101
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Wang F, Bélanger E, Paquet ME, Côté DC, De Koninck Y. Probing pain pathways with light. Neuroscience 2016; 338:248-271. [PMID: 27702648 DOI: 10.1016/j.neuroscience.2016.09.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 09/19/2016] [Accepted: 09/20/2016] [Indexed: 02/06/2023]
Abstract
We have witnessed an accelerated growth of photonics technologies in recent years to enable not only monitoring the activity of specific neurons, while animals are performing certain types of behavior, but also testing whether specific cells, circuits, and regions are sufficient or necessary for initiating, maintaining, or altering this or that behavior. Compared to other sensory systems, however, such as the visual or olfactory system, photonics applications in pain research are only beginning to emerge. One reason pain studies have lagged behind is that many of the techniques originally developed cannot be directly implemented to study key relay sites within pain pathways, such as the skin, dorsal root ganglia, spinal cord, and brainstem. This is due, in part, to difficulties in accessing these structures with light. Here we review a number of recent advances in design and delivery of light-sensitive molecular probes (sensors and actuators) into pain relay circuits to help decipher their structural and functional organization. We then discuss several challenges that have hampered hardware access to specific structures including light scattering, tissue movement and geometries. We review a number of strategies to circumvent these challenges, by delivering light into, and collecting it from the different key sites to unravel how nociceptive signals are encoded at each level of the neuraxis. We conclude with an outlook on novel imaging modalities for label-free chemical detection and opportunities for multimodal interrogation in vivo. While many challenges remain, these advances offer unprecedented opportunities to bridge cellular approaches with context-relevant behavioral testing, an essential step toward improving translation of basic research findings into clinical applications.
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Affiliation(s)
- Feng Wang
- Institut universitaire en santé mentale de Québec, Université Laval, Québec, QC, Canada
| | - Erik Bélanger
- Institut universitaire en santé mentale de Québec, Université Laval, Québec, QC, Canada; Centre d'optique, photonique et laser, Université Laval, Québec, QC, Canada
| | - Marie-Eve Paquet
- Institut universitaire en santé mentale de Québec, Université Laval, Québec, QC, Canada; Département de biochimie, microbiologie et bioinformatique, Université Laval, Québec, QC, Canada
| | - Daniel C Côté
- Institut universitaire en santé mentale de Québec, Université Laval, Québec, QC, Canada; Centre d'optique, photonique et laser, Université Laval, Québec, QC, Canada; Département de physique, de génie physique et d'optique, Université Laval, Québec, QC, Canada
| | - Yves De Koninck
- Institut universitaire en santé mentale de Québec, Université Laval, Québec, QC, Canada; Centre d'optique, photonique et laser, Université Laval, Québec, QC, Canada; Département de psychiatrie et neurosciences, Université Laval, Québec, QC, Canada.
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102
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Buckinx R, Timmermans JP. Targeting the gastrointestinal tract with viral vectors: state of the art and possible applications in research and therapy. Histochem Cell Biol 2016; 146:709-720. [PMID: 27665281 DOI: 10.1007/s00418-016-1496-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/12/2016] [Indexed: 12/11/2022]
Abstract
While there is a large body of preclinical data on the use of viral vectors in gene transfer, relatively little is known about viral gene transfer in the gastrointestinal tract. Viral vector technology is especially underused in the field of neurogastroenterology when compared to brain research. This review provides an overview of the studies employing viral vectors-in particular retroviruses, adenoviruses and adeno-associated viruses-to transduce different cell types in the intestine. Early work mainly focused on mucosal transduction, but had limited success due to the harsh luminal conditions in the gastrointestinal tract and the high turnover rate of enterocytes. More recently, several studies have successfully employed viral gene transfer to target the enteric nervous system and its progenitors. Although several hurdles still need to be overcome, in particular on how to augment transduction efficiency and specific cell targeting, viral vector technology holds strong potential not only as a valid research tool in fundamental gastroenterological research but also as a therapeutic agent in translational (bio)medical research.
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Affiliation(s)
- Roeland Buckinx
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerp, Belgium
| | - Jean-Pierre Timmermans
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerp, Belgium.
