English: Simultaneous imaging of mitochondrial potential and of nuclear modifications studied by time-lapse confocal imaging after the induction of apoptosis by 500 ng/mL AMD. HeLa cells stably expressing H2B-GFP were stained with TMRE to study mitochondrial polarization. Simultaneous time-lapse confocal imaging of TMRE and H2B-GFP was performed by two-photon excitation, every 7 minutes for 15 h and 17 minutes after the induction of apoptosis by the addition of 500 ng/mL AMD. Z-stacks of 85 optical sections were processed to obtain 3D images (surface rendering for chromatin and volume rendering for mitochondrial polarization), which were assembled to produce movies demonstrating the successive steps of 3D chromatin reorganization and changes in mitochondrial potential (based on the green fluorescence of H2B-GFP and red fluorescence of TMRE respectively). In the field of view shown in this movie, we observed 32 cells containing H2B-GFP. Depolarization of mitochondria, as demonstrated by the observation of TMRE red signal reorganization, occurred at three hours and 30 minutes in the first cell and at fourteen hours in the last cell.