A research group from INCYL, USAL and IBSAL advances in the understanding of how auditory neurons respond to the absence of expected sounds.
Imagine you are listening to a repetitive melody and suddenly a tone disappears. Even if you don’t hear it, your brain reacts. A new study reveals how our auditory system not only processes sounds, but also anticipates what is going to happen, generating a response even when an expected tone does not sound. This ability reflects an advanced prediction system that allows us to better adapt to our environment.
To investigate this phenomenon, they used anesthetized rats, and exposed them to sequences of repetitive sounds in which a tone was occasionally omitted. They measured how neurons in the auditory cortex and inferior colliculus – regions of the brain involved in hearing – responded, finding that the brain not only reacts to the sounds present, but is also able to detect their absence, especially in the auditory cortex relative to the inferior colliculus. All this suggests that our brain is continually making predictions about what we are going to hear.
The study, published in Hearing Research, was conducted by researchers from the Auditory and Cognitive Neuroscience Laboratory of the Instituto de Neurociencias de Castilla y León (INCYL), which is part of the University of Salamanca (USAL) and the Instituto de Investigación Biomédica de Salamanca (IBSAL). It also represents the continuation of another one, published by Science Advances last year.
Lao-Rodríguez AB, Pérez-González D, Malmierca MS. Physiological properties of auditory neurons responding to omission deviants in the anesthetized rat. Hear Res. 2024 Oct;452:109107. doi: 10.1016/j.heares.2024.109107. Epub 2024 Aug 28. PMID: 39241554.
