Ultra-structural analysis of human post-mortem brain tissue is important for investigations into the pathomechanism of neuropsychiatric
disor
ders, especially those lacking alternative mo
dels of stu
dying human-specific morphological features. For example, Von Economo Neurons (VENs) mainly locate
d in the anterior cingulate cortex an
d in the anterior part of the insula, which seem to play a role in a variety of neuropsychiatric con
ditions, inclu
ding frontotemporal
dementia, autism an
d schizophrenia, can har
dly be stu
die
d in nonhuman animals. Accor
dingly, little is known about the ultra-structural alterations of these neurons, though important research using qualitative stereological metho
ds has reveale
d that protein expression of the VENs assigns them a role in immune function.
d="spar0010">Formaldehyde, which is the most common fixative in human pathology, interferes with the immunoreactivity of the tissue, possibly leading to unreliable results. Therefore, a method for ultra-structural investigations independent of antigenic properties of the fixated tissue is needed. Here, we propose an approach using electron microscopy to examine cytoskeletal structures, synapses and mitochondria in these cells. We also show that our methodology is able to keep tissue consumption to a minimum, while still allowing for the specimens to be handled with ease by using agar embedded slices in contrast to blocks for the embedding procedure. Accordingly, a stepwise protocol utilising 60 μm thick human post mortem brain sections for electron microscopic ultra-structural investigations is presented.
