Article

Attention-related changes in correlated neuronal activity arise from normalization mechanisms

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Abstract

Attention is believed to enhance perception by altering the activity-level correlations between pairs of neurons. How attention changes neuronal activity correlations is unknown. Using multielectrodes in monkey visual cortex, we measured spike-count correlations when single or multiple stimuli were presented and when stimuli were attended or unattended. When stimuli were unattended, adding a suppressive, nonpreferred stimulus beside a preferred stimulus increased spike-count correlations between pairs of similarly tuned neurons but decreased spike-count correlations between pairs of oppositely tuned neurons. A stochastic normalization model containing populations of oppositely tuned, mutually suppressive neurons explains these changes and also explains why attention decreased or increased correlations: as an indirect consequence of attention-related changes in the inputs to normalization mechanisms. Our findings link normalization mechanisms to correlated neuronal activity and attention, showing that normalization mechanisms shape response correlations and that these correlations change when attention biases normalization mechanisms.

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Acknowledgements

We thank D. Freedman for discussions. We thank J. Cone, S. Ghosh, G. Ibos and T. Luo for comments on an earlier version of the manuscript and S. Sleboda for technical assistance. B.-E.V. is supported by a postdoctoral research fellowship from the Flemish Fund for Scientific Research (FWO). This work was supported by NIH grant R01EY005911.

Author information

Affiliations

  1. Department of Neurobiology, The University of Chicago, Chicago, Illinois, USA.

    • Bram-Ernst Verhoef
    •  & John H R Maunsell
  2. Laboratorium voor Neuro- en Psychofysiologie, KU Leuven, Leuven, Belgium.

    • Bram-Ernst Verhoef

Authors

  1. Search for Bram-Ernst Verhoef in:

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Contributions

B.-E.V. and J.H.R.M. designed the experiments, performed the surgeries and wrote the paper. B.-E.V. performed the experiments and analyzed the data.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Bram-Ernst Verhoef.

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