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Authors & Affiliations
Kira Andrea, Jan J. Hirtz
Abstract
Corticocollicular (CC) projections arise in deep layers of the auditory cortex and modulate upstream auditory information in the inferior colliculus (IC), forming feedback loops. They are crucially involved in auditory-related learning and frequency response modulations in auditory brainstem. Through widefield and 2-photon calcium imaging in awake mice we prior were able to show that layer 5 CC neurons display only a subtle topographic organization when compared to other layer 5 neuron types (Schmitt et al., 2023, Front Neural Circuit). However, these data were acquired under passive listening conditions, and thus did not tackle the behavioral relevance of CC neurons. To investigate the role of topographically organized activity patterns of CC neurons in auditory learning, we trained mice in a two-tone discrimination task. The activity of CC neurons was recorded during the complete training process over multiple days using 2-photon imaging. Preliminary data indicate that following the learning paradigm, the representation of the target frequency in the neuronal ensemble was altered. After mice learned to distinguish the foil from the target frequency, the fraction of target-tuned neurons increased, while the number of foil-tuned neurons remained unaltered. To verify and expand on these findings, we are currently investigating possible learning-induced changes in topographically organized activity patterns. Our results suggest a context-dependent nature of CC neuron activity patterns, emphasizing their role in auditory learning.