title: White matter reduced streamline coherence in young men with autism and mental retardation.
abstract: OBJECTIVE
  It has been proposed that white matter alterations might play a role in autistic disorders; however, published data are mainly limited to high-functioning autism. The goal of this study was to apply diffusion tensor imaging (DTI) and fiber tractography (FT) to study white matter in low-functioning autism and the relationship between white matter and cognitive impairment.
  
  
  METHODS
  Ten low-functioning males with autism (mean age: 19.7 +/- 2.83 years) and 10 age-matched healthy males (mean age: 19.9 +/- 2.64 years) underwent DTI-MRI scanning. fractional anisotropy (FA) maps were analyzed with whole brain voxel-wise and tract-of-interest statistics. Using FT algorithms, white matter tracts connecting the orbitofrontal cortex (OFC) with other brain regions were identified and compared between the two groups. FA mean values of the autistic group were correlated with intelligence quotient (IQ) scores.
  
  
  RESULTS
  Low-functioning autistic subjects showed a reduced tract volume and lower mean FA values in the left OFC network compared with controls. In the autistic group, lower FA values were associated with lower IQ scores.
  
  
  CONCLUSIONS
  We showed evidence of OFC white matter network abnormalities in low-functioning autistic individuals. Our results point to a relationship between the severity of the intellectual impairment and the extent of white matter alterations.
authors.affiliation: Department of Neurosciences, Ophthalmology and Genetics, University of Genoa, Genoa, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Pardini
authors.forename: F G
authors.initials: FG
authors.lastname: Garaci
authors.forename: L
authors.initials: L
authors.lastname: Bonzano
authors.forename: L
authors.initials: L
authors.lastname: Roccatagliata
authors.forename: M G
authors.initials: MG
authors.lastname: Palmieri
authors.forename: E
authors.initials: E
authors.lastname: Pompili
authors.forename: F
authors.initials: F
authors.lastname: Coniglione
authors.forename: F
authors.initials: F
authors.lastname: Krueger
authors.forename: A
authors.initials: A
authors.lastname: Ludovici
authors.forename: R
authors.initials: R
authors.lastname: Floris
authors.forename: F
authors.initials: F
authors.lastname: Benassi
authors.forename: L
authors.initials: L
authors.lastname: Emberti Gialloreti
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D016880:Anisotropy; D001321:Autistic Disorder / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping; D056324:Diffusion Tensor Imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008607:Intellectual Disability / Q000473:pathology*; D007361:Intelligence Tests; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D009434:Neural Pathways / Q000473:pathology; D009483:Neuropsychological Tests; D018709:Statistics, Nonparametric