Cold Spring Harbor, NY When a pedestrian hears the screech of a car's brakes, she has to decide whether, and if so, how, to move in response. Is the action taking place blocks away, or 20 feet to the left?
One of the truly primal mechanisms that we depend on every day of our lives -- acting on the basis of information gathered by our sense of hearing -- is yielding its secrets to modern neuroscience. A team of researchers from Cold Spring Harbor Laboratory (CSHL) today publishes experimental results in the journal Nature which they describe as surprising. The results fill in a key piece of the puzzle about how mammals act on the basis of sound cues.
It's well known that sounds detected by the ears wind up in a part of the brain called the auditory cortex, where they are translated transduced into information that scientists call representations. These representations, in turn, form the informational basis upon which other parts of the brain can make decisions and issue commands for specific actions.
What scientists have not understood is what happens between the auditory cortex and portions of the brain that ultimately issue commands, say, for muscles to move in response to the sound of that car's screeching brakes. To find out, CSHL Professor Anthony Zador and Dr. Petr Znamenskiy trained rats to listen to sounds and to make decisions based on those sounds. When a high-frequency sound is played, the animals are rewarded if they move to the left. When the sound is low-pitched, the reward is given if the animal moves right.
To the striatum
On the simplest level, says Zador, "we know that sound is coming into the ear; and we know what's coming out in the end a decision," in the form of a muscle movement. The surprise, he says, is the destination of the information used by the animal to perform this task of discriminating between sounds of high and low frequency, as revealed in his team's expe
|Contact: Peter Tarr|
Cold Spring Harbor Laboratory