RT Journal Article
SR Electronic
T1 Topographic axonal projection at single-cell precision supports local retinotopy in the mouse superior colliculus
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2022.03.25.485790
DO 10.1101/2022.03.25.485790
A1 Dmitry Molotkov
A1 Leiron Ferrarese
A1 Tom Boissonnet
A1 Hiroki Asari
YR 2023
UL http://biorxiv.org/content/early/2023/04/26/2022.03.25.485790.abstract
AB Retinotopy, like all long-range projections, can arise from the axons themselves or their targets, but the underlying connectivity pattern remains unknown at the fine scale. To address this question, we functionally mapped the spatial organization of the input axons and target neurons in the mouse retinocollicular pathway at single-cell resolution using in vivo two-photon calcium imaging. We found a near-perfect retinotopic tiling of retinal ganglion cell axon terminals, with an average error below 30 μm or 2 degrees of visual angle. The precision of retinotopy was relatively lower for local neurons in the superior colliculus. Subsequent data-driven modelling ascribed it to a low input convergence, on average 5.5 retinal ganglion cell inputs to a postsynaptic cell in the superior colliculus. These results indicate that retinotopy arises largely from topographically precise input from presynaptic cells, rather than elaborating local circuitry to reconstruct the topography by postsynaptic cells.Competing Interest StatementThe authors have declared no competing interest.2Dtwo-dimensionalAAVadeno-associated virusCNMFconstrained non-negative matrix factorizationRFreceptive fieldRGCretinal ganglion cellsSCsuperior colliculusSDstandard deviation.