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103
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Correia SS, Goosens KA. Input-specific contributions to valence processing in the amygdala. ACTA ACUST UNITED AC 2016; 23:534-43. [PMID: 27634144 PMCID: PMC5026206 DOI: 10.1101/lm.037887.114] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 04/26/2016] [Indexed: 10/25/2022]
Abstract
Reward and punishment are often thought of as opposing processes: rewards and the environmental cues that predict them elicit approach and consummatory behaviors, while punishments drive aversion and avoidance behaviors. This framework suggests that there may be segregated brain circuits for these valenced behaviors. The basolateral amygdala (BLA) is one brain region that contributes to both types of motivated behavior. Individual neurons in the BLA can favor positive over negative valence, or vice versa, but these neurons are intermingled, showing no anatomical segregation. The amygdala receives inputs from many brain areas and current theories posit that encoding of positive versus negative valence by BLA neurons is determined by the wiring of each neuron. Specifically, many projections from other brain areas that respond to positive and negative valence stimuli and predictive cues project strongly to the BLA and likely contribute to valence processing within the BLA. Here we review three of these areas, the basal forebrain, the dorsal raphe nucleus and the ventral tegmental area, and discuss how these may promote encoding of positive and negative valence within the BLA.
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Affiliation(s)
- Susana S Correia
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Ki A Goosens
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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104
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Jensen KHR, Berg RW. CLARITY-compatible lipophilic dyes for electrode marking and neuronal tracing. Sci Rep 2016; 6:32674. [PMID: 27597115 PMCID: PMC5011694 DOI: 10.1038/srep32674] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 05/10/2016] [Indexed: 12/21/2022] Open
Abstract
Fluorescent lipophilic dyes, such as DiI, stain cellular membranes and are used extensively for retrograde/anterograde labeling of neurons as well as for marking the position of extracellular electrodes after electrophysiology. Convenient histological clearing techniques, such as CLARITY, enable immunostaining and imaging of large volumes for 3D-reconstruction. However, such clearing works by removing lipids and, as an unintended consequence, also removes lipophilic dyes. To remedy this wash-out, the molecular structure of the dye can be altered to adhere to both membranes and proteins so the dye remains in the tissue after lipid–clearing. Nevertheless, the capacity of such modified dyes to remain in tissue has not yet been tested. Here, we test dyes with molecular modifications that make them aldehyde-fixable to proteins. We use three Dil–analogue dyes, CM-DiI, SP-DiI and FM 1–43FX that are modified to be CLARITY-compatible candidates. We use the challenging adult, myelin-rich spinal cord tissue, which requires prolonged lipid–clearing, of rats and mice. All three dyes remained in the tissue after lipid–clearing, but CM-DiI had the sharpest and FM 1–43FX the strongest fluorescent signal.
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Affiliation(s)
- Kristian H R Jensen
- University of Copenhagen, Department of Neuroscience and Pharmacology, Copenhagen, DK-2200, Denmark
| | - Rune W Berg
- University of Copenhagen, Department of Neuroscience and Pharmacology, Copenhagen, DK-2200, Denmark
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105
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Blessing D, Déglon N. Adeno-associated virus and lentivirus vectors: a refined toolkit for the central nervous system. Curr Opin Virol 2016; 21:61-66. [PMID: 27559630 DOI: 10.1016/j.coviro.2016.08.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 08/05/2016] [Accepted: 08/08/2016] [Indexed: 12/20/2022]
Abstract
The last two decades have witnessed the increasing instrumentalization of viruses, which have progressively evolved into highly potent gene transfer vehicles for a wide spectrum of applications. In the context of the central nervous system (CNS), their unique gene delivery features and targeting specificities have been exploited not only to improve our understanding of basic neurobiology, but also to investigate diseases or deliver therapeutic candidates. As a result, we have started moving away from the opportunistic use of recombinant vectors that are derived from naturally existing viruses toward the rational engineering of tailored lentivirus (LV) and adeno-associated virus (AAV) vectors for specific use in the CNS.
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Affiliation(s)
- Daniel Blessing
- Laboratory of Cellular and Molecular Neurotherapies (LCMN), Department of Clinical Neurosciences (DNC), Lausanne University Hospital (CHUV), Lausanne, Switzerland; Laboratory of Cellular and Molecular Neurotherapies (LCMN), Neuroscience Research Center, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Nicole Déglon
- Laboratory of Cellular and Molecular Neurotherapies (LCMN), Department of Clinical Neurosciences (DNC), Lausanne University Hospital (CHUV), Lausanne, Switzerland; Laboratory of Cellular and Molecular Neurotherapies (LCMN), Neuroscience Research Center, Lausanne University Hospital (CHUV), Lausanne, Switzerland.
