Ubaghs, R. L. E. M. | bioRxiv Science

bioRxiv2026

WhaleSonic: Recordings of cetacean vocal behaviour with hydrophone arrays in Northern Norway

Killer whales, humpback whales, fin whales, and sperm whales converged in a fjord system in Northern Norway during the 2023-2024 winter, where whale watching and fishing vessels add to the acoustic scene. Cetaceans are intensely studied for their acoustic behaviour and communication, and the co-occurrence of four species in confined waters offers a unique opportunity to record them with hydrophone arrays. We present WhaleSonic, a raw acoustic dataset recorded with two synchronised array systems. Four drifting buoys, each carrying a tetrahedral hydrophone array, captured 78 hours of calibrated recordings; seven bottom-mounted hydrophones yielded 52 days of continuous data. Both systems are synchronised to UTC (<1 us and 3-7 ms) and positioned to 2 m accuracy. Transmission experiments and sound velocity measurements provide in-situ ground truth. All data are in physical units and a unified coordinate system, self-documented in HDF5 files, and published with open-source tools. WhaleSonic supports the development of multichannel algorithms for source separation, localisation, sound field analysis, and group communication in free-ranging cetaceans.

animal behavior and cognition↗

bioRxiv2023

Simultaneous single-cell calcium imaging of neuronal population activity and brain-wide BOLD fMRI

Blood Oxygen Level-Dependent (BOLD) functional Magnetic Resonance Imaging (fMRI) allows for non-invasive, indirect recordings of neural activity across the whole brain in both humans and animals. However, the relationship between the local neural population activity and the vascular activity is not completely understood. To investigate this relationship, we present a novel MRI compatible single-photon microscope capable of measuring cellular resolution Ca2+ activity of genetically defined neurons during whole-brain BOLD fMRI in awake behaving mice. Using this combined imaging approach, we found a difference in activity patterns between cells which was dependent on their location with respect to the vasculature. Notably, neurons near the vasculature showed pronounced negative activity during contralateral whisker movements at 3 Hz. In a second proof of concept experiment, we demonstrate the potential of recording both local neural activities, like those in the barrel field (SSp-bfd), and BOLD fMRI readings from interlinked brain regions. In sum, the presented technological advancement paves the way for studies examining the interplay between local brain circuits and overarching brain functions. In addition, the new approach enhances our understanding of the vascular BOLD fMRI signal, providing insights into the determinants of local neurovascular functions and the brains organizational framework across various scales.

neuroscience↗