title: Precentral knob corresponds to the primary motor and premotor area.
abstract: OBJECTIVE
  Cortical mapping during awake surgery assesses intraoperative neurological change in response to electrical stimulation to provide direct information regarding the anatomical localization of the primary motor area (M1). The goal of the present study was to analyze the reliability of the identification of the precentral knob in the axial image of magnetic resonance imaging or functional MRI (fMRI) for the detection of M1.
  
  
  METHODS
  Among patients with brain tumors within or near M1 in whom awake surgery was employed from April 2004 through March 2007, 14 cases were analyzed in which either the M1 or premotor area (PMA) was successfully detected by mapping during awake surgery.
  
  
  RESULTS
  The precentral knob was localized to the PMA in 4 cases and to M1 in 10 cases. By contrast, the gyrus activated by hand clenching in fMRI on the affected side at least partially corresponded to M1 in all cases, while those on the unaffected side corresponded to M1 in 12 of 12 cases.
  
  
  CONCLUSIONS
  These results indicate that the precentral knob corresponds to PMA as well as to M1, whereas the gyrus activated in fMRI corresponds to M1 on the affected and unaffected side.
authors.affiliation: Department of Neurosurgery, Komagome Metropolitan Hospital, Hon-Komagome, Bunkyo-ku, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Shinoura
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
authors.forename: R
authors.initials: R
authors.lastname: Yamada
authors.forename: Y
authors.initials: Y
authors.lastname: Tabei
authors.forename: K
authors.initials: K
authors.lastname: Saito
authors.forename: K
authors.initials: K
authors.lastname: Yagi
mesh_terms: D000368:Aged; D001931:Brain Mapping; D001932:Brain Neoplasms / Q000601:surgery; D005260:Female; D005625:Frontal Lobe / Q000033:anatomy & histology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged