The open- and closed-loop gain-characteristics of the cone/horizontal cell synapse in goldfish retina.
Under constant light-adapted conditions, vision seems to be rather linear. However, the processes underlying the synaptic transmission between cones and second-order neurons (bipolar cells and horizontal cells) are highly nonlinear. In this paper, the gain-characteristics of the transmission from cones to horizontal cells and from horizontal cells to cones are determined with and without negative feedback from horizontal cells to cones. It is shown that 1) the gain-characteristic from cones to horizontal cells is strongly nonlinear without feedback from horizontal cells, 2) the gain-characteristic between cones and horizontal cells becomes linear when feedback is active, and 3) horizontal cells feed back to cones via a linear mechanism. In a quantitative analysis, it will be shown that negative feedback linearizes the synaptic transmission between cones and horizontal cells. The physiological consequences are discussed.
Kraaij
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DA
Research Unit Retinal Signal Processing, The Netherlands Ophthalmic Research Institute, Academic Medical Center, University of Amsterdam, 1105 BA Amsterdam, The Netherlands.
Spekreijse
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Kamermans
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D000818:Animals; D002118:Calcium / Q000378:metabolism; D005246:Feedback / Q000502:physiology; D006054:Goldfish / Q000502:physiology*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000502:physiology; D009415:Nerve Net / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D018408:Patch-Clamp Techniques; D010775:Photic Stimulation; D012160:Retina / Q000166:cytology / Q000502:physiology*; D017949:Retinal Cone Photoreceptor Cells / Q000166:cytology / Q000378:metabolism*; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology
D002118:Calcium