Nonlinear interactions between excitatory and inhibitory retinal synapses control visual output.
The visual system is highly sensitive to dynamic features in the visual scene. However, it is not known how or where this enhanced sensitivity first occurs. We investigated this phenomenon by studying interactions between excitatory and inhibitory synapses in the second synaptic layer of the mouse retina. We found that these interactions showed activity-dependent changes that enhanced signaling of dynamic stimuli. Excitatory signaling from cone bipolar cells to ganglion cells exhibited strong synaptic depression, attributable to reduced glutamate release from bipolar cells. This depression was relieved by amacrine cell inhibitory feedback that activated presynaptic GABA(C) receptors. We found that the balance between excitation and feedback inhibition depended on stimulus frequency; at short interstimulus intervals, excitation was enhanced, attributable to reduced inhibitory feedback. This dynamic interplay may enrich visual processing by enhancing retinal responses to closely spaced temporal events, representing rapid changes in the visual environment.
Department of Ophthalmology, Weill Medical College of Cornell University, Burke Medical Research Institute, White Plains, New York 10605, USA. bos2005@med.cornell.edu
Botir T
BT
Sagdullaev
Erika D
ED
Eggers
Robert
R
Purgert
Peter D
PD
Lukasiewicz
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000818:Animals; D001569:Benzodiazepines / Q000494:pharmacology; D004558:Electric Stimulation / Q000379:methods; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D051379:Mice; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D017711:Nonlinear Dynamics; D018408:Patch-Clamp Techniques; D010721:Phosphinic Acids / Q000494:pharmacology; D010775:Photic Stimulation / Q000379:methods; D017729:Presynaptic Terminals / Q000187:drug effects / Q000502:physiology; D011725:Pyridines / Q000494:pharmacology; D012160:Retina / Q000166:cytology*; D051245:Retinal Bipolar Cells / Q000187:drug effects / Q000502:physiology; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000502:physiology; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
C101879:(1,2,5,6-tetrahydropyridin-4-yl)methylphosphinic acid; D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D010721:Phosphinic Acids; D011725:Pyridines; D001569:Benzodiazepines; C079692:GYKI 53655; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione