Figure 2: (A–D) Brain stem horizontal sections of pyramidotomized rats, not treated with melanin (white arrow indicates the area of transection, the rectangle shows fibrous scar); (A–C) Picture of demyelination (arrow indicates focus of necrosis, asterisks show area where nerve fibers are not revealed); (D) A distal area of spinal cord where extreme swelling of motoneurons was revealed. Detection of Ca2+-dependent acid phosphatase activity.