Representative images of MRI signal and complex modulus map of G' and G''.

<p>Regions of interest: substantia nigra (red line), midbrain (blue line) and hippocampus (yellow line) were marked in T1w-MRI.</p

Representative images of DAB–stained brain slices showing the substantia nigra.

<p>TH+ cells at baseline at -3dpi (a) and directly after MPTP treatment at 3dpi (b) at 50x magnification, indicating a severe loss of dopaminergic neurons induced by MPTP. Iba-1+ at -3dpi (c) and 3dpi (d) at 50x magnification with detail in 200x magnification (scale bar 100 μm), showing a reactive increase in the number of microglia and macrophages in the substantia nigra immediately after MPTP treatment.</p

Results of MRE measurements and histological cell counts in the substantia nigra.

<p>MPTP induced a significant reduction in MRE elasticity (a) and viscosity (b) in the substantia nigra (mean±SEM, n(-3,3,6,10,14,18dpi) = 5). DAB-stained brain sections showed an immediate significant drop in TH+ dopaminergic neurons in the substantia nigra after MPTP treatment (c) (mean±SEM, n(-3dpi) = 4, n(3,6,10,14,18dpi) = 5). DAPI-stained cell amount was decreased by MPTP (d) (mean±SEM, n(-3,3,6,10,14,18dpi) = 2, no statistical analysis). Initially, the amount of Iba1+ microglia and macrophages was significantly raised after MPTP treatment, but ceased over time (e) (mean±SEM, n(-3dpi) = 4, n(3,6,10,14,18dpi) = 5). * vs. -3dpi, *p≤0.05, **p≤0.01, ***p≤0.001. ^# vs. 3dpi, ^# p≤0.05.</p

Results of MRE measurement and histological cell count in the hippocampus.

<p>MPTP induced a transient increase of elasticity (a) and viscosity (b) in the hippocampus at 6dpi (mean±SEM, n(-3,3,6,10,14,18dpi = 5). Quantification of DAPI-stained cells showed an elevated amount at 6dpi (mean±SEM, n(-3,3,6,10,14,18dpi) = 2, no statistical analysis). * vs. -3dpi, **p≤0.01, ***p≤0.001.</p

Results of MRE measurement and histological cell count in the midbrain.

<p>MPTP induced a significant increase of MRE elasticity (a) and viscosity (b) in the midbrain (mean±SEM, n(-3,3,6,10,14,18dpi = 5). DAPI-stained brain sections showed a reduction following MPTP-treatment (c) (mean±SEM, n(-3,3,6,10,14,18dpi) = 2, no statistical analysis). * vs. -3dpi, *p≤0.05, **p≤0.01.</p

Schematic of the mouse MRE apparatus.

<p>Schematic of the mouse MRE apparatus.</p