101
|
Discriminating external and internal causes for heading changes in freely flying Drosophila. PLoS Comput Biol 2013; 9:e1002891. [PMID: 23468601 PMCID: PMC3585425 DOI: 10.1371/journal.pcbi.1002891] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 12/04/2012] [Indexed: 12/03/2022] Open
Abstract
As animals move through the world in search of resources, they change course in reaction to both external sensory cues and internally-generated programs. Elucidating the functional logic of complex search algorithms is challenging because the observable actions of the animal cannot be unambiguously assigned to externally- or internally-triggered events. We present a technique that addresses this challenge by assessing quantitatively the contribution of external stimuli and internal processes. We apply this technique to the analysis of rapid turns (“saccades”) of freely flying Drosophila melanogaster. We show that a single scalar feature computed from the visual stimulus experienced by the animal is sufficient to explain a majority (93%) of the turning decisions. We automatically estimate this scalar value from the observable trajectory, without any assumption regarding the sensory processing. A posteriori, we show that the estimated feature field is consistent with previous results measured in other experimental conditions. The remaining turning decisions, not explained by this feature of the visual input, may be attributed to a combination of deterministic processes based on unobservable internal states and purely stochastic behavior. We cannot distinguish these contributions using external observations alone, but we are able to provide a quantitative bound of their relative importance with respect to stimulus-triggered decisions. Our results suggest that comparatively few saccades in free-flying conditions are a result of an intrinsic spontaneous process, contrary to previous suggestions. We discuss how this technique could be generalized for use in other systems and employed as a tool for classifying effects into sensory, decision, and motor categories when used to analyze data from genetic behavioral screens. Researchers have spent considerable effort studying how specific sensory stimuli elicit behavioral responses and how other behaviors may arise independent of external inputs in conditions of sensory deprivation. Yet an animal in its natural context, such as searching for food or mates, turns both in response to external stimuli and intrinsic, possibly stochastic, decisions. We show how to estimate the contribution of vision and internal causes on the observable behavior of freely flying Drosophila. We developed a dimensionality reduction scheme that finds a one-dimensional feature of the visual stimulus that best predicts turning decisions. This visual feature extraction is consistent with previous literature on visually elicited fly turning and predicts a large majority of turns in the tested environment. The rarity of stimulus-independent events suggests that fly behavior is more deterministic than previously suggested and that, more generally, animal search strategies may be dominated by responses to stimuli with only modest contributions from internal causes.
Collapse
|
102
|
Roura S, Gálvez-Montón C, Bayes-Genis A. Bioluminescence imaging: a shining future for cardiac regeneration. J Cell Mol Med 2013; 17:693-703. [PMID: 23402217 PMCID: PMC3823173 DOI: 10.1111/jcmm.12018] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 12/28/2012] [Indexed: 12/28/2022] Open
Abstract
Advances in bioanalytical techniques have become crucial for both basic research and medical practice. One example, bioluminescence imaging (BLI), is based on the application of natural reactants with light-emitting capabilities (photoproteins and luciferases) isolated from a widespread group of organisms. The main challenges in cardiac regeneration remain unresolved, but a vast number of studies have harnessed BLI with the discovery of aequorin and green fluorescent proteins. First described in the luminous hydromedusan Aequorea victoria in the early 1960s, bioluminescent proteins have greatly contributed to the design and initiation of ongoing cell-based clinical trials on cardiovascular diseases. In conjunction with advances in reporter gene technology, BLI provides valuable information about the location and functional status of regenerative cells implanted into numerous animal models of disease. The purpose of this review was to present the great potential of BLI, among other existing imaging modalities, to refine effectiveness and underlying mechanisms of cardiac cell therapy. We recount the first discovery of natural primary compounds with light-emitting capabilities, and follow their applications to bioanalysis. We also illustrate insights and perspectives on BLI to illuminate current efforts in cardiac regeneration, where the future is bright.
Collapse
Affiliation(s)
- Santiago Roura
- ICREC Research Program, Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP), Badalona, Spain
| | | | | |
Collapse
|
103
|
Elbaz I, Foulkes NS, Gothilf Y, Appelbaum L. Circadian clocks, rhythmic synaptic plasticity and the sleep-wake cycle in zebrafish. Front Neural Circuits 2013; 7:9. [PMID: 23378829 PMCID: PMC3561628 DOI: 10.3389/fncir.2013.00009] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 01/15/2013] [Indexed: 01/31/2023] Open
Abstract
The circadian clock and homeostatic processes are fundamental mechanisms that regulate sleep. Surprisingly, despite decades of research, we still do not know why we sleep. Intriguing hypotheses suggest that sleep regulates synaptic plasticity and consequently has a beneficial role in learning and memory. However, direct evidence is still limited and the molecular regulatory mechanisms remain unclear. The zebrafish provides a powerful vertebrate model system that enables simple genetic manipulation, imaging of neuronal circuits and synapses in living animals, and the monitoring of behavioral performance during day and night. Thus, the zebrafish has become an attractive model to study circadian and homeostatic processes that regulate sleep. Zebrafish clock- and sleep-related genes have been cloned, neuronal circuits that exhibit circadian rhythms of activity and synaptic plasticity have been studied, and rhythmic behavioral outputs have been characterized. Integration of this data could lead to a better understanding of sleep regulation. Here, we review the progress of circadian clock and sleep studies in zebrafish with special emphasis on the genetic and neuroendocrine mechanisms that regulate rhythms of melatonin secretion, structural synaptic plasticity, locomotor activity and sleep.
Collapse
Affiliation(s)
- Idan Elbaz
- The Mina and Everard Goodman Faculty of Life Sciences, The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University Ramat-Gan, Israel
| | | | | | | |
Collapse
|
104
|
Muto A, Ohkura M, Abe G, Nakai J, Kawakami K. Real-time visualization of neuronal activity during perception. Curr Biol 2013; 23:307-11. [PMID: 23375894 DOI: 10.1016/j.cub.2012.12.040] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 12/23/2012] [Accepted: 12/24/2012] [Indexed: 10/27/2022]
Abstract
To understand how the brain perceives the external world, it is desirable to observe neuronal activity in the brain in real time during perception. The zebrafish is a suitable model animal for fluorescence imaging studies to visualize neuronal activity because its body is transparent through the embryonic and larval stages. Imaging studies have been carried out to monitor neuronal activity in the larval spinal cord and brain using Ca(2+) indicator dyes and DNA-encoded Ca(2+) indicators, such as Cameleon, GFP-aequorin, and GCaMPs. However, temporal and spatial resolution and sensitivity of these tools are still limited, and imaging of brain activity during perception of a natural object has not yet been demonstrated. Here we demonstrate visualization of neuronal activity in the optic tectum of larval zebrafish by genetically expressing the new version of GCaMP. First, we demonstrate Ca(2+) transients in the tectum evoked by a moving spot on a display and identify direction-selective neurons. Second, we show tectal activity during perception of a natural object, a swimming paramecium, revealing a functional visuotopic map. Finally, we image the tectal responses of a free-swimming larval fish to a paramecium and thereby correlate neuronal activity in the brain with prey capture behavior.
Collapse
Affiliation(s)
- Akira Muto
- Division of Molecular and Developmental Biology, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | | | | | | | | |
Collapse
|
105
|
Bergeron SA, Hannan MC, Codore H, Fero K, Li GH, Moak Z, Yokogawa T, Burgess HA. Brain selective transgene expression in zebrafish using an NRSE derived motif. Front Neural Circuits 2012; 6:110. [PMID: 23293587 PMCID: PMC3531662 DOI: 10.3389/fncir.2012.00110] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 12/07/2012] [Indexed: 11/13/2022] Open
Abstract
Transgenic technologies enable the manipulation and observation of circuits controlling behavior by permitting expression of genetically encoded reporter genes in neurons. Frequently though, neuronal expression is accompanied by transgene expression in non-neuronal tissues, which may preclude key experimental manipulations, including assessment of the contribution of neurons to behavior by ablation. To better restrict transgene expression to the nervous system in zebrafish larvae, we have used DNA sequences derived from the neuron-restrictive silencing element (NRSE). We find that one such sequence, REx2, when used in conjunction with several basal promoters, robustly suppresses transgene expression in non-neuronal tissues. Both in transient transgenic experiments and in stable enhancer trap lines, suppression is achieved without compromising expression within the nervous system. Furthermore, in REx2 enhancer trap lines non-neuronal expression can be de-repressed by knocking down expression of the NRSE binding protein RE1-silencing transcription factor (Rest). In one line, we show that the resulting pattern of reporter gene expression coincides with that of the adjacent endogenous gene, hapln3. We demonstrate that three common basal promoters are susceptible to the effects of the REx2 element, suggesting that this method may be useful for confining expression from many other promoters to the nervous system. This technique enables neural specific targeting of reporter genes and thus will facilitate the use of transgenic methods to manipulate circuit function in freely behaving larvae.
Collapse
Affiliation(s)
- Sadie A Bergeron
- Program in Genomics of Differentiation, Unit on Behavioral Neurogenetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development Bethesda, MD, USA
| | | | | | | | | | | | | | | |
Collapse
|
106
|
Portugues R, Severi KE, Wyart C, Ahrens MB. Optogenetics in a transparent animal: circuit function in the larval zebrafish. Curr Opin Neurobiol 2012; 23:119-26. [PMID: 23246238 DOI: 10.1016/j.conb.2012.11.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Accepted: 11/05/2012] [Indexed: 11/17/2022]
Abstract
Optogenetic tools can be used to manipulate neuronal activity in a reversible and specific manner. In recent years, such methods have been applied to uncover causal relationships between activity in specified neuronal circuits and behavior in the larval zebrafish. In this small, transparent, genetic model organism, noninvasive manipulation and monitoring of neuronal activity with light is possible throughout the nervous system. Here we review recent work in which these new tools have been applied to zebrafish, and discuss some of the existing challenges of these approaches.
Collapse
Affiliation(s)
- Ruben Portugues
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | | | | | | |
Collapse
|
107
|
Genetic ablation of hypocretin neurons alters behavioral state transitions in zebrafish. J Neurosci 2012; 32:12961-72. [PMID: 22973020 DOI: 10.1523/jneurosci.1284-12.2012] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Sleep is an essential biological need of all animals studied to date. The sleep disorder narcolepsy is characterized by excessive daytime sleepiness, fragmentation of nighttime sleep, and cataplexy. Narcolepsy is caused by selective degeneration of hypothalamic hypocretin/orexin (HCRT) neurons. In mammals, HCRT neurons primarily regulate the sleep/wake cycle, feeding, reward-seeking, and addiction. The role of HCRT neurons in zebrafish is implicated in both sleep and wake regulation. We established a transgenic zebrafish model enabling inducible ablation of HCRT neurons and used these animals to understand the function of HCRT neurons and narcolepsy. Loss of HCRT neurons increased the expression of the HCRT receptor (hcrtr). Behavioral assays revealed that HCRT neuron-ablated larvae had normal locomotor activity, but demonstrated an increase in sleep time during the day and an increased number of sleep/wake transitions during both day and night. Mild sleep disturbance reduced sleep and increased c-fos expression in HCRT neuron-ablated larvae. Furthermore, ablation of HCRT neurons altered the behavioral response to external stimuli. Exposure to light during the night decreased locomotor activity of wild-type siblings, but induced an opposite response in HCRT neuron-ablated larvae. Sound stimulus during the day reduced the locomotor activity of wild-type sibling larvae, while HCRT neuron-ablated larvae demonstrated a hyposensitive response. This study establishes zebrafish as a model for narcolepsy, and indicating a role of HCRT neurons in regulation of sleep/wake transitions during both day and night. Our results further suggest a key role of HCRT neurons in mediating behavioral state transitions in response to external stimuli.
Collapse
|
108
|
Marx V. Rendering the brain-behavior link visible. Nat Methods 2012; 9:953-8. [DOI: 10.1038/nmeth.2183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
109
|
Grama A, Engert F. Direction selectivity in the larval zebrafish tectum is mediated by asymmetric inhibition. Front Neural Circuits 2012; 6:59. [PMID: 22969706 PMCID: PMC3432856 DOI: 10.3389/fncir.2012.00059] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 08/14/2012] [Indexed: 11/13/2022] Open
Abstract
The extraction of the direction of motion is an important computation performed by many sensory systems and in particular, the mechanism by which direction-selective retinal ganglion cells (DS-RGCs) in the retina acquire their selective properties, has been studied extensively. However, whether DS-RGCs simply relay this information to downstream areas or whether additional and potentially de novo processing occurs in these recipient structures is a matter of great interest. Neurons in the larval zebrafish tectum, the largest retino-recipent area in this animal, show direction-selective (DS) responses to moving visual stimuli but how these properties are acquired is still unknown. In order to study this, we first used two-photon calcium imaging to classify the population responses of tectal cells to bars moving at different speeds and in different directions. Subsequently, we performed in vivo whole cell electrophysiology on these DS tectal neurons and we found that their inhibitory inputs were strongly biased toward the null direction of motion, whereas the excitatory inputs showed little selectivity. In addition, we found that excitatory currents evoked by a stimulus moving in the preferred direction occurred before the inhibitory currents whereas a stimulus moving in the null direction evoked currents in the reverse temporal order. The membrane potential modulations resulting from these currents were enhanced by the spike generation mechanism to generate amplified direction selectivity in the spike output. Thus, our results implicate a local inhibitory circuit in generating direction selectivity in tectal neurons.
Collapse
Affiliation(s)
- Abhinav Grama
- Department of Molecular and Cellular Biology, Harvard University Cambridge, MA, USA
| | | |
Collapse
|
110
|
Ahrens MB, Li JM, Orger MB, Robson DN, Schier AF, Engert F, Portugues R. Brain-wide neuronal dynamics during motor adaptation in zebrafish. Nature 2012; 485:471-7. [PMID: 22622571 PMCID: PMC3618960 DOI: 10.1038/nature11057] [Citation(s) in RCA: 430] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 03/15/2012] [Indexed: 01/31/2023]
Abstract
A fundamental question in neuroscience is how entire neural circuits generate behaviour and adapt it to changes in sensory feedback. Here we use two-photon calcium imaging to record the activity of large populations of neurons at the cellular level, throughout the brain of larval zebrafish expressing a genetically encoded calcium sensor, while the paralysed animals interact fictively with a virtual environment and rapidly adapt their motor output to changes in visual feedback. We decompose the network dynamics involved in adaptive locomotion into four types of neuronal response properties, and provide anatomical maps of the corresponding sites. A subset of these signals occurred during behavioural adjustments and are candidates for the functional elements that drive motor learning. Lesions to the inferior olive indicate a specific functional role for olivocerebellar circuitry in adaptive locomotion. This study enables the analysis of brain-wide dynamics at single-cell resolution during behaviour.
Collapse
Affiliation(s)
- Misha B Ahrens
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, Massachusetts 02138, USA
- Computational and Biological Learning Lab, Department of Engineering, Cambridge University, Trumpington Street, Cambridge CB2 1PZ, UK
| | - Jennifer M Li
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, Massachusetts 02138, USA
| | - Michael B Orger
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Av. Brasília, Doca de Pedrouos, 1400-038 Lisboa, Portugal
| | - Drew N Robson
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, Massachusetts 02138, USA
| | - Alexander F Schier
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, Massachusetts 02138, USA
| | - Florian Engert
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, Massachusetts 02138, USA
| | - Ruben Portugues
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, Massachusetts 02138, USA
| |
Collapse
|
111
|
Beretta CA, Dross N, Guiterrez-Triana JA, Ryu S, Carl M. Habenula circuit development: past, present, and future. Front Neurosci 2012; 6:51. [PMID: 22536170 PMCID: PMC3332237 DOI: 10.3389/fnins.2012.00051] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 03/27/2012] [Indexed: 12/23/2022] Open
Abstract
The habenular neural circuit is attracting increasing attention from researchers in fields as diverse as neuroscience, medicine, behavior, development, and evolution. Recent studies have revealed that this part of the limbic system in the dorsal diencephalon is involved in reward, addiction, and other behaviors and its impairment is associated with various neurological conditions and diseases. Since the initial description of the dorsal diencephalic conduction system (DDC) with the habenulae in its center at the end of the nineteenth century, increasingly sophisticated techniques have resolved much of its anatomy and have shown that these pathways relay information from different parts of the forebrain to the tegmentum, midbrain, and hindbrain. The first part of this review gives a brief historical overview on how the improving experimental approaches have allowed the stepwise uncovering much of the architecture of the habenula circuit as we know it today. Our brain distributes tasks differentially between left and right and it has become a paradigm that this functional lateralization is a universal feature of vertebrates. Moreover, task dependent differential brain activities have been linked to anatomical differences across the left–right axis in humans. A good way to further explore this fundamental issue will be to study the functional consequences of subtle changes in neural network formation, which requires that we fully understand DDC system development. As the habenular circuit is evolutionarily highly conserved, researchers have the option to perform such difficult experiments in more experimentally amenable vertebrate systems. Indeed, research in the last decade has shown that the zebrafish is well suited for the study of DDC system development and the phenomenon of functional lateralization. We will critically discuss the advantages of the zebrafish model, available techniques, and others that are needed to fully understand habenular circuit development.
