Your brain might not be as ’old’ as you think

Our standard way of measuring brain activity could be giving us a misleading picture of how our brains age, argues Dr Kamen Tsvetanov from the Department of Psychology. We're an ageing society, with more and more people living into old age, so it's crucial that we understand how age affects how the brain functions - Kamen Tsvetanov How 'old' is your brain? Put another way, how 'aged' is your brain? The standard, scientific answer, suggests that the older you get, the greater the changes in the activity of your neurons. In fact, my colleagues and I have found out that this isn't necessarily the case: older brains may be more similar to younger brains than we'd previously thought. In our study, published recently in the journal Human Brain Mapping, we've shown that changes in the ageing brain previously observed using functional magnetic resonance imaging (fMRI) - one of the standard ways of measuring brain activity - may be due to changes in our blood vessels, rather than changes in the activity of our nerve cells, our neurons. Given the large number of fMRI studies used to assess the ageing brain, this has important consequences for understanding how the brain changes with age and it challenges current theories of ageing. The fundamental problem of fMRI is that it measures the activity of our neurons indirectly through changes in regional blood flow. Without careful correction for age differences in how the blood vessels respond, differences in fMRI signals may be erroneously regarded as differences in our neurons.