title: Approach sensitivity in the retina processed by a multifunctional neural circuit.
abstract: The detection of approaching objects, such as looming predators, is necessary for survival. Which neurons and circuits mediate this function? We combined genetic labeling of cell types, two-photon microscopy, electrophysiology and theoretical modeling to address this question. We identify an approach-sensitive ganglion cell type in the mouse retina, resolve elements of its afferent neural circuit, and describe how these confer approach sensitivity on the ganglion cell. The circuit's essential building block is a rapid inhibitory pathway: it selectively suppresses responses to non-approaching objects. This rapid inhibitory pathway, which includes AII amacrine cells connected to bipolar cells through electrical synapses, was previously described in the context of night-time vision. In the daytime conditions of our experiments, the same pathway conveys signals in the reverse direction. The dual use of a neural pathway in different physiological conditions illustrates the efficiency with which several functions can be accommodated in a single circuit.
authors.affiliation: Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Münch
authors.forename: Rava Azeredo
authors.initials: RA
authors.lastname: da Silveira
authors.forename: Sandra
authors.initials: S
authors.lastname: Siegert
authors.forename: Tim James
authors.initials: TJ
authors.lastname: Viney
authors.forename: Gautam B
authors.initials: GB
authors.lastname: Awatramani
authors.forename: Botond
authors.initials: B
authors.lastname: Roska
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000235:genetics; D000818:Animals; D001710:Biotin / Q000031:analogs & derivatives / Q000378:metabolism; D003198:Computer Simulation; D017630:Connexins / Q000172:deficiency; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics; D008164:Luminescent Proteins / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D008959:Models, Neurological; D009039:Motion Perception / Q000502:physiology; D009415:Nerve Net / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009433:Neural Inhibition / Q000235:genetics; D009474:Neurons / Q000145:classification* / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D010775:Photic Stimulation; D010879:Piperazines / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D012160:Retina / Q000166:cytology*; D014794:Visual Fields / Q000235:genetics / Q000502:physiology; D014795:Visual Pathways / Q000502:physiology; D000097004:Gap Junction delta-2 Protein
chemical_list: D001710:Biotin; D017630:Connexins; D018691:Excitatory Amino Acid Antagonists; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D009419:Nerve Tissue Proteins; D010879:Piperazines; D011810:Quinoxalines; D000097004:Gap Junction delta-2 Protein; C070614:neurobiotin; C062865:2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline; C050592:3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid