Cortical asymmetry of auditory predictive coding in mice and humans

• Applicant: Dr. Gesa Berretz
• Subject Area: Biological Psychology and Cognitive Neuroscience
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 535285885

There is ample evidence that hemispheric differences in the representation of communication sounds exist in mice and men: in both species, the left auditory cortex shows more activation in response to conspecific vocalizations compared to the right auditory cortex indicating a left-hemispheric dominance for the processing of vocalizations. However, the underlying neural mechanisms that give rise to this asymmetry have remained unaddressed. This gives reason to analyze both if identical neurobiological mechanisms generate communication asymmetries in humans and mice. Auditory processing involves the prediction of incoming input and the comparison of said predictions to the actual auditory signal. The resulting prediction errors inform the whole processing stream in language comprehension from words to sentences. It remains unknown how these predictive processes relate to the emergence of left-hemispheric language dominance. In the planned project, I will investigate whether predictive processes in the mouse brain exhibit a lateralization between the hemispheres that matches the lateralization of language in humans. For this purpose, I will conduct experiments in mice and humans to study the micro- and macro-level of neural activity, using state-of-the-art experimental and analytical techniques. The main objectives of the proposed project are to compare lateralization of neural responses to predictable and unpredictable communication sounds in the mouse auditory cortex with calcium wide-field imaging and in the human auditory cortex using MEG, and to quantitatively relate the activities from mouse and human recordings. In the planned experiment, humans and mice will be exposed to predictable and unpredictable, but otherwise identical stimuli. Lever or button press will result in the presentation of a known sound in 90% of the trials. In the remaining 10% of trials, lever or button press will result in a deviant sound. In this case, the timing and acoustics of a stimulus are predictable as they result from the lever press. Additionally, these two sounds will be presented at random time points throughout the experiment. Here, the presentation is unpredictable as it is not coupled to a lever press. As stimuli, I will use conspecific vocalizations to investigate interhemispheric differences. This paradigm will enable us to compare responses to expected and unexpected stimulus presentations. Further, by contrasting expected known and expected unknown stimulus presentations, it is possible to rule out any motor effects of neural responses as both trial types are accompanied by a motor response. Lastly, it will be possible to investigate differences in hemispheric responses.

• DFG Programme: WBP Fellowship
• International Connection: Netherlands
• Hosts: Professor Dr. Bernhard Englitz; Professor Dr. Floris de Lange, Ph.D.