Can't count sheep or picture the faces of loved ones? You may have APHANTASIA: Condition describes people who don't have a 'mind's eye'
Visualisation is created in a network of regions across the brain
These include the frontal and parietal lobes, which 'organise' the process, and the temporal and occipital lobes that represent so-called 'mind's eye'
An inability to visualise may result from faults across this network
Concept was first identified in 1880 but is a little-understood condition