1
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Zengel J, Wang YX, Seo JW, Ning K, Hamilton JN, Wu B, Raie M, Holbrook C, Su S, Clements DR, Pillay S, Puschnik AS, Winslow MM, Idoyaga J, Nagamine CM, Sun Y, Mahajan VB, Ferrara KW, Blau HM, Carette JE. Hardwiring tissue-specific AAV transduction in mice through engineered receptor expression. Nat Methods 2023; 20:1070-1081. [PMID: 37291262 PMCID: PMC10333121 DOI: 10.1038/s41592-023-01896-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 04/25/2023] [Indexed: 06/10/2023]
Abstract
The development of transgenic mouse models that express genes of interest in specific cell types has transformed our understanding of basic biology and disease. However, generating these models is time- and resource-intensive. Here we describe a model system, SELective Expression and Controlled Transduction In Vivo (SELECTIV), that enables efficient and specific expression of transgenes by coupling adeno-associated virus (AAV) vectors with Cre-inducible overexpression of the multi-serotype AAV receptor, AAVR. We demonstrate that transgenic AAVR overexpression greatly increases the efficiency of transduction of many diverse cell types, including muscle stem cells, which are normally refractory to AAV transduction. Superior specificity is achieved by combining Cre-mediated AAVR overexpression with whole-body knockout of endogenous Aavr, which is demonstrated in heart cardiomyocytes, liver hepatocytes and cholinergic neurons. The enhanced efficacy and exquisite specificity of SELECTIV has broad utility in development of new mouse model systems and expands the use of AAV for gene delivery in vivo.
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Affiliation(s)
- James Zengel
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Yu Xin Wang
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
- Center for Genetic Disorders and Aging, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Jai Woong Seo
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Ke Ning
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, USA
| | - James N Hamilton
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Bo Wu
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Marina Raie
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Colin Holbrook
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Shiqi Su
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Derek R Clements
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
- Immunology Program, Stanford University School of Medicine, Stanford, CA, USA
| | - Sirika Pillay
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Andreas S Puschnik
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Monte M Winslow
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Juliana Idoyaga
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
- Immunology Program, Stanford University School of Medicine, Stanford, CA, USA
| | - Claude M Nagamine
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, USA
- Palo Alto Veterans Administration, Palo Alto, CA, USA
| | - Vinit B Mahajan
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, USA
- Palo Alto Veterans Administration, Palo Alto, CA, USA
| | - Katherine W Ferrara
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Helen M Blau
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Jan E Carette
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA.
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2
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Merlin S, Vidyasagar T. Optogenetics in primate cortical networks. Front Neuroanat 2023; 17:1193949. [PMID: 37284061 PMCID: PMC10239886 DOI: 10.3389/fnana.2023.1193949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Accepted: 05/08/2023] [Indexed: 06/08/2023] Open
Abstract
The implementation of optogenetics in studies on non-human primates has generally proven quite difficult, but recent successes have paved the way for its rapid increase. Limitations in the genetic tractability in primates, have been somewhat overcome by implementing tailored vectors and promoters to maximize expression and specificity in primates. More recently, implantable devices, including microLED arrays, have made it possible to deliver light deeper into brain tissue, allowing targeting of deeper structures. However, the greatest limitation in applying optogenetics to the primate brain is the complex connections that exist within many neural circuits. In the past, relatively cruder methods such as cooling or pharmacological blockade have been used to examine neural circuit functions, though their limitations were well recognized. In some ways, similar shortcomings remain for optogenetics, with the ability to target a single component of complex neural circuits being the greatest challenge in applying optogenetics to systems neuroscience in primate brains. Despite this, some recent approaches combining Cre-expressing and Cre-dependent vectors have overcome some of these limitations. Here we suggest that optogenetics provides its greatest advantage to systems neuroscientists when applied as a specific tool to complement the techniques of the past, rather than necessarily replacing them.
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Affiliation(s)
- Sam Merlin
- Medical Science, School of Science, Western Sydney University, Campbelltown, NSW, Australia
| | - Trichur Vidyasagar
- Department of Optometry and Vision Sciences, School of Health Science, The University of Melbourne, Parkville, VIC, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
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3
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Saha R, Wu K, Bloom RP, Liang S, Tonini D, Wang JP. A review on magnetic and spintronic neurostimulation: challenges and prospects. NANOTECHNOLOGY 2022; 33:182004. [PMID: 35013010 DOI: 10.1088/1361-6528/ac49be] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 01/10/2022] [Indexed: 06/14/2023]
Abstract
In the treatment of neurodegenerative, sensory and cardiovascular diseases, electrical probes and arrays have shown quite a promising success rate. However, despite the outstanding clinical outcomes, their operation is significantly hindered by non-selective control of electric fields. A promising alternative is micromagnetic stimulation (μMS) due to the high permeability of magnetic field through biological tissues. The induced electric field from the time-varying magnetic field generated by magnetic neurostimulators is used to remotely stimulate neighboring neurons. Due to the spatial asymmetry of the induced electric field, high spatial selectivity of neurostimulation has been realized. Herein, some popular choices of magnetic neurostimulators such as microcoils (μcoils) and spintronic nanodevices are reviewed. The neurostimulator features such as power consumption and resolution (aiming at cellular level) are discussed. In addition, the chronic stability and biocompatibility of these implantable neurostimulator are commented in favor of further translation to clinical settings. Furthermore, magnetic nanoparticles (MNPs), as another invaluable neurostimulation material, has emerged in recent years. Thus, in this review we have also included MNPs as a remote neurostimulation solution that overcomes physical limitations of invasive implants. Overall, this review provides peers with the recent development of ultra-low power, cellular-level, spatially selective magnetic neurostimulators of dimensions within micro- to nano-range for treating chronic neurological disorders. At the end of this review, some potential applications of next generation neuro-devices have also been discussed.
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Affiliation(s)
- Renata Saha
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, United States of America
| | - Kai Wu
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, United States of America
| | - Robert P Bloom
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, United States of America
| | - Shuang Liang
- Department of Chemical Engineering and Material Science, University of Minnesota, Minneapolis, MN 55455, United States of America
| | - Denis Tonini
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, United States of America
| | - Jian-Ping Wang
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, United States of America
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4
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Halverson HE, Kim J, Khilkevich A, Mauk MD, Augustine GJ. Feedback inhibition underlies new computational functions of cerebellar interneurons. eLife 2022; 11:77603. [PMID: 36480240 PMCID: PMC9771357 DOI: 10.7554/elife.77603] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 12/07/2022] [Indexed: 12/13/2022] Open
Abstract
The function of a feedback inhibitory circuit between cerebellar Purkinje cells and molecular layer interneurons (MLIs) was defined by combining optogenetics, neuronal activity recordings both in cerebellar slices and in vivo, and computational modeling. Purkinje cells inhibit a subset of MLIs in the inner third of the molecular layer. This inhibition is non-reciprocal, short-range (less than 200 μm) and is based on convergence of one to two Purkinje cells onto MLIs. During learning-related eyelid movements in vivo, the activity of a subset of MLIs progressively increases as Purkinje cell activity decreases, with Purkinje cells usually leading the MLIs. Computer simulations indicate that these relationships are best explained by the feedback circuit from Purkinje cells to MLIs and that this feedback circuit plays a central role in making cerebellar learning efficient.
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Affiliation(s)
- Hunter E Halverson
- Center for Learning and Memory, The University of TexasAustinUnited States
| | - Jinsook Kim
- Program in Neuroscience & Mental Health, Lee Kong Chian School of Medicine, Nanyang Technological UniversitySingaporeSingapore,Institute of Molecular and Cell BiologySingaporeSingapore
| | - Andrei Khilkevich
- Center for Learning and Memory, The University of TexasAustinUnited States
| | - Michael D Mauk
- Center for Learning and Memory, The University of TexasAustinUnited States,Department of Neuroscience, The University of TexasAustinUnited States
| | - George J Augustine
- Program in Neuroscience & Mental Health, Lee Kong Chian School of Medicine, Nanyang Technological UniversitySingaporeSingapore,Institute of Molecular and Cell BiologySingaporeSingapore
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5
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Martinetti LE, Bonekamp KE, Autio DM, Kim HH, Crandall SR. Short-Term Facilitation of Long-Range Corticocortical Synapses Revealed by Selective Optical Stimulation. Cereb Cortex 2021; 32:1932-1949. [PMID: 34519352 PMCID: PMC9070351 DOI: 10.1093/cercor/bhab325] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/10/2021] [Accepted: 08/11/2021] [Indexed: 11/14/2022] Open
Abstract
Short-term plasticity regulates the strength of central synapses as a function of previous activity. In the neocortex, direct synaptic interactions between areas play a central role in cognitive function, but the activity-dependent regulation of these long-range corticocortical connections and their impact on a postsynaptic target neuron is unclear. Here, we use an optogenetic strategy to study the connections between mouse primary somatosensory and motor cortex. We found that short-term facilitation was strong in both corticocortical synapses, resulting in far more sustained responses than local intracortical and thalamocortical connections. A major difference between pathways was that the synaptic strength and magnitude of facilitation were distinct for individual excitatory cells located across all cortical layers and specific subtypes of GABAergic neurons. Facilitation was dependent on the presynaptic calcium sensor synaptotagmin-7 and altered by several optogenetic approaches. Current-clamp recordings revealed that during repetitive activation, the short-term dynamics of corticocortical synapses enhanced the excitability of layer 2/3 pyramidal neurons, increasing the probability of spiking with activity. Furthermore, the properties of the connections linking primary with secondary somatosensory cortex resemble those between somatosensory-motor areas. These short-term changes in transmission properties suggest long-range corticocortical synapses are specialized for conveying information over relatively extended periods.
