Brain Cell Repulsion is a mail art project begun by Ryosuke Cohen in June 1985.
He prints 150 copies (30 x 42 cm) with a small silkscreen system called a Cyclostyle (now out of production).
Each participant is mailed a Brain Cell print along with a documentation list of contributors worldwide.
Cohen also uses Brain Cell prints in the Fractal Portrait Project (another long running art series by Cohen) and as additions to Mail Art Add and Pass pages.
Cohen described the origin of the project's name in 1985: "Well, I'll title my work 'Brain Cell', because the structure of a brain through a microscope looks like the diagram of the Mail Art network.