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Limits to the temporal fidelity of cortical spike rate signals

Nature Neuroscience volume 5, pages 463471 (2002) | Download Citation

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Abstract

The cerebral cortex processes information primarily through changes in the spike rates of neurons within local ensembles. To evaluate how reliably the average spike rate of a group of cortical neurons can represent a time-varying signal, we simulated an ensemble with realistic spike discharge behavior. We found that weak interneuronal correlation, or synchrony, allows the variability in spike rates of individual neurons to compromise the ensemble representation of time-varying signals. Brief cycles of sinusoidal modulation at frequencies above 115 Hz could not be represented by an ensemble of hundreds of neurons whose interneuronal correlation mimics that of the visual cortex. The spike variability and correlation assumed in our simulations are likely to apply to many areas of cortex and therefore may constrain the fidelity of neural computations underlying higher brain function.

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Acknowledgements

Supported by HHMI, NIH grants RR00166 and EY11378 and the McKnight Foundation. M.E.M. was supported by an NIH training grant (GM07108), a Poncin grant and an ARCS fellowship. We thank C. Brody, J. Ditterich, J. Gold, M. Leon and M. McKinley for comments and discussion.

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  1. Howard Hughes Medical Institute, Department of Physiology and Biophysics, Regional Primate Research Center, University of Washington, Box 357290, Seattle, Washington 98195-7290, USA

    • Mark E. Mazurek
    •  & Michael N. Shadlen

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The authors declare no competing financial interests.

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Correspondence to Michael N. Shadlen.

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https://doi.org/10.1038/nn836

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