Zebrafish

…virtual reality for head-fixed adult zebrafish, linking spatial cognition to telencephalic circuits. Behavioural training, two-photon imaging and circuit-level methods reveal how functional neuron types represent virtual environments and how experience refines those representations. Virtual-environment manipulations test cognitive inference and prediction, connecting internal models used in navigation and planning to neural organisation.

The nervous system scales with animal size, maintaining function while minimizing wire. In contrast to most animal organs, which scale through the proliferation of dividing cells of similar size, brains expand by modulating the size of non-dividing neuronal cells to innervate space during development. As a result, there is notable diversity in neuronal size and structure within individual brains and between different species. This diversity raises an important question: how do neurons maintain computational function across diverse sizes while minimizing wiring costs? Two theoretical results ha

Understanding the neuromechanical principles of collective motor behaviors is a longstanding question at the intersection between neuroscience, motor control and fluid mechanics. Striking examples of these behaviors include the patterns formed by fishes swimming or birds flying in schooling formations. What is the advantage of schooling? What central vs peripheral control mechanisms are involved in these emergent behaviors? Modeling the closed loop interaction between the neural and mechanical components describing collective behaviors is a complex task. It requires accurate modeling and si

…a spiking neuromechanical model of the zebrafish, focusing on how proprioceptive signals from Piezo2-expressing neurons modulate the activity of the spinal cord's central pattern generator (CPG) network, thus regulating the locomotor output. A spiking neural network comprising the main classes of interneurons in the zebrafish locomotor circuits, namely V2a, V0d and motoneur

Sensory information is first processed by various thalamic nuclei before reaching the pallium in amniotes, where it is used for higher-order computations such as integrating diverse sensory information that can be utilized to form associations. In teleost fish, the dorsal thalamic nuclei, believed to be analogous to the amniote thalamus, projects primarily to the subpallium. However, the major diencephalic input to the pallium originates from the preglomerular nucleus (PG), suggesting that it may perform analogous functions to the amniote thalamocortical pathway. To examine this, we first mapp

Biological agents continually reconcile the internal states of their brain circuits with incoming sensory and environmental evidence to evaluate when and how to act. The brains of biological agents, including animals and humans, exploit many evolutionary innovations, chiefly modularity—observable at the level of anatomically-defined brain regions, cortical layers, and cell types among others—that can be repurposed in a compositional manner to endow the animal with a highly flexible behavioral repertoire. Accordingly, their behaviors show their own modularity, yet such behavioral modules seldom

A head direction (HD) cell fires when an animal faces a particular azimuthal direction (Taube and Bassett 2003). Recurrent connections among HD cells create a ring-attractor network that continuously encodes HD (Ajabi et al. 2023). Indeed, in the Drosophila HD system, three rings interact to linearly integrate angular head velocity (AHV), with two of the rings receiving countervailing velocity-dependent inputs (Turner-Evans et al. 2017). In contrast, for the desert locust an alternative mechanism has been proposed (Zittrell et al. 2023; Pabst et al. 2024). There, velocity modulates synaptic

Animals use their whole body to navigate their environment and solve tasks. Zebrafish (Dario rerio) need to coordinate tail and fin movements and can serve as a model organism for the study of locomotion and locomotion generation and dysregulation. Behavioral tracking of zebrafish has usually restricted itself to tracking in the (x,y) plane with an overhead camera. This precludes studies that investigate postural control or navigation in naturalistic, three-dimensional conditions. To study full body coordination we built a rig that allows us to track larval zebrafish in 3D with high resolution

Leucine rich repeat transmembrane proteins (LRRMTs) are synaptic adhesion proteins able to influence synapse development and function. LRRTM4, one of the 4 members of this protein group, is able to induce presynaptic differentiation and plays a significant role in excitatory synapse development. LRRTM4 polymorphisms have been linked to multiple neuropsychiatric diseases, but the underlying mechanisms are currently unclear. Therefore, we aimed to better understand the role of this gene for brain function by combining a battery of behavioural assays with transcriptomic and metabolomic analysis u

…receptor analog, and the behavior of zebrafish (Danio rerio).Methods:Zebrafish wer

The habenula (Hb) is a diencephalic brain region implicated in adaptive behaviors and neuropsychiatric disorders. Two main Hb subdivisions, the lateral habenula and medial habenula, have been shown to play different roles in diverse behaviors, ranging from classical and operant learning to the prediction of outcomes, fear, addiction, and social interactions. However, our understanding of cytoarchitecture and topography of the vertebrate Hb, as well as how different Hb microcircuits are organized across species, remains limited. In this study, we utilized a combination of single-cell and spatia

…response to sunlight in zebrafish (D. rerio) and blind cavefish (P. andruzzii), the latter servin

Vaccinia-related kinase 1 (VRK1) is a predominantly nuclear serine/threonine kinase implicated in nucleus disassembly and reassembly, cell cycle, and transcription regulation. VRK1 mutations in humans have been linked to several neurodegenerative diseases, including spinal muscular atrophy associated with microcephaly and impaired cognitive and motor function. Thus, it has been identified as potentially involved in the maintenance and development of the nervous system. However, precise pathophysiological mechanisms and VRK1 involvement in cognitive and motor dysfunction progression have yet to

