Laid flat, the cortex would cover roughly:

1. The figure shows how much folding hides. 2. It is a surprisingly large area. 3. If the gray matter of the cortex were laid out flat, its surface area would be roughly one square meter. 4. So the answer is one square metre. _Source: OpenStax 'Anatomy and Physiology 2e', Ch 13 'Anatomy of the Nervous System'_