Magnetic resonance imaging (MRI) is one of the best techniques for imaging the brain because it gives very high quality images, with excellent contrast between the different types of tissues.
Dr Richard Watts and his team at the University of Canterbury are studying what happens to the brain when it gets injured or diseased, and what happens in the brain when you carry out different tasks while in the MRI machine. This is called functional MRI.
Looking at brain injuries
Richard’s team are studying the brains of a group of boxers using MRI. They are comparing a group of professional boxers with a similar group who have never boxed. Boxers make good case studies because they get frequent blows (chronic shocks) to the head. Richard wants to know if there are any cumulative effects from all those knocks. They are looking to see if, over time, many blows may have some lasting changes on the brain.
Looking at the brain in action
Richard is also looking at the functions of different parts of the brain. Functional MRI can reveal which parts of the brain are active when someone is doing different activities. It involves having someone in an MRI machine alternate between performing tasks and resting.
An example of a task that is used in this work is the n-back test. The subject is shown a sequence of letters, and asked if the current letter matches the one presented ‘n’ letters ago. Matching the last-but-one letter (n=2) is quite difficult, and matching letters further back is even worse. This test shows which parts of the brain are involved in working memory and recall.
Images of the brain are taken throughout the time the person is in the machine. The differences in the images produced are identified as being due to performing the task. Richard and his team can then work out from these images which parts of the brain were involved in the task.
MRI has an important advantage over other techniques like X-ray – it is so much safer since it does not involve ionising radiation. This means it is possible to do studies of child development as children grow, and to follow disease as it progresses in a patient, as well as the effects of any treatments. In Christchurch, the researchers are particularly interested in using this technique to learn more about Parkinson's disease, depression, bipolar disorder and responses to facial expressions.
The results from these kinds of studies are providing new information on how a diseased brain and a healthy brain work and will lead to a much greater understanding of the human brain.
Brain scientist, Tracy Melzer from the New Zealand Brain Research Institute, hopes that magnetic resonance imaging (MRI) scans of blood flow in the brain will help pinpoint early changes of Parkinson's disease and dementia. Find out more in this Radio New Zealand interview.
Search for early signs of dementia with Parkinson's disease