Four alpha ganglion cell types in mouse retina: Function, structure, and molecular signatures

• Published in: PloS one 2017-07, Vol.12 (7), p.e0180091-e0180091
• Main Authors: Krieger, Brenna, Qiao, Mu, Rousso, David L, Sanes, Joshua R, Meister, Markus
• Format: Article
• Language: English
• Subjects: Action potential; Action Potentials - physiology; Analysis; Animals; Asymmetry; Axons; Axons - metabolism; BASIC (programming language); Biology and Life Sciences; Brain; Cellular biology; Channels; Dendrites - metabolism; Diagnosis; Electrophysiology; Female; Ganglion cysts; Gene expression; Genetic aspects; Genetic engineering; Health aspects; Integrases - metabolism; Kinetics; Laboratory animals; Light effects; Male; Mammals; Medicine and Health Sciences; Mice; Molecular structure; Morphology; Neurofilaments; Neurons; Neurosciences; Physiology; Polarity; Potassium Channels, Voltage-Gated - metabolism; Receptive field; Retina; Retina - cytology; Retinal ganglion cells; Retinal Ganglion Cells - metabolism; Signaling; Social Sciences; Structure-function relationships; Transgenic mice; Transient response; Visual aspects; Visual Pathways - physiology; Visual signals
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0180091

The retina communicates with the brain using ≥30 parallel channels, each carried by axons of distinct types of retinal ganglion cells. In every mammalian retina one finds so-called "alpha" ganglion cells (αRGCs), identified by their large cell bodies, stout axons, wide and mono-stratified dendritic fields, and high levels of neurofilament protein. In the mouse, three αRGC types have been described based on responses to light steps: On-sustained, Off-sustained, and Off-transient. Here we employed a transgenic mouse line that labels αRGCs in the live retina, allowing systematic targeted recordings. We characterize the three known types and identify a fourth, with On-transient responses. All four αRGC types share basic aspects of visual signaling, including a large receptive field center, a weak antagonistic surround, and absence of any direction selectivity. They also share a distinctive waveform of the action potential, faster than that of other RGC types. Morphologically, they differ in the level of dendritic stratification within the IPL, which accounts for their response properties. Molecularly, each type has a distinct signature. A comparison across mammals suggests a common theme, in which four large-bodied ganglion cell types split the visual signal into four channels arranged symmetrically with respect to polarity and kinetics.