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Affiliation(s)
| | | | - Dawn M Autio
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Hye-Hyun Kim
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
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6
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Shapiro JT, Michaud NM, King JL, Crowder NA. Optogenetic Activation of Interneuron Subtypes Modulates Visual Contrast Responses of Mouse V1 Neurons. Cereb Cortex 2021; 32:1110-1124. [PMID: 34411240 DOI: 10.1093/cercor/bhab269] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/08/2021] [Accepted: 07/12/2021] [Indexed: 12/23/2022] Open
Abstract
Interneurons are critical for information processing in the cortex. In vitro optogenetic studies in mouse primary visual cortex (V1) have sketched the connectivity of a local neural circuit comprising excitatory pyramidal neurons and distinct interneuron subtypes that express parvalbumin (Pvalb+), somatostatin (SOM+), or vasoactive intestinal peptide (VIP+). However, in vivo studies focusing on V1 orientation tuning have ascribed discrepant computational roles to specific interneuron subtypes. Here, we sought to clarify the differences between interneuron subtypes by examining the effects of optogenetic activation of Pvalb+, SOM+, or VIP+ interneurons on contrast tuning of V1 neurons while also accounting for cortical depth and photostimulation intensity. We found that illumination of the cortical surface produced a similar spectrum of saturating additive photostimulation effects in all 3 interneuron subtypes, which varied with cortical depth rather than light intensity in Pvalb+ and SOM+ cells. Pyramidal cell modulation was well explained by a conductance-based model that incorporated these interneuron photostimulation effects.
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Affiliation(s)
- Jared T Shapiro
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Nicole M Michaud
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Jillian L King
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Nathan A Crowder
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
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7
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Shin S, Santi A, Huang S. Conditional Pten knockout in parvalbumin- or somatostatin-positive neurons sufficiently leads to autism-related behavioral phenotypes. Mol Brain 2021; 14:24. [PMID: 33504340 PMCID: PMC7839207 DOI: 10.1186/s13041-021-00731-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 01/05/2021] [Indexed: 02/07/2023] Open
Abstract
Disrupted GABAergic neurons have been extensively described in brain tissues from individuals with autism spectrum disorder (ASD) and animal models for ASD. However, the contribution of these aberrant inhibitory neurons to autism-related behavioral phenotypes is not well understood. We examined ASD-related behaviors in mice with conditional Pten knockout in parvalbumin (PV)-expressing or somatostatin (Sst)-expressing neurons, two common subtypes of GABAergic neurons. We found that mice with deletion of Pten in either PV-neurons or Sst-neurons displayed social deficits, repetitive behaviors and impaired motor coordination/learning. In addition, mice with one copy of Pten deletion in PV-neurons exhibited hyperlocomotion in novel open fields and home cages. We also examined anxiety behaviors and found that mice with Pten deletion in Sst-neurons displayed anxiety-like behaviors, while mice with Pten deletion in PV-neurons exhibited anxiolytic-like behaviors. These behavioral assessments demonstrate that Pten knockout in the subtype of inhibitory neurons sufficiently gives rise to ASD-core behaviors, providing evidence that both PV- and Sst-neurons may play a critical role in ASD symptoms.
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Affiliation(s)
- Sangyep Shin
- Program in Neuroscience, Hussman Institute for Autism, Baltimore, MD 21201 USA
| | - Andrea Santi
- Program in Neuroscience, Hussman Institute for Autism, Baltimore, MD 21201 USA
| | - Shiyong Huang
- Program in Neuroscience, Hussman Institute for Autism, Baltimore, MD 21201 USA
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8
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Li Y, Ritchie EM, Steinke CL, Qi C, Chen L, Zheng B, Jin Y. Activation of MAP3K DLK and LZK in Purkinje cells causes rapid and slow degeneration depending on signaling strength. eLife 2021; 10:63509. [PMID: 33475086 PMCID: PMC7870138 DOI: 10.7554/elife.63509] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 01/19/2021] [Indexed: 12/16/2022] Open
Abstract
The conserved MAP3K Dual-Leucine-Zipper Kinase (DLK) and Leucine-Zipper-bearing Kinase (LZK) can activate JNK via MKK4 or MKK7. These two MAP3Ks share similar biochemical activities and undergo auto-activation upon increased expression. Depending on cell-type and nature of insults DLK and LZK can induce pro-regenerative, pro-apoptotic or pro-degenerative responses, although the mechanistic basis of their action is not well understood. Here, we investigated these two MAP3Ks in cerebellar Purkinje cells using loss- and gain-of function mouse models. While loss of each or both kinases does not cause discernible defects in Purkinje cells, activating DLK causes rapid death and activating LZK leads to slow degeneration. Each kinase induces JNK activation and caspase-mediated apoptosis independent of each other. Significantly, deleting CELF2, which regulates alternative splicing of Map2k7, strongly attenuates Purkinje cell degeneration induced by LZK, but not DLK. Thus, controlling the activity levels of DLK and LZK is critical for neuronal survival and health.
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Affiliation(s)
- Yunbo Li
- Neurobiology Section, Division of Biological Sciences, University of California San DiegoLa JollaUnited States
| | - Erin M Ritchie
- Neurobiology Section, Division of Biological Sciences, University of California San DiegoLa JollaUnited States
| | - Christopher L Steinke
- Neurobiology Section, Division of Biological Sciences, University of California San DiegoLa JollaUnited States
| | - Cai Qi
- Neurobiology Section, Division of Biological Sciences, University of California San DiegoLa JollaUnited States
| | - Lizhen Chen
- Neurobiology Section, Division of Biological Sciences, University of California San DiegoLa JollaUnited States
| | - Binhai Zheng
- Department of Neurosciences, School of Medicine, University of California San DiegoLa JollaUnited States,VA San Diego Healthcare SystemSan DiegoUnited States
| | - Yishi Jin
- Neurobiology Section, Division of Biological Sciences, University of California San DiegoLa JollaUnited States,Department of Neurosciences, School of Medicine, University of California San DiegoLa JollaUnited States,Kavli Institute of Brain and Mind, University of California San DiegoLa JollaUnited States
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9
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Kim J, Augustine GJ. Molecular Layer Interneurons: Key Elements of Cerebellar Network Computation and Behavior. Neuroscience 2020; 462:22-35. [PMID: 33075461 DOI: 10.1016/j.neuroscience.2020.10.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/02/2020] [Accepted: 10/05/2020] [Indexed: 02/05/2023]
Abstract
Molecular layer interneurons (MLIs) play an important role in cerebellar information processing by controlling Purkinje cell (PC) activity via inhibitory synaptic transmission. A local MLI network, constructed from both chemical and electrical synapses, is organized into spatially structured clusters that amplify feedforward and lateral inhibition to shape the temporal and spatial patterns of PC activity. Several recent in vivo studies indicate that such MLI circuits contribute not only to sensorimotor information processing, but also to precise motor coordination and cognitive processes. Here, we review current understanding of the organization of MLI circuits and their roles in the function of the mammalian cerebellum.
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Affiliation(s)
- Jinsook Kim
- Lee Kong Chian School of Medicine Nanyang Technological University Singapore 308238, Singapore
| | - George J Augustine
- Lee Kong Chian School of Medicine Nanyang Technological University Singapore 308238, Singapore.
