Extended Data Figure 2. Intracranial pressure measurements and assessment of CSF drainage and brain influx.

a, Intracranial pressure (ICP) was measured in four different steps of intra-cisterna magna (i.c.m.) injection of 2 μL or 5 μL of tracer solution: pre-injection, during injection, post-injection (with syringe inside the cisterna magna) and post-injection (with syringe out of the cisterna magna). A significant increase in ICP for each volume was observed during injection when compared to pre-injection and post-injection (syringe in). Significantly higher ICP values post-injection (syringe in) were observed when compared to ICP values pre-injection. A significant decrease in ICP for each volume was observed post-injection (syringe out) when compared to all other steps of i.c.m. injection. No significant differences in ICP values were observed between groups injected with 2 μL or 5 μL of tracer for any of the analyzed steps of the i.c.m. injection method (mean ± s.e.m., n = 7 per group; repeated measures two-way ANOVA with Bonferroni’s post-hoc test; *vs pre-injection; ^#vs during injection; ^&vs post-injection (syringe in); data was pooled from 2 independent experiments). b, ICP was measured 30, 60 and 120 min post injection (p.i.) of 2, 5 or 10 μL of tracer solution into the CSF and compared to ICP values in non-injected mice. Significant differences were observed between ICP values of non-injected mice and mice injected with 2 μL of tracer at 30 min and 120 min post-injection (mean ± s.e.m., n = 5 per group; one-way ANOVA with Bonferroni’s post-hoc test). c, Seven days after meningeal lymphatic ablation, a volume of 2 μL of fluorescent OVA-A647 was injected into the CSF and drainage of tracer into the dCLNs was assessed 2 h later. d, Representative images of OVA-A647 (red) drained into the dCLNs, stained for LYVE-1 (green) and with DAPI (blue; scale bar, 200 μm). e, Quantification of OVA-A647 area fraction (%) in the dCLNs showed significantly less amount of tracer in the Visudyne/photoconversion group than in control groups. f, Representative brain sections stained with DAPI (blue) showing OVA-A647 (red) influx into the brain parenchyma of mice from Visudyne/photoconversion and control groups (scale bar, 5 mm; inset scale bar, 1 mm). g, Quantification of OVA-A647 area fraction (%) in brain sections showing a significant decrease in the Visudyne/photoconversion group when compared to control groups. Data in e and g is presented as mean ± s.e.m., n = 6 per group; one-way ANOVA with Bonferroni’s post-hoc test was used in e and g; c–g is representative of 2 independent experiments.