Reproducible and persistent weakness in adult rats after surgical resection of motor cortex: evaluation with limb placement test

Abstract

The purpose of this study was to develop a new rat model for surgical brain injury with motor weakness and to find an adequate behavior test for the application of the model. Thirty rats were divided into three groups: craniectomy (n = 10), durotomy (n = 10), and corticectomy (n = 10) groups. The coordinates of the three points from the bregma (coordinate A = +4,+1, B = -2,+1, and C = +4,+6). We evaluated right limb motor performance by the modified limb placement test and the cylinder test. Persistent motor weakness was observed for 2 months in the corticectomy group by the limb placement test, whereas the cylinder test could not detect the weakness. We established a reproducible and persistent rat brain injury model and found that the modified limb placement test is sensitive enough to evaluate residual subtle weakness in this model.