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10
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Sanfilippo C, Musumeci G, Kazakova M, Mazzone V, Castrogiovanni P, Imbesi R, Di Rosa M. GNG13 Is a Potential Marker of the State of Health of Alzheimer's Disease Patients' Cerebellum. J Mol Neurosci 2020; 71:1046-1060. [PMID: 33057964 DOI: 10.1007/s12031-020-01726-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 10/01/2020] [Indexed: 12/12/2022]
Abstract
Brain regions such as the cerebellum (CB) have been neglected for a long time in the study of Alzheimer's disease (AD) pathogenesis. In reference to a new emerging hypothesis according to which there is an altered cerebellar synaptic processing in AD, we verified the possible role played by new biomarkers in the CB of AD patients compared with not-demented healthy control subjects (NDHS). Using a bioinformatics approach, we have collected several microarray datasets and obtained 626 cerebella sample biopsies belonging to subjects who did not die from causes related to neurological diseases and 199 cerebella belonging to AD. The analysis of logical relations between the transcriptome dataset highlighted guanine nucleotide-binding protein (G protein) gamma 13 (GNG13) as a potential new biomarker for Purkinje cells (PCs). We have correlated GNG13 expression levels with already widely existing bibliography of PC marker genes, such as Purkinje cell protein 2 (PCP2), Purkinje cell protein 4 (PCP4), and cerebellin 3 (CBLN3). We showed that expression levels of GNG13 and PCP2, PCP4, and CBLN3 were significantly correlated with each other in NDHS and in AD and significantly reduced in AD patients compared with NDHS subjects. In addition, we highlighted a negative correlation between the expression levels of PC biomarkers and age. From the outcome of our investigation, it is possible to conclude that the identification of GNG13 as a potentially biomarker in PCs represents also a state of health of CB, in association with the expression of PCP2, PCP4, and CBLN3.
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Affiliation(s)
- Cristina Sanfilippo
- IRCCS Centro Neurolesi Bonino Pulejo, Strada Statale 113, C.da Casazza, 98124, Messina, Italy
| | - Giuseppe Musumeci
- Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology Section, School of Medicine, University of Catania, Catania, Italy
| | - Maria Kazakova
- Department of Medical Biology, Medical Faculty, Medical University, Plovdiv, Bulgaria
| | - Venera Mazzone
- Department G.F. Ingrassia, Anatomy, School of Medicine, University of Catania, Catania, Italy
| | - Paola Castrogiovanni
- Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology Section, School of Medicine, University of Catania, Catania, Italy
| | - Rosa Imbesi
- Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology Section, School of Medicine, University of Catania, Catania, Italy
| | - Michelino Di Rosa
- Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology Section, School of Medicine, University of Catania, Catania, Italy.
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11
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Babl SS, Rummell BP, Sigurdsson T. The Spatial Extent of Optogenetic Silencing in Transgenic Mice Expressing Channelrhodopsin in Inhibitory Interneurons. Cell Rep 2020; 29:1381-1395.e4. [PMID: 31665647 DOI: 10.1016/j.celrep.2019.09.049] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 08/05/2019] [Accepted: 09/18/2019] [Indexed: 02/09/2023] Open
Abstract
Optogenetic stimulation of inhibitory interneurons has become a commonly used strategy for silencing neuronal activity. This is typically achieved using transgenic mice expressing excitatory opsins in inhibitory interneurons throughout the brain, raising the question of how spatially extensive the resulting inhibition is. Here, we characterize neuronal silencing in VGAT-ChR2 mice, which express channelrhodopsin-2 in inhibitory interneurons, as a function of light intensity and distance from the light source in several cortical and subcortical regions. We show that light stimulation, even at relatively low intensities, causes inhibition not only in brain regions targeted for silencing but also in their subjacent areas. In contrast, virus-mediated expression of an inhibitory opsin enables robust silencing that is restricted to the region of opsin expression. Our results reveal important constraints on using inhibitory interneuron activation to silence neuronal activity and emphasize the necessity of carefully controlling light stimulation parameters when using this silencing strategy.
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Affiliation(s)
- Susanne Stefanie Babl
- Institute of Neurophysiology, Neuroscience Center, Goethe University, Frankfurt, Germany
| | - Brian Paul Rummell
- Institute of Neurophysiology, Neuroscience Center, Goethe University, Frankfurt, Germany
| | - Torfi Sigurdsson
- Institute of Neurophysiology, Neuroscience Center, Goethe University, Frankfurt, Germany.
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12
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Functional interrogation of neural circuits with virally transmitted optogenetic tools. J Neurosci Methods 2020; 345:108905. [PMID: 32795553 DOI: 10.1016/j.jneumeth.2020.108905] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 08/03/2020] [Accepted: 08/06/2020] [Indexed: 12/12/2022]
Abstract
The vertebrate brain comprises a plethora of cell types connected by intertwined pathways. Optogenetics enriches the neuroscientific tool set for disentangling these neuronal circuits in a manner which exceeds the spatio-temporal precision of previously existing techniques. Technically, optogenetics can be divided in three types of optical and genetic combinations: (1) it is primarily understood as the manipulation of the activity of genetically modified cells (typically neurons) with light, i.e. optical actuators. (2) A second combination refers to visualizing the activity of genetically modified cells (again typically neurons), i.e. optical sensors. (3) A completely different interpretation of optogenetics refers to the light activated expression of a genetically induced construct. Here, we focus on the first two types of optogenetics, i.e. the optical actuators and sensors in an attempt to give an overview into the topic. We first cover methods to express opsins into neurons and introduce strategies of targeting specific neuronal populations in different animal species. We then summarize combinations of optogenetics with behavioral read out and neuronal imaging. Finally, we give an overview of the current state-of-the-art and an outlook on future perspectives.
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13
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Aswendt M, Pallast N, Wieters F, Baues M, Hoehn M, Fink GR. Lesion Size- and Location-Dependent Recruitment of Contralesional Thalamus and Motor Cortex Facilitates Recovery after Stroke in Mice. Transl Stroke Res 2020; 12:87-97. [PMID: 32166716 PMCID: PMC7803721 DOI: 10.1007/s12975-020-00802-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/06/2020] [Accepted: 03/03/2020] [Indexed: 01/01/2023]
Abstract
Brain lesions caused by cerebral ischemia or hemorrhage lead to a local breakdown of energy homeostasis followed by irreversible cell death and long-term impairment. Importantly, local brain lesions also generate remote functional and structural disturbances, which contribute to the behavioral deficit but also impact the recovery of function. While spontaneous recovery has been associated with endogenous repair mechanisms at the vascular, neural, and immune cell levels, the impact of structural plasticity on sensory-motor dysfunction and recovery thereof remains to be elucidated by longitudinal imaging in a mouse model. Here, we applied behavioral assessments, in vivo fiber tracking, and histological validation in a photothrombotic stroke mouse model. Atlas-based whole-brain structural connectivity analysis and ex vivo histology revealed secondary neurodegeneration in the ipsilesional brain areas, mostly in the dorsal sensorimotor area of the thalamus. Furthermore, we describe for the first time a lesion size-dependent increase in structural connectivity between the contralesional primary motor cortex and thalamus with the ipsilesional cortex. The involvement of the contralesional hemisphere was associated with improved functional recovery relative to lesion size. This study highlights the importance of in vivo fiber tracking and the role of the contralesional hemisphere during spontaneous functional improvement as a potential novel stroke biomarker and therapeutic targets.
