Exeter MR Research Centre
DTI and Tractography
Collaborators
Hemispheric connectivity in the aged brain
To better understand change to interhemispheric interaction and cerebral laterality with age we are investigating the relationship between age-related change to brain microstructural connectivity, functional lateralization, and cognitive performance. The central aim of this research is to determine whether individual differences in age-related cognitive decline are reflected in functional reorganization in the brain, and whether these changes are mediated by the degree of structural preservation. This project will help us better understand why some people experience greater cognitive decline with age than do others.
To extend our studies of how the two cerebral hemispheres contribute to higher cognition we are running a combined fMRI and DTI investigation of reasoning in people with autism or Asperger syndrome. The reasoning task involves integrating information to reach a conclusion. This process draws upon widely-distributed brain networks, the connectivity of which may be disturbed in autism. Converging evidence from several brain-imaging techniques can tell us how these networks differ in the normal and the autistic brain.
References
Roser M.E, Corballis M.C, Jansari A, Fulford J, Benattayallah A, Adams W.M. Bilateral redundancy gain and callosal integrity in a man with callosal lipoma: a diffusion-tensor imaging study.. In Neurocase, 2011.
Brain connectivity in the presence of callosal lipoma
Curvilinear lipoma are congenital malformations that occur as a result of the persistence and maldifferentiation of the primitive meninges during embryonic development, and have been associated with callosal malformation ranging from hypogenesis to agenesis. We investigated hemispheric interaction in a man with a peri-splenial lipoma using diffusion-tensor imaging, comparison to his neurologically-normal identical twin, and comparison to a control group. Reduced structural connectivity through the posterior corpus callosum was associated with an abnormal pattern of interhemispheric interaction, highlighting the importance of this region, and suggesting that lipomas are associated with subtle abnormalities in brain and behaviour even when white matter appears grossly normal.
|
Relational integration in autism and Asperger syndrome
Drawing information together has been hypothesised to be be disrupted in autism and Asperger syndrome. In conjunction with autism support groups in Devon we are conducting a combined fMRI and DTI study of Relational Integration in adults with autism or Asperger syndrome. We have found that, contrary to expectations, individuals on the autistic spectrum performed very well on the task. Whether their brain activity differs from that seen in non-AS individuals is currently being investigated, as is the role of structural connectivity in modulating patterns of brain activation.
