When we are engaged in a task, our brain's auditory system changes how it works. One of the main auditory centers of the brain, auditory cortex, is filled with neural activity that is not sound driven – rather, this activity times the task, each neuron ticking at a different moment during task performance.
Researchers at Hebrew University have discovered how this happens. The study, led by Prof. Israel Nelken from the Edmond and Lily Safra Center for Brain Sciences (ELSC) and the Institute of Life Sciences, is based on the PhD research of Ana Polterovich, with contributions from Alex Kazakov, Maciej M. Jankowski, and Johannes Niediek.
They found that when we are engaged in the task, neurons in the brain's auditory cortex show large bursts of activity that aren't caused directly by sounds. Instead, these 'ticks' are tied to specific moments in a task, suggesting that the auditory cortex is deeply in synch with behavior.
In consequence, instead of responding strongly to every sound, the brain produces smaller but more distinctive responses to sounds that guide task performance.
"Our results show that the brain doesn't just react to sounds—it shapes how they're represented, depending on what we're doing," said Prof. Nelken. "When we're engaged in a task, the auditory cortex listens more efficiently to the sounds that occur in that task."
What's New
Until now, scientists knew that attention improves how we perceive sounds—but how the brain achieves this was unclear. This study reveals that the brain doesn't simply boost its response to sounds; it uses the timing and demands of behavior in order to get ready for the incoming sounds. In other words, the auditory system tunes itself in real time.
Why It Matters
This discovery changes our understanding of how attention works in the brain. Instead of acting like a simple volume knob that turns up important sounds, attention acts more like an adaptive filter, reshaping how neurons communicate and improving their efficiency.
Computer modelling by the team showed how this happens: the timing activity that occurs during task engagement temporarily damps certain neural connections, creating clearer, more informative patterns of activity during sound presentations.
By uncovering this mechanism, the team provides new insight into one of neuroscience's big questions: how our brains make sense of an overwhelming world of sensations.
