Ever have the experience of getting into a car, closing the door, and accidentally shutting the seatbelt in the door?
What's interesting about this is that most of the time, we immediately realize it's happened, reopen the door, and pull the belt out. It's barely even a conscious thought. The sound is wrong, and that registers instantly. We recognize when something "sounds off" about noises we're familiar with -- when latches don't seat properly, when the freezer door hasn't completely closed, even things like the difference between a batter's solid hit and a tip during a baseball game.
Turns out, scientists at New York University have just figured out that there's a brain structure that's devoted to that exact phenomenon.
A research team led by neuroscientist David Schneider trained mice to learn to associate a particular sound with pushing a lever for a treat. After learning the sound, it became as habituated in their brains as our own expectation of what the car door closing is supposed to sound like. If after that the tone was varied even a little, or the timing between the lever push and the sound was changed, a part of the mouse's brain began to fire rapidly.
The activated part of the brain is a cluster of neurons in the auditory cortex, but I think of it as the "What The Hell Just Happened?" module."We listen to the sounds our movements produce to determine whether or not we made a mistake," Schneider said. "This is most obvious for a musician or when speaking, but our brains are actually doing this all the time, such as when a golfer listens for the sound of her club making contact with the ball. Our brains are always registering whether a sound matches or deviates from expectations. In our study, we discovered that the brain is able to make precise predictions about when a sound is supposed to happen and what it should sound like... Because these were some of the same neurons that would have been active if the sound had actually been played, it was as if the brain was recalling a memory of the sound that it thought it was going to hear."