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Regulation of Cortical Dynamic Range by Background Synaptic Noise and Feedforward Inhibition.

  • Khubieh A Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada M5G 0A4 School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
  • Ratté S Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada M5G 0A4 Department of Physiology and the Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada.
  • Lankarany M Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada M5G 0A4 Department of Physiology and the Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada.
  • Prescott SA Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada M5G 0A4 Department of Physiology and the Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada.
  • 2015-07-26
Published in:
  • Cerebral cortex (New York, N.Y. : 1991). - 2016
dynamic range
feedforward inhibition
gain control
noise
pyramidal neuron
Animals
Cerebral Cortex
Computer Simulation
Male
Models, Neurological
Neural Inhibition
Patch-Clamp Techniques
Pyramidal Cells
Rats, Sprague-Dawley
Synapses
Synaptic Transmission
Time Factors
Tissue Culture Techniques
English The cortex encodes a broad range of inputs. This breadth of operation requires sensitivity to weak inputs yet non-saturating responses to strong inputs. If individual pyramidal neurons were to have a narrow dynamic range, as previously claimed, then staggered all-or-none recruitment of those neurons would be necessary for the population to achieve a broad dynamic range. Contrary to this explanation, we show here through dynamic clamp experiments in vitro and computer simulations that pyramidal neurons have a broad dynamic range under the noisy conditions that exist in the intact brain due to background synaptic input. Feedforward inhibition capitalizes on those noise effects to control neuronal gain and thereby regulates the population dynamic range. Importantly, noise allows neurons to be recruited gradually and occludes the staggered recruitment previously attributed to heterogeneous excitation. Feedforward inhibition protects spike timing against the disruptive effects of noise, meaning noise can enable the gain control required for rate coding without compromising the precise spike timing required for temporal coding.
Language
  • English
Open access status
bronze
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Persistent URL
https://sonar.ch/global/documents/99552
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