Well clearly it means the "brain" (the cerebrum) contains less than the remaining 10% neurons https://www.cancer.gov/publications/dictionaries/cancer-terms/def/

Well clearly it means the "brain" (the cerebrum) contains less than the remaining 10% neurons https://www.cancer.gov/publications/dictionaries/cancer-terms/def/cerebrum https://www.cancer.gov/publications/dictionaries/cancer-term... Shared with the midbrain and spinal cord. Of course I am excluding PNS neurons