cerebral cortex vs cortex

cerebral cortex

noun
  • The grey, folded, outermost layer of the cerebrum that is responsible for higher brain processes such as sensation, voluntary muscle movement, thought, reasoning, and memory. 

cortex

noun
  • The outer layer of an internal organ or body structure, such as the kidney or the brain. 

  • The tissue of a stem or root that lies inward from the epidermis, but exterior to the vascular tissue. 

  • The outer surface of a piece of flint. 

How often have the words cerebral cortex and cortex occurred in a corpus of books? (source: Google Ngram Viewer )