neocortex vs pallium

neocortex

noun
  • The top layer of the cerebral hemispheres in the brain of mammals; part of the cerebral cortex. 

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 neocortex and pallium occurred in a corpus of books? (source: Google Ngram Viewer )