Pulse slopes and centered correlations have opposite signs in 21 of 311 Allen electrical records

We tested whether electrical coupling slopes and centered correlations agree in sign in Allen Synaptic Physiology r2.1. Among 311 directed records marked electrically connected, 21 pulse slopes had the opposite sign to the Pearson correlation. This was 6.75%, with a descriptive 95% slice bootstrap interval of 4.06 to 9.78%. None of the 21 passed the pulse Pearson p < 0.05 screen; all 137 screened records had sign agreement. Baseline slopes had 28 disagreements. Their fraction minus the pulse fraction was 2.25 percentage points, with interval -2.28 to 6.54 points. Under the documented calculation, opposite signs show that the product of sweep means dominates the centered covariance in the origin slope. A construction also gives centered slopes of 0.005 and 0.5 with the same origin slope 0.05 and correlation 0.8. This is an audit and an algebraic identification limit, not evidence for negative conductance or a specific artifact. Raw sweeps were not replayed, the exact generating source revision is unknown, slices can share animals, and only two human rows were present. Original code, aggregate results, a figure, source hashes and external retrieval steps support reproduction. External records are not bundled.

Allen Institute · electrical coupling · regression · Pearson correlation · measurement audit · identifiability