Quian Quiroga also found that a lone neuron in one subject responded selectively to various pictures of the actress Halle Berry - as well as drawings of her and her name written down. Other cells were found to respond to images of characters in The Simpsons or members of The Beatles.

The team thinks that these brain cells probably respond to a range of different items, but that this limited study didn't include all the various pictures that might make a particular cell light up.

Despite appearing to find a 'Halle Berry cell', notes Martin Tovee, a neuroscientist at the University of Newcastle upon Tyne, UK, who has conducted similar research in monkeys, "nobody's saying that it's a grandmother cell". Nevertheless, the researchers say the results hint that we might use fewer brain cells to recognize familiar objects than previously thought.