PROFESSOR DECLAN MURPHY, INSTITUTE OF PSYCHIATRY, LONDON
Brain anatomy of autism: a multi-centre study
There is increasing evidence that people with Autism spectrum disorder (ASD) have abnormalities in the way that some brain regions develop - and this may underpin some of the clinical symptoms typically expressed in people with the disorder. The cause of the differences in brain development is unknown - but it is most likely a combination of genetic and environmental factors. However, in people with ASD it is unknown how brain abnormalities are related to genes and/or the environment. Twin studies are a powerful approach for examining the genetic and environmental contribution(s) to brain differences. There has been only one prior twin study of brain anatomy in a group of people with ASD; and this reported preliminary evidence for ‘genetic’ effects on some brain differences, but ‘environmental’ effects on others. In addition there is a single case report. These were a valuable first steps. However brain scientists are increasingly aware that it is not just how big, or small, particular brain regions are that is crucial. Equally important is how brain regions are 'connected up' to each other. Nevertheless, nobody has examined how brain ‘connectivity’ is affected in twins (i.e. what causes brain regions to be ‘wired up’ differently in people with autism).
It has recently become possible to examine ‘connectivity’ using a technique called diffusion tensor magnetic resonance imaging (DT-MRI). This does not use any ionizing radiation, or injections. Thus our aim is to investigate the genetic and environmental determinants of brain anatomy and ‘connectivity’ in twins with and without ASD. We will use both conventional structural MRI and newer DT-MRI approaches to examine specific neural systems implicated in the disorder (e.g. language systems). The sample will be recruited from our large UK twin registers, and will bring together experts in autism, genetics, psychology, brain imaging, and behaviour. We anticipate that if our efforts are successful we will be able to initiate large-scale international twin studies using brain imaging. This study will help us understand more about the cause(s) of autism.