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Amplification of trial-to-trial response variability by neurons in visual cortex

Carandini, M; (2004) Amplification of trial-to-trial response variability by neurons in visual cortex. PLOS BIOL , 2 (9) , Article e264. 10.1371/journal.pbio.0020264. Green open access

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Abstract

The visual cortex responds to repeated presentations of the same stimulus with high variability. Because the firing mechanism is remarkably noiseless, the source of this variability is thought to lie in the membrane potential fluctuations that result from summated synaptic input. Here this hypothesis is tested through measurements of membrane potential during visual stimulation. Surprisingly, trial-to-trial variability of membrane potential is found to be low. The ratio of variance to mean is much lower for membrane potential than for firing rate. The high variability of firing rate is explained by the threshold present in the function that converts inputs into firing rates. Given an input with small, constant noise, this function produces a firing rate with a large variance that grows with the mean. This model is validated on responses recorded both intracellularly and extracellularly. In neurons of visual cortex, thus, a simple deterministic mechanism amplifies the low variability of summated synaptic inputs into the large variability of firing rate. The computational advantages provided by this amplification are not known.

Type: Article
Title: Amplification of trial-to-trial response variability by neurons in visual cortex
Open access status: An open access version is available from UCL Discovery
DOI: 10.1371/journal.pbio.0020264
Publisher version: http://dx.doi.org/10.1371/journal.pbio.0020264
Language: English
Additional information: © 2004 Matteo Carandini. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Keywords: CORTICAL-NEURONS, SPIKE TRAINS, CONTRAST INVARIANCE, IN-VIVO, CAT, CELLS, ORIENTATION, NOISE, DISCRIMINATION, SELECTIVITY
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Institute of Ophthalmology
URI: https://discovery.ucl.ac.uk/id/eprint/8372
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