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Affiliation(s)
- Markus Aswendt
- Department of Neurology, Faculty of Medicine, University of Cologne and University Hospital Cologne, Kerpener Strasse, 62 50937, Cologne, Germany. .,Cognitive Neuroscience, Research Center Juelich, Institute of Neuroscience and Medicine (INM-3), Juelich, Germany.
| | - Niklas Pallast
- Department of Neurology, Faculty of Medicine, University of Cologne and University Hospital Cologne, Kerpener Strasse, 62 50937, Cologne, Germany
| | - Frederique Wieters
- Department of Neurology, Faculty of Medicine, University of Cologne and University Hospital Cologne, Kerpener Strasse, 62 50937, Cologne, Germany
| | - Mayan Baues
- Department of Neurology, Faculty of Medicine, University of Cologne and University Hospital Cologne, Kerpener Strasse, 62 50937, Cologne, Germany
| | - Mathias Hoehn
- Cognitive Neuroscience, Research Center Juelich, Institute of Neuroscience and Medicine (INM-3), Juelich, Germany.,Department of Radiology, Leiden University Medical Center, Leiden, Netherlands
| | - Gereon R Fink
- Department of Neurology, Faculty of Medicine, University of Cologne and University Hospital Cologne, Kerpener Strasse, 62 50937, Cologne, Germany.,Cognitive Neuroscience, Research Center Juelich, Institute of Neuroscience and Medicine (INM-3), Juelich, Germany
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14
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Imayoshi I, Tabuchi S, Matsumoto M, Kitano S, Miyachi H, Kageyama R, Yamanaka A. Light-induced silencing of neural activity in Rosa26 knock-in and BAC transgenic mice conditionally expressing the microbial halorhodopsin eNpHR3. Sci Rep 2020; 10:3191. [PMID: 32081938 PMCID: PMC7035371 DOI: 10.1038/s41598-020-59984-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 02/06/2020] [Indexed: 12/25/2022] Open
Abstract
An engineered light-inducible chloride pump, Natronomonas pharaonis halorhodopsin 3 (eNpHR3) enables temporally and spatially precise inhibition of genetically defined cell populations in the intact nervous tissues. In this report, we show the generation of new mouse strains that express eNpHR3-EYFP fusion proteins after Cre- and/or Flp-mediated recombination to optically inhibit neuronal activity. In these mouse strains, Cre/Flp recombination induced high levels of opsin expression. We confirmed their light-induced activities by brain slice whole-cell patch clamp experiments. eNpHR3-expressing neurons were optically hyperpolarized and silenced from firing action potentials. In prolonged silencing of action potentials, eNpHR3 was superior to eNpHR2, a former version of the engineered pump. Thus, these eNpHR3 mouse strains offer reliable genetic tools for light-induced inhibiting of neuronal activity in defined sets of neurons.
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Affiliation(s)
- Itaru Imayoshi
- Research Center for Dynamic Living Systems, Graduate School of Biostudies, Kyoto University, Kyoto, 606-8501, Japan. .,Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, 606-8507, Japan. .,World Premier International Research Initiative-Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto, 606-8501, Japan.
| | - Sawako Tabuchi
- Research Institute of Environmental Medicine, Nagoya University, Nagoya, 464-8601, Japan
| | - Mami Matsumoto
- Research Center for Dynamic Living Systems, Graduate School of Biostudies, Kyoto University, Kyoto, 606-8501, Japan.,Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, 606-8507, Japan
| | - Satsuki Kitano
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, 606-8507, Japan
| | - Hitoshi Miyachi
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, 606-8507, Japan
| | - Ryoichiro Kageyama
- Research Center for Dynamic Living Systems, Graduate School of Biostudies, Kyoto University, Kyoto, 606-8501, Japan. .,Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, 606-8507, Japan. .,World Premier International Research Initiative-Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto, 606-8501, Japan.
| | - Akihiro Yamanaka
- Research Institute of Environmental Medicine, Nagoya University, Nagoya, 464-8601, Japan
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15
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Goyer D, Roberts MT. Long-range Channelrhodopsin-assisted Circuit Mapping of Inferior Colliculus Neurons with Blue and Red-shifted Channelrhodopsins. J Vis Exp 2020. [PMID: 32090997 DOI: 10.3791/60760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
When investigating neural circuits, a standard limitation of the in vitro patch clamp approach is that axons from multiple sources are often intermixed, making it difficult to isolate inputs from individual sources with electrical stimulation. However, by using channelrhodopsin assisted circuit mapping (CRACM), this limitation can now be overcome. Here, we report a method to use CRACM to map ascending inputs from lower auditory brainstem nuclei and commissural inputs to an identified class of neurons in the inferior colliculus (IC), the midbrain nucleus of the auditory system. In the IC, local, commissural, ascending, and descending axons are heavily intertwined and therefore indistinguishable with electrical stimulation. By injecting a viral construct to drive expression of a channelrhodopsin in a presynaptic nucleus, followed by patch clamp recording to characterize the presence and physiology of channelrhodopsin-expressing synaptic inputs, projections from a specific source to a specific population of IC neurons can be mapped with cell type-specific accuracy. We show that this approach works with both Chronos, a blue light-activated channelrhodopsin, and ChrimsonR, a red-shifted channelrhodopsin. In contrast to previous reports from the forebrain, we find that ChrimsonR is robustly trafficked down the axons of dorsal cochlear nucleus principal neurons, indicating that ChrimsonR may be a useful tool for CRACM experiments in the brainstem. The protocol presented here includes detailed descriptions of the intracranial virus injection surgery, including stereotaxic coordinates for targeting injections to the dorsal cochlear nucleus and IC of mice, and how to combine whole cell patch clamp recording with channelrhodopsin activation to investigate long-range projections to IC neurons. Although this protocol is tailored to characterizing auditory inputs to the IC, it can be easily adapted to investigate other long-range projections in the auditory brainstem and beyond.
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Affiliation(s)
- David Goyer
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan
| | - Michael T Roberts
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan;
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16
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Nakajima M, Schmitt LI. Understanding the circuit basis of cognitive functions using mouse models. Neurosci Res 2019; 152:44-58. [PMID: 31857115 DOI: 10.1016/j.neures.2019.12.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 12/01/2019] [Accepted: 12/09/2019] [Indexed: 01/13/2023]
Abstract
Understanding how cognitive functions arise from computations occurring in the brain requires the ability to measure and perturb neural activity while the relevant circuits are engaged for specific cognitive processes. Rapid technical advances have led to the development of new approaches to transiently activate and suppress neuronal activity as well as to record simultaneously from hundreds to thousands of neurons across multiple brain regions during behavior. To realize the full potential of these approaches for understanding cognition, however, it is critical that behavioral conditions and stimuli are effectively designed to engage the relevant brain networks. Here, we highlight recent innovations that enable this combined approach. In particular, we focus on how to design behavioral experiments that leverage the ever-growing arsenal of technologies for controlling and measuring neural activity in order to understand cognitive functions.
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Affiliation(s)
- Miho Nakajima
- McGovern Institute for Brain Research and the Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - L Ian Schmitt
- McGovern Institute for Brain Research and the Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, United States; Center for Brain Science, RIKEN, Wako, Saitama, Japan.
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17
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Affiliation(s)
- Franziska Schneider-Warme
- Institute for Experimental Cardiovascular Medicine, Faculty of Medicine, University Heart Center, Medical Center-University of Freiburg, Elsässer Str. 2Q, 79110 Freiburg, Germany
| | - Ursula Ravens
- Institute for Experimental Cardiovascular Medicine, Faculty of Medicine, University Heart Center, Medical Center-University of Freiburg, Elsässer Str. 2Q, 79110 Freiburg, Germany.,Institute for Physiology, Faculty of Medicine Carl Gustav Carus, TU Dresden, 01307 Dresden, Germany
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18
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Ingram TGJ, King JL, Crowder NA. Divisive Inhibition Prevails During Simultaneous Optogenetic Activation of All Interneuron Subtypes in Mouse Primary Visual Cortex. Front Neural Circuits 2019; 13:40. [PMID: 31191259 PMCID: PMC6546973 DOI: 10.3389/fncir.2019.00040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 05/08/2019] [Indexed: 01/02/2023] Open
Abstract
The mouse primary visual cortex (V1) has become an important brain area for exploring how neural circuits process information. Optogenetic tools have helped to outline the connectivity of a local V1 circuit comprising excitatory pyramidal neurons and several genetically-defined inhibitory interneuron subtypes that express parvalbumin, somatostatin, or vasoactive intestinal peptide. Optogenetic modulation of individual interneuron subtypes can alter the visual responsiveness of pyramidal neurons with distinct forms of inhibition and disinhibition. However, different interneuron subtypes have potentially opposing actions, and the potency of their effects relative to each other remains unclear. Therefore, in this study we simultaneously optogenetically activated all interneuron subtypes during visual processing to explore whether any single inhibitory effect would predominate. This aggregate interneuron activation consistently inhibited pyramidal neurons in a divisive manner, which was essentially identical to the pattern of inhibition produced by activating parvalbumin-expressing interneurons alone.
