cerebral cortex vs pallium

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. 

pallium

noun
  • The cerebral cortex. 

  • The mantle of a mollusc. 

  • A large cloak worn by Greek philosophers and teachers. 

  • A woolen liturgical vestment resembling a collar and worn over the chasuble in the Western Christian liturgical tradition, conferred on archbishops by the Pope, equivalent to the Eastern Christian omophorion. 

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