title: Retinal and Tectal "Driver-Like" Inputs Converge in the Shell of the Mouse Dorsal Lateral Geniculate Nucleus.
abstract: The dorsal lateral geniculate nucleus (dLGN) is a model system for understanding thalamic organization and the classification of inputs as "drivers" or "modulators." Retinogeniculate terminals provide the primary excitatory drive for the relay of information to visual cortex (V1), while nonretinal inputs act in concert to modulate the gain of retinogeniculate signal transmission. How do inputs from the superior colliculus, a visuomotor structure, fit into this schema? Using a variety of anatomical, optogenetic, and in vitro physiological techniques in mice, we show that dLGN inputs from the superior colliculus (tectogeniculate) possess many of the ultrastructural and synaptic properties that define drivers. Tectogeniculate and retinogeniculate terminals converge to innervate one class of dLGN neurons within the dorsolateral shell, the primary terminal domain of direction-selective retinal ganglion cells. These dLGN neurons project to layer I of V1 to form synaptic contacts with dendrites of deeper-layer neurons. We suggest that tectogeniculate inputs act as "backseat drivers," which may alert shell neurons to movement commands generated by the superior colliculus. Significance statement: The conventional view of the dorsal lateral geniculate nucleus (dLGN) is that of a simple relay of visual information between the retina and cortex. Here we show that the dLGN receives strong excitatory input from both the retina and the superior colliculus. Thus, the dLGN is part of a specialized visual channel that provides cortex with convergent information about stimulus motion and eye movement and positioning.
authors.affiliation: Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky 40292, and martha.bickford@louisville.edu william.guido@louisville.edu.
authors.forename: Martha E
authors.initials: ME
authors.lastname: Bickford
authors.affiliation: Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky 40292, and.
authors.forename: Na
authors.initials: N
authors.lastname: Zhou
authors.affiliation: Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia 23284.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Krahe
authors.affiliation: Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky 40292, and.
authors.forename: Gubbi
authors.initials: G
authors.lastname: Govindaiah
authors.affiliation: Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky 40292, and martha.bickford@louisville.edu william.guido@louisville.edu.
authors.forename: William
authors.initials: W
authors.lastname: Guido
mesh_terms: D000818:Animals; D005260:Female; D005829:Geniculate Bodies / Q000502:physiology* / Q000648:ultrastructure; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D046529:Microscopy, Electron, Transmission; D018408:Patch-Clamp Techniques; D012160:Retina; D014795:Visual Pathways / Q000502:physiology* / Q000648:ultrastructure; D014796:Visual Perception / Q000502:physiology*
keywords: corticogeniculate; frequency dependent depression; optogenetics; retinogeniculate; tectogeniculate; ultrastructure