Acute impairment of mitochondrial movement by Aβ oligomers as revealed by time-lapse imaging of Mito-DsRed expressing neurons. (a) Representative images of a hippocampal neuron expressing Mito-DsRed (red), which was also stained by MitoTracker (green). The merged image (the 3rd panel) shows that Mito-DsRed and MitoTracker signals are perfectly colocalized in this transfected neuron, whereas MitoTracker also labeled many more mitochondria in surrounding cells. (b) Representative images from time-lapse sequences before and after 30 min exposure to Aβ1-42 oligomers. The left panels represent a snapshot of the mitochondrial distribution in a Mito-DsRed-expressing neuron. The right panels represent the movement traces of mitochondria derived from 5-min time-lapse sequences. The movement traces were generated from the time-lapse sequence using Zprojection followed by division against the first frame using ImageJ software . (c) Quantitative analysis showing the number of moving mitochondria after 30 min treatment with the control saline and different concentration of Aβ-O. The data were normalized against the number of moving mitochondria before the 30 min treatment with 100% indicating no change. Triple asterisks: p < 0.0005 (comparing to vehicle, Student's t-test).