New York – Halle Berry? Jennifer Aniston? Everybody knows them. And now a surprising study finds that even individual cells in your brain act as if they recognize them.
The work could help shed light on how the brain stores information, an expert said.
When scientists sampled brain-cell activity in people who were scrutinizing dozens of pictures, they found some individual cells that reacted to a particular celebrity, landmark, animal or object.
In one case, a single cell was activated by different photos of Berry, including some in her “Catwoman” costume, a drawing of her and even the words “Halle Berry.”
The findings appear in a part of the brain that transforms what people perceive into what they’ll eventually remember, said Dr. Itzhak Fried of the University of California-Los Angeles, a senior investigator on the project.
The findings do not mean that a particular person or object is recognized and remembered by only one brain cell, Fried said.
“There is not only one cell that codes for Jennifer Aniston. That would be impossible,” Fried said.
Nor do they mean that a given brain cell will react to only one person or object, he said, because the study participants were tested with only a relatively limited number of pictures. In fact, some cells were found to respond to more than one person, or to a person and an object.
What the study does suggest, Fried and colleagues say in today’s issue of the journal Nature, is that the brain appears to use relatively few cells to record something it sees.
That’s in contrast to the idea that it uses a huge network of brain cells instead.
It’s surprising that an individual neuron would react so specifically to a given person, said the study’s other senior investigator, Christof Koch of the California Institute of Technology.
“It’s much more specific than people used to think,” Koch said.
Charles Connor, who studies how the brain processes visual information, called the results striking. He didn’t participate in the study.
Nobody would have predicted that conceptual information relating to Aniston, for example, would be signaled so clearly by single cells, said Connor, who works at Johns Hopkins University.
The “really dramatic finding,” he said, is that a single brain cell can respond so consistently to completely different pictures of a given person.
“That will surprise everybody,” Connor said.
The part of the brain the researchers studied draws heavily on memory as well as signals from what the eye sees, so the result may illustrate how memory is represented in the brain and how it relates to visual signals, he said.
He noted that in one participant, one brain cell responded both to Aniston and to Lisa Kudrow, her co-star on the TV hit “Friends.”
“That’s a tantalizing glimpse at how neurons represent concepts like membership in the cast of ‘Friends’ and could lead to much more extensive studies of how conceptual information is organized in human memory,” he said.
