Published: January 26, 2018
Simulation Analysis of Temporal Coding by Ionotropic Glutamate Receptors of Retinal OFF-type Bipolar Cells [PDF]
(Received August 2, 2017; Accepted November 15, 2017)
Keywords: retinal off-type bipolar cells, ionotropic glutamate receptors, mathematical models, computer simulation, visual information processing
OFF-type bipolar cells (OFF-BCs) are interneurons connecting cone and retinal ganglion cells in the retina. In the mammalian retina, the cone signals are received by alpha-amino- 3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate-type ionotropic glutamate receptors (iGluRs) in OFF-BCs. The bipolar cells in the retina respond to continuous variations in light with a graded potential in an analogue manner. It is not clear what role the kinetics of the iGluRs play in the temporal coding and synaptic transmission from the cones to the OFFBCs. In this study, we analyzed the role of the kinetics of AMPA receptors (AMPARs) in transmitting visual information to the OFF-BCs by a computer simulation using developed mathematical models. We showed that the AMPARs modulated the frequency characteristics which strongly depend on baseline glutamate level. Our results also demonstrated that the response of OFF-BCs to square-wave pulse of glutamate was similar to ON-OFF type when baseline glutamate level around 0.5 mM, and enhanced temporal contrasts. The results suggest that the function would improve sensitivities of the spatio-temporal contrast in collaboration with the local eye movement. This modeling study of retinal neurons would lead to improvement and development of more effective stimulation for devices of retinal prostheses.
Corresponding author: Akito Ishihara
Cite this article
Akito Ishihara, Simulation Analysis of Temporal Coding by Ionotropic Glutamate Receptors of Retinal OFF-type Bipolar Cells, Sens. Mater., Vol. 30, No. 2, 2018, p. 299-313.