Betz cells are the largest cells in the nervous system by cell body size. These giant pyramidal neurons reside in the fifth layer of the motor cortex.
Understanding Brain Cell Size
While the number of neurons in the brain is vast (estimated at 86±8 billion in the human brain, with a similar number of non-neuronal cells), size isn't the only factor determining a cell's function. Numerous studies, like the creation of the largest ever atlas of human brain cells revealing over 3,000 cell types (https://www.nature.com/articles/d41586-023-03192-2), focus on cellular diversity and function rather than just size. Even though dogs have more cortical neurons than many larger brained animals (https://www.frontiersin.org/journals/neuroanatomy/articles/10.3389/fnana.2017.00118/full), Betz cells maintain their title as the largest by cell body size. It is important to note that "giant cell tumors," while named for their large cells, are not brain cells but rather rare bone tumors (https://www.hopkinsmedicine.org/health/conditions-and-diseases/brain-tumor/brain-tumor-types).
- Key Point: The largest brain cell by cell body size is the Betz cell. This doesn't negate the importance or size of other brain cells, which contribute significantly to brain function. Current research highlights the vast diversity and complexity of the human brain's cellular composition.
