Scientists have long wondered whether the brain contains ''grandmother'' cells -- one or a few neurons that fire in response to the familiar face of your grandmother. A new study suggests that the answer may be yes.
And it is not just Grandma.
If you are a Halle Berry fan, you have a Halle Berry cell or two in your brain. Not a region, but a single cell or a small handful that fire in response to her face in various angles and poses, her body in a cat suit, the string of letters in her name and other distinct features of the actress who plays Cat Woman.
Dr. Christof Koch, a neuroscientist at the California Institute of Technology who helped conduct the study, said some neuroscientists had long argued for specialized neurons.
Others have said the brain does not have enough neurons to be that specialized, Dr. Koch said.
They contend that large groups of neurons, say as many as a million, fire with different patterns for different perceptions -- one for Barbara Bush, another for your own grandmother and another for an elderly woman in the grocery store.
Dr. Koch and colleagues implanted electrodes in the brains of people being assessed for epilepsy surgery, who were then shown the images of their favorite people or places.
For one man, the same neuron or neurons fired whenever he was shown Ms. Berry. A woman had a cell that fired in response to the Sydney Opera House.
It is too soon to conclude that one neuron is dedicated to one object, Dr. Koch said, but the findings do lend strong support to the idea of specialized neurons.
The results of the study were published last month in the journal Nature.