Doctor Ellen Lebienluft explains how brain imaging data is being combined with genetic research to understand how bipolar disorder affects brain function.

One of the things that we know about bipolar disorder is that it runs in families or in other words that it’s heritable. In fact, among psychiatric illnesses it’s one of the more heritable illnesses that we study. If a child has a parent who has bipolar disorder, that child is about 9-times more likely to develop the illness than is a child who does not have a parent with bipolar disorder. But there’s a very important thing to remember about that. If the rate of bipolar disorder in the community is about 3% and that child who has a parent with bipolar disorder is 9 times more likely to develop the illness, that gives that child about a 30% chance of having the illness. In other words, most children who have a parent with bipolar disorder will not develop the illness. We need to understand what the genetics underlying bipolar disorder are. We also need to understand who with a family history of bipolar disorder develops the illness and who doesn’t. That means that it’s very important for us to study these children at risk. Now, we’re studying them in many different ways. One of the ways we study children with bipolar disorder and adults with bipolar disorder is using brain imaging. In particular we want to try and understand what parts of the brain work differently when for example there’s an emotional stimulus like a face that has an emotion on it, or when the person gets rewarded or punished while playing a game. These are so called emotional stimuli and since bipolar disorder is an illness of emotion, we want to understand how the brain of someone with bipolar disorder processes these stimuli differently than does the brain of somebody without bipolar disorder. We and a number of other labs use functional MRI to do those kinds of studies. We are currently doing those kinds of studies in children who have parents who have bipolar disorder or who have siblings with bipolar disorder. In fact, we don’t have the brain imaging data just yet but we do know that children with bipolar disorder have difficulty identifying faces properly. They can’t label face emotion properly. In fact we’ve now found that children at risk for bipolar disorder who don’t have the illness, who don’t have any psychiatric illness, they also have this problem labeling face emotion. We’re now imaging their brains to see what's happening with the amygdala and the prefrontal cortex and other parts of the brain that we know are involved in processing emotional faces. How can we put that together with the genes? Well what we can do is what’s called imaging genetics, which is to look at amygdala functions; so you might have a child who has bipolar disorder or an adult with bipolar disorder or a child at risk for bipolar disorder, you’d have them in the scanner, you’d have them looking at an emotional face and trying to label it. So we could see 'well what part of the brain is the amygdala working differently in these people' and let’s say you had a child at risk or two children at risk, and one had abnormal amygdala activation and the other didn’t. Well, is it related to what genes they have? So in that way you can put together what their genotype is, what their actual genetic architecture is of that individual, put it together with what’s happening with that individual's amygdala. Over time [we can] get some idea of [how this]can this help us identify who is at risk? Now it’s very, very important to say that these are very early days with this kind of research. We cannot yet use brain imaging to diagnose bipolar disorder in people having symptoms, much less use imaging or genetics to identify who is going to develop the illness. This is still a number of years away and that's very, very important to emphasize, but it is something that research groups are working towards so that ultimately we can be making these diagnosis based not just on symptoms but on what’s happening with brain function.

imaging, neuroimaging, gene, brain, bipolar, disorder, family, heredity, emotion, genetics, ellen, lebienluft