One Face, One Neuron; October 2005; Scientific American Magazine; by Diane Martindale; 2 Page(s)

When you spot a celebrity on a magazine cover, your brain recognizes the image in an instant--an effect that seems to occur because of a single neuron. A recent study indicates that our brains employ far fewer cells to interpret a given image than previously believed, and the findings could help neuroscientists determine how memories are formed and stored.

Exactly how the human brain works to record and remember an image is the subject of much debate and speculation. In previous decades, two extreme views have emerged. One says that millions of neurons work in concert, piecing together various bits of information into one coherent picture, whereas the other states that the brain contains a separate neuron to recognize each individual object and person. In the 1960s neurobiologist Jerome Lettvin named the latter idea the "grandmother cell" theory, meaning that the brain has a neuron devoted just for recognizing each family member. Lose that neuron, and you no longer recognize grandma.