Photomicrographs illustrating coronal sections through the macaque monkey cerebellum. (A) Nissl-stained section illustrating the three major layers of the cerebellum: the granule cell layer (GCL), the Purkinje cell layer (PCL) and the molecular layer (ML). The locations of several large Purkinje cells (asterisks) are shown. (B) Immunoreactivity resulting from exposure of adjacent section to plasma from a representative child with autism (age 4 years). Golgi neurons (black arrows) are clearly labeled and lie adjacent to or below the Purkinje cell layer. Ghost images of Purkinje cells are marked with asterisks. Lighter, though consistent, labeling of basket cells (white arrows) was also observed with this plasma. Only plasma from subjects that provided this level of staining of the Golgi cells in the cerebellum was used for analysis of other brain regions. Calibration bar, 100 μm.