Reticulospinal neurons of e larval zebrafish Brachydanio rerio have been categorized into 27 different types (Kimmel et al.: Journal of Comparative Neurology 205:112–127, 1982. Metcalfe et al.: Journal of Comparative Neurology 251:147–159, 1986).Nineteen of ese occur as bilateral pairs which are individually identifiable. Since considerable remolding of brain structures (e.g., cell Cited by: 141. 01, · Brainstem reticulospinal neurons are phylogenetically conserved across vertebrates and form a major descending motor control system at receives convergent sensory inputs and sends motor commands to spinal circuitry (Kohashi and Oda, 2008). e zebrafish reticular formation, located in e hindbrain, extends longitudinally rough most of e Cited by: 119. 01, 2008 · ere is currently an unmet need for a erapy at promotes e regenerative process of remyelination in central nervous system diseases, notably multiple sclerosis (MS). A high- roughput model is, erefore, required to screen potential erapeutic drugs and to refine genomic and proteomic data from MS lesions. Here, we review e value of e zebrafish (Danio rerio) larva as a model of Cited by: 67. ple, 27 reticulospinal neuronal types have been identified in e larva of e zebrafish, Brachydanio rerio. Eight of ese are groups of a small number of equivalent neurons and 19 are single identifiable individuals on each side of e brain (Metcalfe et al, 1986). Of e reticulospinal neurons of fish, e M-cells are oroughly characterized. Gahtan. E., Tanger. P., and Baier, H. (2005) Visual prey capture in larval zebrafish is controlled by identified reticulospinal neurons downstream of e tectum. e Journal of neuroscience: e official journal of e Society for Neuroscience. 25(40):9294-9303. e descending motor control neurons of e larval zebrafish, including e reticulospinal cells, vestibulospinal cells, and e nucleus of e medial longitudinal fasciculus (nMLF), are e pri y pa way by which locomotor information is transmitted to e spinal cord. ey number approximately ree hundred, in many cases are individually identifiable, and act as e sole pa way of. Neural stem cells in e subventricular zone (SVZ) of e adult mammalian forebrain are a potential source of neurons for neural tissue repair after brain insults such as ischemic stroke and traumatic brain injury (TBI). Recent studies show at neurogenesis in e ventricular zone (VZ) of e adult zebrafish telencephalon has features in common wi neurogenesis in e adult mammalian SVZ. In zebrafish, CB 1 Rs are highly expressed in e hindbrain where ey are associated wi reticulospinal neurons .In fact, zebrafish express bo CB 1 Rs and CB 2 Rs in e embryonic stages of development .CB 1 R expression appears low in early development prior to 24 hpf but increases as development proceeds, whereas CB 2 R expression follows e reverse pattern, wi high levels prior. Feb 21, · Neurogenesis in e developing central nervous system consists of e induction and proliferation of neural progenitor cells and eir subsequent differentiation into mature neurons. External as well as internal cues orchestrate neurogenesis in a precise temporal and spatial way. In e last 20 years, e zebrafish has proven to be an excellent model organism to study neurogenesis in e embryo. Feb 25, · Locomotion-related signals from e brain reach e spinal cord by way of excitatory reticulospinal neurons of e hindbrain (Dubuc et al., 2008. Grillner and Georgopoulos, 1996. Jordan et al., 2008. Roberts et al., 2008).V2a neurons in e hindbrain, similar to e ones in e spinal cord, are glutamatergic and project eir axons ipsilaterally (Cepeda-Nieto et al., 2005. Kinkhabwala et al. We have examined e morphology of identified reticulospinal neurons in larval zebrafish by retrogradely labeling em wi horseradish peroxidase. We described e morphology of 27 different types of reticulospinal neurons found in e hindbrain 5 days after fertilization. In translucent larval zebrafish activation of identifiable reticulospinal neurons can be monitored in vivo by calcium imaging. ese studies demonstrate at stimuli at elicit e C-start activate a distributed population of reticulospinal neurons in parallel wi e M-cell (Gahtan et al., 2002). However, because is imaging technique. (D-F) 48 hour embryos, as described on e left were stained wi RMO44, an antibody at recognizes e identifiable pri y reticulospinal neurons of zebrafish. Neuronal cell bodies are identified and labeled as shown (RoL 2, which is normally found in r2 of a wild-type embryo. M, which is in r4). 05, 2005 · In zebrafish, motor commands generated in e brain are conveyed to e spinal cord rough a small number of reticulospinal (RS) neurons. ere are ∼150 RS neurons, e cell bodies of which are arranged in a bilaterally symmetric array in midbrain and hindbrain. J.A. Buford, in Encyclopedia of Neuroscience, 2009. Lateral Reticulospinal Tracts. e lateral reticulospinal tract is a bilateral system. Like e medial reticulospinal tract from e NRGc, neurons of e lateral reticulospinal tract ei er descend ipsilaterally or . 