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Computational subunits in thin dendrites of pyramidal cells

Nature Neuroscience volume 7, pages 621627 (2004) | Download Citation

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Abstract

The thin basal and oblique dendrites of cortical pyramidal neurons receive most of the synaptic inputs from other cells, but their integrative properties remain uncertain. Previous studies have most often reported global linear or sublinear summation. An alternative view, supported by biophysical modeling studies, holds that thin dendrites provide a layer of independent computational 'subunits' that sigmoidally modulate their inputs prior to global summation. To distinguish these possibilities, we combined confocal imaging and dual-site focal synaptic stimulation of identified thin dendrites in rat neocortical pyramidal neurons. We found that nearby inputs on the same branch summed sigmoidally, whereas widely separated inputs or inputs to different branches summed linearly. This strong spatial compartmentalization effect is incompatible with a global summation rule and provides the first experimental support for a two-layer 'neural network' model of pyramidal neuron thin-branch integration. Our findings could have important implications for the computing and memory-related functions of cortical tissue.

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Acknowledgements

We thank M. Hausser, M. London and Y. Schiller for their helpful comments on an earlier version of the manuscript. This study was supported by the National Institutes of Health, Israeli Science Foundation, National Science Foundation and the Rappaport Foundation.

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Affiliations

  1. Department of Physiology, Technion Medical School, Bat-Galim, Haifa 31096, Israel.

    • Alon Polsky
    •  & Jackie Schiller
  2. Department of Biomedical Engineering University of Southern California, University Park, Los Angeles, California 90089-1451, USA.

    • Bartlett W Mel

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The authors declare no competing financial interests.

Corresponding author

Correspondence to Jackie Schiller.

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DOI

https://doi.org/10.1038/nn1253

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