Fig. 4.

Single-cell screening of intracellular calcium levels during long exposure to Aβ42 shows a subpopulation of Aβ42-resistant cells. On day 1, cells exposed to Aβ42 were distributed mainly around a single population well fit by a single Gaussian. However, by day 2, cells begin to reveal the effect of Aβ42, and the cell distribution shows the emergence of a second subpopulation which is better defined at day 3. This subpopulation was not observed at day 7. This persistent subpopulation is presumably made of cells resistant to Aβ. The bar plot corresponds to the averaged free cytosolic calcium for days 1, 2, 3, and 7. The average free cytosolic calcium of the whole cell population does not reveal the existence of subpopulations of cells with different sensitivity to Aβ42