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106
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Treweek JB, Gradinaru V. Extracting structural and functional features of widely distributed biological circuits with single cell resolution via tissue clearing and delivery vectors. Curr Opin Biotechnol 2016; 40:193-207. [PMID: 27393829 DOI: 10.1016/j.copbio.2016.03.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 03/10/2016] [Accepted: 03/15/2016] [Indexed: 12/13/2022]
Abstract
The scientific community has learned a great deal from imaging small and naturally transparent organisms such as nematodes and zebrafish. The consequences of genetic mutations on their organ development and survival can be visualized easily and with high-throughput at the organism-wide scale. In contrast, three-dimensional information is less accessible in mammalian subjects because the heterogeneity of light-scattering tissue elements renders their organs opaque. Likewise, genetically labeling desired circuits across mammalian bodies is prohibitively slow and costly via the transgenic route. Emerging breakthroughs in viral vector engineering, genome editing tools, and tissue clearing can render larger opaque organisms genetically tractable and transparent for whole-organ cell phenotyping, tract tracing and imaging at depth.
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Affiliation(s)
- Jennifer Brooke Treweek
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Viviana Gradinaru
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
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107
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Lee H, Oh WC, Seong J, Kim J. Advanced Fluorescence Protein-Based Synapse-Detectors. Front Synaptic Neurosci 2016; 8:16. [PMID: 27445785 PMCID: PMC4927625 DOI: 10.3389/fnsyn.2016.00016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 06/13/2016] [Indexed: 11/13/2022] Open
Abstract
The complex information-processing capabilities of the central nervous system emerge from intricate patterns of synaptic input-output relationships among various neuronal circuit components. Understanding these capabilities thus requires a precise description of the individual synapses that comprise neural networks. Recent advances in fluorescent protein engineering, along with developments in light-favoring tissue clearing and optical imaging techniques, have rendered light microscopy (LM) a potent candidate for large-scale analyses of synapses, their properties, and their connectivity. Optically imaging newly engineered fluorescent proteins (FPs) tagged to synaptic proteins or microstructures enables the efficient, fine-resolution illumination of synaptic anatomy and function in large neural circuits. Here we review the latest progress in fluorescent protein-based molecular tools for imaging individual synapses and synaptic connectivity. We also identify associated technologies in gene delivery, tissue processing, and computational image analysis that will play a crucial role in bridging the gap between synapse- and system-level neuroscience.
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Affiliation(s)
- Hojin Lee
- Center for Functional Connectomics, Korea Institute of Science and TechnologySeoul, South Korea; Neuroscience Program, Korea University of Science and TechnologyDaejeon, South Korea
| | - Won Chan Oh
- Center for Functional Connectomics, Korea Institute of Science and Technology Seoul, South Korea
| | - Jihye Seong
- Neuroscience Program, Korea University of Science and TechnologyDaejeon, South Korea; Center for Diagnosis Treatment Care of Dementia, Korea Institute of Science and TechnologySeoul, South Korea
| | - Jinhyun Kim
- Center for Functional Connectomics, Korea Institute of Science and TechnologySeoul, South Korea; Neuroscience Program, Korea University of Science and TechnologyDaejeon, South Korea
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108
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El-Shamayleh Y, Ni AM, Horwitz GD. Strategies for targeting primate neural circuits with viral vectors. J Neurophysiol 2016; 116:122-34. [PMID: 27052579 PMCID: PMC4961743 DOI: 10.1152/jn.00087.2016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 04/05/2016] [Indexed: 11/22/2022] Open
Abstract
Understanding how the brain works requires understanding how different types of neurons contribute to circuit function and organism behavior. Progress on this front has been accelerated by optogenetics and chemogenetics, which provide an unprecedented level of control over distinct neuronal types in small animals. In primates, however, targeting specific types of neurons with these tools remains challenging. In this review, we discuss existing and emerging strategies for directing genetic manipulations to targeted neurons in the adult primate central nervous system. We review the literature on viral vectors for gene delivery to neurons, focusing on adeno-associated viral vectors and lentiviral vectors, their tropism for different cell types, and prospects for new variants with improved efficacy and selectivity. We discuss two projection targeting approaches for probing neural circuits: anterograde projection targeting and retrograde transport of viral vectors. We conclude with an analysis of cell type-specific promoters and other nucleotide sequences that can be used in viral vectors to target neuronal types at the transcriptional level.
