Cross-Species Local Organization of Intrinsic Spatiotemporal Speed Scales in Retinal Ganglion Cell Functional Manifolds

Abstract

We asked whether retinal ganglion cells (RGCs) possess a locally organized intrinsic spatiotemporal speed scalethat is reproducible across vertebrate species. For each RGC, a characteristic scale was defined as v* =sigma/tau, where sigma denotes a receptive-field spatial scale and tau a temporal response scale. The keyanalysis deliberately separated this quantity from the functional coordinates used to construct each cell manifold.Across public salamander, mouse, and marmoset datasets (4,131 RGCs in the assembled analysis), neighboringcells on speed-independent functional manifolds had more similar rank(v*) than expected under labelpermutation. Using one common rank-based statistic at k=12, local-organization effects were 7.14% insalamander, 8.30% in mouse, and 19.59% in marmoset, with permutation p values of 0.0028, <0.0002, and<0.0002, respectively. The sign of the effect persisted across 45 combinations of neighborhood size and distancemetric, and leave-one-species-out parameter transfer remained positive and significant in all three held-outdatasets. However, analyses seeking a shared global speed direction or one exact cross-species distanceresponse law were not supported. These results therefore support a narrower empirical principle: localcharacteristic-speed organization is reproducible across these three datasets, whereas global manifold geometryis species- or dataset-dependent. This is an exploratory cross-dataset computational study and does not establisha biological universal law. Keywords: retinal ganglion cell; receptive field; functional manifold; characteristic speed; cross-species analysis Datasets, such as Python code, are also included.