What is a picture worth?

Natural History, Sept, 2004

The average human brain has 100 billion neurons, and, contrary to myth, a person uses every one of them. But how many are needed at a given time for a simple task?

Ifat Levy, a neuroscientist at the Hebrew University of Jerusalem, and her colleagues have calculated that when you see the image of a face or a house, at least a million neurons fire in the area of your brain responsible for object recognition, and between 30 million and 400 million fire in the visual cortex as a whole. So, as the investigators titled their article, "One picture is worth at least a million neurons." (Current Biology 14:996 1001, June 8, 2004)