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Affiliation(s)
- Tony G J Ingram
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Jillian L King
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Nathan A Crowder
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada
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19
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Kilias A, Canales A, Froriep UP, Park S, Egert U, Anikeeva P. Optogenetic entrainment of neural oscillations with hybrid fiber probes. J Neural Eng 2018; 15:056006. [PMID: 29923505 PMCID: PMC6125198 DOI: 10.1088/1741-2552/aacdb9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
OBJECTIVE Optogenetic modulation of neural activity is a ubiquitous tool for basic investigation of brain circuits. While the majority of optogenetic paradigms rely on short light pulses to evoke synchronized activity of optically sensitized cells, many neurobiological processes are associated with slow local field potential (LFP) oscillations. Therefore, we developed a hybrid fiber probe capable of simultaneous electrophysiological recording and optical stimulation and used it to investigate the utility of sinusoidal light stimulation for evoking oscillatory neural activity in vivo across a broad frequency range. APPROACH We fabricated hybrid fiber probes comprising a hollow cylindrical array of 9 electrodes and a flexible optical waveguide integrated within the core. We implanted these probes in the hippocampus of transgenic Thy1-ChR2-YFP mice that broadly express the blue-light sensitive cation channel channelrhodopsin 2 (ChR2) in excitatory neurons across the brain. The effects of the sinusoidal light stimulation were characterized and contrasted with those corresponding to pulsed stimulation in the frequency range of physiological LFP rhythms (3-128 Hz). MAIN RESULTS Within hybrid probes, metal electrode surfaces were vertically aligned with the waveguide tip, which minimized optical stimulation artifacts in neurophysiological recordings. Sinusoidal stimulation resulted in reliable and coherent entrainment of LFP oscillations up to 70 Hz, the cutoff frequency of ChR2, with response amplitudes inversely scaling with the stimulation frequencies. Effectiveness of the stimulation was maintained for two months following implantation. SIGNIFICANCE Alternative stimulation patterns complementing existing pulsed protocols, in particular sinusoidal light stimulation, are a prerequisite for investigating the physiological mechanisms underlying brain rhythms. So far, studies applying sinusoidal stimulation in vivo were limited to single stimulation frequencies. We show the feasibility of sinusoidal stimulation in vivo to induce coherent LFP oscillations across the entire frequency spectrum supported by the gating dynamics of ChR2 and introduce a hybrid fiber probe tailored to continuous light stimulation.
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Affiliation(s)
- Antje Kilias
- Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany
- Biomicrotechnology, Institute for Microsystems Engineering, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Andres Canales
- Department of Materials Science and Engineering, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ulrich P. Froriep
- Department of Materials Science and Engineering, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Simons Center for the Social Brain, Massachusetts Institute of Technology, Hannover, Germany
- Fraunhofer Institute for Toxicology and Experimental Medicine, Hannover, Germany
| | - Seongjun Park
- Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ulrich Egert
- Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany
- Biomicrotechnology, Institute for Microsystems Engineering, University of Freiburg, Freiburg, Germany
| | - Polina Anikeeva
- Department of Materials Science and Engineering, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
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20
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14-3-3 Proteins in Glutamatergic Synapses. Neural Plast 2018; 2018:8407609. [PMID: 29849571 PMCID: PMC5937437 DOI: 10.1155/2018/8407609] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 03/13/2018] [Accepted: 03/27/2018] [Indexed: 11/18/2022] Open
Abstract
The 14-3-3 proteins are a family of proteins that are highly expressed in the brain and particularly enriched at synapses. Evidence accumulated in the last two decades has implicated 14-3-3 proteins as an important regulator of synaptic transmission and plasticity. Here, we will review previous and more recent research that has helped us understand the roles of 14-3-3 proteins at glutamatergic synapses. A key challenge for the future is to delineate the 14-3-3-dependent molecular pathways involved in regulating synaptic functions.
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21
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Berglind F, Andersson M, Kokaia M. Dynamic interaction of local and transhemispheric networks is necessary for progressive intensification of hippocampal seizures. Sci Rep 2018; 8:5669. [PMID: 29618778 PMCID: PMC5884800 DOI: 10.1038/s41598-018-23659-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 03/02/2018] [Indexed: 12/02/2022] Open
Abstract
The detailed mechanisms of progressive intensification of seizures often occurring in epilepsy are not well understood. Animal models of kindling, with progressive intensification of stimulation-induced seizures, have been previously used to investigate alterations in neuronal networks, but has been obscured by limited recording capabilities during electrical stimulations. Remote networks in kindling have been studied by physical deletions of the connected structures or pathways, inevitably leading to structural reorganisations and related adverse effects. We used optogenetics to circumvent the above-mentioned problems inherent to electrical kindling, and chemogenetics to temporarily inhibit rather than ablate the remote interconnected networks. Progressively intensifying afterdischarges (ADs) were induced by repetitive photoactivation of principal neurons in the hippocampus of anaesthetized transgenic mice expressing ChR2. This allowed, during the stimulation, to reveal dynamic increases in local field potentials (LFPs), which coincided with the start of AD intensification. Furthermore, chemogenetic functional inhibition of contralateral hippocampal neurons via hM4D(Gi) receptors abrogated AD progression. These findings demonstrate that, during repeated activation, local circuits undergo acute plastic changes with appearance of additional network discharges (LFPs), leading to transhemispheric recruitment of contralateral dentate gyrus, which seems to be necessary for progressive intensification of ADs.
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Affiliation(s)
- Fredrik Berglind
- Epilepsy Centre, Department of Clinical Sciences, Lund University Hospital, Lund, Sweden
| | - My Andersson
- Epilepsy Centre, Department of Clinical Sciences, Lund University Hospital, Lund, Sweden
| | - Merab Kokaia
- Epilepsy Centre, Department of Clinical Sciences, Lund University Hospital, Lund, Sweden.
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22
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Igarashi H, Ikeda K, Onimaru H, Kaneko R, Koizumi K, Beppu K, Nishizawa K, Takahashi Y, Kato F, Matsui K, Kobayashi K, Yanagawa Y, Muramatsu SI, Ishizuka T, Yawo H. Targeted expression of step-function opsins in transgenic rats for optogenetic studies. Sci Rep 2018; 8:5435. [PMID: 29615713 PMCID: PMC5882906 DOI: 10.1038/s41598-018-23810-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 03/20/2018] [Indexed: 12/12/2022] Open
Abstract
Rats are excellent animal models for experimental neuroscience. However, the application of optogenetics in rats has been hindered because of the limited number of established transgenic rat strains. To accomplish cell-type specific targeting of an optimized optogenetic molecular tool, we generated ROSA26/CAG-floxed STOP-ChRFR(C167A)-Venus BAC rats that conditionally express the step-function mutant channelrhodopsin ChRFR(C167A) under the control of extrinsic Cre recombinase. In primary cultured cortical neurons derived from this reporter rat, only Cre-positive cells expressing ChRFR(C167A) became bi-stable, that is, their excitability was enhanced by blue light and returned to the baseline by yellow~red light. In bigenic pups carrying the Phox2B-Cre driver, ChRFR(C167A) was specifically expressed in the rostral parafacial respiratory group (pFRG) in the medulla, where endogenous Phox2b immunoreactivity was detected. These neurons were sensitive to blue light with an increase in the firing frequency. Thus, this transgenic rat actuator/reporter system should facilitate optogenetic studies involving the effective in vivo manipulation of the activities of specific cell fractions using light of minimal intensity.
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Affiliation(s)
- Hiroyuki Igarashi
- Department of Physiology and Pharmacology, Tohoku University Graduate school of Medicine, Sendai, Japan. .,Research Fellow of the Japan Society for the Promotion of Science (JSPS Research Fellow), Tokyo, Japan.
| | - Keiko Ikeda
- Department of Physiology, International University of Health and Welfare, Narita, Chiba, Japan.,Division of Biology, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Hiroshi Onimaru
- Department of Physiology, Showa University School of Medicine, Shinagawa, Tokyo, Japan
| | - Ryosuke Kaneko
- Department of Genetic and Behavioural Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Kyo Koizumi
- Department of Developmental Biology and Neuroscience, Tohoku University Graduate School of Life Sciences, Sendai, Japan
| | - Kaoru Beppu
- Department of Super-network Brain Physiology, Tohoku University Graduate School of Life Sciences, Sendai, Japan
| | - Kayo Nishizawa
- Department of Molecular Genetics, Institute of Biomedical Sciences, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Yukari Takahashi
- Department of Neuroscience, The Jikei University School of Medicine, Tokyo, Japan
| | - Fusao Kato
- Department of Neuroscience, The Jikei University School of Medicine, Tokyo, Japan
| | - Ko Matsui
- Department of Super-network Brain Physiology, Tohoku University Graduate School of Life Sciences, Sendai, Japan
| | - Kazuto Kobayashi
- Department of Molecular Genetics, Institute of Biomedical Sciences, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioural Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Shin-Ichi Muramatsu
- Division of Neurology, Jichi Medical School, Tochigi, Japan.,Center for Gene & Cell Therapy, The Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Toru Ishizuka
- Department of Developmental Biology and Neuroscience, Tohoku University Graduate School of Life Sciences, Sendai, Japan
| | - Hiromu Yawo
- Department of Physiology and Pharmacology, Tohoku University Graduate school of Medicine, Sendai, Japan. .,Department of Developmental Biology and Neuroscience, Tohoku University Graduate School of Life Sciences, Sendai, Japan.