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Affiliation(s)
- Yasmine El-Shamayleh
- Department of Physiology and Biophysics and Washington National Primate Research Center, University of Washington, Seattle, Washington; and
| | - Amy M Ni
- Department of Neuroscience and Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Gregory D Horwitz
- Department of Physiology and Biophysics and Washington National Primate Research Center, University of Washington, Seattle, Washington; and
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109
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Porrero C, Rodríguez-Moreno J, Quetglas JI, Smerdou C, Furuta T, Clascá F. A Simple and Efficient In Vivo Non-viral RNA Transfection Method for Labeling the Whole Axonal Tree of Individual Adult Long-Range Projection Neurons. Front Neuroanat 2016; 10:27. [PMID: 27047347 PMCID: PMC4796015 DOI: 10.3389/fnana.2016.00027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 03/04/2016] [Indexed: 11/13/2022] Open
Abstract
We report a highly efficient, simple, and non-infective method for labeling individual long-range projection neurons (LRPNs) in a specific location with enough sparseness and intensity to allow complete and unambiguous reconstructions of their entire axonal tree. The method is based on the "in vivo" transfection of a large RNA construct that drives the massive expression of green fluorescent protein. The method combines two components: injection of a small volume of a hyperosmolar NaCl solution containing the Pal-eGFP-Sindbis RNA construct (Furuta et al., 2001), followed by the application of high-frequency electric current pulses through the micropipette tip. We show that, although each component alone increases transfection efficacy, compared to simple volume injections of standard RNA solution, the highest efficacy (85.7%) is achieved by the combination of both components. In contrast with the infective viral Sindbis vector, RNA transfection occurs exclusively at the position of the injection micropipette tip. This method simplifies consistently labeling one or a few isolated neurons per brain, a strategy that allows unambiguously resolving and quantifying the brain-wide and often multi-branched monosynaptic circuits created by LRPNs.
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Affiliation(s)
- César Porrero
- Department of Anatomy and Neuroscience, School of Medicine, Autónoma University Madrid, Spain
| | - Javier Rodríguez-Moreno
- Department of Anatomy and Neuroscience, School of Medicine, Autónoma University Madrid, Spain
| | - José I Quetglas
- Laboratorio de Vectores, Centro de Investigación Médica AplicadaPamplona, Spain; Instituto de Investigación Sanitaria de Navarra, Navarra Institute for Health ResearchPamplona, Spain
| | - Cristian Smerdou
- Laboratorio de Vectores, Centro de Investigación Médica AplicadaPamplona, Spain; Instituto de Investigación Sanitaria de Navarra, Navarra Institute for Health ResearchPamplona, Spain
| | - Takahiro Furuta
- Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University Kyoto, Japan
| | - Francisco Clascá
- Department of Anatomy and Neuroscience, School of Medicine, Autónoma University Madrid, Spain
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110
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Reardon TR, Murray AJ, Turi GF, Wirblich C, Croce KR, Schnell MJ, Jessell TM, Losonczy A. Rabies Virus CVS-N2c(ΔG) Strain Enhances Retrograde Synaptic Transfer and Neuronal Viability. Neuron 2016; 89:711-24. [PMID: 26804990 DOI: 10.1016/j.neuron.2016.01.004] [Citation(s) in RCA: 182] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 09/22/2015] [Accepted: 12/24/2015] [Indexed: 12/20/2022]
Abstract
Virally based transsynaptic tracing technologies are powerful experimental tools for neuronal circuit mapping. The glycoprotein-deletion variant of the SAD-B19 vaccine strain rabies virus (RABV) has been the reagent of choice in monosynaptic tracing, since it permits the mapping of synaptic inputs to genetically marked neurons. Since its introduction, new helper viruses and reagents that facilitate complementation have enhanced the efficiency of SAD-B19(ΔG) transsynaptic transfer, but there has been little focus on improvements to the core RABV strain. Here we generate a new deletion mutant strain, CVS-N2c(ΔG), and examine its neuronal toxicity and efficiency in directing retrograde transsynaptic transfer. We find that by comparison with SAD-B19(ΔG), the CVS-N2c(ΔG) strain exhibits a reduction in neuronal toxicity and a marked enhancement in transsynaptic neuronal transfer. We conclude that the CVS-N2c(ΔG) strain provides a more effective means of mapping neuronal circuitry and of monitoring and manipulating neuronal activity in vivo in the mammalian CNS.
