early visual areas activated by the search display. We then combined fMRI and MEG data to explore the temporal dynamics of functional connections between the frontoparietal network and the early visual areas. Searching for a target item resulted in significantly enhanced phase–phase coupling between the frontoparietal network and the visual areas contralateral to the perceived or remembered location of that target. This enhancement of spatially specific phase–phase coupling occurred before the N2pc effect and was significantly associated with it on a trial-by-trial basis. The combination of these two imaging modalities suggests that perceptual and working memory search are underpinned by the synchronization of a frontoparietal network and the relevant sensory cortices.

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