Sanchez-Valpuesta, M. | Search bioRxiv

bioRxiv2026

Descending somatosensory and motor cortical inputs shape auditory processing in the midbrain

Integrating multisensory and behavioral information is essential for sensory perception. In the auditory system, multisensory and behavioral influences emerge early in subcortical structures. Descending projections from non-auditory cortical areas are well positioned to convey such signals, yet how they shape subcortical auditory processing remains poorly understood. Here, we investigated corticocollicular projections from the primary somatosensory (S1) and motor (M1) cortices to the inferior colliculus (IC), a principal integration center in the auditory midbrain. We found that trunk- and limb-related regions of S1 and M1 form prominent monosynaptic projections to the IC, and that optogenetic activation of these projections robustly drives IC activity. Notably, a substantial population of cortical-responsive neurons did not respond to sound. In sound-responsive neurons, concurrent cortical stimulation enhanced sound-evoked responses, whereas cortical activation preceding sound onset suppressed them. Furthermore, both cortical-responsive IC neurons and deep-layer S1 and M1 neurons exhibited locomotion-related modulation and anticipatory activity prior to movement onset, suggesting that these descending pathways convey movement-related signals to the IC. Together, our findings identify a descending sensorimotor circuit that integrates body- and movement-related information with auditory processing in the auditory midbrain.

neuroscience↗

bioRxiv2023

Auditory feedback-independent maintenance of song performance through daily singing in adult songbirds

Many songbirds learn to produce songs through vocal practice early in life and continue to sing numerous renditions of their learned songs daily throughout their lifetime. While it is well-known that adult songbirds sing as part of a mating ritual, the functions of singing behavior outside of reproductive contexts are not fully understood. Here, we demonstrate that adult singing outside of reproductive contexts serves to prevent passive changes in song performance. We suppressed the daily singing behavior of adult zebra finches produced in the solo context for two weeks using a reversible behavioral manipulation and examined the effect on song performance. Our results indicated that suppressing daily singing significantly decreased the pitch of song elements and both the amplitude and duration of song motifs. These findings suggest that adult song is not acoustically stable without singing, and that adult birds maintain their song performance by daily singing. Moreover, we found that the changes in song structure caused by singing suppression were substantially recovered within two weeks of free singing, even in deafened birds. Thus, the recovery of song performance does not necessarily require auditory feedback but is predominantly caused by singing behavior per se (i.e., the physical act of singing). Finally, unlike the auditory feedback-dependent song plasticity reported previously, the passive song changes caused by singing suppression were not significantly dependent on age. Taken together, our findings demonstrate that adult songbirds maintain song performance by preventing passive song changes through the physical act of daily singing throughout their life. Such daily singing likely functions as vocal training to maintain the neural and/or muscular system in optimal conditions for song performance in reproductive contexts, similar to how human singers and athletes practice daily to maintain their performance.

animal behavior and cognition↗