This animation shows how a region of the brain called the cerebral cortex develops in a human fetus.

The cerebral cortex is an outer layer of the brain that plays a role in many processes, including memory, perception, and planning. As shown in the animation, most of the neurons in the cerebral cortex arise from neural stem cells that undergo repeated divisions. The cortical neurons are born near the ventricle and migrate upward toward the surface of the cortex. The neurons form multiple layers over time, with the newest neurons being added to the outermost parts of the cortex.

This animation is a clip from a 2013 Holiday Lecture Series, Medicine in the Genomic Era. Depending on students’ background, it may be helpful to pause the animation at various points to discuss different steps in the developmental process.