grey matter vs psyche

grey matter

noun
  • Brains; a person's ability to think. 

  • A collection of cell bodies and (usually) dendritic connections, in contrast to white matter. 

  • Literal brains as a general substance. 

psyche

noun
  • The human mind as the central force in thought, emotion, and behavior of an individual. 

  • The human soul, mind, or spirit. 

  • A small white butterfly, Leptosia nina, family Pieridae, of Asia and Australasia. 

verb
  • To put (someone) into a required psychological frame of mind. 

  • To treat (someone) using psychoanalysis. 

  • To intimidate (someone) emotionally using psychology. 

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