What This Study Is About
Scientists wanted to find out if the brain uses the exact same "code" at the level of individual brain cells (neurons) when we actually see an object versus when we just imagine it. They also wanted to understand how this relates to aphantasia—the inability to visualize, or create mental imagery (the ability to picture things in your mind).
How They Studied It
Researchers studied a small group of epilepsy patients who already had tiny electrodes (sensors) implanted in their brains for medical reasons. This allowed scientists to listen to individual neurons in the brain's visual center while patients looked at real pictures and then tried to imagine those same pictures.
What They Found
They discovered that seeing and imagining are like using the same software on a computer. Amazingly, about 40% of the exact same neurons that fired when patients saw an object also fired when they just imagined it! The brain was literally "replaying" the visual code, suggesting that imagination is deeply visual, rather than just a language-like description in our heads.
What This Might Mean
For people with aphantasia, this suggests two exciting possibilities. Either their brains still "replay" these visual codes but another part of the brain fails to "read" the signal, or their brains format the visual code slightly differently, keeping it from reaching conscious awareness. However, because this was a very small study on patients with epilepsy, we can't be certain this applies to everyone, but it points us in an exciting new direction!
One Interesting Detail
The researchers used a deep AI neural network (a computer program modeled on the human brain) to decode the brain activity. The AI was so good at reading the neurons that it could actually reconstruct the exact object the person was looking at or imagining!