title: Brodmann area 12: an historical puzzle relevant to FTLD.
abstract: BACKGROUND
  Brodmann brain maps, assembled in 1909, are still in use, but understanding of their animal-human homology is uncertain. Furthermore, in 1909, Brodmann did not identify human area 12 (BA12), a location now important to understanding of frontotemporal lobar degeneration (FTLD).
  
  
  METHODS
  We re-examined Brodmann's areas, both animal and human, in his 1909 monograph and other literature, both historical and contemporary, and projected BA12 onto the medial surface of a fixed human brain to show its location.
  
  
  RESULTS
  We found Brodmann did identify human BA12 in later maps (1910 and 1914), but that his brain areas, contrary to his own aims as a comparative anatomist, are now used as physiologic loci in human brain.
  
  
  CONCLUSIONS
  Because of its current link with frontotemporal dementia, BA12's transition from animal (1909) to human (1910 and 1914) is not only an historical puzzle. It impacts how Brodmann's areas, based on comparative animal-human cytoarchitecture, are widely used in current research as functional loci in human brain.
authors.affiliation: Department of Neurology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8666, Japan. kawa@med.showa-u.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Kawamura
authors.forename: M W
authors.initials: MW
authors.lastname: Miller
authors.forename: H
authors.initials: H
authors.lastname: Ichikawa
authors.forename: K
authors.initials: K
authors.lastname: Ishihara
authors.forename: A
authors.initials: A
authors.lastname: Sugimoto
mesh_terms: D001931:Brain Mapping / Q000266:history*; D005625:Frontal Lobe / Q000503:physiopathology*; D057174:Frontotemporal Lobar Degeneration / Q000503:physiopathology*; D049673:History, 20th Century; D006801:Humans