The adult mouse was perfused transcardially with 4% PFA following anesthetization with avertin. The brain was dissected out and postfixed by immersion in 4% paraformaldehyde (PFA) overnight at 4 °C, embedded in paraffin and cut into 5-µm-thick sagittal sections, which were deparaffinized using a standard histology protocol immediately before immunohistochemical staining. In the staining procedure, tissue sections were permeabilized with 0.5% Triton X-100 (Sigma) for 10 minutes, then blocked with the buffer containing 10% normal goat serum (Sigma), 1% (w/v) bovine serum albumin (BSA) and 0.2% (v/v) Triton X-100 for 2 hours at RT, followed by incubation with primary antibodies of anti-TLR9 polyclonal (Invitrogen) and anti-NeuN monoclonal (Millipore) antibodies at 1:50 dilution in dilution buffer (2% normal goat serum, 1% BSA, 0.1% Triton X-100) overnight at 4 °C. Samples were subsequently incubated with FITC- and/or Cy3-conjugated species-specific secondary antibody/antibodies in the dilution buffer (1:200 dilution) for 1 hour at RT. VECTASHIELD Mounting Medium with DAPI (Vector Laboratories) was used to mount the fluorescently labeled samples and to stain cell nuclei. Images were digitally acquired using a fluorescence microscope (Nikon Eclipse 660) equipped with Spot cooled CCD camera (Diagnostic Instruments).