MRI scans can reveal how a brain is ageingDennis Hallinan / Alamy Stock PhotoLately, my brain has felt decidedly ancient. Im only in my 40s, but last week I completely blanked on the date of my wedding anniversary, forgot the name of a friends son and couldnt seem to concentrate on any work.So when I was asked to write a column for New Scientist all about the brain, one question immediately came to mind: how old is mine? Years of research show that organs such as our heart, kidneys and ovaries dont all age