University of Oxford researchers have been using a technique called Resting-state fMRI to detect similarities among people with a common brain condition. In a paper published in the Proceedings of the National Academy of Sciences, the scientists had people undergo fMRI scanning while doing nothing at all. This provided a baseline reading which can be correlated with readings of others:
The group at FMRIB [Centre for Functional Magnetic Resonance Imaging of the Brain], led by Dr Clare Mackay and Steve Smith, has already shown the value of the technique. Last year they found differences in young people’s brain activity using resting-state fMRI according to whether or not they had a gene variant that is linked to increased risk of Alzheimer’s. This difference in brain activity is decades before any symptoms of the disease would be apparent.
Clare said at the time: ‘We have shown that brain activity is different in people with this version of the gene decades before any memory problems might develop. We’ve also shown that this form of fMRI, where people just lie in the scanner doing nothing, is sensitive enough to pick up these changes. These are exciting first steps towards a tantalising prospect: a simple test that will be able to distinguish who will go on to develop Alzheimer’s.’
As well as the potential clinical relevance of this form of brain scanning, the hope is that resting-state fMRI could connect differences in people’s brain activity with factors like age, sex, genes, behaviour, or disease progression.
Another great advantage of resting-state fMRI is that everyone will be conducting their experiments in the same way. This means that data can be combined from groups all over the world to map out the functioning networks in the brain – essentially giving the complete wiring diagram of the brain.
This is what the new paper by the international collaboration set out in PNAS this week. They show how it is possible to combine data from over 1000 volunteers collected at 35 different centres across the world (including Oxford). With all the data, they show they find the same patterns of networks functioning in the brain and are able to begin to see differences between different groups of people by age and by sex.
The PNAS paper compares this approach to genomics. Indeed, the maps produced of connections in the brain are being called the ‘connectome’ in the same way that the genome is the map of all our genes.
Steve Smith does see the analogy with genomics, suggesting that mapping out the connections which determine how our brains work is similar in concept to decoding our genes to discover how our body works. And there is also the similarity in approach – big international consortiums gathering data to pinpoint variation between people to gain more understanding about disease.