A whole range of different perceptions can remind us of the same concept. The smell of newly-cut grass, the sound of an ice-cream van and the sight of sunshine can, for instance, all remind us of summer. Researchers from the University of Leicester, the University of California, Los Angeles and the California Institute of Technology looked into the processing of visual and auditory stimuli relating to three well-known people - Oprah Winfrey, Luke Skywalker and the footballer Diego Maradona. They found that whatever the nature of the stimulus - pictures, the name being spoken out loud or the written name itself - the auditory and visual pathways used to process them all converged to fire the same, single neuron in a part of the brain called the hippocampus; a neuron, which, in effect, carried the brain's conception of the celebrity. One of the researchers carrying out the study even found his picture and name led to a single neuron despite the fact that the participants had only met him a few days previously. Which just goes to show, you don't have to be a celebrity to get your own brain cell.