The choroid plexus produces cerebrospinal fluid (CSF) by transporting ions and water from adjacent blood vessels to the brain ventricles. The choroid plexus plays additional roles in brain development and homeostasis by secreting neurotrophic molecules and serving as a CSF-blood barrier and immune interface. Previous studies highlighted that several transporters on the epithelial cells transport water and ions into the ventricles and tight junctions of the cells are involved in the CSF-blood barrier. Yet, how the choroid plexus epithelial cells maintain the brain ventricle system and influence

Understanding the biological underpinnings of gene-environment interactions (GxE) in humans is challenging. Therefore, animal models, with their controlled genetic backgrounds and environments can provide invaluable insights. This study aims to identify the genetic background of a particular “freezing” behaviour observed in beagle dogs, as a mechanism coping with stress. An intriguing observation was made in 50 kennel-raised beagles: upon leaving the kennel, 14 exhibited "freezing" behaviour and remained immobile during the 30-minute test, while 9 showed normal activity and 27 dogs were initia

…plane illumination microscopy, the zebrafish brain is an attractive model that allow for whole brai

…In zebrafish, RGCs project their axons to downstream brain areas known as arborization fields (AFs). Previous anatomical studies have demonstrated that each RGC axon targets one or a few of AF1-9 and 10 distinct layers of AF10 (optic tectum). Although it was proposed that each projection type represents one functional type, the correspondence between morphology and function of genetically defined RGC subtypes is still unclear. To address this question, we focused on RGC s

Axon diameter varies up to 100-fold between distinct neurons in the central nervous system with larger axons exhibiting faster nerve conduction velocity. Further axon diameter influences myelination and its dynamic regulation might help fine-tune the timing of signal propagation and thus neural circuit function. Despite its importance, we know surprisingly little about how axons grow to such different diameters in the living nervous system and which mechanisms underlie this diversity. To fully understand how nervous systems are built, functionally mature, and remain healthy, we need to underst

Cerebrospinal fluid (CSF) is integral to brain architecture, providing mechanical and nutritional support to the tissue while clearing metabolic waste. Recent research reveals its potential role in neuromodulation through its transport of various signaling molecules. Yet, to what extend CSF impacts the direct delivery of such molecules is poorly understood. CSF circulation is tightly regulated by a combination of factors such as cardiac activity, glial regulation, and notably, ciliary beating of ependymal cells lining the brain ventricles. Ciliary dysfunction, as observed in ciliopathies, ofte

Zebrafish is becoming an increasingly popular animal for modelling seizures and epilepsy. Various pharmacological and genetic models are utilized for both discovering new anti-epileptic drugs and for investigating fundamental mechanisms regulating neural excitability, seizures, and epilepsy. We aimed at developing multiple pharmacologically induced seizure and epilepsy models, in order to utilize these models for high-throughput behavioural screens and for functional brain imaging. We showed that several parameters of locomotor behaviours and spatial exploration are altered in seizure and epil

…the first avulsion axotomy model in zebrafish. Using in vivo confocal imaging we have characterized the long-term dynamics of microglia-neuron interactions in response to peripheral nerve injury.In vivo time-lapse imaging confirmed that peripheral nerve injury triggered a microglial response in the CNS. This response was characteri

Clinical studies continuously unveil the increase risk of neurodevelopmental disorders in association with specific genetic variants. The impact of these mutations on the signal cascades leading to alterations of the brain functions, is frequently unclear. This is the case for the cdkl5 gene, encoding the Cyclin-Dependent-Kinase-Like-5 enzyme, whose mutations are linked to CDKL deficiency disorder (CDD). This is neurodevelopmental disease characterized by impairment of cognitive and motor skills. Here, we aim to elucidate the pathophysiological mechanisms associated with the lack of Cdkl5, emp

…Specifically, Danio rerio (zebrafish) utilizes sensory feedback from multiple modalities to regulate their target tracking behavior during rheotaxis. We have previously shown that zebrafish tracks the trajectories of a D-shaped tube that obscure the flow during their innate rheotaxis. We investigate the impact of the quality of multisensory information on the target tracking performance of zebrafish within a custom-built swim tunnel. To achieve this, we use a transparent D-shaped tube to obscure

TDP-43 is the hallmark protein of several neurodegenerative diseases, including Amyotrophic Lateral Sclerosis (ALS). This RNA-binding protein can form membrane-less condensates through liquid-liquid phase separation (LLPS). This biophysical process is considered to contribute to the regulation of TDP-43 functions but the precise mechanisms governing TDP-43 LLPS and its implications in homeostasis as well as pathology remain incompletely understood.In this study, we aimed to elucidate the influence of RNA-binding on TDP-43 dynamics and localization in vivo. By applying confocal imaging workflow