Apical dendrite shape did not predict orientation tuning in 1,524 to 3,779 MICrONS mouse L2/3 neurons; two small-sample claims of Weiler et al. 2022 did not replicate

Question: does dendrite shape predict orientation tuning in mouse visual cortex? Weiler et al. (2022) reconstructed about 30 L2/3 pyramidal cells. They reported that the apical tree is elongated along the preferred orientation after retinotopic mapping (cc = 0.5), and that sharply tuned cells have less complex apical trees (r = 0.58 with tuning width). We tested both claims in the MICrONS mouse, which has in vivo two-photon tuning and an electron-microscopy reconstruction for each cell (12,829 coregistered neurons, v661 skeletons). We calibrated the image-frame conventions from the digital twin responses. We mapped each apical axis to visual space with a local retinotopic fit and compared it with the preferred bar orientation against shuffle nulls. Result for C1: in 1,524 tuned excitatory V1 L2/3 cells, the alignment was not above the null (mean cos 2 delta 0.050; within-scan null 0.078, p = 0.083; local null 0.055, p = 0.73). All 15 variants were inside or below the null range, and the signed one-axis test went in the opposite direction. Result for C2: in 3,779 V1 L2/3 cells, apical Sholl peak did not predict in vivo gOSI (rho 0.007; r 95% CI -0.015 to 0.049; depth- and scan-adjusted slope -0.021, CI -0.055 to 0.036). Other areas, layers and complexity measures gave the same result. In random 30-cell subsets, |r| >= 0.58 occurred in 0.12% of draws. Limitations: one mouse; most skeletons are automated. A post hoc proofread subset (136 cells, mostly higher visual areas) gave a weak trend in the Weiler direction (rho -0.27; adjusted slope -0.19, p = 0.13) that is not resolved. Unproofread cells with complete-looking apical trees (n = 2,589) were null. The tuning stimulus was Monet noise, not gratings.

MICrONS · dendritic morphology · orientation selectivity · apical dendrite · Sholl analysis · retinotopy · replication · structure-function · mouse visual cortex · layer 2/3 · connectomics · null result