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Affiliation(s)
- Thomas R Reardon
- Departments of Neuroscience and Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA
| | - Andrew J Murray
- Departments of Neuroscience and Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA.
| | - Gergely F Turi
- Department of Neuroscience, Columbia University, New York, NY 10032, USA
| | - Christoph Wirblich
- Department of Microbiology and Immunology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Katherine R Croce
- Departments of Neuroscience and Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA
| | - Matthias J Schnell
- Department of Microbiology and Immunology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Thomas M Jessell
- Departments of Neuroscience and Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10032, USA.
| | - Attila Losonczy
- Department of Neuroscience, Columbia University, New York, NY 10032, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10032, USA
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111
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Beier KT, Mundell NA, Pan YA, Cepko CL. Anterograde or Retrograde Transsynaptic Circuit Tracing in Vertebrates with Vesicular Stomatitis Virus Vectors. ACTA ACUST UNITED AC 2016; 74:1.26.1-1.26.27. [PMID: 26729030 DOI: 10.1002/0471142301.ns0126s74] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Viruses have been used as transsynaptic tracers, allowing one to map the inputs and outputs of neuronal populations, due to their ability to replicate in neurons and transmit in vivo only across synaptically connected cells. To date, their use has been largely restricted to mammals. In order to explore the use of such viruses in an expanded host range, we tested the transsynaptic tracing ability of recombinant vesicular stomatitis virus (rVSV) vectors in a variety of organisms. Successful infection and gene expression were achieved in a wide range of organisms, including vertebrate and invertebrate model organisms. Moreover, rVSV enabled transsynaptic tracing of neural circuitry in predictable directions dictated by the viral envelope glycoprotein (G), derived from either VSV or rabies virus (RABV). Anterograde and retrograde labeling, from initial infection and/or viral replication and transmission, was observed in Old and New World monkeys, seahorses, jellyfish, zebrafish, chickens, and mice. These vectors are widely applicable for gene delivery, afferent tract tracing, and/or directional connectivity mapping. Here, we detail the use of these vectors and provide protocols for propagating virus, changing the surface glycoprotein, and infecting multiple organisms using several injection strategies.
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Affiliation(s)
- Kevin T Beier
- Department of Biology, Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California.,These authors contributed equally to this unit
| | - Nathan A Mundell
- Department of Genetics, Department of Ophthalmology, Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts.,These authors contributed equally to this unit
| | - Y Albert Pan
- Department of Neuroscience and Regenerative Medicine, Department of Neurology, James & Jean Culver Vision Discovery Institute, Medical College of Georgia, Augusta University, Augusta, Georgia.,These authors contributed equally to this unit
| | - Constance L Cepko
- Department of Genetics, Department of Ophthalmology, Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts
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112
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113
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Architectonic Mapping of the Human Brain beyond Brodmann. Neuron 2015; 88:1086-1107. [DOI: 10.1016/j.neuron.2015.12.001] [Citation(s) in RCA: 266] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 10/13/2015] [Accepted: 11/20/2015] [Indexed: 12/25/2022]
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114
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Gründemann J, Lüthi A. Ensemble coding in amygdala circuits for associative learning. Curr Opin Neurobiol 2015; 35:200-6. [PMID: 26531780 DOI: 10.1016/j.conb.2015.10.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 10/06/2015] [Accepted: 10/07/2015] [Indexed: 01/18/2023]
Abstract
Associative fear learning in the basolateral amygdala (BLA) is crucial for an animal's survival upon environmental threats. BLA neurons are defined on the basis of their projection target, genetic markers, and associated function. BLA principal neuron responses to threat signaling stimuli are potentiated upon associative fear learning, which is tightly controlled by defined interneuron subpopulations. In addition, BLA population activity correlates with behavioral states and threat or safety signals. BLA neuronal ensembles activated by different behavioral signals can be identified using immediate early gene markers. The next challenge will be to determine the activity patterns and coding properties of defined BLA ensembles in relation to the whole neuronal population.
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Affiliation(s)
- Jan Gründemann
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Andreas Lüthi
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland.
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