title: Fronto-thalamic volumetry markers of somatic delusions and hallucinations in schizophrenia.
abstract: Although the psychotic phenomena of schizophrenia have been extensively investigated, somatic delusions and hallucinations have seldom been reported and their mechanisms are substantially unexplored. Here, we aimed to identify the brain structural correlates of somatic psychotic phenomena using combined volumetry and diffusivity structural neuroimaging techniques. Seventy-five individuals with a DSM-IV-TR diagnosis of schizophrenia and 75 healthy controls (HC) underwent a comprehensive clinical assessment, a high-resolution T1-weighted magnetic resonance imaging and a diffusion tensor imaging protocol using a 3T MRI scanner. Voxel-based volumetry and mean diffusivity (MD) of gray matter (GM) and fractional anisotropy (FA) of white matter (WM) of the whole brain were calculated for each subject. Reduced left fronto-insular GM volume was found in patients with somatic delusions compared with patients without somatic delusions and HC. Increased GM volume was found in the bilateral thalami, primarily in the right ventral-anterior thalamic nucleus projecting to the prefrontal-temporal cortices and the bilateral pars triangularis of the inferior frontal lobe, of patients with somatic hallucinations and HC compared with patients without somatic hallucinations. No differences emerged in GM MD and in WM FA between patients with and without psychotic somatic phenomena (i.e. delusions or hallucinations). These findings provide the first evidence that a frontal-thalamic structural perturbation mediates somatic psychotic phenomena in schizophrenia.
authors.affiliation: IRCCS Santa Lucia Foundation, Neuropsychiatry laboratory, Department of Clinical and Behavioral Neurology, Via Ardeatina, 306-00179 Rome, Italy. g.spalletta@hsantalucia.it
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Spalletta
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Piras
authors.forename: Ivo
authors.initials: I
authors.lastname: Alex Rubino
authors.forename: Carlo
authors.initials: C
authors.lastname: Caltagirone
authors.forename: Sabrina
authors.initials: S
authors.lastname: Fagioli
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D016880:Anisotropy; D001931:Brain Mapping; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005625:Frontal Lobe / Q000473:pathology*; D006212:Hallucinations / Q000209:etiology / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology; D012559:Schizophrenia / Q000150:complications; D012563:Schizophrenia, Paranoid / Q000209:etiology / Q000473:pathology*; D013788:Thalamus / Q000473:pathology*