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 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 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 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 Cross-Frequency Phase-Phase Coupling between Theta and Gamma Oscillations in the Hippocampus

2012 ◽  
Vol 32 (2) ◽  
pp. 423-435 ◽  
Author(s):  
M. A. Belluscio ◽  
K. Mizuseki ◽  
R. Schmidt ◽  
R. Kempter ◽  
G. Buzsaki
Keyword(s):  
Gamma Oscillations ◽  
Phase Coupling ◽  
Phase Phase ◽  
Frequency Phase

Theta-gamma phase-phase coupling during working memory maintenance in the human hippocampus

2015 ◽  
Vol 6 (4) ◽  
pp. 149-157 ◽  
Author(s):  
Leila Chaieb ◽  
Marcin Leszczynski ◽  
Nikolai Axmacher ◽  
Marlene Höhne ◽  
Christian E. Elger ◽  
...  
Keyword(s):  
Working Memory ◽  
Gamma Phase ◽  
Phase Coupling ◽  
Human Hippocampus ◽  
Phase Phase

Inter- and intra-hemispheric spatiotemporal organization of spontaneous electrocortical oscillations

1996 ◽  
Vol 76 (1) ◽  
pp. 423-437 ◽  
Author(s):  
K. D. MacDonald ◽  
B. Brett ◽  
D. S. Barth
Keyword(s):  
Time Series ◽  
Somatosensory Cortex ◽  
Phase Locking ◽  
Sensory Information ◽  
Gamma Oscillations ◽  
Sensory Cortex ◽  
Electrode Arrays ◽  
Sharp Wave ◽  
Lower Amplitude ◽  
The Right

1. Two 64-channel epipial electrode arrays were positioned on homologous locations of the right and left hemisphere, covering most of primary and secondary auditory and somatosensory cortex in eight lightly anesthetized rats. Array placement was verified with the use of cytochrome oxidase histochemistry. 2. Middle-latency auditory and somatosensory evoked potentials (MAEPs and MSEPs, respectively) and spontaneous oscillations in the frequency range of 20-40 Hz (gamma oscillations) were recorded and found to be spatially constrained to regions of granular cortex, suggesting that both phenomena are closely associated with sensory information processing. 3. The MAEP and MSEP consisted of an initial biphasic sharp wave in primary auditory and somatosensory cortex, respectively, and a similar biphasic sharp wave occurred approximately 4-8 ms later in secondary sensory cortex of the given modality. Averaged gamma oscillations also revealed asynchronous activation of sensory cortex, but with a shorter 2-ms delay between oscillations in primary and secondary regions. Although the long latency shift of the MAEP and MSEP may be due in part to asynchronous activation of parallel thalamocortical projections to primary and secondary sensory cortex, the much shorter shift of gamma oscillations in a given modality is consistent with intracortical coupling of these regions. 4. Gamma oscillations occurred independently in auditory and somatosensory cortex within a given hemisphere. Furthermore, time series averaging revealed that there was no phase-locking of oscillations between the sensory modalities. 5. Gamma oscillations were loosely coupled between hemispheres; oscillations occurring in auditory or somatosensory cortex of one hemisphere were often associated with lower-amplitude oscillations in homologous contralateral sensory cortex. Yet, the fact that time series averaging revealed no interhemispheric phase-locking suggests that the corpus callosum may not coordinate the bilateral gamma oscillations, and that a thalamic modulatory influence may be involved.

Reward-Associated Gamma Oscillations in Ventral Striatum Are Regionally Differentiated and Modulate Local Firing Activity

2010 ◽  
Vol 103 (3) ◽  
pp. 1658-1672 ◽  
Author(s):  
Tobias Kalenscher ◽  
Carien S. Lansink ◽  
Jan V. Lankelma ◽  
Cyriel M. A. Pennartz
Keyword(s):  
Ventral Striatum ◽  
Phase Locking ◽  
Gamma Oscillations ◽  
Brain Regions ◽  
Reward Processing ◽  
Temporal Organization ◽  
Gamma Activity ◽  
Neural Ensembles ◽  
Gamma Range ◽  
Gamma Power

Oscillations of local field potentials (LFPs) in the gamma range are found in many brain regions and are supposed to support the temporal organization of cognitive, perceptual, and motor functions. Even though gamma oscillations have also been observed in ventral striatum, one of the brain's most important structures for motivated behavior and reward processing, their specific function during ongoing behavior is unknown. Using a movable tetrode array, we recorded LFPs and activity of neural ensembles in the ventral striatum of rats performing a reward-collection task. Rats were running along a triangle track and in each round collected one of three different types of rewards. The gamma power of LFPs on subsets of tetrodes was modulated by reward-site visits, discriminated between reward types, between baitedness of reward locations and was different before versus after arrival at a reward site. Many single units in ventral striatum phase-locked their discharge pattern to the gamma oscillations of the LFPs. Phase-locking occurred more often in reward-related than in reward-unrelated neurons and LFPs. A substantial number of simultaneously recorded LFPs correlated poorly with each other in terms of gamma rhythmicity, indicating that the expression of gamma activity was heterogeneous and regionally differentiated. The orchestration of LFPs and single-unit activity by way of gamma rhythmicity sheds light on the functional architecture of the ventral striatum and the temporal coordination of ventral striatal activity for modulating downstream areas and regulating synaptic plasticity.

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