tokens: Nine animals served as control animals , whereas 20 animals received a focal arachnoid scar at C1-C2 , which was produced by placement of a kaolin soaked fibrin sponge on the posterior surface of the spinal cord .
folded_tokens: nine animal serve as control animal , whereas 20 animal receive a focal arachnoid scar at c1-c2 , which be produce by placement of a kaolin soak fibrin sponge on the posterior surface of the spinal cord .