This rather technical post is a response to a recent Observer article by Vaughan Bell. In it he follows up on a recent internet discussion around the validity or otherwise of fMRI methods. A blog post by StokesBlog responded. I must admit I hesitate to step into the fray. I think “flaws” in neuroimaging methods are sometimes overstated, but I don’t want people to think I am flawed, so perhaps I should keep my head down. Oh well, here goes…
In previous posts, I described the science behind the Four Mountains Test, a memory test which we developed using computer generated landscapes to assess the ability to recognize places from their layout even when the viewpoint changes. The test was designed from the outset to depend on a part of the brain, the hippocampus, which is important in forming new memories of the events we experience but also in maintaining a sense of direction and keeping track of where we are as we move about. We found that patients with damage to the hippocampus had particular difficulty with the test.
Think of the last time you attended a wedding. You can probably remember the room around you, the place where you sat, the other guests around you and so on. Forming this type of memory depends on the hippocampus, an ancient part of the brain that is buried deep in the temporal lobes, a few centimetres in from your ears. People with damage to the hippocampus are unable to form new long-lasting memories of events and it is also one of the first parts of the brain to be affected in Alzheimer’s Disease. Being able to test abilities that depend on a fully-functioning hippocampus could one day be useful in identifying more serious memory problems that might require further investigation and treatment.
How do we recognize places and why do we sometimes get lost? In everyday life we use many strategies to help us keep track of where we are and get quickly and directly to an intended destination. For example, we might look out for distinctive landmarks and signs, we might consult maps. People also talk about having a sense of direction, for example, you might be able to point accurately toward some distant location which you cannot see (think of a local shop for example), and you may be able to keep track of these locations as you move about. This is the first of three posts that look at the brain basis of such skills. Based on this understanding my colleagues and I developed a test to assess them. It is called the Four Mountains test and is featured in Channel 4′s Hidden Talent show (to be shown on Tuesday 15th May at 9pm). These posts give a flavour of the scientific background to the test.