Sounds are often fleeting and gone in a moment. For a child to learn the sound of new word, an adult to identify a strange sound on an unlit street, or anyone to enjoy a piece of music, they must use short-term memory to freeze the ephemeral sound in mind.
How the brain does this was unclear, but it is addressed in an article just published in PNAS, “Stimulus-specific suppression preserves information inauditory short-term memory”. Using a new technique, we were able to see the patterns of activity within the brain of individual volunteers that corresponded to remembering a particular sound. It was found that a region in the brain that is known to process sounds during listening also plays a role in maintaining auditory information in short-term memory.
Annika Linke, the first author, explains, however that “How this region – auditory cortex – was recruited during listening and short-term memory differed. Memory performance was mainly affected by the distinctiveness of the brain’s activity patterns during listening. But while holding the sounds in memory, auditory cortex selectively switched off, probably to protect fragile representations from being overwritten.”
Revealing how memory works in the healthy brain will help us understand why some people’s memory is better than others, and guide work to help individuals whose ability to store information over brief time intervals is reduced, such as children suffering from dyslexia. The next time you replay a sound in your mind’s ear, spare a thought for the hard work of your auditory cortex.