Synapse size balance had no clear link to movie response similarity in 1,441 Allen V1 connections

We tested whether balanced synapse sizes relate to similar visual responses in one Allen V1 Deep Dive mouse. We joined individual contact sizes to a published matched activity table. The sample had 1,441 connections, including 177 with multiple contacts. With contact count, mean size, geometry and both cell roles controlled, a 0.1 balance increase gave a 0.00505 change in movie response correlation. The nominal 95% dyadic interval was -0.01095 to 0.02105. Three alternative activity measures also had intervals that included zero. The repeated-only graph had just seven independent endpoint contrasts. Additional controls left 0.055% of its balance variation. Thus, the data do not resolve a size-balance relation. A larger anatomical panel repeated an earlier conditional size-allocation result. One mouse, selected connections, summary activity measures and uncertain size-to-strength mapping limit the study. Code, contact records, source hashes, independent checks and figures are supplied.

Allen Institute · connectomics · size balance · movie response · identifiability · dyadic uncertainty