A mechanism that the brain uses to filter out distracting thoughts to focus on a single bit of information has been discovered by researchers at the Kavli Institute for Systems Neuroscience and Centre for the Biology of Memory at the Norwegian University of Science and Technology.

They found that the hippocampus selectively tunes in to different frequencies of gamma waves coming from different brain areas. The lower gamma wave frequencies are used to transmit memories of past experiences, and the higher frequencies are used to convey what is happening where you are right now.

“The classical view has been that signaling inside the brain is hardwired, subject to changes caused by modification of connections between neurons,” says Edvard Moser, Kavli Institute for Systems Neuroscience director. “Our results suggest that the brain is a lot more flexible. Among the thousands of inputs to a given brain cell, the cell can choose to listen to some and ignore the rest and the selection of inputs is changing all the time. We believe that the gamma switch is a general principle of the brain, employed throughout the brain to enhance interregional communication.”