In 19 mice, 367 matched spine comparisons gave a shaft-distance calcium correlation contrast of −0.010

We tested whether shared spine calcium variation follows shaft distance at similar spacing between spine centers. We used the released Jenks visual-cortex data. All recorded spines could enter. Geometry alone set the matches. Short distances were 2 to less than 5 micrometers. Long distances were 10 to less than 20 micrometers. The other distance differed by at most 0.5 micrometer within the same field. We removed each visual direction mean on common accepted trials. In 367 shaft-distance comparisons from 19 mice, the short-minus-long residual correlation contrast was −0.0098. Its 95% mouse bootstrap interval was −0.0427 to 0.0239. The Holm-adjusted sign-flip p value was 0.583. A second test varied center distance at matched shaft distance. Its 184 comparisons from 16 mice gave 0.0497. The interval was 0.0039 to 0.1002; adjusted p was 0.122. Removal of source-marked large shaft-event trials reduced that estimate to 0.0202. The interval was −0.0229 to 0.0625. Neither main test established a local correlation gain under the planned correction. The intervals are not equivalence bounds. Restricted geometry, different distance endpoints, processed calcium signals, and shared input limit interpretation. We provide fixed matched panels, compact source data, code, figures, and source hashes. An audit rebuilt all 305 fields from 44 original MATLAB files. A fresh offline run reproduced all 46 numerical result files exactly.

structure and function · dendritic spine · calcium imaging · dendritic distance · spatial matching · visual cortex · trial residual correlation · mouse