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When brain switches from hearing to listening: Study

ANI | Updated: Dec 15, 2021 13:44 IST

Basel [Switzerland], December 15 (ANI): Researchers at the University of Basel have tracked the neuronal fingerprint of the two types of sound processing in the mouse brain to understand the switch from hearing to listening.
The study has been published in the 'Cell Reports Journal'.
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, played a role in how sound processing in the brain adjusted accordingly. Neuroscientists Professor Tania Rinaldi Barkat and Dr Gioia De Franceschi from the Department of Biomedicine at the University of Basel have provided an accurate account of what happens in this process.
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," explained De Franceschi.

"We actually found ten distinct and specific types of activity change," De Franceschi added.
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.
The auditory pathway in the brain consisted of a number of different nuclei that relayed acoustic information from the cochlea to the primary auditory cortex. Two of the four areas along the auditory pathway studied by the researchers were 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," said Barkat.
"Surprisingly, however, this wasn't the case," Barkat added.
Attention also altered activity in brain areas previously thought to perform only basic forms of sound processing.
"The results make it clear that even the detection of a simple sound is a cognitive process that profoundly and extensively shapes the way the brain works, even at very early stages of sensory processing," the researchers concluded. (ANI)