title: Reduced gray matter volume of pars opercularis is associated with impaired social communication in high-functioning autism spectrum disorders.
abstract: BACKGROUND
  Recent literature suggests that the inferior frontal gyrus, especially its posterior portion, has an important role in imitation and social reciprocity and in the pathophysiology of their disturbance in autism spectrum disorders (ASD). However, the structural abnormality of this region has not fully been clarified in subjects with ASD.
  
  
  METHODS
  Here we obtained magnetic resonance images from 13 right-handed men with high-functioning ASD (Asperger disorder [n = 10] or autism [n = 3]) and from 11 age-, parental socioeconomic background-, and intelligence quotient-matched right-handed typical men. A reliable manual tracing methodology was employed to measure the gray matter volume of the pars opercularis, corresponding to Brodmann area 44, and the pars triangularis, corresponding to Brodmann area 45.
  
  
  RESULTS
  A significant gray matter volume reduction of both the pars opercularis and triangularis was found bilaterally in the subjects with ASD compared with the typical control subjects. The effect size seemed to be larger for pars opercularis (1.25) than for pars triangularis (.90). The reduced volume of right as well as total pars opercularis showed a significant association with the increased severity of social communication problems in the ASD group.
  
  
  CONCLUSIONS
  The current findings support an important role of pars opercularis, a center of the mirror neuron system, in the pathophysiology of ASD.
authors.affiliation: Department of Neuropsychiatry, University of Tokyo, Japan.
authors.forename: Syudo
authors.initials: S
authors.lastname: Yamasaki
authors.forename: Hidenori
authors.initials: H
authors.lastname: Yamasue
authors.forename: Osamu
authors.initials: O
authors.lastname: Abe
authors.forename: Motomu
authors.initials: M
authors.lastname: Suga
authors.forename: Haruyasu
authors.initials: H
authors.lastname: Yamada
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Inoue
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kuwabara
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kawakubo
authors.forename: Noriaki
authors.initials: N
authors.lastname: Yahata
authors.forename: Shigeki
authors.initials: S
authors.lastname: Aoki
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Kano
authors.forename: Nobumasa
authors.initials: N
authors.lastname: Kato
authors.forename: Kiyoto
authors.initials: K
authors.lastname: Kasai
mesh_terms: D000293:Adolescent; D000328:Adult; D001284:Atrophy / Q000523:psychology; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000150:complications / Q000473:pathology* / Q000523:psychology*; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D036421:Nerve Fibers, Unmyelinated / Q000473:pathology*; D011859:Radiography; D012920:Social Behavior Disorders / Q000150:complications / Q000473:pathology*