The anatomy of extended limbic pathways in Asperger syndrome: A preliminary diffusion tensor imaging tractography study
NeuroImage. 2009-08-01; 47(2): 427-434
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1. Neuroimage. 2009 Aug 15;47(2):427-34. doi: 10.1016/j.neuroimage.2009.05.014. Epub
2009 May 14.
The anatomy of extended limbic pathways in Asperger syndrome: a preliminary
diffusion tensor imaging tractography study.
Pugliese L(1), Catani M, Ameis S, Dell’Acqua F, Thiebaut de Schotten M, Murphy C,
Robertson D, Deeley Q, Daly E, Murphy DG.
(1)Section of Brain Maturation, Institute of Psychiatry, King’s College London,
London SE5 8AF, UK.
It has been suggested that people with autistic spectrum disorder (ASD) have
altered development (and connectivity) of limbic circuits. However, direct
evidence of anatomical differences specific to white matter pathways underlying
social behaviour and emotions in ASD is lacking. We used Diffusion Tensor Imaging
Tractography to compare, in vivo, the microstructural integrity and age-related
differences in the extended limbic pathways between subjects with Asperger
syndrome and healthy controls. Twenty-four males with Asperger syndrome (mean age
23+/-12 years, age range: 9-54 years) and 42 age-matched male controls (mean age
25+/-10 years, age range: 9-54 years) were studied. We quantified tract-specific
diffusivity measurements as indirect indexes of microstructural integrity (e.g.
fractional anisotropy, FA; mean diffusivity, MD) and tract volume (e.g. number of
streamlines) of the main limbic tracts. The dissected limbic pathways included
the inferior longitudinal fasciculus, inferior frontal occipital fasciculus,
uncinate, cingulum and fornix. There were no significant between-group
differences in FA and MD. However, compared to healthy controls, individuals with
Asperger syndrome had a significantly higher number of streamlines in the right
(p=.003) and left (p=.03) cingulum, and in the right (p=.03) and left (p=.04)
inferior longitudinal fasciculus. In contrast, people with Asperger syndrome had
a significantly lower number of streamlines in the right uncinate (p=.02). Within
each group there were significant age-related differences in MD and number of
streamlines, but not FA. However, the only significant age-related between-group
difference was in mean diffusivity of the left uncinate fasciculus (Z(obs)=2.05)
(p=.02). Our preliminary findings suggest that people with Asperger syndrome have
significant differences in the anatomy, and maturation, of some (but not all)
PMID: 19446642 [Indexed for MEDLINE]