title: Localized gray matter volume reductions in the pars triangularis of the inferior frontal gyrus in individuals at clinical high-risk for psychosis and first episode for schizophrenia.
abstract: Recent studies have suggested an important role for Broca's region and its right hemisphere counterpart in the pathophysiology of schizophrenia, owing to its roles in language and interpersonal information processing. Broca's region consists of the pars opercularis (PO) and the pars triangularis (PT). Neuroimaging studies have suggested that they have differential functional roles in healthy individuals and contribute differentially to the pathogenesis of schizophrenic symptoms. However, volume changes in these regions in subjects with ultra-high risk for psychosis (UHR) or first-episode schizophrenia (FES) have not been clarified. In the present 3 Tesla magnetic resonance imaging study, we separately measured the gray matter volumes of the PO and PT using a reliable manual-tracing volumetry in 80 participants (20 with UHR, 20 with FES, and 40 matched controls). The controls constituted two groups: the first group was matched for age, sex, parental socioeconomic background, and intelligence quotient to UHR (n=20); the second was matched for those to FES (n=20). Compared with matched controls, the volume of the bilateral PT, but not that of the PO, was significantly reduced in the subjects with UHR and FES. The reduced right PT volume, which showed the largest effect size among regions-of-interest in the both UHR and FES groups, correlated with the severity of the positive symptoms also in the both groups. These results suggest that localized gray matter volume reductions of the bilateral PT represent a vulnerability to schizophrenia in contrast to the PO volume, which was previously found to be reduced in patients with chronic schizophrenia. The right PT might preferentially contribute to the pathogenesis of psychotic symptoms.
authors.affiliation: Department of Neuropsychiatry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. iwashiro-tky@umin.ac.jp
authors.forename: Norichika
authors.initials: N
authors.lastname: Iwashiro
authors.forename: Motomu
authors.initials: M
authors.lastname: Suga
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Takano
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Inoue
authors.forename: Tatsunobu
authors.initials: T
authors.lastname: Natsubori
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Satomura
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Koike
authors.forename: Noriaki
authors.initials: N
authors.lastname: Yahata
authors.forename: Mizuho
authors.initials: M
authors.lastname: Murakami
authors.forename: Masaki
authors.initials: M
authors.lastname: Katsura
authors.forename: Wataru
authors.initials: W
authors.lastname: Gonoi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Sasaki
authors.forename: Hidemasa
authors.initials: H
authors.lastname: Takao
authors.forename: Osamu
authors.initials: O
authors.lastname: Abe
authors.forename: Kiyoto
authors.initials: K
authors.lastname: Kasai
authors.forename: Hidenori
authors.initials: H
authors.lastname: Yamasue
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000473:pathology*; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D011569:Psychiatric Status Rating Scales; D011618:Psychotic Disorders / Q000473:pathology* / Q000503:physiopathology; D012044:Regression Analysis; D012559:Schizophrenia / Q000473:pathology* / Q000503:physiopathology; D055815:Young Adult