AUTHOR=Chang Le , Ran Yanli , Yang Mingpo , Auferkorte Olivia , Butz Elisabeth , Hüser Laura , Haverkamp Silke , Euler Thomas , Schubert Timm TITLE=Spike desensitisation as a mechanism for high-contrast selectivity in retinal ganglion cells JOURNAL=Frontiers in Cellular Neuroscience VOLUME=17 YEAR=2024 URL=https://www.frontiersin.org/journals/cellular-neuroscience/articles/10.3389/fncel.2023.1337768 DOI=10.3389/fncel.2023.1337768 ISSN=1662-5102 ABSTRACT=

In the vertebrate retina, several dozens of parallel channels relay information about the visual world to the brain. These channels are represented by the different types of retinal ganglion cells (RGCs), whose responses are rendered selective for distinct sets of visual features by various mechanisms. These mechanisms can be roughly grouped into synaptic interactions and cell-intrinsic mechanisms, with the latter including dendritic morphology as well as ion channel complement and distribution. Here, we investigate how strongly ion channel complement can shape RGC output by comparing two mouse RGC types, the well-described ON alpha cell and a little-studied ON cell that is EGFP-labelled in the Igfbp5 mouse line and displays an unusual selectivity for stimuli with high contrast. Using patch-clamp recordings and computational modelling, we show that a higher activation threshold and a pronounced slow inactivation of the voltage-gated Na+ channels contribute to the distinct contrast tuning and transient responses in ON Igfbp5 RGCs, respectively. In contrast, such a mechanism could not be observed in ON alpha cells. This study provides an example for the powerful role that the last stage of retinal processing can play in shaping RGC responses.