Light- and dopamine-regulated receptive field plasticity in primate horizontal cells

Cullen Eye Institute, Baylor College of Medicine, Houston, Texas 77030, USA.
The Journal of Comparative Neurology (Impact Factor: 3.23). 08/2011; 519(11):2125-34. DOI: 10.1002/cne.22604
Source: PubMed


Center-surround antagonistic receptive fields (CSARFs) are building blocks for spatial vision and contrast perception. Retinal horizontal cells (HCs) are the first lateral elements along the visual pathway, and are thought to contribute to receptive field surrounds of higher order neurons. Primate HC receptive fields have not been found to change with light, and dopaminergic modulation has not been investigated. Recording intracellularly from HCs in dark-adapted macaque retina, we found that H1-HCs had large receptive fields (λ = 1,158 ± 137 μm) that were reduced by background light (-45%), gap junction closure (-53%), and D1 dopamine receptor activation (-48%). Tracer coupling was modulated in a correlative manner, suggesting that coupling resistance plays a dominant role in receptive field formation under low light conditions. The D1 antagonist SCH23390 increased the size of receptive fields (+13%), suggesting tonic dopamine release in the dark. Because light elevates dopamine release in primate retina, our results support a dopaminergic role in post-receptoral light adaptation by decreasing HC receptive field diameters, which influences the center-surround receptive field organization of higher-order neurons and thereby spatial contrast sensitivity.

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Available from: Ai-Jun Zhang, Apr 11, 2014
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    • "There is no consensus among the authors how the electrical coupling and receptive field size of horizontal cells change with retinal adaptation. Some authors reported that the electric coupling between horizontal cells is minimal during prolong periods in darkness (fish: Mangel and Dowling 1985; Tornqvist et al. 1988; Yang 1991), while other authors state that background light significantly decreases the electrical coupling among cells (turtle: Weiler and Akopian 1992; amphibian: Dong and McReynolds 1991; primate: Zhang et al. 2011). Still other authors argue that the coupling between mammalian horizontal cells is minimal in darkness as well as under background illumination with intensity higher than 3 log units above the rod threshold. "
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    • "Dopamine is known to play a key role in the adaptation of retinal processing to different light levels as well as circadian changes in retinal physiology (e.g. Herrmann et al., 2011; Witkovsky, 2004; Zhang et al., 2011). However, more work is required to better understand the links between cellular and circuit effects of neuromodulators, the consequences for the processing of sensory information, and their role in the natural ecological context of an organism's life. "
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