Exploring Neural Dynamics in the Auditory Telencephalon of Crows using Functional Ultrasound Imaging

Crows, known for advanced cognitive abilities and vocal communication, rely on intricate auditory systems. While the neuroanatomy of corvid auditory pathways is partially explored, the underlying neurophysiological mechanisms are largely unknown. This study used functional ultrasound imaging (fUSi) to investigate sound-induced cerebral blood volume (CBV) changes in the field L complex of the crows auditory telencephalon, a functional analogue to the mammalian auditory cortex. FUSi revealed frequency-specific CBV responses, showing a tonotopic organization within the field L complex, with low frequencies in the posterior-dorsal region and high frequencies in the anterior-ventral region, similar to neuronal patterns reported in other songbirds. The responses were more robust when the crows were awake compared to when they were anesthetized. Machine learning analyses showed fUSi signals could be used to classify sound types accurately. Shorter stimuli reliably triggered transient CBV increases, while longer sounds resulted in variable responses, including negative deflections. This variability in CBV responses suggests a delineation of subregions within the field L complex with the central region (L2) as the primary processing hub and outer regions (L1, L3) integrating auditory information. These findings highlight the potential of fUSi for providing high-resolution insights into functional systems in corvids, enabling future exploration of task-related cognitive dynamics.