Fig. 6.

Short-term valproic acid exposure prevents formation of Closure 5 as a biomechanically active structure. A) Representative reflection-mode images of live-imaged 22 somite stage embryos cultured for 8 h in 0 mM or 1 mM VPA. The borders of the neural folds are outlined by the dashed white lines, indicating a more elliptical caudal PNP morphology in the 0 mM embryo. Red dashed lines indicate the Closure 5 laser ablation region. B) The change in PNP width (After–Before) due to Closure 5 laser ablation was quantified at each 1% of the PNP's length as a measure of lateral neural fold recoil. Caudal PNP width increased significantly more in 21–24 somite stage embryos cultured for 8 h in 0 mM (n = 6) than in 1 mM VPA (n = 7). The green line indicates the region of significant difference, p < 0.05 following Bonferroni post-hoc.