Collapse
Affiliation(s)
- Carlo A Beretta
- Department of Cell and Molecular Biology, Medical Faculty Mannheim, Heidelberg University Mannheim, Germany
| | | | | | | | | |
Collapse
|
112
|
Schuster S. Fast-starts in hunting fish: decision-making in small networks of identified neurons. Curr Opin Neurobiol 2012; 22:279-84. [DOI: 10.1016/j.conb.2011.12.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 11/28/2011] [Accepted: 12/04/2011] [Indexed: 01/12/2023]
|
113
|
Del Bene F, Wyart C. Optogenetics: A new enlightenment age for zebrafish neurobiology. Dev Neurobiol 2012; 72:404-14. [DOI: 10.1002/dneu.20914] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
114
|
Affiliation(s)
- Kit D Longden
- Department of Bioengineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | | |
Collapse
|
115
|
Hinz FI, Dieterich DC, Tirrell DA, Schuman EM. Non-canonical amino acid labeling in vivo to visualize and affinity purify newly synthesized proteins in larval zebrafish. ACS Chem Neurosci 2012; 3:40-49. [PMID: 22347535 DOI: 10.1021/cn2000876] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Protein expression in the nervous system undergoes regulated changes in response to changes in behavioral states, in particular long-term memory formation. Recently, methods have been developed (BONCAT and FUNCAT), which introduce non-canonical amino acids bearing small bio-orthogonal functional groups into proteins using the cells' own translational machinery. Using the selective 'click reaction', this allows for the identification and visualization of newly synthesized proteins in vitro. Here we demonstrate that non-canonical amino acid labeling can be achieved in vivo in an intact organism capable of simple learning behavior, the larval zebrafish. We show that azidohomoalanine is metabolically incorporated into newly synthesized proteins, in a time- and concentration-dependent manner, but has no apparent toxic effect and does not influence simple behaviors such as spontaneous swimming and escape responses. This enables fluorescent labeling of newly synthesized proteins in whole mount larval zebrafish. Furthermore, stimulation with a GABA antagonist that elicits seizures in the larval zebrafish causes an increase in protein synthesis throughout the proteome, which can also be visualized in intact larvae.
Collapse
Affiliation(s)
- Flora I. Hinz
- Division of Biology, California Institute of Technology, Pasadena, California
91125, United States
- Max Planck Institute for Brain Research, D-60528 Frankfurt am Main, Germany
| | - Daniela C. Dieterich
- Emmy Noether Research Group Neuralomics, Leibniz Institute for Neurobiology, D-39118 Magdeburg,
Germany
| | - David A. Tirrell
- Division of Chemistry
and Chemical
Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Erin M. Schuman
- Division of Biology, California Institute of Technology, Pasadena, California
91125, United States
- Max Planck Institute for Brain Research, D-60528 Frankfurt am Main, Germany
| |
Collapse
|
116
|
|
117
|
Norton WHJ. Measuring Larval Zebrafish Behavior: Locomotion, Thigmotaxis, and Startle. NEUROMETHODS 2012. [DOI: 10.1007/978-1-61779-597-8_1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
118
|
Simmich J, Staykov E, Scott E. Zebrafish as an appealing model for optogenetic studies. PROGRESS IN BRAIN RESEARCH 2012; 196:145-62. [PMID: 22341325 DOI: 10.1016/b978-0-444-59426-6.00008-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Optogenetics, the use of light-based protein tools, has begun to revolutionize biological research. The approach has proven especially useful in the nervous system, where light has been used both to detect and to manipulate activity in targeted neurons. Optogenetic tools have been deployed in systems ranging from cultured cells to primates, with each offering a particular combination of advantages and drawbacks. In this chapter, we provide an overview of optogenetics in zebrafish. Two of the greatest attributes of the zebrafish model system are external fertilization and transparency in early life stages. Combined, these allow researchers to observe the internal structures of developing zebrafish embryos and larvae without dissections or other interference. This transparency, combined with the animals' small size, simple husbandry, and similarity to mammals in many structures and processes, has made zebrafish a particularly popular model system in developmental biology. The easy optical access also dovetails with optogenetic tools, allowing their use in intact, developing, and behaving animals. This means that optogenetic studies in embryonic and larval zebrafish can be carried out in a high-throughput fashion with relatively simple equipment. As a consequence, zebrafish have been an important proving ground for optogenetic tools and approaches and have already yielded important new knowledge about the neural circuits underlying behavior. Here, we provide a general introduction to zebrafish as a model system for optogenetics. Through descriptions and analyses of important optogenetic studies that have been done in zebrafish, we highlight the advantages and liabilities that the system brings to optogenetic experiments.
Collapse
Affiliation(s)
- Joshua Simmich
- School of Biomedical Sciences, The University of Queensland, St. Lucia, Queensland, Australia
| | | | | |
Collapse
|
119
|
Kettunen P. Calcium imaging in the zebrafish. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:1039-71. [PMID: 22453983 DOI: 10.1007/978-94-007-2888-2_48] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The zebrafish (Danio rerio) has emerged as a new model system during the last three decades. The fact that the zebrafish larva is transparent enables sophisticated in vivo imaging. While being the vertebrate, the reduced complexity of its nervous system and small size make it possible to follow large-scale activity in the whole brain. Its genome is sequenced and many genetic and molecular tools have been developed that simplify the study of gene function. Since the mid 1990s, the embryonic development and neuronal function of the larval, and later, adult zebrafish have been studied using calcium imaging methods. The choice of calcium indicator depends on the desired number of cells to study and cell accessibility. Dextran indicators have been used to label cells in the developing embryo from dye injection into the one-cell stage. Dextrans have also been useful for retrograde labeling of spinal cord neurons and cells in the olfactory system. Acetoxymethyl (AM) esters permit labeling of larger areas of tissue such as the tectum, a region responsible for visual processing. Genetically encoded calcium indicators have been expressed in various tissues by the use of cell-specific promoters. These studies have contributed greatly to our understanding of basic biological principles during development and adulthood, and of the function of disease-related genes in a vertebrate system.
