a, Difference in bouton abundance between perpendicular and parallel bowtie bins for OS LM boutons in different ΔRF distance bins. ΔRF distance bins contain same number of boutons (number on top). b, Same as in a but in different OSI bins. Slope = 54% (P = 0.056, two-sided permutation test, obtained by shuffling boutons’ OSI). The number of boutons in each bin is indicated at the top. c, Difference in bouton abundance between preferred motion direction and opposite bins for DS LM boutons in different ΔRF distance bins. d, Same as in c but in different DSI bins. Slope = 75% (P = 0.13, two-sided permutation test, obtained by shuffling boutons’ DSI). Shading in a, c, 95% confidence interval obtained by reshuffling group identities.