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23
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Dobbins DL, Klorig DC, Smith T, Godwin DW. Expression of channelrhodopsin-2 localized within the deep CA1 hippocampal sublayer in the Thy1 line 18 mouse. Brain Res 2018; 1679:179-184. [PMID: 29191773 PMCID: PMC5752121 DOI: 10.1016/j.brainres.2017.11.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 11/20/2017] [Accepted: 11/22/2017] [Indexed: 12/21/2022]
Abstract
Optogenetic proteins are powerful tools for advancing our understanding of neural circuitry. However, the precision of optogenetics is dependent in part on the extent to which expression is limited to cells of interest. The Thy1-ChR2 transgenic mouse is commonly used in optogenetic experiments. Although general expression patterns in these animals have been characterized, a detailed evaluation of cell-type specificity is lacking. This information is critical for interpretation of experimental results using these animals. We characterized ChR2 expression under the Thy1promoter in line 18 in comparison to known expression profiles of hippocampal cell types using immunohistochemistry in CA1. ChR2 expression did not colocalize with parvalbumin or calbindin expressing interneurons. However, we found ChR2 expression to be localized in the deep sublayer of CA1 in calbindin-negative pyramidal cells. These findings demonstrate the utility of the Thy1-ChR2-YFP mouse to study the activity and functional role of excitatory neurons located in the deep CA1 pyramidal cell layer.
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Affiliation(s)
- Dorothy L Dobbins
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
| | - David C Klorig
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Thuy Smith
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Dwayne W Godwin
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC, USA
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24
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Gobbo F, Marchetti L, Jacob A, Pinto B, Binini N, Pecoraro Bisogni F, Alia C, Luin S, Caleo M, Fellin T, Cancedda L, Cattaneo A. Activity-dependent expression of Channelrhodopsin at neuronal synapses. Nat Commun 2017; 8:1629. [PMID: 29158498 PMCID: PMC5696361 DOI: 10.1038/s41467-017-01699-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 10/06/2017] [Indexed: 12/14/2022] Open
Abstract
Increasing evidence points to the importance of dendritic spines in the formation and allocation of memories, and alterations of spine number and physiology are associated to memory and cognitive disorders. Modifications of the activity of subsets of synapses are believed to be crucial for memory establishment. However, the development of a method to directly test this hypothesis, by selectively controlling the activity of potentiated spines, is currently lagging. Here we introduce a hybrid RNA/protein approach to regulate the expression of a light-sensitive membrane channel at activated synapses, enabling selective tagging of potentiated spines following the encoding of a novel context in the hippocampus. This approach can be used to map potentiated synapses in the brain and will make it possible to re-activate the neuron only at previously activated synapses, extending current neuron-tagging technologies in the investigation of memory processes.
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Affiliation(s)
- Francesco Gobbo
- Bio@SNS, Scuola Normale Superiore, piazza dei Cavalieri 7, 56126, Pisa, Italy.,NEST, Scuola Normale Superiore, piazza San Silvestro 12, 56127, Pisa, Italy
| | - Laura Marchetti
- Bio@SNS, Scuola Normale Superiore, piazza dei Cavalieri 7, 56126, Pisa, Italy.,NEST, Scuola Normale Superiore, piazza San Silvestro 12, 56127, Pisa, Italy.,Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, piazza San Silvestro 12, 56127, Pisa, Italy
| | - Ajesh Jacob
- Bio@SNS, Scuola Normale Superiore, piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - Bruno Pinto
- Bio@SNS, Scuola Normale Superiore, piazza dei Cavalieri 7, 56126, Pisa, Italy.,Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy
| | - Noemi Binini
- Optical Approaches to Brain Function Laboratory, Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genova, Italy
| | - Federico Pecoraro Bisogni
- Optical Approaches to Brain Function Laboratory, Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genova, Italy
| | - Claudia Alia
- Bio@SNS, Scuola Normale Superiore, piazza dei Cavalieri 7, 56126, Pisa, Italy.,Istituto di Neuroscienze, Consiglio Nazionale delle Ricerche, via Moruzzi 1, 56124, Pisa, Italy
| | - Stefano Luin
- NEST, Scuola Normale Superiore, piazza San Silvestro 12, 56127, Pisa, Italy
| | - Matteo Caleo
- Istituto di Neuroscienze, Consiglio Nazionale delle Ricerche, via Moruzzi 1, 56124, Pisa, Italy
| | - Tommaso Fellin
- Optical Approaches to Brain Function Laboratory, Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genova, Italy
| | - Laura Cancedda
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy.,Dulbecco Telethon Institute, via Varese 16b, 00185, Rome, Italy
| | - Antonino Cattaneo
- Bio@SNS, Scuola Normale Superiore, piazza dei Cavalieri 7, 56126, Pisa, Italy.
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25
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Optogenetic Tools for Subcellular Applications in Neuroscience. Neuron 2017; 96:572-603. [PMID: 29096074 DOI: 10.1016/j.neuron.2017.09.047] [Citation(s) in RCA: 216] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 03/30/2017] [Accepted: 09/26/2017] [Indexed: 12/21/2022]
Abstract
The ability to study cellular physiology using photosensitive, genetically encoded molecules has profoundly transformed neuroscience. The modern optogenetic toolbox includes fluorescent sensors to visualize signaling events in living cells and optogenetic actuators enabling manipulation of numerous cellular activities. Most optogenetic tools are not targeted to specific subcellular compartments but are localized with limited discrimination throughout the cell. Therefore, optogenetic activation often does not reflect context-dependent effects of highly localized intracellular signaling events. Subcellular targeting is required to achieve more specific optogenetic readouts and photomanipulation. Here we first provide a detailed overview of the available optogenetic tools with a focus on optogenetic actuators. Second, we review established strategies for targeting these tools to specific subcellular compartments. Finally, we discuss useful tools and targeting strategies that are currently missing from the optogenetics repertoire and provide suggestions for novel subcellular optogenetic applications.
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26
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Abstract
Since the last review paper published in Cerebellum in 2002 [1], there has been a substantial increase in the number of experiments utilizing transgenic manipulations in murine cerebellar Purkinje cells. Most of these approaches were made possible with the use of the Cre/loxP methodology and pcp2/L7 based Cre recombinase expressing transgenic mouse strains. This review aims to summarize all studies which used Purkinje cell specific transgenesis since the first use of mouse strain with Purkinje cell specific Cre expression in 2002.
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Affiliation(s)
- Anna Sługocka
- Center for Experimental Medicine, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
- Department of Physiology, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
| | - Jan Wiaderkiewicz
- Department of Pharmacology & Physiology, The George Washington University, 2300 Eye St., NW, Washington, DC, 20037, USA
| | - Jaroslaw J Barski
- Center for Experimental Medicine, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland.
- Department of Physiology, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland.
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27
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Chang WJ, Chang WP, Shyu BC. Suppression of cortical seizures by optic stimulation of the reticular thalamus in PV-mhChR2-YFP BAC transgenic mice. Mol Brain 2017; 10:42. [PMID: 28865483 PMCID: PMC5581470 DOI: 10.1186/s13041-017-0320-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 08/16/2017] [Indexed: 11/21/2022] Open
Abstract
Deep brain stimulation in thalamic regions has been proposed as a treatment for epilepsy. The electrical current excites thalamocortical activity which is controlled by γ-aminobutyric acid (GABA)ergic interneurons in the reticular thalamic nucleus (nRT). Previous studies showed that enhancing GABAergic inhibitory strength in the nRT reduces the duration and power of seizures, indicating that the thalamus plays an important role in modulating cortical seizures. The aim of the present study was to apply optogenetics to study the role of the nRT in modulating cortical seizures. We used PV-ChR2-EYFP transgenic mice from Jackson Laboratories, in which only Channelrhodopsin-2 (ChR2) is expressed in parvalbumin-expressing interneurons. Cortical seizure-like activity was induced by electrical stimulation of the corpus callosum after applying 4-aminopyridine. ChR2 expression was abundant in the nRT and cerebellum in PV-ChR2-EYFP transgenic mice. Light stimulation in the nRT caused burst firing in regions of the thalamus and nRT in vitro. Multi-unit activity increased during high-frequency (100 and 50 Hz) light stimulation in the S1 region and thalamus in vivo. Corpus callosum stimulation-induced seizure-like activity was effectively suppressed by high-frequency (100 Hz) and long-duration (10 s) light stimulation. The suppressive effects were reversed by applying a GABAB receptor antagonist but not a GABAA receptor antagonist in the cortex. The results indicated that light stimulation affected thalamocortical relay neurons by activating ChR2-expression neurons in the nRT. High-frequency and long-duration light stimulation was more effective in suppressing cortical seizure-like activity. GABAB receptors may participate in suppressing seizure-like activity.
