In vertebrates, spinal circuits drive rhythmic firing in motoneurons the appropriate sequence to produce locomotor movements. These become active early during development and mature gradually acquire flexibility necessary accommodate increased behavioral repertoire of adult animals. The focus here is elucidate how different pools are organized recruited membrane properties contribute their mode operation. For this purpose, we have used <i>in vitro</i> preparation zebrafish. We show that...

It was recently suggested that supplying the brain with new neurons could counteract Alzheimer's disease (AD). This provocative idea requires further testing in experimental models which molecular basis of disease-induced neuronal regeneration be investigated. We previously found zebrafish stimulates neural stem cell (NSC) plasticity and neurogenesis AD help to understand mechanisms harnessed for developing diseased mammalian brains. Here, by performing single-cell transcriptomics, we...

Neural networks in the spinal cord can generate locomotion absence of rhythmic input from higher brain structures or sensory feedback because they contain an intrinsic source excitation. However, molecular identity interneurons underlying excitatory drive within locomotor circuit has remained unclear. Using optogenetics, we show that activation a molecularly defined class ipsilateral premotor elicits locomotion. These represent module and are sufficient to produce coordinated swimming...

Significance An intriguing feature of the nervous system is its plasticity—the remarkable lifelong capacity to change and adapt in light intrinsic extrinsic stimuli. Among many different adaptive mechanisms that occur within system, changes neurotransmission form an important plasticity-bestowing mechanism reconfiguration neuronal circuits. Here, we reveal physical activity spinal cord injury can switch neurotransmitter phenotype fast axial motoneurons coexpress glutamate. Furthermore, our...

Abstract Physical exercise stimulates adult neurogenesis, yet the underlying mechanisms remain poorly understood. A fundamental component of innate neuroregenerative capacity zebrafish is proliferative and neurogenic ability neural stem/progenitor cells. Here, we show that in intact spinal cord, this plasticity response can be activated by physical demonstrating cholinergic neurotransmission from locomotor neurons activates cells, leading to neurogenesis zebrafish. We also GABA acts a...

Significance Purkinje cells, the key cells for cerebellar computations, are thought to function similarly throughout cerebellum and comprise a uniform neuronal population. Here, we challenge this notion by providing detailed evidence that organized into distinct types, each exhibiting specific activity patterns associated with particular phase of zebrafish swim cycle during locomotion. Connectivity experiments suggest all identified cell types participate in orchestrating circuit ensembles,...

Abstract The adult zebrafish spinal cord displays an impressive innate ability to regenerate after traumatic insults, yet the underlying adaptive cellular mechanisms remain elusive. Here, we show that while and tissue responses injury are largely conserved among vertebrates, large-size fast motoneurons remarkably resilient by remaining viable functional. We also reveal dynamic changes in motoneuron glutamatergic input, excitability, calcium signaling, underscore critical role of calretinin...

Abstract It has been reported that neurons generated in the adult brain show sex‐specific differences several regions of lower vertebrates and mammals. The present study questioned whether cell proliferation survival zebrafish ( Danio rerio ) cerebellum, most mitotically active area teleost brain, is sexually differentiated. Adult were treated with thymidine analogue 5′‐bromo‐2′‐deoxyuridine (BrdU) allowed to survive for 24 h (short‐term) 21 days (long‐term). BrdU immunohistochemistry...

While cholinergic neuromodulation is important for locomotor circuit operation, the specific neuronal mechanisms that acetylcholine employs to regulate and fine-tune speed of locomotion are largely unknown. Here, we show interneurons present in zebrafish spinal cord differentially control excitability distinct classes motoneurons (slow, intermediate fast) a muscarinic dependent manner. Moreover, reveal m2-type receptors (mAChRs) fast motoneurons, but not slow their activation decreases...

Abstract The β 2 ‐adrenergic receptors (ARs) are G‐protein‐coupled that mediate the physiological responses to adrenaline and noradrenaline. present study aimed determine regional distribution of ‐ARs in adult zebrafish ( Danio rerio ) brain by means vitro autoradiographic immunohistochemical methods. localization ‐ARs, agreement with quantitative β‐adrenoceptor autoradiography, showed a wide brain. cerebellum dorsal zone periventricular hypothalamus exhibited highest density [ 3 H]CGP‐12177...

Neuronal networks in the spinal cord generate and execute all locomotor-related movements by transforming descending signals from supraspinal areas into appropriate rhythmic activity patterns. In these networks, neurons that arise same progenitor domain share similar distribution patterns, neurotransmitter phenotypes, morphological electrophysiological features. However, subgroups of them participate different functionally distinct microcircuits to produce locomotion at speeds modalities. To...

The development of nervous system atlases is a fundamental pursuit in neuroscience, since they constitute tool to improve our understanding the and behavior. As such, neurotransmitter maps are valuable resources decipher organization functionality. We present here first comprehensive quantitative map neurons found adult zebrafish spinal cord. Our study overlays detailed information regarding anatomical positions, sizes, phenotypes, projection patterns neurons. also show that co-expression...

Abstract Purkinje cells are critically involved in processing the cerebellar functions by shaping and coordinating commands that they receive. Here, we demonstrate experimentally adult zebrafish valvular part of cerebellum, exhibited variable firing functional responses allowed categorization into three classes. Compared with corpus cerebelli, receive weak occasional input from inferior olive not active during locomotion. Together, our findings expand further regional differences cell...

Abstract The proper functioning of the heart relies on intricate interplay between central nervous system and local neuronal networks within itself. While innervation has been extensively studied, organization functionality intracardiac (IcNS) remain largely unexplored. Here, we present a comprehensive taxonomy IcNS, utilizing single-cell RNA sequencing, anatomical studies, electrophysiological techniques. Our findings reveal diverse array types exceeding previous expectations. We identify...

Abstract The α 2A ‐adrenoceptor (AR) subtype, a G protein‐coupled receptor located both pre‐ and postsynaptically, mediates adrenaline/noradrenaline functions. present study aimed to determine the ‐AR distribution in adult zebrafish ( Danio rerio ) brain by means of immunocytochemistry. Detailed mapping showed labeling ‐ARs, neuropil, neuronal somata fibers, glial processes, blood vessels. A high density immunoreactivity was found ventral telencephalic area, preoptic, pretectal, hypothalamic...

Cardiomyocytes play key roles during cardiogenesis, but have poorly understood features, especially in prenatal stages. Here, we characterized human cardiomyocytes, 6.5–7 weeks post-conception, by integrating single-cell RNA sequencing, spatial transcriptomics, and ligand-receptor interaction information. Using a computational workflow developed to dissect cell type heterogeneity, localize types, explore their molecular interactions, identified eight types of developing cardiomyocyte, more...

Zebrafish have an impressive capacity to regenerate neurons in the central nervous system. However, regeneration of principal neuron evolutionary conserved cerebellum, Purkinje cell (PC), is believed be limited developmental stages based on invasive lesions. In contrast, non-invasive type-specific ablation by induced apoptosis closely represents a process neurodegeneration. We demonstrate that ablated larval PC population entirely recovers number, quickly reestablishes electrophysiological...