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Effects of noisy adaptation on neural spiking statistics Tilo Schwalger,Benjamin Lindner, Karin Fisch, Jan Benda Max-Planck Institute for the Physics of Complex Systems, Dresden Stochastic Models in Neuroscience, Marseille 2010 LMU, Munich
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Neurons show spike-frequency adaptation Gabbiani & Krapp, J Neurophysiol 2006 Intrinsic negative feedback
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Outline What is the source of noise? ● Stratagy and introduction of the model ● ISI statistics for two cases i.“deterministic adaptation” + stochastic receptor current ii.“Stochastic adaptation” + deterministic receptor current ● “mixed case”
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What is the source of variability? – The strategy ● Introduce variability by stochastic ion currents (channel noise), e.g. ● Modelling signal transduction of auditory receptor cells ● Receptor current ● Sodium current ● Potassium (delayed rectifier) current ● Adaptation current (M-type)
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What is the source of variability? – The strategy ● Introduce variability by stochastic ion currents (channel noise), e.g. ● Modelling signal transduction of auditory receptor cells ● Receptor current ● Sodium current ● Potassium (delayed rectifier) current ● Adaptation current (M-type) ● Study separately the effect of a specific channel noise ● on the interspike interval (ISI) statistics ● ISI density, firing rate, coefficient of variation (CV), skewness, excess, … ● ISI serial correlation coefficient ● Compare different predictions with experimental data Interspike interval [ms ] Probability density
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What is the source of variability? – The strategy ● Introduce variability by stochastic ion currents (channel noise), e.g. ● Modelling signal transduction of auditory receptor cells ● Receptor current ● Sodium current ● Potassium (delayed rectifier) current ● Adaptation current (M-type) ● Study separately the effect of a specific channel noise ● on the interspike interval (ISI) statistics ● ISI density, firing rate, coefficient of variation (CV), skewness, excess, … ● ISI serial correlation coefficient ● Compare different predictions with experimental data ● Here: stochastic adaptation current vs. Stochastic receptor current in a simplified model Interspike interval [ms ] Probability density
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M-type adaptation current ● Two-state channel model ● (voltage-gated) ● Adaptation current with finite number of channels ● voltage-gated potassium current ● Slow kinetics # M-channels open # M- channels
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Perfect integrate-and-fire model Stochastic adaption current White noise: fast receptor channels
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Perfect integrate-and-fire model membrane Potential V M-channel activation fraction of open M-channels W Time [ms] Stochastic adaption current White noise: fast receptor channels threshold reset
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Perfect integrate-and-fire model membrane Potential V M-channel activation fraction of open M-channels W Time [ms] Stochastic adaption current White noise: fast receptor channels threshold reset Firing rate Time [ms]
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Diffusion approximation of channel noise ● adaptation split up in deterministic and noise part ● Additive noise approximation:
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Two limit cases Deterministic adaptation
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Two limit cases Stochastic adaptation Deterministic adaptation
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Deterministic adaptation (N a →∞) ● Mean adaptation approximation reduced input current much larger than mean ISI
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Deterministic adaptation (N a →∞) Inverse Gaussian ISI density Negative ISI correlations Gerstein & Mandelbrot, 1964
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Stochastic adaptation current acts as a colored noise ● Slow modulation of instantaneous firing rate ● due to slow noise process η(t) ● average over fast dynamics of
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Stochastic adaptation current acts as a colored noise ● Slow modulation of instantaneous firing rate ● due to slow noise process η(t) ● average over fast dynamics of → Colored noise-driven PIF neuron
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Colored noise model captures ISI density
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ISI density: B. Lindner, Phys Rev E 2004 small noise
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Stochastic adaptation yields positive ISI correlations Positive ISI correlations B. Lindner, Phys Rev E 2004
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ISI density – comparison Determistic adaptation Stochastic adaptation Same CV Inverse Gaussian fails!
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ISI density – comparison Determistic adaptation Stochastic adaptation
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How to discriminate from an inverse Gaussian density? skewnes s Inverse Gaussian
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How to discriminate from an inverse Gaussian density? skewnes s excess (kurtosis) Inverse Gaussian
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How to discriminate from an inverse Gaussian density? skewnes s excess (kurtosis) Inverse Gaussian Defin e inverse Gaussian distribution:
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Separation of deterministic and stochastic adaptation Rescaled skewness Rescaled excess
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Dependence on the adaptation time- scale Rescaled excess Serial correlation coefficient at lag 1
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Skewness and excess of ISIs – theory ● PIF model driven by colored noise ● Fokker-Planck equation for p(v,η,t) ● Initial condition + fire&reset rule
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Skewness and excess of ISIs – theory ● PIF model driven by colored noise ● Fokker-Planck equation for p(v,η,t) ● Initial condition ● ISI density + fire&reset rule
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Skewness and excess of ISIs – theory ● PIF model driven by colored noise ● Fokker-Planck equation for p(v,η,t) ● Initial condition ● ISI density ● Variable transformation ● Fokker-Planck equation + fire&reset rule
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Skewness and excess of ISIs – theory ● Small noise expansion
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Mixed case – fast and slow fluctuations D>0 fixed, vary number of channels
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Simulation of Hodgkin-Huxley type model with M-current Modified Traub-Miles model (Ermentrout, 2000) Mixed case Serial correlations
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Summary ● Introduced an integrate-and-fire-model with stochastic adaptation current ● (channel noise) ● Case of deterministic adaptation current and white current noise: ● inverse Gaussian ISI distribution and negative serial correlations ● Case of stochastic adaptation current and no white noise: ● peaked ISI distribution and positive serial correlations ● Results might be useful to determine the dominant source of noise
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Acknowledgements Karin Fisch LMU, Munich Benjamin Lindner MPIPKS, Dresden Jan Benda LMU, Munich
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Variability depends on sound intensity Karin Fisch & Jan Benda, LMU
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