To be able to track each listener's brain activity on a millisecond basis, Henry and Obleser record-ed the electroencephalographic signal from listeners' scalps. First, the authors demonstrated that every listener's brain was "dragged along" (this is what entrainment, a French word, literally means) by the slow cyclic changes in melody; listeners' neural activity waxed and waned. Second, the listeners' ability to discover the fleeting gaps hidden in the melodic changes was by no means constant over time. Instead, it also "oscillated" and was governed by the brain's waxing and wan-ing. The researchers could predict from a listener's slow brain wave whether or not an upcoming gap would be detected or would slip under the radar.
Why is that? "The slow waxings and wanings of brain activity are called neural oscillations. They regulate our ability to process incoming information", Molly Henry explains. Jonas Obleser adds that "from these findings, an important conclusion emerges: All acoustic fluctuations we encoun-ter appear to shape our brain's activity. Apparently, our brain uses these rhythmic fluctuations to be prepared best for processing important upcoming information".
The researchers hope to be able to use the brain's coupling to its acoustic environment as a new measure to study the problems of listeners with hearing loss or people who stutter.
|Contact: Molly Henry|