Fig. 3: 40 Hz light flickering increases glymphatic flow measured by DCE-MRI.

a Schematic protocol of DCE-MRI. b Representative pseudocolour-scaled sagittal images of brains from mice exposed to normal light or 40 Hz light flickering; numbers indicate the time elapsed after injecting the Gd-DTPA tracer into the cisterna magna. (scale bars, 3 mm). c–f Signal intensity plots based on % signal change from baseline in time signal curves, triggered by either normal light or 40 Hz light flickering and acquired from the basal forebrain, prefrontal lobe, hippocampus and superior colliculus, demonstrated an earlier rise in signal intensity following Gd-DTPA injection and a greater overall elevation (the horizontal red lines represent time points with statistically significant differences). g–j Quantification of the infusion rate demonstrated a faster increase in signal prior to reaching its peak after exposure to 40 Hz light flickering (each dot represents a region of the hemisphere, n = 5 mice exposed to normal light, n = 6 mice exposed to 40 Hz, mean ± SEM in the bar graphs, *P < 0.05, unpaired Student’s t-test).