Collapse
Affiliation(s)
- Petronella Kettunen
- Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Sweden.
| |
Collapse
|
120
|
Milanese C, Sager JJ, Bai Q, Farrell TC, Cannon JR, Greenamyre JT, Burton EA. Hypokinesia and reduced dopamine levels in zebrafish lacking β- and γ1-synucleins. J Biol Chem 2011; 287:2971-83. [PMID: 22128150 DOI: 10.1074/jbc.m111.308312] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
α-Synuclein is strongly implicated in the pathogenesis of Parkinson disease. However, the normal functions of synucleins and how these relate to disease pathogenesis are uncertain. We characterized endogenous zebrafish synucleins in order to develop tractable models to elucidate the physiological roles of synucleins in neurons in vivo. Three zebrafish genes, sncb, sncg1, and sncg2 (encoding β-, γ1-, and γ2-synucleins respectively), show extensive phylogenetic conservation with respect to their human paralogues. A zebrafish α-synuclein orthologue was not found. Abundant 1.45-kb sncb and 2.7-kb sncg1 mRNAs were detected in the CNS from early development through adulthood and showed overlapping but distinct expression patterns. Both transcripts were detected in catecholaminergic neurons throughout the CNS. Zebrafish lacking β-, γ1-, or both synucleins during early development showed normal CNS and body morphology but exhibited decreased spontaneous motor activity that resolved as gene expression recovered. Zebrafish lacking both β- and γ1-synucleins were more severely hypokinetic than animals lacking one or the other synuclein and showed delayed differentiation of dopaminergic neurons and reduced dopamine levels. Phenotypic abnormalities resulting from loss of endogenous zebrafish synucleins were rescued by expression of human α-synuclein. These data demonstrate that synucleins have essential phylogenetically conserved neuronal functions that regulate dopamine homeostasis and spontaneous motor behavior. Zebrafish models will allow further elucidation of the molecular physiology and pathophysiology of synucleins in vivo.
Collapse
Affiliation(s)
- Chiara Milanese
- Pittsburgh Institute for Neurodegenerative Diseases and Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
| | | | | | | | | | | | | |
Collapse
|
121
|
Abstract
A central goal of modern neuroscience is to obtain a mechanistic understanding of higher brain functions under healthy and diseased conditions. Addressing this challenge requires rigorous experimental and theoretical analysis of neuronal circuits. Recent advances in optogenetics, high-resolution in vivo imaging, and reconstructions of synaptic wiring diagrams have created new opportunities to achieve this goal. To fully harness these methods, model organisms should allow for a combination of genetic and neurophysiological approaches in vivo. Moreover, the brain should be small in terms of neuron numbers and physical size. A promising vertebrate organism is the zebrafish because it is small, it is transparent at larval stages and it offers a wide range of genetic tools and advantages for neurophysiological approaches. Recent studies have highlighted the potential of zebrafish for exhaustive measurements of neuronal activity patterns, for manipulations of defined cell types in vivo and for studies of causal relationships between circuit function and behavior. In this article, we summarize background information on the zebrafish as a model in modern systems neuroscience and discuss recent results.
Collapse
Affiliation(s)
- Rainer W Friedrich
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstr. 66, CH-4058 Basel, Switzerland.
| | | | | |
Collapse
|
122
|
An image-free opto-mechanical system for creating virtual environments and imaging neuronal activity in freely moving Caenorhabditis elegans. PLoS One 2011; 6:e24666. [PMID: 21969859 PMCID: PMC3182168 DOI: 10.1371/journal.pone.0024666] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Accepted: 08/15/2011] [Indexed: 11/19/2022] Open
Abstract
Non-invasive recording in untethered animals is arguably the ultimate step in the analysis of neuronal function, but such recordings remain elusive. To address this problem, we devised a system that tracks neuron-sized fluorescent targets in real time. The system can be used to create virtual environments by optogenetic activation of sensory neurons, or to image activity in identified neurons at high magnification. By recording activity in neurons of freely moving C. elegans, we tested the long-standing hypothesis that forward and reverse locomotion are generated by distinct neuronal circuits. Surprisingly, we found motor neurons that are active during both types of locomotion, suggesting a new model of locomotion control in C. elegans. These results emphasize the importance of recording neuronal activity in freely moving animals and significantly expand the potential of imaging techniques by providing a mean to stabilize fluorescent targets.
Collapse
|
123
|
Sundvik M, Kudo H, Toivonen P, Rozov S, Chen YC, Panula P. The histaminergic system regulates wakefulness and orexin/hypocretin neuron development via histamine receptor H1 in zebrafish. FASEB J 2011; 25:4338-47. [PMID: 21885652 DOI: 10.1096/fj.11-188268] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The histaminergic and hypocretin/orexin (hcrt) neurotransmitter systems play crucial roles in alertness/wakefulness in rodents. We elucidated the role of histamine in wakefulness and the interaction of the histamine and hcrt systems in larval zebrafish. Translation inhibition of histidine decarboxylase (hdc) with morpholino oligonucleotides (MOs) led to a behaviorally measurable decline in light-associated activity, which was partially rescued by hdc mRNA injections and mimicked by histamine receptor H1 (Hrh1) antagonist pyrilamine treatment. Histamine-immunoreactive fibers targeted the dorsal telencephalon, an area that expresses histamine receptors hrh1 and hrh3 and contains predominantly glutamatergic neurons. Tract tracing with DiI revealed that projections from dorsal telencephalon innervate the hcrt and histaminergic neurons. Translation inhibition of hdc decreased the number of hcrt neurons in a Hrh1-dependent manner. The reduction was rescued by overexpression of hdc mRNA. hdc mRNA injection alone led to an up-regulation of hcrt neuron numbers. These results suggest that histamine is essential for the development of a functional and intact hcrt system and that histamine has a bidirectional effect on the development of the hcrt neurons. In summary, our findings provide evidence that these two systems are linked both functionally and developmentally, which may have important implications in sleep disorders and narcolepsy. development via histamine receptor H1 in zebrafish.
Collapse
Affiliation(s)
- Maria Sundvik
- Neuroscience Center and Institute of Biomedicine, Anatomy, Faculty of Medicine, P.O.B. 63, 00014 University of Helsinki, Haartmaninkatu 8, 00290 Helsinki, Finland
| | | | | | | | | | | |
Collapse
|
124
|
Wyart C, Del Bene F. Let there be light: zebrafish neurobiology and the optogenetic revolution. Rev Neurosci 2011; 22:121-30. [PMID: 21615266 DOI: 10.1515/rns.2011.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Optogenetics has revolutionized the toolbox arsenal that neuroscientists now possess to investigate neuronal circuit function in intact and living animals. With a combination of light emitting 'sensors' and light activated 'actuators', we can monitor and control neuronal activity with minimal perturbation and unprecedented spatiotemporal resolution. Zebrafish neuronal circuits represent an ideal system to apply an optogenetic based analysis owing to its transparency, relatively small size and amenability to genetic manipulation. In this review, we describe some of the most recent advances in the development and applications of optogenetic sensors (i.e., genetically encoded calcium indicators and voltage sensors) and actuators (i.e., light activated ion channels and ion pumps). We focus mostly on the tools that have already been successfully applied in zebrafish and on those that show the greatest potential for the future. We also describe crucial technical aspects to implement optogenetics in zebrafish including strategies to drive a high level of transgene expression in defined neuronal populations, and recent optical advances that allow the precise spatiotemporal control of sample illumination.
