Researchers from Washington University in St Louis have been looking into the links between people's personality and how their brain changes as they age. They gave MRI scans to 79 people between the ages of 44 and 88 who also took personality tests. Neuroticism - a tendency to see events in a negative or fearful light - was associated with lower volumes of grey matter in the frontal and medial temporal brain regions, whereas conscientiousness was associated with higher volumes. The same effects held true for a part of the brain called the orbitofrontal cortex which is involved in social and emotional processing. There was no clear link between levels of extroversion and changes in brain volume. It was unclear whether people's personalities affected how their brains changed with age or whether it was the changes to people's brains that affected their temperament.