Cell-body distance gave no clear gain in PSP rise-time predictions in four Allen slice groups

We tested whether cell-body distance improves predictions of the rise time of a postsynaptic potential (PSP). We used 2,100 detected connections in the Allen Synaptic Physiology r2.1 small database, with mouse visual cortex and human temporal cortex in separate groups. We held out whole inferred donors and compared ridge models with cell labels, with and without distance. No primary rise-time gain interval was wholly above zero after correction for four groups. Mouse inhibitory connections had a 0.31% reduction in squared log error, with a conditional 98.75% donor bootstrap interval of -0.80% to 1.43%. In the same sample, distance reduced onset-latency error by 7.18%, with a descriptive 95% interval of 3.04% to 11.44%. Human excitatory rise-time predictions became worse at all tested penalties. Other penalties and joint cell labels gave no clear rise-time gain. These results restrict the use of cell-body distance as a timing predictor in these slice data. They do not test dendritic path length or establish a difference between the two outcome gains. Missing measurements, inferred donor labels, and uncertainty that conditions on fitted models limit the result.

Allen Institute · synaptic rise time · cell-body distance · donor validation · null result