Collapse
Affiliation(s)
- Claire Wyart
- Institut du Cerveau et de la Moelle epiniere, Centre de Recherche, CHU Pitié-Salpétrière, Paris, France.
| | | |
Collapse
|
125
|
Abstract
This review provides an overview of the assays that are used for measuring escape and avoidance behavior in zebrafish, with a specific focus on zebrafish larvae during the first week of development. Zebrafish larvae display a startle response when exposed to tactile, acoustic, or visual stimuli and will avoid dark areas, moving objects, conspecifics, and open spaces. Emotional states such as fear and anxiety might be induced when larvae are exposed to stimuli that they would normally escape from or avoid. Although these emotional states probably differ between species and change during development, much can be learned about human fear and anxiety using zebrafish as a model system. The molecular mechanisms of fear and anxiety are highly conserved in vertebrates and are present during early zebrafish development. Larvae during the first week of development display elevated cortisol levels in response to stress and are sensitive to the same anxiolytics that are used for the management of anxiety in humans. Zebrafish larvae are well suited for high-throughput analyses of behavior, and automated systems have been developed for imaging and analyzing the behavior of zebrafish larvae in multiwell plates. These high-throughput analyses will not only provide a wealth of information on the genes and environmental factors that influence escape and avoidance behaviors and the emotional states that might accompany them but will also facilitate the discovery of novel pharmaceuticals that could be used in the management of anxiety disorders in humans.
Collapse
Affiliation(s)
- Ruth M Colwill
- Department of Psychology, Brown University, Providence, RI 02912, USA
| | | |
Collapse
|
126
|
Affiliation(s)
- David M Raizen
- Department of Neurology, University of Pennsylvania School of Medicine
| | | |
Collapse
|
127
|
Lillesaar C. The serotonergic system in fish. J Chem Neuroanat 2011; 41:294-308. [PMID: 21635948 DOI: 10.1016/j.jchemneu.2011.05.009] [Citation(s) in RCA: 206] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 05/07/2011] [Accepted: 05/16/2011] [Indexed: 01/20/2023]
Abstract
Neurons using serotonin (5-HT) as neurotransmitter and/or modulator have been identified in the central nervous system in representatives from all vertebrate clades, including jawless, cartilaginous and ray-finned fishes. The aim of this review is to summarize our current knowledge about the anatomical organization of the central serotonergic system in fishes. Furthermore, selected key functions of 5-HT will be described. The main focus will be the adult brain of teleosts, in particular zebrafish, which is increasingly used as a model organism. It is used to answer not only genetic and developmental biology questions, but also issues concerning physiology, behavior and the underlying neuronal networks. The many evolutionary conserved features of zebrafish combined with the ever increasing number of genetic tools and its practical advantages promise great possibilities to increase our understanding of the serotonergic system. Further, comparative studies including several vertebrate species will provide us with interesting insights into the evolution of this important neurotransmitter system.
Collapse
Affiliation(s)
- Christina Lillesaar
- Zebrafish Neurogenetics Group, Laboratory of Neurobiology and Development (NED), Institute of Neurobiology Albert Fessard, Gif-sur-Yvette, France.
| |
Collapse
|
128
|
Abbott M, Volkoff H. Thyrotropin Releasing Hormone (TRH) in goldfish (Carassius auratus): role in the regulation of feeding and locomotor behaviors and interactions with the orexin system and cocaine- and amphetamine regulated transcript (CART). Horm Behav 2011; 59:236-45. [PMID: 21192941 DOI: 10.1016/j.yhbeh.2010.12.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 11/24/2010] [Accepted: 12/19/2010] [Indexed: 01/15/2023]
Abstract
TRH is a peptide produced by the hypothalamus which major function in mammals is the regulation of TSH secretion by the pituitary. In fish, TRH does not appear to affect TSH secretion, suggesting that it might regulate other functions. In this study, we assessed the effects of central (intracerebroventricular, icv) injections of TRH on feeding and locomotor behavior in goldfish. TRH at 10 and 100 ng/g, but not 1 ng/g, significantly increased feeding and locomotor behaviors, as indicated by an increase in food intake and in the number of total feeding acts as compared to saline-injected fish. In order to assess possible interactions between TRH and other appetite regulators, we examined the effects of icv injections of TRH on the hypothalamic expression of orexin, orexin receptor and CART. The mRNA expression levels of all three peptides were significantly increased in fish injected with TRH at 100 ng/g as compared to saline-injected fish. Fasting increased TRH, orexin, and orexin receptor hypothalamic mRNA levels and decreased CART hypothalamic mRNA levels. Our results suggest that TRH is involved in the regulation of feeding/locomotor activity in goldfish and that this action is associated with a stimulation of both the orexin and CART systems.
Collapse
Affiliation(s)
- Meagan Abbott
- Department of Biology, Memorial University of Newfoundland, St John's, NL A1B3X9 Canada
| | | |
Collapse
|
129
|
Renninger SL, Schonthaler HB, Neuhauss SCF, Dahm R. Investigating the genetics of visual processing, function and behaviour in zebrafish. Neurogenetics 2011; 12:97-116. [PMID: 21267617 DOI: 10.1007/s10048-011-0273-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 01/04/2011] [Indexed: 12/11/2022]
Abstract
Over the past three decades, the zebrafish has been proven to be an excellent model to investigate the genetic control of vertebrate embryonic development, and it is now also increasingly used to study behaviour and adult physiology. Moreover, mutagenesis approaches have resulted in large collections of mutants with phenotypes that resemble human pathologies, suggesting that these lines can be used to model diseases and screen drug candidates. With the recent development of new methods for gene targeting and manipulating or monitoring gene expression, the range of genetic modifications now possible in zebrafish is increasing rapidly. Combined with the classical strengths of the zebrafish as a model organism, these advances are set to substantially expand the type of biological questions that can be addressed in this species. In this review, we outline how the potential of the zebrafish can be harvested in the context of eye development and visual function. We review recent technological advances used to study the formation of the eyes and visual areas of the brain, visual processing on the cellular, subcellular and molecular level, and the genetics of visual behaviour in vertebrates.