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Affiliation(s)
- Wei Jen Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529 Taiwan, ROC
| | - Wei Pang Chang
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Alabama, Birmingham, AL 35211 USA
| | - Bai Chuang Shyu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529 Taiwan, ROC
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Lo SQ, Sng JCG, Augustine GJ. Defining a critical period for inhibitory circuits within the somatosensory cortex. Sci Rep 2017; 7:7271. [PMID: 28779074 PMCID: PMC5544762 DOI: 10.1038/s41598-017-07400-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 06/28/2017] [Indexed: 11/21/2022] Open
Abstract
Although experience-dependent changes in brain inhibitory circuits are thought to play a key role during the “critical period” of brain development, the nature and timing of these changes are poorly understood. We examined the role of sensory experience in sculpting an inhibitory circuit in the primary somatosensory cortex (S1) of mice by using optogenetics to map the connections between parvalbumin (PV) expressing interneurons and layer 2/3 pyramidal cells. Unilateral whisker deprivation decreased the strength and spatial range of inhibitory input provided to pyramidal neurons by PV interneurons in layers 2/3, 4 and 5. By varying the time when sensory input was removed, we determined that the critical period closes around postnatal day 14. This yields the first precise time course of critical period plasticity for an inhibitory circuit.
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Affiliation(s)
- Shun Qiang Lo
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.,Institute of Molecular and Cell Biology (A*STAR), Singapore, Singapore.,Marine Biological Laboratory, Woods Hole, USA
| | - Judy C G Sng
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Singapore Institute of Clinical Sciences, Agency for Science and Technology (A*STAR), Singapore, Singapore
| | - George J Augustine
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore. .,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore. .,Institute of Molecular and Cell Biology (A*STAR), Singapore, Singapore. .,Marine Biological Laboratory, Woods Hole, USA.
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29
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Thalamic Spindles Promote Memory Formation during Sleep through Triple Phase-Locking of Cortical, Thalamic, and Hippocampal Rhythms. Neuron 2017; 95:424-435.e6. [DOI: 10.1016/j.neuron.2017.06.025] [Citation(s) in RCA: 288] [Impact Index Per Article: 41.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 05/07/2017] [Accepted: 06/15/2017] [Indexed: 11/22/2022]
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Tung JK, Berglund K, Gross RE. Optogenetic Approaches for Controlling Seizure Activity. Brain Stimul 2016; 9:801-810. [PMID: 27496002 PMCID: PMC5143193 DOI: 10.1016/j.brs.2016.06.055] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 06/21/2016] [Accepted: 06/28/2016] [Indexed: 01/01/2023] Open
Abstract
Optogenetics, a technique that utilizes light-sensitive ion channels or pumps to activate or inhibit neurons, has allowed scientists unprecedented precision and control for manipulating neuronal activity. With the clinical need to develop more precise and effective therapies for patients with drug-resistant epilepsy, these tools have recently been explored as a novel treatment for halting seizure activity in various animal models. In this review, we provide a detailed and current summary of these optogenetic approaches and provide a perspective on their future clinical application as a potential neuromodulatory therapy.
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Affiliation(s)
- Jack K Tung
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA; Department of Neurosurgery, Emory University, Atlanta, GA
| | - Ken Berglund
- Department of Neurosurgery, Emory University, Atlanta, GA
| | - Robert E Gross
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA; Department of Neurosurgery, Emory University, Atlanta, GA.
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31
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Conti R, Assayag O, de Sars V, Guillon M, Emiliani V. Computer Generated Holography with Intensity-Graded Patterns. Front Cell Neurosci 2016; 10:236. [PMID: 27799896 PMCID: PMC5065964 DOI: 10.3389/fncel.2016.00236] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 09/28/2016] [Indexed: 11/16/2022] Open
Abstract
Computer Generated Holography achieves patterned illumination at the sample plane through phase modulation of the laser beam at the objective back aperture. This is obtained by using liquid crystal-based spatial light modulators (LC-SLMs), which modulate the spatial phase of the incident laser beam. A variety of algorithms is employed to calculate the phase modulation masks addressed to the LC-SLM. These algorithms range from simple gratings-and-lenses to generate multiple diffraction-limited spots, to iterative Fourier-transform algorithms capable of generating arbitrary illumination shapes perfectly tailored on the base of the target contour. Applications for holographic light patterning include multi-trap optical tweezers, patterned voltage imaging and optical control of neuronal excitation using uncaging or optogenetics. These past implementations of computer generated holography used binary input profile to generate binary light distribution at the sample plane. Here we demonstrate that using graded input sources, enables generating intensity graded light patterns and extend the range of application of holographic light illumination. At first, we use intensity-graded holograms to compensate for LC-SLM position dependent diffraction efficiency or sample fluorescence inhomogeneity. Finally we show that intensity-graded holography can be used to equalize photo evoked currents from cells expressing different levels of chanelrhodopsin2 (ChR2), one of the most commonly used optogenetics light gated channels, taking into account the non-linear dependence of channel opening on incident light.
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Affiliation(s)
- Rossella Conti
- Wave Front Engineering Microscopy Group, Neurophotonics Laboratory, Centre National de la Recherche Scientifique, UMR 8250, University Paris Descartes Paris, France
| | - Osnath Assayag
- Wave Front Engineering Microscopy Group, Neurophotonics Laboratory, Centre National de la Recherche Scientifique, UMR 8250, University Paris Descartes Paris, France
| | - Vincent de Sars
- Wave Front Engineering Microscopy Group, Neurophotonics Laboratory, Centre National de la Recherche Scientifique, UMR 8250, University Paris Descartes Paris, France
| | - Marc Guillon
- Wave Front Engineering Microscopy Group, Neurophotonics Laboratory, Centre National de la Recherche Scientifique, UMR 8250, University Paris Descartes Paris, France
| | - Valentina Emiliani
- Wave Front Engineering Microscopy Group, Neurophotonics Laboratory, Centre National de la Recherche Scientifique, UMR 8250, University Paris Descartes Paris, France
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32
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Ellens DJ, Gaidica M, Toader A, Peng S, Shue S, John T, Bova A, Leventhal DK. An automated rat single pellet reaching system with high-speed video capture. J Neurosci Methods 2016; 271:119-27. [PMID: 27450925 DOI: 10.1016/j.jneumeth.2016.07.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/15/2016] [Accepted: 07/18/2016] [Indexed: 11/29/2022]
Abstract
BACKGROUND Single pellet reaching is an established task for studying fine motor control in which rats reach for, grasp, and eat food pellets in a stereotyped sequence. Most incarnations of this task require constant attention, limiting the number of animals that can be tested and the number of trials per session. Automated versions allow more interventions in more animals, but must be robust and reproducible. NEW METHOD Our system automatically delivers single reward pellets for rats to grasp with their forepaw. Reaches are detected using real-time computer vision, which triggers video acquisition from multiple angles using mirrors. This allows us to record high-speed (>300 frames per second) video, and trigger interventions (e.g., optogenetics) with high temporal precision. Individual video frames are triggered by digital pulses that can be synchronized with behavior, experimental interventions, or recording devices (e.g., electrophysiology). The system is housed within a soundproof chamber with integrated lighting and ventilation, allowing multiple skilled reaching systems in one room. RESULTS We show that rats acquire the automated task similarly to manual versions, that the task is robust, and can be synchronized with optogenetic interventions. COMPARISON WITH EXISTING METHODS Existing skilled reaching protocols require high levels of investigator involvement, or, if ad libitum, do not allow for integration of high-speed, synchronized data collection. CONCLUSION This task will facilitate the study of motor learning and control by efficiently recording large numbers of skilled movements. It can be adapted for use with modern neurophysiology, which demands high temporal precision.
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Affiliation(s)
- Damien J Ellens
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Matt Gaidica
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, United States
| | - Andrew Toader
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Sophia Peng
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Shirley Shue
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Titus John
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States
| | - Alexandra Bova
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, United States
| | - Daniel K Leventhal
- Neurology Service, VA Ann Arbor Health System, Ann Arbor, MI 48109, United States; Department of Neurology, University of Michigan, Ann Arbor, MI 48109, United States; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States.
