Gamma-cycle duration predicts instantaneous amplitude, spike rate and synchrony in macaque V1.

Spyropoulos, G.; Dowdall, J. R.; Scholvinck, M. L.; Bosman, C. A.; Lima, B.; Peter, A.; Onorato, I.; Klon-Lipok, J.; Roese, R.; Neuenschwander, S.; Singer, W.; Vinck, M.; Fries, P.

doi:10.1101/793729

bioRxiv · 10.1101/793729

Gamma-cycle duration predicts instantaneous amplitude, spike rate and synchrony in macaque V1.

Spyropoulos, G.·Dowdall, J. R.·Scholvinck, M. L.·Bosman, C. A.·Lima, B.·Peter, A.·Onorato, I.·Klon-Lipok, J.·Roese, R.·Neuenschwander, S.·Singer, W.·Vinck, M.·Fries, P.

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Abstract

Circuits of excitatory and inhibitory neurons can generate rhythmic activity in the gamma frequency-range (30-80Hz). Individual gamma-cycles show spontaneous variability in amplitude and duration. The mechanisms underlying this variability are not fully understood. We recorded local-field-potentials (LFPs) and spikes from awake macaque V1, and developed a noise-robust method to detect gamma-cycle amplitudes and durations. Amplitudes and durations showed a weak but positive correlation. This correlation, and the joint amplitude-duration distribution, is well reproduced by a dampened harmonic oscillator driven by stochastic noise. We show that this model accurately fits LFP power spectra and is equivalent to a linear PING (Pyramidal Interneuron Network Gamma) circuit. The model recapitulates two additional features of V1 gamma: (1) Amplitude-duration correlations decrease with oscillation strength; (2) Amplitudes and durations exhibit strong and weak autocorrelations, respectively, depending on oscillation strength. Finally, longer gamma-cycles are associated with stronger spike-synchrony, but lower spike-rates in both (putative) excitatory and inhibitory neurons. In sum, V1 gamma-dynamics are well described by the simplest possible model of gamma: A linear harmonic oscillator driven by noise.

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Spyropoulos, G., Dowdall, J. R., Scholvinck, M. L., Bosman, C. A., Lima, B., Peter, A., Onorato, I., Klon-Lipok, J., Roese, R., Neuenschwander, S., Singer, W., Vinck, M., Fries, P.. 2019-10-05. Gamma-cycle duration predicts instantaneous amplitude, spike rate and synchrony in macaque V1.. https://doi.org/10.1101/793729

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