Collapse
Affiliation(s)
- Sabine L Renninger
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | | | | | | |
Collapse
|
130
|
Investigations of the in vivo requirements of transient receptor potential ion channels using frog and zebrafish model systems. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 704:341-57. [PMID: 21290305 DOI: 10.1007/978-94-007-0265-3_19] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Transient Receptor Potential (TRP) channels are cation channels that serve as cellular sensors on the plasma membrane, and have other less-well defined roles in intracellular compartments. The first TRP channel was identified upon molecular characterization of a fly mutant with abnormal photoreceptor function. More than 20 TRP channels have since been identified in vertebrates and invertebrate model systems, and these are divided into subfamilies based on structural similarities. The biophysical properties of TRP channels have primarily been explored in tissue culture models. The in vivo requirements for TRPs have been studied in invertebrate models like worm and flies, and also in vertebrate models, primarily mice and rats. Frog and zebrafish model systems offer certain experimental advantages relative to mammalian systems, and here a selection of papers which capitalize on these advantages to explore vertebrate TRP channel biology are reviewed. For instance, frog oocytes are useful for biochemistry and for electrophysiology, and these features were exploited in the identifcation TRPC1 as a candidate vertebrate mechanoreceptor. Also, the spinal neurons from frog embryos can be readily grown in culture. This feature was used to establish a role for TRPC1 in axon pathfinding in these neurons, and to explore how TRPC1 activity is regulated in this context. Zebrafish embryos are transparent making them well suited for in vivo imaging studies. This quality was exploited in a study in which the trpc2 gene promoter was used to label and trace the axon pathway of a subset of olfactory sensory neurons. Another experimental advantage of zebrafish is the speed and low cost of manipulating gene expression in embryos. Using these methods, it has been shown that TRPN1 is necessary for mechanosensation in zebrafish hair cells. Frogs and fish genomes have been mined to make inferences regarding evolutionary diversification of the thermosensitive TRP channels. Finally, TRPM7 is required for early morphogenesis in mice but not in fish; the reason for this difference is unclear, but it has caused zebrafish to be favored for exploration of TRPM7's role in later events in embryogenesis. The special experimental attributes of frogs and zebrafish suggest that these animals will continue to play an important role as models in future explorations of TRP channel biology.
Collapse
|
131
|
Rinkwitz S, Mourrain P, Becker TS. Zebrafish: an integrative system for neurogenomics and neurosciences. Prog Neurobiol 2010; 93:231-43. [PMID: 21130139 DOI: 10.1016/j.pneurobio.2010.11.003] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 11/08/2010] [Accepted: 11/22/2010] [Indexed: 10/18/2022]
Abstract
Rapid technological advances over the past decade have moved us closer to a high throughput molecular approach to neurobiology, where we see the merging of neurogenetics, genomics, physiology, imaging and pharmacology. This is the case more in zebrafish than in any other model organism commonly used. Recent improvements in the generation of transgenic zebrafish now allow genetic manipulation and live imaging of neuronal development and function in early embryonic, larval, and adult animals. The sequenced zebrafish genome and comparative genomics give unprecedented insights into genome evolution and its relation to genome structure and function. There is now information on embryonic and larval expression of over 12,000 genes and just under 1000 mutant phenotypes. We review the remarkable similarity of the zebrafish genetic blueprint for the nervous system to that of mammals and assess recent technological advances that make the zebrafish a model of choice for elucidating the development and function of neuronal circuitry, transgene-based neuroanatomy, and small molecule neuropharmacology.
Collapse
Affiliation(s)
- Silke Rinkwitz
- Brain and Mind Research Institute, Sydney Medical School, University of Sydney, 100 Mallett St., Camperdown, NSW 2050, Australia
| | | | | |
Collapse
|
132
|
Spontaneous seizures and altered gene expression in GABA signaling pathways in a mind bomb mutant zebrafish. J Neurosci 2010; 30:13718-28. [PMID: 20943912 DOI: 10.1523/jneurosci.1887-10.2010] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Disruption of E3 ubiquitin ligase activity in immature zebrafish mind bomb mutants leads to a failure in Notch signaling, excessive numbers of neurons, and depletion of neural progenitor cells. This neurogenic phenotype is associated with defects in neural patterning and brain development. Because developmental brain abnormalities are recognized as an important feature of childhood neurological disorders such as epilepsy and autism, we determined whether zebrafish mutants with grossly abnormal brain structure exhibit spontaneous electrical activity that resembles the long-duration, high-amplitude multispike discharges reported in immature zebrafish exposed to convulsant drugs. Electrophysiological recordings from agar immobilized mind bomb mutants at 3 d postfertilization confirmed the occurrence of electrographic seizure activity; seizure-like behaviors were also noted during locomotion video tracking of freely behaving mutants. To identify genes differentially expressed in the mind bomb mutant and provide insight into molecular pathways that may mediate these epileptic phenotypes, a transcriptome analysis was performed using microarray. Interesting candidate genes were further analyzed using conventional reverse transcriptase-PCR and real-time quantitative PCR, as well as whole-mount in situ hybridization. Approximately 150 genes, some implicated in development, transcription, cell metabolism, and signal transduction, are differentially regulated, including downregulation of several genes necessary for GABA-mediated signaling. These findings identify a collection of gene transcripts that may be responsible for the abnormal electrical discharge and epileptic activities observed in a mind bomb zebrafish mutant. This work may have important implications for neurological and neurodevelopmental disorders associated with mutations in ubiquitin ligase activity.
