Biology subjects

Migault, G.

Publications and source records attributed to Migault, G..

6 recordsLinked to original sources

bioRxiv2026

Fiber-Coupled Rotating Two-Photon Light-Sheet Microscopy for Physiological Vestibular Imaging in Larval Zebrafish

Physiological vestibular stimulation requires macroscopic rotation of the animal, making simultaneous high-resolution neural imaging technically demanding. Here we present a fiber-coupled rotating two-photon light-sheet microscope for physiological pitch-axis vestibular imaging in larval zebrafish. Two-photon excitation is attractive in this context because near-infrared excitation avoids visible-light contamination of the visual environment. Femtosecond pulses were delivered to the rotating microscope through a broadband hollow-core negative-curvature fiber previously characterized in static light-sheet configurations. The rotating instrument maintained the axial mechanical stability required for cellular-resolution imaging, with submicron mean axial displacement over the characterized angular range. Fiber performance under rotation was also stable: bend-induced transmission changes were small in the relevant curvature regime, and circular input polarization suppressed rotation-dependent polarization artefacts to below 1\% in the sample plane. The dominant rotation-sensitive optical limitation was not the fiber but perturbation of the thermal lens in the sample chamber. Reducing fluid motion along the excitation path suppressed this artefact and restored stable imaging during dynamic rotation. With this system, we recorded brain-wide vestibular responses during sinusoidal pitch stimulation and resolved anatomically organized cellular response patterns across the brain. These results establish rotating two-photon light-sheet microscopy as a practical solution for vestibular imaging in experiments that require physiological stimulation together with darkness or controlled visual conditions.

neuroscience↗

bioRxiv2024

Distinct and Asymmetric Neuronal Responses to Pitch- and Roll-Axis Vestibular Stimulation in larval zebrafish

SO_SCPLOWUMMARYC_SCPLOWThe vestibular apparatus plays a pivotal role in maintaining postural equilibrium and processing movement signals, underscoring its importance in studying certain neurological disorders. Here, we present a rotating light-sheet microscope, enabling brain-wide functional recordings during dynamic vestibular stimulation along the pitch axes in addition to the roll axis in head-restrained zebrafish larvae. The system incorporates a double galvanometer mirror configuration, is amenable to 3D printing, and enhances scanning efficiency. Employing this apparatus, we have successfully conducted the first comprehensive mapping of zebrafish brain responses to dynamic pitch-tilt vestibular stimulation. Through Fourier and regression analyses, we report an asymmetry in neuronal recruitment during nose-up versus nose-down pitch tilts within critical regions, including the cerebellum, oculomotor nucleus, caudal hindbrain, and vestibular nucleus, highlighting physiological adaptations to downward motion. We identified specific brain regions, notably the cerebellum and medial-rostral rhombencephalon, that respond to roll-but not pitch-tilt vestibular stimuli. Furthermore, we have identified a transgenic line that closely correlates with our functional mappings and demonstrates a significant response to vestibular stimulation. The elucidation of brain-wide neuronal circuits involved in vestibular processing establishes a foundational framework for subsequent detailed investigations into the molecular and genetic mechanisms underlying postural control and motion perception.

neuroscience↗

bioRxiv2023

A Versatile and Open Source One- and Two-Photon Light-Sheet Microscope Design

Two-photon light sheet microscopy offers great potential for a range of biological applications. Still, its practical implementation is impeded by the high cost of laser sources, the complexity of construction, and the challenges associated with adapting to existing microscope setups. Here, we release an open-source design that addresses these limitations by providing detailed building instructions for transforming a brightfield microscope into a versatile one- and two-photon light sheet system. Our design incorporates a specially designed broadband hollow core fiber, enabling the simultaneous utilization of visible laser alongside an expansive pulsed laser source from another setup. This integration allows for uncompromised image resolution and speed. Furthermore, the design reduces the complexity of construction, alignment, and overall cost, thereby significantly enhancing the accessibility of this technology (https://github.com/LJPZebra/OLU).

neuroscience↗

bioRxiv2023

Magnetic actuation of otoliths allows behavioral and brain-wide neuronal exploration of vestibulo-motor processing in larval zebrafish.

The vestibular system in the inner ear plays a central role in sensorimotor control by informing the brain about the orientation and acceleration of the head. However, most experiments in neurophysiology are performed using head-fixed configurations, depriving animals of vestibular inputs. To overcome this limitation, we decorated the utricular otolith of the vestibular system in larval zebrafish with paramagnetic nanoparticles. This procedure effectively endowed the animal with magneto-sensitive capacities: applied magnetic field gradients induced forces on the otoliths resulting in robust behavioral responses comparable to that evoked by rotating the animal by up to 25{degrees}. We recorded the whole-brain neuronal response to this fictive motion stimulation using light-sheet functional imaging. Experiments performed in unilaterally injected fish revealed the activation of a commissural inhibition between the brain hemispheres. This magnetic-based stimulation technique for larval zebrafish opens new perspectives to functionally dissect the neural circuits underlying vestibular processing and to develop multisensory virtual environments, including vestibular feedback. HighlightsO_LIAfter injecting a ferrofluid into the inner ear of a larval zebrafish, the ear-stones can be actuated via magnetic forces. C_LIO_LIThis method allows one to elicit vestibular-like behavioral responses without impairing physiological inner ear functions. C_LIO_LIIt is compatible with brain-scale functional imaging and thus offers a promising avenue to investigate the neural underpinnings of vestibular-driven behaviors. C_LI eTOCFerrofluid injection into zebrafish inner ear allows magnetic manipulation of ear-stones to evoke vestibular responses in static animals. This in vivo method is compatible with brain-scale imaging, offering a promising approach to investigate neural mechanisms underlying vestibular-driven behaviors.

neuroscience↗

bioRxiv2021

Compositional Restricted Boltzmann Machines Unveil the Brain-Wide Organization of Neural Assemblies

Patterns of endogenous activity in the brain reflect a stochastic exploration of the neuronal state space that is constrained by the underlying assembly organization of neurons. Yet it remains to be shown that this interplay between neurons and their assembly dynamics indeed suffices to generate whole-brain data statistics. Here we recorded the activity from ~ 40,000 neurons simultaneously in zebrafish larvae, and show that a data-driven generative model of neuron-assembly interactions can accurately reproduce the mean activity and pairwise correlation statistics of their spontaneous activity. This model, the compositional Restricted Boltzmann Machine (cRBM), unveils ~ 200 neural assemblies, which compose neurophysiological circuits and whose various com-binations form successive brain states. We then performed in silico perturbation experiments to determine the interregional functional connectivity, which is conserved across individual animals and correlates well with structural connectivity. Our results showcase how cRBMs can capture the coarse-grained organization of the zebrafish brain. Notably, this generative model can readily be deployed to parse neural data obtained by other large-scale recording techniques.

neuroscience↗

bioRxiv2018

Whole-brain calcium imaging during physiological vestibular stimulation in larval zebrafish

During in vivo functional imaging, animals are head-fixed and thus deprived from vestibular inputs, which severely hampers the design of naturalistic virtual environments. To overcome this limitation, we developed a miniaturized ultra-stable light-sheet microscope that can be dynamically rotated during imaging along with a head-restrained zebrafish larva. We demonstrate that this system enables whole-brain functional imaging at single-cell resolution under controlled vestibular stimulation. We recorded for the first time the dynamic whole-brain response of a vertebrate to physiological vestibular stimulation. This development largely expands the potential of virtual-reality systems to explore complex multisensory-motor integration in 3D.

neuroscience↗