Network variability limits stimulus-evoked spike timing precision in retinal ganglion cells.
Visual, auditory, somatosensory, and olfactory stimuli generate temporally precise patterns of action potentials (spikes). It is unclear, however, how the precision of spike generation relates to the pattern and variability of synaptic input elicited by physiological stimuli. We determined how synaptic conductances evoked by light stimuli that activate the rod bipolar pathway control spike generation in three identified types of mouse retinal ganglion cells (RGCs). The relative amplitude, timing, and impact of excitatory and inhibitory input differed dramatically between On and Off RGCs. Spikes evoked by repeated somatic injection of identical light-evoked synaptic conductances were more temporally precise than those evoked by light. However, the precision of spikes evoked by conductances that varied from trial to trial was similar to that of light-evoked spikes. Thus, the rod bipolar pathway modulates different RGCs via unique combinations of synaptic input, and RGC temporal variability reflects variability in the input this circuit provides.
Murphy
Gabe J
GJ
Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195, USA. gjmurphy@u.washington.edu
Rieke
Fred
F
D000200:Action Potentials / Q000502:physiology* / Q000528:radiation effects; D000818:Animals; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods; D051379:Mice; D008810:Mice, Inbred C57BL; D008959:Models, Neurological; D018408:Patch-Clamp Techniques; D010775:Photic Stimulation / Q000379:methods; D012165:Retinal Ganglion Cells / Q000502:physiology*; D013569:Synapses / Q000502:physiology* / Q000528:radiation effects; D009435:Synaptic Transmission / Q000502:physiology / Q000528:radiation effects; D014795:Visual Pathways / Q000502:physiology* / Q000528:radiation effects