In one mouse V1 panel, a half-second lag score agreed with 142 of 310 recorded one-way synapse directions

We tested whether recorded synapse direction agrees with temporal response order in mouse visual cortex. We used 193 cells with reviewed axons, three sessions, and eight repeats of a two-minute movie per session. New half-second trial arrays used exact plane timestamps. All 6,668 pairs recorded in the same session entered the test. After average movie responses and repeat means were removed, the event lag sign agreed with 142 of 310 recorded one-way directions (45.8%). The central 95% repeat resampling range was 43.2% to 51.0%. A model with a separate timing term for each cell gave a direction coefficient of -0.003875. Its repeat range was -0.006763 to -0.000537. A separate neuron-weight range was -0.010553 to +0.002914. Both ranges condition on this panel. Odd and even repeat event lag scores had correlation 0.036 across the one-way pairs. The dF/F sign agreement was 41.0%. Same-plane and longer-lag checks are preserved. The tested score did not give a useful simple forward direction rule in this fixed panel. It does not measure synaptic delay or identify reverse causal flow. One mouse, selected cells, slow calcium signals, low repeat agreement and partial axons limit the result. The package contains exact trial arrays, the selected graph, code, source hashes, every main repeat draw, figures and repeat instructions. Independent calculations check direction, regression, resampling and the complete source synapse recount.

functional connectomics · V1 Deep Dive · temporal response order · lagged covariance · synapse direction · calcium imaging · repeat reliability · open benchmark