Dynamic contraction activities at multiple CCs can drive soma translocation. (a, left) The typical neuron is divided into three regions (marked by colored brackets) roughly corresponding to regions around three CCs: dLP (red), pLP (green), and TP (blue). (a, right) Changes in the total local strain energy (see Materials and methods) of three regions of the GC shown on the left during a 60-min observation period. Arrows, asynchronous contraction of two or three CCs; arrowheads, synchronous contraction of three CCs. Additionally, three more cases are shown in b–d. The dynamic and asynchronous contraction can also be observed in the 18 cases in Fig. S2. (b) CC at dLP pulled the soma forward in a migrating GC. (b, top) Line scan of stress along the cell axis during the observation time. Cyan line, soma center; green dots, position of the dominant CC. (b, middle) Local strain energies at dLP, pLP, and TP. (b, bottom) Soma translocation with time. Pink shade, CC activities at dLP pulled the soma forward. (c and d) Two other migrating GCs showing rapid soma translocation when CC activities at TP and pLP were high, respectively, and strain energies at LP (S_dLP + S_pLP) versus TP (S_TP) were highly unbalanced (black bar vs. gray bar). More detailed analysis of five cases similar to b–d are shown in Fig. 3 and Fig. S3, and a total number of 28 GCs were summarized in e. (e) Cross-correlation of the velocity of soma translocation with [S_dLP + S_pLP] (marked as “LP”), S_TP (“TP”), and [(S_dLP + S_pLP) − S_TP] (“Δ”). (e, top) Cross-correlation coefficient for the example cell in d. Red horizontal lines represent the approximate upper and lower confidence bounds (95%), assuming that migration velocity and traction energy are completely uncorrelated. (e, bottom) Averaged cross-correlation coefficient for all 28 migrating cells examined.