The short version
- Mice trained to spot a mouse call inside a hiss did better the longer they had heard the hiss before the call arrived.
- They also did better when the frequency bands in the background moved together, giving the noise more structure.
- The study used 10 mice and tested only two kinds of background, so it says nothing yet about people.
Neuroscientists at the Donders Institute, Radboud University, trained 10 mice for four to six weeks to lick whenever a mouse call appeared inside a steady background hiss. The call arrived at a random moment in the first six seconds. While the mice listened, the team recorded from 64 sites in their primary auditory cortex. The study was published in PLOS Biology on November 12.
The longer the hiss had been playing before the call, the more often the mice caught it, and the cortex’s signal for the call sharpened over the same seconds while its picture of the background stayed the same. Mice also did better when the background’s frequency bands rose and fell together, a more structured kind of noise. “Mice showed improved performance and neural encoding if they could sample the statistics longer per trial,” the authors write. Switching on one class of inhibitory neurons with light helped in the less structured noise and hurt in the more structured one.
The authors list the limits: two kinds of background, a three-mouse group for one of the light experiments, and one brain area. It is a mechanism study in mice, not a hearing aid.
For the human side of the problem, see our piece on speech-in-noise hearing and the retina.
