Figure 1.

Pallidal lesions. A, A 40 μm histological section taken from a sagittal 300 μm slice obtained from an animal perfused transcardially with saline containing choline instead of Na⁺ (see Materials and Methods). Dots approximately depict the border between pallidum (right) and neostriatum (left). B, A similar section taken from an ibotenic acid-lesioned animal. Notice a marked reduction in cellular profiles in the right side (pallidum). The inset shows the approximate trajectory of the lesioning needle when using the coordinates described in Materials and Methods. Injections were placed as far as possible from the striatopallidal border to avoid diffusion of ibotenic acid into the neostriatum. Methylene blue was used to stain the injection site. Histological sections were processed for Nissl staining.