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Spontaneous variability in gamma dynamics described by a damped harmonic oscillator driven by noise
Georgios Spyropoulos1, Matteo Saponati2,3, Jarrod Robert Dowdall2,3
1Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, 60528, Frankfurt, Germany. georgios.spyropoulos@esi-frankfurt.de.
Nature Communications
|April 20, 2022
Summary
Neural circuits create gamma-rhythmic activity with natural variability. A simple damped harmonic oscillator model driven by noise accurately explains these gamma-dynamics in the brain.
Area of Science:
- Neuroscience
- Computational Neuroscience
Background:
- Neural circuits generate gamma-rhythmic activity (30-80 Hz) essential for brain function.
- Spontaneous variability in gamma-cycle amplitude and duration is observed but not fully understood.
Purpose of the Study:
- Investigate the mechanisms underlying spontaneous variability in gamma-cycle amplitude and duration.
- Determine if a simple biophysical model can explain observed gamma-dynamics.
Main Methods:
- Recorded local-field potentials (LFPs) and neuronal spikes from awake macaque V1.
- Developed a noise-robust method for detecting gamma-cycle amplitude and duration.
- Modeled gamma-dynamics using a noise-driven damped harmonic oscillator.
Main Results:
- A weak positive correlation between gamma-cycle amplitude and duration was found.
- The noise-driven damped harmonic oscillator model accurately reproduced LFP power spectra and joint amplitude-duration distributions.
- Model predictions matched observed relationships between oscillation strength and amplitude-duration correlations, as well as autocorrelations.
- Longer gamma-cycles correlated with increased spike synchrony and decreased firing rates in both excitatory and inhibitory neurons.
Conclusions:
- V1 gamma-dynamics are effectively described by a simple, noise-driven damped harmonic oscillator model.
- This model provides a parsimonious explanation for the observed variability and properties of gamma oscillations.
- The findings suggest that noise-driven dynamics are fundamental to generating gamma rhythms in the visual cortex.
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