Neuronal Modulations Between Hearing and Listening Revealed

It is intuitively clear to us that there is a difference between passive hearing and active listening. Attention and an animated state, but also movement, play a role in how sound processing in the brain adjusts accordingly. Neuroscientists at the University of Basel published in Cell Reports their findings that reveal precisely how the brain adjusts to this change.

For their study, the researchers examined the activity of neurons in four different areas in the brains of mice known to be involved in increasingly complex sound processing. During the experiment, the animals were either passively hearing the sounds played to them, or actively listening to them to receive a reward for detecting the sounds.

It was shown that the majority of neurons changed their activity when switching between hearing and listening. “But this doesn’t mean that all neurons behaved the same way,” explains co-lead researcher Gioia De Franceschi “We actually found ten distinct and specific types of activity change.”

While most of the neurons showed a change that was probably related to varying levels of attention, some of them also showed patterns of activity that were related to the arousal level of the mice, their movement, the availability of a reward, or a combination of these factors.

Two of the four areas along the auditory pathway studied by the researchers are thought to be at a higher level in terms of processing complexity. “At the beginning of our study, we suspected that these were the areas particularly affected by attention to sounds,” concluded co-lead researcher Tania Rinaldi Barkat. “Surprisingly, however, this wasn’t the case.”