(A) Optic nerve recordings of spontaneous GC spiking activity in wt and nob mice after 30 min of dark adaptation. The spontaneous activity of nob GCs shows oscillatory spiking patterns with a mean frequency of 4.79 ± 0.13 Hz (n = 46 isolated units). (B) In this example, the GC fundamental frequency is 4 Hz. (C) GFP-positive cells in wt/SPIG1+ mice show an increased inward current during a light flash, e.g., an ON response (blue trace). In nob/SPIG1+ mice, GFP-positive GCs lack a light-evoked inward current and show oscillating inward currents. (D) Inhibitory and excitatory currents in GFP-positive wt/SPIG1+ (blue) and nob/SPIG1+ (red) GCs recorded under voltage-clamp conditions (holding potential: 0 and −70 mV, respectively). In nob mice, both excitatory and inhibitory inputs oscillated with a mean frequency of 5.10 ± 0.22 Hz (n = 36) and 4.50 ± 0.38 Hz (n = 8), respectively. The data underlying this figure can be found at https://figshare.com/account/home#/projects/65990. GC, ganglion cell; GFP, green fluorescent protein; SPIG1, SPARC-related protein-containing immunoglobulin domains 1; wt, wild type.