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Network adaptation improves temporal representation of naturalistic stimuli in drosophila eye: II Mechanisms

Nikolaev, A., Zheng, L., Wardill, T.J., O'Kane, C.J., de Polavieja, G.G. and Juusola, M. (2009) Network adaptation improves temporal representation of naturalistic stimuli in drosophila eye: II Mechanisms. Plos One, 4 (1). Art no.e4306. ISSN 1932-6203

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Abstract

Retinal networks must adapt constantly to best present the ever changing visual world to the brain. Here we test the hypothesis that adaptation is a result of different mechanisms at several synaptic connections within the network. In a companion paper (Part I), we showed that adaptation in the photoreceptors (R1-R6) and large monopolar cells (LMC) of the Drosophila eye improves sensitivity to under-represented signals in seconds by enhancing both the amplitude and frequency distribution of LMCs' voltage responses to repeated naturalistic contrast series. In this paper, we show that such adaptation needs both the light-mediated conductance and feedback-mediated synaptic conductance. A faulty feedforward pathway in histamine receptor mutant flies speeds up the LMC output, mimicking extreme light adaptation. A faulty feedback pathway from L2 LMCs to photoreceptors slows down the LMC output, mimicking dark adaptation. These results underline the importance of network adaptation for efficient coding, and as a mechanism for selectively regulating the size and speed of signals in neurons. We suggest that concert action of many different mechanisms and neural connections are responsible for adaptation to visual stimuli. Further, our results demonstrate the need for detailed circuit reconstructions like that of the Drosophila lamina, to understand how networks process information.

Item Type: Article
Copyright, Publisher and Additional Information: © 2009 Nikolaev et al. 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 author and source are credited.
Keywords: Visual; Photoreceptor Synapse; Graded Potentials; Light Adaptation; Compound Eye; Melanogaster; Histamine; Channel; Lamina; Transmission
Institution: The University of Sheffield
Academic Units: The University of Sheffield > Faculty of Science (Sheffield) > School of Biological Sciences (Sheffield) > Department of Biomedical Science (Sheffield)
Depositing User: Miss Anthea Tucker
Date Deposited: 09 Mar 2010 10:50
Last Modified: 16 Jun 2014 07:28
Published Version: http://dx.doi.org/10.1371/journal.pone.0004306
Status: Published
Publisher: Public Library Science
Refereed: Yes
Identification Number: 10.1371/journal.pone.0004306
URI: http://eprints.whiterose.ac.uk/id/eprint/10586

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