Fig. 5.

Differential regenerative responses of longitudinal neurons are partially dependent on the size of the remnant fragment. a, b Schematics demonstrating the shifts in amputation sites used to obtain remnant fragments of varying sizes. c–h Quantification of longitudinal neurons in regenerates with shifted amputation sites at time 0 cut, 24hpa, and 7dpa. c Regenerates from an aborally shifted amputation site in large animals regenerated their longitudinal neurons (p = 0.046; F _2,14 = 5.58, p = 0.017, η_p² = 0.44, n = 8), resembling regenerates of small- and medium-sized animals bisected at the midline of the oral-aboral axis (d). e Regenerates from an orally shifted amputation site in medium animals did not regenerate their longitudinal neurons (p = 1.00; F _2,24 = 21.67, p < 0.001, η_p² = 0.64, n = 13), resembling regenerates from large animals bisected at the midline of the oral-aboral axis (f). g Regenerates from an orally shifted amputation site in small animals did not regenerate their longitudinal neurons (p = 0.47; F _2,24 = 8.56, p = 0.002, η_p² = 0.42, n = 13), which is different from medium animals bisected at the midline of the O-A axis (h). See Additional file 15: Table S5 for full model results. Data points in c–h represent means ± SEM, *p ≤ 0.05