Meet the scientists!

I am especially interested in how we recognize places, how we find our way about in the world and why we sometimes get lost. Some of the parts of the brain most critical for wayfinding are also important for forming new memories. These areas begin to malfunction in the early stages of Alzheimer’s Disease, and as you might expect, patients have problems with memory and sometimes get lost in familiar places. By understanding how the system works we may be able to contribute to the development of new methods for the diagnosis and treatment of this illness which currently affects over 700,000 people in the UK.

But how can we look inside the brain to find out what is going on? This was once very difficult, and scientists had to rely on studying the effects of brain injuries and careful experiments with patients undergoing brain surgery and with animals. But new imaging technologies developed over the last 30 years have made it possible to measure aspects of brain function in healthy people.

One of the most useful techniques I use is magnetic resonance imaging (MRI). An MRI scanner uses a strong and precisely-controlled magnetic field, together with radio waves, to create a detailed 3D image of the brain, illustrated here with a slice through a scan of my own head. If you want to see a slightly more gruesome 3D version, with my head “cut open” click here.

MRI scans are very useful in themselves (e.g., doctors use them to diagnose and treat disease and brain injury), but functional MRI (fMRI) takes MRI to another level. It is a way of tuning the scanner to be sensitive to small changes in blood flow that occur when brain cells send signals to one another. The information can be gathered very quickly: a new image of the whole brain can be made every 2-3 seconds. The person inside the scanner has to keep very still, but they can do complex tasks (using a computer display and buttons for example). By comparing activity we see during different, carefully-designed tasks we can figure out how each part of the brain contributes to each one. For example, I used a modified video game (Quake 2 – see the picture below) to compare brain activity seen when people were finding their way around a virtual town with activity when they followed a fixed, familiar route – although on the surface these tasks are very similar, they seem to rely on different brain systems. The example here shows areas (in yellow) that are more active in more accurate navigators when finding new direct routes.

I also use computers to create models of brain function – these are programs that mimic the signalling of neurons and the connections between them (usually in a massively simplified way). We use models to make predictions that we can test and compare in experiments. They help us understand how the real brain might work, for example, how it could learn, store and represent different kinds of information.

New techniques like fMRI allow us to investigate the workings of the human brain in a way that was scarcely imaginable 30 years ago, but in my view we are only at the very beginning of an exciting journey of discovery. We already know that different parts of the brain do different things. We know in some detail what some of those things are, and we know something about the way that brain cells connect together and encode different types of information. The way the different functions are laid out doesn’t seem to be random – nearby parts do similar things. Perhaps there are some simple rules or principles that explain the layout. I’ve always been interested in how the brain is organized, and in the future I hope to do more work looking at how these patterns can be described and explained, and how they emerge.

The brain is sometimes described as the most complex object in the known universe, and it certainly seems very complex indeed now. But perhaps when we understand it better, it will seem simpler.

Actually, my working days are very varied. Each day I do some of the following: scanning people’s brains, looking at brain scans and analyzing brain imaging data; devising new things for people to do in the scanner; programming computer models of brain function and running simulations; supervising PhD and Masters students, and helping them plan new experiments and make sense of their results; thinking through new experiments with colleagues and collaborators; reading and writing scientific papers, reviewing other scientists’ work and applying for money to support further research; giving presentations, lectures and seminars to students and other researchers; attending presentations by other scientists; marking students’ work and writing references for them; university administration, for example, deciding which applicants can join our MSc course.

This would be an opportunity for a school science club or class (maybe even your class) to spend the day at the University of York, learning about neuroimaging and planning an experiment. It would culminate in a chance to scan the teacher as she or he does the task they’ve designed. In order to make this happen we’d have to get ethical approval, which is needed for all experiments involving human participants to ensure no-one is harmed or upset. Normally this is only given once the experiment is finalized so it might not be possible to design and run the experiment on the same day, but maybe some of the planning could be done in advance. And of course, we couldn’t force the teacher to be scanned, so I would volunteer to be a substitute if they were unwilling or unable to be scanned. In any event, we’d analyze the data, and send pictures back to the school. I am not sure how far £500 would go, but perhaps we could afford to video the day, interviewing the students (they will probably be able to explain things in a more down to earth way than us) and then put the result on YouTube. I this would be a great way to help young people from around the world learn about fMRI.