A formalin‐perfusion fixation method for histophysiological study of the central nervous system with the electron microscope

Abstract

A study of the water changes of the tissue after fixation, and components of the washing and fixing solutions are adjusted to leave unchanged the normal water content of the brain. The effect of the washing solution on the brain waves was followed by electroencephalographic recordings. It was shown that they persisted for much longer periods (6 to 14 minutes) than the washing time (40 to 60 seconds). After fixation, the areas selected for further study under the electron microscope are immersed in osmium tetroxide and uranyl acetate. After being embedded in Epon, the sections were stained with lead acetate. A few low-power illustrations of the excellent preservation achieved in different areas of the brain are shown. The problems encountered in the proper fixation of the central nervous system are discussed. This method has the advantage of using a cheap, innocuous fixative and a very simple modus operandi. It seems most appropriate for a systematic study of different, fine neuron-anatomical regions and for carrying out certain histophysiological studies in the central nervous system.