Which brain region is identified by the nervous tissue sample described as in the image?

• A. Cerebellum
• B. Brainstem
• C. Cerebral cortex
• D. Thalamus

Answer: (A)

Recognizing the brain region from tissue slides relies on distinctive cell patterns and organization. The cerebellum is easy to identify because its cortex has three layers arranged in a highly organized way and the surface shows leaf-like folds called folia. In the middle layer you’ll see Purkinje cells—a single, regular row of large, flask-shaped neurons whose bodies form a distinct boundary between the outer molecular layer and the inner granular layer. The molecular layer contains primarily dendrites and parallel fibers, while the granular layer is packed with many small neurons. This combination—a clear Purkinje cell layer sandwiched between two densely patterned layers and the characteristic folia—points to the cerebellum. Other regions lack this exact arrangement: the cerebral cortex has multiple layers with a variety of neuron types, the thalamus is composed of nuclei, and the brainstem contains mixed nuclei and tracts without the same three-layer cerebellar cortex pattern.