Regions of increased activation in the insula cortex of the brain in people with a family history of mood disorder (copyright Heather Whalley)
The centuries old desire to understand the relationship between brain and behaviour in human life has been dramatically realised by recent advances in brain imaging and by magnetic resonance imaging (MRI) in particular. MRI has already revolutionised research in psychiatry, psychology and neuroscience, and is now providing insights into social behaviour that is transforming our understanding of brain function.
MRI allows researchers to examine brain structure in exquisite detail, to provide in vivo demonstrations of the structural abnormalities underlying neurological conditions such as multiple sclerosis and stroke. As it does not use radiation, MRI can also be used to the monitor brain lesions over time, for example in response to treatment, even in children. MRI techniques also allow investigators to map out the complex connections between different brain regions. Another adaptation, to allow functional MRI studies (fMRI), is however how MRI has arguably made its greatest impact.
The discovery that oxy-and deoxygenated blood have different magnetic properties has enabled the use of MRI to examine brain function in living people. This has led to the mapping of feelings, thoughts and behaviours, and the ability to localise disruptions of brain function to particular regions and the connections between them. Schizophrenia, bipolar disorder and depression, which were once regarded as being outside the domain of scientific endeavour, are now regarded as being disorders of the brain and potentially amenable to the increasingly powerful tools of neuroscience.
My particular research interest is in the use of MRI to understand the mechanisms of psychiatric disorders, by studying people at high genetic risk. They are at high risk because they come from multiply affected families or are known to carry risk genes. In these studies, I have shown effects of risk genes on brain structure and function, and that these effects precede the development of illness. I have also been able to demonstrate changes in brain structure and function over time as people become unwell and that such changes could, in future, be used to guide early treatment and possibly prevention.
In contrast to schizophrenia and bipolar disorder, studies of depression have been fewer in number and less is known about the mechanisms underlying this very common and often disabling condition. In the next phase of my work, I will improve our understanding of depression using the ever improving spatial and biological resolution offered by MRI.
It is thanks therefore to MRI that we have a better understanding of brain morphology and function in the major mental illnesses. Advances in neuroimaging are now rapidly being combined with advances in other fields such as genetics. We are approaching the time when MRI will not only advance our understanding of the causes of illness – but will also help personalise our treatments and predictions to specific individuals.
Dr Heather Whalley is a Dorothy Hodgkin Fellow at the Division of Psychiatry, University of Edinburgh. Her work is on brain function in high risk bipolar disorder and schizophrenia.