The gamma cycle

@article{Fries2007TheGC,
  title={The gamma cycle},
  author={P. Fries and D. Nikolic and W. Singer},
  journal={Trends in Neurosciences},
  year={2007},
  volume={30},
  pages={309-316}
}
Activated neuronal groups typically engage in rhythmic synchronization in the gamma-frequency range (30-100 Hz). Experimental and modeling studies demonstrate that each gamma cycle is framed by synchronized spiking of inhibitory interneurons. Here, we review evidence suggesting that the resulting rhythmic network inhibition interacts with excitatory input to pyramidal cells such that the more excited cells fire earlier in the gamma cycle. Thus, the amplitude of excitatory drive is recoded into… Expand
The gamma cycle and its role in the formation of assemblies
TLDR
The winner- take-all hypothesis is combined with binding-by-synchrony and confirmed, starting from an oscillatory net- work model with several stored patterns and identifying temporal coding assemblies with coherent patterns. Expand
Fast rhythm cycles as atomic fragments of cortical processing and learning
  • J. Jitsev
  • Computer Science
  • BMC Neuroscience
  • 2014
TLDR
The presented network model provides interpretation of the gamma cycle as an elementary fragment of ongoing processing and learning, where each cycle embeds a winner-take-all-like computation that supports memory trace formation and memory trace maintenance in hierarchical recurrent network pathways of the cortex. Expand
Driving fast-spiking cells induces gamma rhythm and controls sensory responses
TLDR
The timing of a sensory input relative to a gamma cycle determined the amplitude and precision of evoked responses and provided the first causal evidence that distinct network activity states can be induced in vivo by cell-type-specific activation. Expand
Integration, coincidence detection and resonance in networks of spiking neurons expressing gamma oscillations and asynchronous states
TLDR
Computational models are used to investigate how brain circuits generate oscillations in a manner consistent with microelectrode recordings in humans, and it is predicted that asynchronous states provide the highest responsiveness to external stimuli, while Gamma oscillations tend to overall diminish responsiveness. Expand
Sparse Gamma Rhythms Arising through Clustering in Adapting Neuronal Networks
TLDR
Several testable predictions are developed regarding the formation and characteristics of gamma rhythms with sparsely firing excitatory neurons and the relationship between the number of clusters arising spontaneously in the network as it relates to the adaptation time constant. Expand
Gamma-Phase Shifting in Awake Monkey Visual Cortex
TLDR
It is found that stronger neuronal activation leads to spikes earlier in the gamma cycle, i.e., gamma-phase shifting is brought about by an interplay between overall excitation and gamma-rhythmic synaptic input and has interesting consequences for neuronal coding, competition, and plasticity. Expand
Gamma oscillations as integrators of local competition for activity and global competition for coherence
TLDR
This work approaches the modeling of the temporal grouping of neural units from the perspective of oscillatory neural network systems based on phase model oscillators, and demonstrates the combination of two recently discussed mechanisms, referred to as "acceleration" and "pooling", which realizes in a complementary manner a competition for activity on a local scale, while providing a competition on a non-local scale. Expand
A stochastic model of input effectiveness during irregular gamma rhythms
TLDR
A stochastic modelling approach to this question is presented that yields a very fast computation of the effectiveness of inputs to cells involved in gamma rhythms, and shows that CTC can be quite vulnerable to rhythm and input variability, which both decrease phase preference. Expand
Membrane Properties and the Balance between Excitation and Inhibition Control Gamma-Frequency Oscillations Arising from Feedback Inhibition
TLDR
Simulation results indicate that the membrane potential noise amplitude has a large impact on network frequency and that the balance between excitatory and inhibitory currents controls network stability and sensitivity to external inputs. Expand
Phase-locking patterns underlying effective communication in exact firing rate models of neural networks
Macroscopic oscillations in the brain have been observed to be involved in many cognitive tasks but their role is not completely understood. One of the suggested functions of the oscillations is toExpand
...
1
2
3
4
5
...

References

SHOWING 1-10 OF 77 REFERENCES
New Roles for the Gamma Rhythm: Population Tuning and Preprocessing for the Beta Rhythm
TLDR
It is shown that gamma and beta rhythms have different properties with respect to creation of cell assemblies, and experimental evidence showing that such a separation can occur in hippocampal slices is presented. Expand
Synchronized oscillations in interneuron networks driven by metabotropic glutamate receptor activation
TLDR
It is proposed that interneuron network oscillations, in conjunction with intrinsic membrane resonances and long-loop (such as thalamocortical) interactions, contribute to 40-Hz rhythms in vivo. Expand
Shunting Inhibition Improves Robustness of Gamma Oscillations in Hippocampal Interneuron Networks by Homogenizing Firing Rates
TLDR
It is shown that GABA(A) receptor-mediated inhibition in mature interneurons of the hippocampal dentate gyrus is shunting rather than hyperpolarizing, which may confer increased robustness to gamma oscillations in the brain. Expand
Synchronization and Oscillatory Dynamics in Heterogeneous, Mutually Inhibited Neurons
TLDR
It is shown numerically that the behavior of mildly heterogeneous networks can be related to thebehavior of single, self-inhibiting cells, which can be studied analytically. Expand
Inhibitory Postsynaptic Potentials Carry Synchronized Frequency Information in Active Cortical Networks
TLDR
Intracellular injection of synaptic conductances having the characteristics of the recorded EPSPs and IPSPs reveal that IPSPs are important in controlling the timing and probability of action potential generation in pyramidal cells. Expand
Odour encoding by temporal sequences of firing in oscillating neural assemblies
TLDR
It is reported here that the active neurons composing these ensembles change in a stimulus-specific manner and with a high degree of reliability on a cycle-by-cycle basis during an odour response, which allows combinatorial representations in time as well as in space. Expand
Effects of Noisy Drive on Rhythms in Networks of Excitatory and Inhibitory Neurons
TLDR
An analysis of the conditions under which noise leads to phase walkthrough of the I-cells or suppression of the E-cells shows that PING rhythms at frequencies far below the gamma range are robust to noise only if network parameter values are tuned very carefully. Expand
Phase Sensitivity of Synaptic Modifications in Oscillating Cells of Rat Visual Cortex
TLDR
Investigating in layer II/III pyramidal cells of rat visual cortex slices how synapses change when synchronized, oscillatory multifiber activity impinges on postsynaptic neurons during membrane potential (Vm) oscillations at 20 and 40 Hz finds that synaptic plasticity remains exquisitely sensitive to the timing of discharges. Expand
Modification of discharge patterns of neocortical neurons by induced oscillations of the membrane potential
TLDR
Oscillations impose a precise temporal window for the integration of synaptic inputs, favouring coincidence detection and they generate temporally-structured responses whose timing and amplitude are largely independent of the input. Expand
Mechanisms of Gamma Oscillations in the Hippocampus of the Behaving Rat
TLDR
This work examines the generation of gamma oscillation currents in the hippocampus, using two-dimensional, 96-site silicon probes and identifies two gamma generators, one in the dentate gyrus and another in the CA3-CA1 regions. Expand
...
1
2
3
4
5
...