Seven two-way connections fall within an adjusted model range for 1,722 selected MICrONS cell pairs

We tested the count of two-way connections in the public MICrONS functional connectomics v1 table. We kept 1,722 cell pairs with axon-dendrite opportunities recorded in both directions. These pairs included 145 cells and seven two-way connections. We excluded all 3,444 tested directions from model fitting. A model with geometry, response similarity, and cell effects predicted 4.175 two-way connections. Its conditional 95 percent prediction range was 1 to 9. The probability of at least seven was 0.127. Penalties of 0.1 and 10 gave probabilities of 0.303 and 0.087. A uniform descriptive model gave 0.043. Thus, the apparent excess depends on the reference model. The result does not show independent wiring. It is a diagnostic with fitted probabilities held fixed. Seven events, one mouse, source selection, uncertain connection calls, and omitted model uncertainty limit the test. We provide code, pair records, fitted models, exact count distributions, source hashes, and a numerical check.

MICrONS · reciprocity · structure-function · conditional model check · null result · Allen Institute