Fig. 4. Effect of line width on spindle kymograph analysis. Spindle kymograph analysis was performed as described in Fig. 3 and supplementary Fig. S2. To create a kymograph, a vertical rectangular region of interest (roi) in the x-y scan (A) was used, from which a vertical single pixel column was generated via the brightest point horizontal (x-directed) projection. The width of the roi was varied to investigate the effect of horizontal sampling range on the Fourier analysis. Three line widths were used; 5, 10 and 20 pixels corresponding to 0.35, 0.7 and 1.4 µm, respectively, as shown in A. Panels B and C correspond to the analysis of the near chromosomal areas, also shown in Fig. 3G and H, respectively; panels D and E correspond to the analysis of overlapping microtubule areas, also shown in Fig. 3M and N, respectively.