19, · Traumatic spinal cord injury (SCI) results in persistent functional deficits due to e lack of axon regeneration wi in e mammalian CNS. After SCI, chondroitin sulfate proteoglycans (CSPGs) inhibit axon regrow via putative interactions wi e LAR-family protein tyrosine phosphatases, PTPσ and LAR, localized on e injured axon tips. Unlike mammals, e sea lamprey, Petromyzon inus. Recent findings on e nature and origin of segmentation in zebrafish, Brachydanio rerio, are reviewed. Segmented peripheral tissues include e trunk and tail myotomes, at are derived from. We found several dye-coupled neurons wi in e reticulospinal network indicating functional gap ctional connectivity in e developing zebrafish brain. Introduction Ever since electrical synapses were first described (Furshpan and Potter, 1957), eir role in e formation and function of neural circuits has been e focus of intense study. In teleosts, developing reticulospinal neurons have been classified into several families based on shared morphological features, and it has been suggested at each rhombomere develops basically e same set of neurons as e o ers. Serial homologies have been recognized in e Mau ner, MiD2 and MiD3 neurons of zebrafish. Hindbrain reticulospinal neurons in wild-type (A) and mutant (B) embryos labeled wi mAb 3A at 36 hpf. 209 Zebraﬁsh mutants in early neural development. Zebrafish genetics. One such set of ree repeated reticulospinal neurons e Mau ner cell, MiD2cm, and MiD3cm is ought to produce different forms of e escape response at fish use to avoid predators. We used laser ablations in larval zebrafish to test e hypo esis at ese segmental hindbrain cells form a functional group. Reticulospinal neurons. Reticulospinal neurons are located in and presumably derive from multiple rhombomeres in e mouse, including r4 (Fig. 1C. Auclair et al., 1999). However, rhombomere-specific fate mapping of e reticulospinal neurons has not been performed in rodents. 15, 2008 · Brainstem reticulospinal neurons (RSNs) serve as e major descending system in vertebrate sensorimotor integration. One of e paired RSNs in zebrafish, e Mau ner (M) cell, is ought to initiate fast escape from sudden noxious stimuli. Two o er paired RSNs, morphologically homologous to e M-cell, are also suggested to play key roles in controlling fast escape. Archerfish use two powerful C-starts: one to escape reats, e o er to secure prey at ey have downed wi a shot of water. e two C-starts are kinematically equivalent and variable in bo phases, and e predictive C-starts – used in hunting – are adjusted in terms of e angle of turning and e final linear speed to where and when eir prey will hit e water surface. In larval zebrafish about ~60 of e total population of reticulospinal neurons are also activated by a stimulus at elicits e M-spike and C-start escape. A well-studied group of ese reticulospinal neurons are e bilaterally paired M-cell homologues denoted MiD2cm and MiD3cm. ese neurons exhibit morphological similarities to e M-cell. In zebrafish, e hindbrain segments contain serially repeated classes of individually identifiable neurons. We took advantage of e transparency of larval zebrafish and used confocal calcium imaging in e intact fish to study e activity of one set of individually identified, serially homologous reticulospinal cells (e Mau ner cell. zebrafish ere is a fur er manifestation of e segmental organization of e hindbrain. individual reticulospinal neurons, which can be visualized by retrograde labeling from e spinal cord (Metcalfe et al., 1986), have eir cell bodies arranged in a stereo-typical ladder-like array in rhombomeres 2 to 7 (Fig. 2B). ese reticulospinal neurons. For example, reticular neurons in rhombomeres (r) 1–4 in larval zebrafish, including large, ipsilaterally projecting reticulospinal neurons in r4 at are likely to be homologous to pRS neurons in e most caudal portion of e mammalian PRF, have been shown to be involved in regulating e spinal locomotor network (Kimura et al. ). Kimmel CB (1982) Reticulospinal and vestibulospinal neurons in e young larva of a teleost fish, Brachydanio rerio. Prog Brain Res 57:1–24 Google Scholar Kimmel CB, Powell SL, Metcalfe WK (1982) Brain neurons which project to e spinal cord in young larvae of e zebrafish. e neural tube of zebrafish embryos is, like at of o er vertebrates, highly polarized along its dorsoventral axis. In e spinal cord, sensory neurons form at dorsal aspects, whereas motor neurons and e floorplate develop at ventrolateral and ventral positions, respectively, and interneurons occupy intermediate regions (Fig. 1). Feb 08, · Moreover, none of e reticulospinal neurons were observed to contain CB. e presence of CR in a large population of reticulospinal neurons was reported before in fish (Díaz-Regueira and Anadón 2000. Castro et al. 2005. Graña et al. , ) as well as in o er vertebrate species (Smeets and González 2000. Morona and González 2009). 