Regional variation in the organization and connectivity of the first synapse in the primate night vision pathway
Aindrila Saha,
Juan Zuniga,
Kainat Mian,
Haoshen Zhai,
Paul J. Derr,
Mrinalini Hoon,
Raunak Sinha
Affiliations
Aindrila Saha
Department of Neuroscience, University of Wisconsin, Madison, WI, USA; McPherson Eye Research Institute, University of Wisconsin, Madison, WI, USA
Juan Zuniga
Department of Neuroscience, University of Wisconsin, Madison, WI, USA
Kainat Mian
Department of Neuroscience, University of Wisconsin, Madison, WI, USA
Haoshen Zhai
Department of Neuroscience, University of Wisconsin, Madison, WI, USA
Paul J. Derr
Department of Neuroscience, University of Wisconsin, Madison, WI, USA
Mrinalini Hoon
Department of Neuroscience, University of Wisconsin, Madison, WI, USA; McPherson Eye Research Institute, University of Wisconsin, Madison, WI, USA; Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, WI, USA; Corresponding author
Raunak Sinha
Department of Neuroscience, University of Wisconsin, Madison, WI, USA; McPherson Eye Research Institute, University of Wisconsin, Madison, WI, USA; Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, WI, USA; Corresponding author
Summary: Sensitivity of primate daylight vision varies across the visual field. This is attributed to regional variations in cone photoreceptor density and synaptic connectivity of the underlying circuitry. In contrast, we have limited understanding of how synapse organization of the primate night vision pathway changes across space. Using serial electron microscopy, we reconstructed the first synapse of the night vision pathway between rod photoreceptors and second-order neurons, at multiple locations from the central part of the primate retina, fovea, to the periphery. We find that most facets of the rod synapse connectivity vary across retinal regions. However, rod synaptic divergence and convergence patterns do not change in the same manner across locations. Moreover, patterns of rod synapse organization are tightly correlated with photoreceptor density. Such regional heterogeneities revise the connectivity diagram of the primate rod synapse which will shape synapse function and sensitivity of the night vision pathway across visual space.
