The auditory cortex and the emotional valence of sounds.

How and where sensory stimuli, such as tones or lights, are linked to valence is an important unresolved question in the field of neuroscience. The auditory cortex is essential to analyse the identity and the behavioural importance of tones paired with emotional events. On the contrary, whether the auditory cortex may also encode information on the emotional-motivational valence of sounds is much more controversial. Here, we reviewed recent studies showing that the activity of cortical neurons reflects information about the content of emotional stimuli paired with tones. Critically, the blockade of these neuronal processes prevents animals from recognising sounds as aversive or pleasant. Based on these findings, we proposed a conceptual model in which the auditory cortex may incorporate ascending information from subcortical nuclei about the valence of sounds in sound representations and may consequently drive the activity of subcortical structures towards emotionally laden tones. This hypothesis may also have important implications in the characterisation of neural circuits engaged by maladaptive affective disorders, such as phobias.