15, · However, unlike reticulospinal neurons, which traverse e medial and lateral longitudinal fasciculi to contact targets in e spinal cord, prepontine escape neurons project rough lateral fiber tracts and terminate in a dense neuropil zone in e caudal hindbrain and must erefore drive at least e majority of spinal cord motor neurons. 9 Deliagina T. G., Fagerstedt P. Responses of reticulospinal neurons in intact lamprey to vestibular and visual inputs. J. Neurophysiol. 83 2000 864878 Link. ISI Google Scholar. Deliagina T. G., Grillner S., Orlovsky G. N., Ullén F. Visual input affects e response to roll in reticulospinal neurons of e lamprey. Exp. Brain Res. 95 1993. e existence of a primitive CNS function involved in e activation of all vertebrate behaviors, generalized arousal (GA), has been proposed. Here, we provide an overview of e neuroanatomical, neurophysiological and molecular properties of reticular neurons wi in e nucleus gigantocellularis (NGC) of e mammalian medulla, and propose at e properties of ese neurons equip em. 1998 2002 NIH Ad: Functional Organization of e Zebrafish Hindbrain (PI) $761,400 (direct + indirect costs), 30 time. [NIH = National Institutes of Heal ] 1996 1999 NSF Ad: Calcium Signaling in e Brain of Behaving Zebrafish.(PI) $180,000 (direct + indirect costs), 50 time. [NSF = National Science Foundation]. e homeodomain transcription factor Or opedia (Otp) is essential in restricting e fate of multiple classes of secreting neurons in e neuroendocrine hypo alamus of vertebrates. However, ere is little information on e intercellular factors at regulate Otp expression during development. Here, we identified two otp or ologues in zebrafish (otp1 and otp2) and explored otp1 in e. Society for Neuroscience 31st Annual Meeting, San Diego, CA -15, 2001. 21. Gahtan, E. and O'Malley, D.M. Analysis of Spontaneous activity in control and reticulospinal ablated zebrafish larvae. Society for Neuroscience 30 Annual Meeting, New Orleans, LA. ember 4-, 2000 22. F: Reticulospinal neurons (rsn) labeled wi anti‐acetylated tubulin at 24 hpf. G,H: Commissural neurons (cn) labeled wi zn8 antibody at 30 hpf. Commissural neurons are absent in anterior rhombomeres and in posterior rhombomeres produce aberrant commissures (c) . Questions I am addressing include: How do reticulospinal and spinal neurons and circuits generate startle behavior? And, how are gate transitions due to e physics of movement mediated neurally? To address ese questions I examine reticulospinal and spinal interneuron morphology and function in zebrafish and examine comparatively species at. target for reticulospinal axons in e zebrafish hindbrain. Many reticulospinal neurons project an axon along a tract which is located just lateral to e floor plate region [ 171. ese axons are also disarrayed in e hindbrain of cyc- I and floor plate ablated embryos (K Hatta et al: Sot. Work in zebrafish showed at e hindbrain segments contained morphologically similar reticulospinal neurons in successive segments. e idea at e segments arose via duplication events in evolution led to e prediction at e serially repeated neurons would be functionally related to one ano er. Figure. Fate mapping of LVST neurons and reticulospinal neurons. A, e b1r4-Cre line, which expresses e Cre recombinase under e control of e Hoxb1 r4 enhancer, is crossed wi e ROSA26YY reporter line to label r4 derivatives by YFP expression.B, C, Schematic diagrams of E16.5 brain in e parasagittal plane illustrating e location of YFP-positive r4 and r4 derivatives (green), . Reticulospinal neurons in r2 are activated during visually evoked escape behavior. Ectopic expression of ephrinB2a increased e probability at neurons projected to r2. 2. 07, · Oligodendrocytes form myelin around axons of e central nervous system, enabling saltatory conduction. Recent work has established at axons can regulate certain aspects of oligodendrocyte development and myelination, yet re kably oligodendrocytes in culture retain e ability to differentiate in e absence of axons and elaborate myelin shea s around syn etic axon . Activation of motor patters via reticulospinal neurons by electrical stimulation in e larval zebrafish brainstem. Soc. Neurosci. Abs., 565.7. Severi KE, Orger MB, Talsania S, Kampff AR, O’Malley DM, Engert F (2007). Diversity of visuo-motor response profiles of larval zebrafish reticulospinal neurons revealed by in vivo calcium imaging. AAAS Annual Meeting 13 - 16 February Seattle, WA Neuroscience Newsroom 19 - 23 ober Chicago, IL. 01, · Delayed dea of identified reticulospinal neurons after spinal cord injury in lampreys./Comp Neurol. 5: 269-282. Shifman, M. I., R. E. Yumul, C. Laramore, and M. E. Selzer. 2009. Expression of e repulsive guidance molecule RGM and its .