Fig. 1
Validation of pharmacological modulation of CSF formation and neuronal activity. A Four conditions with high and low CSF formation combined with high and low neuronal activity were achieved by different anesthesia protocols. B Representative axial T2w images depict subarachnoidal space under ISO (red) and MED (blue). Inset shows superposition of volumes under the two conditions. C 3D visualization indicates position of the slice for DWI (red) and shows the fluid-filled volume (blue) in the rat brain derived from anatomical images. DWI (right) was used for measuring ADC in the aqueduct (central bright structure in the zoomed image) as surrogate for CSF flow. D Boxplots display percent change of volume of subarachnoidal space or of aqueductal flow. Kruskal–Wallis test indicated an effect of experimental condition on volume of subarachnoidal space (p < 0.001). ANOVA test showed an effect of experimental condition on aqueductal flow (p < 0.001). Significant differences between groups determined by post-hoc analysis with Mann–Whitney-U and Student’s t-test, respectively, are indicated in the graphs (ISO n = 6; MED n = 6; ISO+MED n = 6; ISO+AZE n = 6; MED+AZE n = 6; ISO+MED+AZE n = 7). E Exemplary traces show optical Ca2+-recordings of spontaneous brain activity in neocortex. F Analysis of power spectra of Ca2+-recordings under MED, ISO+MED and ISO for the frequency ranges of 0.1–1 Hz, 1–4 Hz and 1–20 Hz respectively (MED N = 3 animals; ISO+MED N = 5 animals; ISO N = 3 animals; each averaged over 30 spectra per animal). ANOVA test indicated effect of experimental condition for 0.1–1 Hz (p < 0.001) and for 1–4 Hz (p < 0.01). Significant differences between groups determined by post-hoc analysis with Student’s t-test are indicated in the graphs.* p < 0.05, ** p < 0.01, *** p < 0.001