Collapse
|
133
|
Appelbaum L, Wang G, Yokogawa T, Skariah GM, Smith SJ, Mourrain P, Mignot E. Circadian and homeostatic regulation of structural synaptic plasticity in hypocretin neurons. Neuron 2010; 68:87-98. [PMID: 20920793 DOI: 10.1016/j.neuron.2010.09.006] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/09/2010] [Indexed: 12/12/2022]
Abstract
Neurons exhibit rhythmic activity that ultimately affects behavior such as sleep. In living zebrafish larvae, we used time-lapse two-photon imaging of the presynaptic marker synaptophysin in hypocretin/orexin (HCRT) neurons to determine the dynamics of synaptic modifications during the day and night. We observed circadian rhythmicity in synapse number in HCRT axons. This rhythm is regulated primarily by the circadian clock but is also affected by sleep deprivation. Furthermore, NPTX2, a protein implicated in AMPA receptor clustering, modulates circadian synaptic changes. In zebrafish, nptx2b is a rhythmic gene that is mostly expressed in hypothalamic and pineal gland cells. Arrhythmic transgenic nptx2b overexpression (hcrt:NPTX2b) increases synapse number and abolishes rhythmicity in HCRT axons. Finally, hcrt:NPTX2b fish are resistant to the sleep-promoting effects of melatonin. This behavioral effect is consistent with NPTX2b-mediated increased activity of HCRT circuitry. These data provide real-time in vivo evidence of circadian and homeostatic regulation of structural synaptic plasticity.
Collapse
Affiliation(s)
- Lior Appelbaum
- Center for Narcolepsy, Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, California 94305, USA.
| | | | | | | | | | | | | |
Collapse
|
134
|
McLean DL, Fetcho JR. Movement, technology and discovery in the zebrafish. Curr Opin Neurobiol 2010; 21:110-5. [PMID: 20970321 DOI: 10.1016/j.conb.2010.09.011] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 09/19/2010] [Accepted: 09/22/2010] [Indexed: 01/06/2023]
Abstract
Zebrafish provide unique opportunities for optogenetic studies of behavior. Here, we review the most recent work using optogenetic and imaging approaches to study the neuronal circuits controlling movements in the transparent zebrafish. Specifically, we focus on what we have learned from zebrafish about neuronal migration, network formation and behavioral control, and what the future may hold.
Collapse
Affiliation(s)
- David L McLean
- Department of Neurobiology and Physiology, Northwestern University, Evanston, IL 60208, USA
| | | |
Collapse
|
135
|
Nevin LM, Robles E, Baier H, Scott EK. Focusing on optic tectum circuitry through the lens of genetics. BMC Biol 2010; 8:126. [PMID: 20920150 PMCID: PMC2949621 DOI: 10.1186/1741-7007-8-126] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Accepted: 09/24/2010] [Indexed: 11/10/2022] Open
Abstract
The visual pathway is tasked with processing incoming signals from the retina and converting this information into adaptive behavior. Recent studies of the larval zebrafish tectum have begun to clarify how the 'micro-circuitry' of this highly organized midbrain structure filters visual input, which arrives in the superficial layers and directs motor output through efferent projections from its deep layers. The new emphasis has been on the specific function of neuronal cell types, which can now be reproducibly labeled, imaged and manipulated using genetic and optical techniques. Here, we discuss recent advances and emerging experimental approaches for studying tectal circuits as models for visual processing and sensorimotor transformation by the vertebrate brain.
Collapse
Affiliation(s)
- Linda M Nevin
- Department of Physiology, University of California, San Francisco, 1550 4th Street, San Francisco, CA 94158-23241, USA.
| | | | | | | |
Collapse
|
136
|
Norton W, Bally-Cuif L. Adult zebrafish as a model organism for behavioural genetics. BMC Neurosci 2010; 11:90. [PMID: 20678210 PMCID: PMC2919542 DOI: 10.1186/1471-2202-11-90] [Citation(s) in RCA: 232] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Accepted: 08/02/2010] [Indexed: 01/06/2023] Open
Abstract
Recent research has demonstrated the suitability of adult zebrafish to model some aspects of complex behaviour. Studies of reward behaviour, learning and memory, aggression, anxiety and sleep strongly suggest that conserved regulatory processes underlie behaviour in zebrafish and mammals. The isolation and molecular analysis of zebrafish behavioural mutants is now starting, allowing the identification of novel behavioural control genes. As a result of this, studies of adult zebrafish are now helping to uncover the genetic pathways and neural circuits that control vertebrate behaviour.
Collapse
Affiliation(s)
- William Norton
- CNRS, UPR, Institute of Neurobiology Albert Fessard, Gif-sur-Yvette, France.
| | | |
Collapse
|
137
|
Wong K, Stewart A, Gilder T, Wu N, Frank K, Gaikwad S, Suciu C, Dileo J, Utterback E, Chang K, Grossman L, Cachat J, Kalueff AV. Modeling seizure-related behavioral and endocrine phenotypes in adult zebrafish. Brain Res 2010; 1348:209-15. [PMID: 20547142 DOI: 10.1016/j.brainres.2010.06.012] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 06/04/2010] [Accepted: 06/05/2010] [Indexed: 11/16/2022]
Abstract
Larval zebrafish (Danio rerio) have recently been suggested as a high-throughput experimental model of epilepsy-related pathogenetic states. Here we use adult zebrafish to study behavioral symptoms associated with drug-evoked seizures. Experimental epilepsy-like states were evoked in zebrafish by exposure for 20min to three chemoconvulsant drugs: caffeine (250mg/L; 1.3mM), pentylenetetrazole (1.5g/L; 11.0mM) and picrotoxin (100mg/L; 0.17mM). Fish behavior was analyzed using manual and video-tracking methods (Noldus Ethovision XT7). Compared to their respective controls, all three drug-treated groups showed robust seizure-like responses (hyperactivity bouts, spasms, circular and corkscrew swimming) accompanied by elevated whole-body cortisol levels (assessed by ELISA). In contrast, control fish did not display seizure-like behaviors and had significantly lower cortisol levels. Paralleling behavioral and endocrine phenotypes observed in clinical and rodent studies, our data implicates adult zebrafish as an emerging experimental model for epilepsy research.
Collapse
Affiliation(s)
- Keith Wong
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
138
|
|
139
|
|
140
|
|