Learning Objectives

Identify the characteristic triangular morphology of pyramidal neurons. Distinguish between neurons and the surrounding glial cells. Understand the composition of the neuropil background in H&E staining. Recognize the cellular architecture of the cerebral cortex at medium magnification.

Cellular Histology: The Cerebral Cortex

At medium magnification, the cerebral cortex reveals a complex network of signaling cells and support structures set against a dense background of cellular processes.

• Pyramidal Neurons: Easily identified by their triangular (pyramidal) shape. These are the primary excitatory neurons of the mammalian prefrontal cortex and the corticospinal tract.
• Glial Cells: Appear as scattered, small, dark nuclei. These include astrocytes (support), oligodendrocytes (myelination), and microglia (immune defense). They are significantly more numerous than neurons.
• Neuropil: The pink, fibrillar background seen in H&E sections. It consists of a dense network of unmyelinated axons, dendrites, and glial cell processes.
• Cellular Orientation: In the neocortex, the apex of the triangular pyramidal cells typically points toward the cortical surface (pial surface).

Histologic Identification Summary

Activity