March 2014

Dr Chris Martin has renewed his Royal Society University Research Fellowship for a further three years of funding (£341K), until October 2017.

Lay summary

How does the brain work to allow us to think, feel and act? What goes wrong in diseases of the brain and how can we develop better treatments for these diseases? A big problem in trying to answer these questions is that unlike a complicated piece of machinery, it is not possible for us to look inside the brain to inspect the mechanisms and parts, or to watch it ‘in action’. Or is it? One of the most exciting advances in the study of the brain over the last few decades is the development of brain imaging methods that allow us to capture images of the human brain ‘at work’. This is called functional brain imaging. Not only could this technology really improve our understanding of how the brain works, it also promises major insights into diseases and new treatments. Already functional brain imaging experiments are producing enough new information about the brain to fill several thousand scientific publications per year, and hardly a week goes by without the results of an interesting brain imaging study making the news. This is a really exciting area of science to work in right now, as it seems likely that what we can currently achieve with these tools is merely the tip of the iceberg. However, before we can achieve the full potential of functional brain imaging methods, it is vital that we have a much better understanding of where the signals that are used to create these images come from. This is the aim of my research. The signals that are measured in functional brain imaging are not based on the activity of brain cells (neurons) directly, but are actually caused by changes in the flow of blood to these neurons and their usage of oxygen. When a particular part of the brain becomes active, its cells require more blood to provide the extra nutrients (oxygen and glucose) that are used up by the extra workload. This is exactly the same as if, for example, you suddenly started to exercise a muscle in your arm. So brain imaging signals are actually indicators of changes in the blood and not changes in the activity of neurons. Because of this, if we don’t know the relationship between the blood changes and the neuronal activity changes, then we won’t know how to properly interpret brain imaging signals. After all, it is the neurons and not the blood that do the ‘work’ of the brain and so it is the activity of these that we really want to know about. The best way to find out about the relationship between the blood and neuronal activity changes is to conduct experiments where both the imaging signals (which come from blood), and the actual neuronal activity are measured simultaneously. Because measuring neuronal activity means having to get access to and record from the brain directly, these kinds of experiments can only be done in animals. There are quite a number of scientists and research groups working on this problem now, and a lot of progress has already been made. However, there are still many questions that need to be addressed, for example, how do diseases of the brain affect the relationships between blood and neuronal activity changes? How do drugs which alter brain chemistry affect brain imaging signals? My research will provide answers to such questions. In summary, brain imaging tools provide us with a remarkable window through which we can view the brain in action. My research will help us to understand what we see through this window, and make the most of these tools and the information that they could give us in future years.