title: Rapid development of Purkinje cell excitability, functional cerebellar circuit, and afferent sensory input to cerebellum in zebrafish.
abstract: The zebrafish has significant advantages for studying the morphological development of the brain. However, little is known about the functional development of the zebrafish brain. We used patch clamp electrophysiology in live animals to investigate the emergence of excitability in cerebellar Purkinje cells, functional maturation of the cerebellar circuit, and establishment of sensory input to the cerebellum. Purkinje cells are born at 3 days post-fertilization (dpf). By 4 dpf, Purkinje cells spontaneously fired action potentials in an irregular pattern. By 5 dpf, the frequency and regularity of tonic firing had increased significantly and most cells fired complex spikes in response to climbing fiber activation. Our data suggest that, as in mammals, Purkinje cells are initially innervated by multiple climbing fibers that are winnowed to a single input. To probe the development of functional sensory input to the cerebellum, we investigated the response of Purkinje cells to a visual stimulus consisting of a rapid change in light intensity. At 4 dpf, sudden darkness increased the rate of tonic firing, suggesting that afferent pathways carrying visual information are already active by this stage. By 5 dpf, visual stimuli also activated climbing fibers, increasing the frequency of complex spiking. Our results indicate that the electrical properties of zebrafish and mammalian Purkinje cells are highly conserved and suggest that the same ion channels, Nav1.6 and Kv3.3, underlie spontaneous pacemaking activity. Interestingly, functional development of the cerebellum is temporally correlated with the emergence of complex, visually-guided behaviors such as prey capture. Because of the rapid formation of an electrically-active cerebellum, optical transparency, and ease of genetic manipulation, the zebrafish has great potential for functionally mapping cerebellar afferent and efferent pathways and for investigating cerebellar control of motor behavior.
authors.affiliation: Department of Physiology, David Geffen School of Medicine at University of California Los Angeles Los Angeles, CA, USA ; Interdepartmental Ph.D. Program in Molecular, Cellular, and Integrative Physiology, David Geffen School of Medicine at University of California Los Angeles Los Angeles, CA, USA.
authors.forename: Jui-Yi
authors.initials: JY
authors.lastname: Hsieh
authors.affiliation: Department of Physiology, David Geffen School of Medicine at University of California Los Angeles Los Angeles, CA, USA ; Interdepartmental Ph.D. Program in Molecular, Cellular, and Integrative Physiology, David Geffen School of Medicine at University of California Los Angeles Los Angeles, CA, USA.
authors.forename: Brittany
authors.initials: B
authors.lastname: Ulrich
authors.affiliation: Department of Physiology, David Geffen School of Medicine at University of California Los Angeles Los Angeles, CA, USA.
authors.forename: Fadi A
authors.initials: FA
authors.lastname: Issa
authors.affiliation: Department of Neurology, David Geffen School of Medicine at University of California Los Angeles Los Angeles, CA, USA.
authors.forename: Jijun
authors.initials: J
authors.lastname: Wan
authors.affiliation: Department of Physiology, David Geffen School of Medicine at University of California Los Angeles Los Angeles, CA, USA ; Interdepartmental Ph.D. Program in Molecular, Cellular, and Integrative Physiology, David Geffen School of Medicine at University of California Los Angeles Los Angeles, CA, USA ; Molecular Biology Institute, David Geffen School of Medicine at University of California Los Angeles Los Angeles, CA, USA.
authors.forename: Diane M
authors.initials: DM
authors.lastname: Papazian
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000344:Afferent Pathways / Q000254:growth & development / Q000502:physiology; D000818:Animals; D030801:Animals, Genetically Modified; D002531:Cerebellum / Q000254:growth & development* / Q000502:physiology*; D062557:NAV1.6 Voltage-Gated Sodium Channel / Q000378:metabolism; D009847:Olivary Nucleus / Q000254:growth & development / Q000502:physiology; D018408:Patch-Clamp Techniques; D010775:Photic Stimulation; D011689:Purkinje Cells / Q000502:physiology*; D051670:Shaw Potassium Channels / Q000378:metabolism; D014796:Visual Perception / Q000502:physiology; D015027:Zebrafish / Q000254:growth & development* / Q000502:physiology*; D029961:Zebrafish Proteins / Q000378:metabolism
chemical_list: D062557:NAV1.6 Voltage-Gated Sodium Channel; D051670:Shaw Potassium Channels; D029961:Zebrafish Proteins; C554341:kcnc3a protein, zebrafish
keywords: Purkinje cell; cerebellum; climbing fiber; parallel fiber; patch clamp; visual input; zebrafish