Table 1.

Tissue preparation and processing methods for electron microscopic imaging

Steps	Long-term formalin fixed human brains	Fixed-frozen sectioned human brains
1	Postfixed with 4% paraformaldehyde +2.5% glutaraldehyde in 0.1M PB for 2 weeks at 4°C	Postfixed with 4% paraformaldehyde +2.5% glutaraldehyde in 0.1M PB for 14 hours at 4°C
2	Vibratome section at 80 μm, store in 0.1M PB	Washed and stored in 0.1M PB
3	Osmification in OsO4 0.1M PB for 20 min and washed in 0.1M PB
4	Dehydration in graded ethanol solutions and 100% acetone
5	1:1 acetone/Araldite for 1 hour at room temperature and in pure Araldite overnight at 4°C
6	Flat embedding on siliconized slides with Araldite
7	Polymeriztion at 60°C for 48 hours in oven
8	Dissection of white matter from embedded sections and glue to blank resin blocks
9	Thin sectioning at 70-80 nm and stain grids with uranyl acetate and lead citrate solutions
10	Examination of ultrathin sections on electron microscope, image processing and quantification