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Saunders BT, Richard JM, Janak PH. Contemporary approaches to neural circuit manipulation and mapping: focus on reward and addiction. Philos Trans R Soc Lond B Biol Sci 2016; 370:20140210. [PMID: 26240425 DOI: 10.1098/rstb.2014.0210] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Tying complex psychological processes to precisely defined neural circuits is a major goal of systems and behavioural neuroscience. This is critical for understanding adaptive behaviour, and also how neural systems are altered in states of psychopathology, such as addiction. Efforts to relate psychological processes relevant to addiction to activity within defined neural circuits have been complicated by neural heterogeneity. Recent advances in technology allow for manipulation and mapping of genetically and anatomically defined neurons, which when used in concert with sophisticated behavioural models, have the potential to provide great insight into neural circuit bases of behaviour. Here we discuss contemporary approaches for understanding reward and addiction, with a focus on midbrain dopamine and cortico-striato-pallidal circuits.
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Affiliation(s)
- Benjamin T Saunders
- Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Jocelyn M Richard
- Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Patricia H Janak
- Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, MD 21218, USA The Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, MD 21218, USA
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Cheng MY, Aswendt M, Steinberg GK. Optogenetic Approaches to Target Specific Neural Circuits in Post-stroke Recovery. Neurotherapeutics 2016; 13:325-40. [PMID: 26701667 PMCID: PMC4824024 DOI: 10.1007/s13311-015-0411-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Stroke is a leading cause of death and disability in the USA, yet treatment options are very limited. Functional recovery can occur after stroke and is attributed, in part, to rewiring of neural connections in areas adjacent to or remotely connected to the infarct. A better understanding of neural circuit rewiring is thus an important step toward developing future therapeutic strategies for stroke recovery. Because stroke disrupts functional connections in peri-infarct and remotely connected regions, it is important to investigate brain-wide network dynamics during post-stroke recovery. Optogenetics is a revolutionary neuroscience tool that uses bioengineered light-sensitive proteins to selectively activate or inhibit specific cell types and neural circuits within milliseconds, allowing greater specificity and temporal precision for dissecting neural circuit mechanisms in diseases. In this review, we discuss the current view of post-stroke remapping and recovery, including recent studies that use optogenetics to investigate neural circuit remapping after stroke, as well as optogenetic stimulation to enhance stroke recovery. Multimodal approaches employing optogenetics in conjunction with other readouts (e.g., in vivo neuroimaging techniques, behavior assays, and next-generation sequencing) will advance our understanding of neural circuit reorganization during post-stroke recovery, as well as provide important insights into which brain circuits to target when designing brain stimulation strategies for future clinical studies.
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Affiliation(s)
- Michelle Y Cheng
- Department of Neurosurgery, R281, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305-5327, USA.
| | - Markus Aswendt
- Department of Neurosurgery, R281, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305-5327, USA
| | - Gary K Steinberg
- Department of Neurosurgery, R281, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305-5327, USA.
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Luminopsins integrate opto- and chemogenetics by using physical and biological light sources for opsin activation. Proc Natl Acad Sci U S A 2016; 113:E358-67. [PMID: 26733686 DOI: 10.1073/pnas.1510899113] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Luminopsins are fusion proteins of luciferase and opsin that allow interrogation of neuronal circuits at different temporal and spatial resolutions by choosing either extrinsic physical or intrinsic biological light for its activation. Building on previous development of fusions of wild-type Gaussia luciferase with channelrhodopsin, here we expanded the utility of luminopsins by fusing bright Gaussia luciferase variants with either channelrhodopsin to excite neurons (luminescent opsin, LMO) or a proton pump to inhibit neurons (inhibitory LMO, iLMO). These improved LMOs could reliably activate or silence neurons in vitro and in vivo. Expression of the improved LMO in hippocampal circuits not only enabled mapping of synaptic activation of CA1 neurons with fine spatiotemporal resolution but also could drive rhythmic circuit excitation over a large spatiotemporal scale. Furthermore, virus-mediated expression of either LMO or iLMO in the substantia nigra in vivo produced not only the expected bidirectional control of single unit activity but also opposing effects on circling behavior in response to systemic injection of a luciferase substrate. Thus, although preserving the ability to be activated by external light sources, LMOs expand the use of optogenetics by making the same opsins accessible to noninvasive, chemogenetic control, thereby allowing the same probe to manipulate neuronal activity over a range of spatial and temporal scales.
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Abstract
After the discovery of Channelrhodopsin, a light-gated ion channel, only a few people saw the diverse range of applications for such a protein. Now, more than 10 years later Channelrhodopsins have become widely accepted as the ultimate tool to control the membrane potential of excitable cells via illumination. The demand for more application-specific Channelrhodopsin variants started a race between protein engineers to design improved variants. Even though many engineered variants have undisputable advantages compared to wild-type variants, many users are alienated by the tremendous amount of new variants and their perplexing names. Here, we review new variants whose efficacy has already been proven in neurophysiological experiments, or variants which are likely to extend the optogenetic toolbox. Variants are described based on their mechanistic and operational properties in terms of expression, kinetics, ion selectivity, and wavelength responsivity.
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Affiliation(s)
- Jonas Wietek
- Experimental Biophysics, Humboldt University Berlin, Invalidenstrasse 42, 10115, Berlin, Germany
| | - Matthias Prigge
- Department of Neurobiology, Weizmann Institute of Science, Herzel 234, 76100, Rehovot, Israel.
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37
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Hartmann DA, Underly RG, Watson AN, Shih AY. A murine toolbox for imaging the neurovascular unit. Microcirculation 2015; 22:168-82. [PMID: 25352367 DOI: 10.1111/micc.12176] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Accepted: 10/22/2014] [Indexed: 12/13/2022]
Abstract
The neurovascular unit (NVU) coordinates many essential functions in the brain including blood flow control, nutrient delivery, and maintenance of BBB integrity. These functions are the result of a cellular and molecular interplay that we are just beginning to understand. Cells of the NVU can now be investigated in the intact brain through the combined use of high-resolution in vivo imaging and non-invasive molecular tools to observe and manipulate cell function. Mouse lines that target transgene expression to cells of the NVU will be of great value in future work. However, a detailed evaluation of target cell specificity and expression pattern within the brain is required for many existing lines. The purpose of this review was to catalog mouse lines available to cerebrovascular biologists and to discuss their utility and limitations in future imaging studies.
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Affiliation(s)
- David A Hartmann
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina, USA
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Distinct Functional Modules for Discrete and Rhythmic Forelimb Movements in the Mouse Motor Cortex. J Neurosci 2015; 35:13311-22. [PMID: 26424880 DOI: 10.1523/jneurosci.2731-15.2015] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Movements of animals are composed of two fundamental dynamics: discrete and rhythmic movements. Although the movements with distinct dynamics are thought to be differently processed in the CNS, it is unclear how they are represented in the cerebral cortex. Here, we investigated the cortical representation of movement dynamics by developing prolonged transcranial optogenetic stimulation (pTOS) using awake, channelrhodopsin-2 transgenic mice. We found two domains that induced discrete forelimb movements in the forward and backward directions, and these sandwiched a domain that generated rhythmic forelimb movements. The forward discrete movement had an intrinsic velocity profile and the rhythmic movement had an intrinsic oscillation frequency. Each of the forward discrete and rhythmic domains possessed intracortical synaptic connections within its own domain, independently projected to the spinal cord, and weakened the neuronal activity and movement induction of the other domain. pTOS-induced movements were also classified as ethologically relevant movements. Forepaw-to-mouth movement was mapped in a part of the forward discrete domain, while locomotion-like movement was in a part of the rhythmic domain. Interestingly, photostimulation of the rhythmic domain resulted in a nonrhythmic, continuous lever-pull movement when a lever was present. The motor cortex possesses functional modules for distinct movement dynamics, and these can adapt to environmental constraints for purposeful movements. Significance statement: Animal behavior has discrete and rhythmic components, such as reaching and locomotion. It is unclear how these movements with distinct dynamics are represented in the cerebral cortex. We investigated the dynamics of movements induced by long-duration transcranial photostimulation on the dorsal cortex of awake channelrhodopsin-2 transgenic mice. We found two domains causing forward and backward discrete forelimb movements and a domain for rhythmic forelimb movements. A domain for forward discrete movement and a domain for rhythmic movement mutually weakened neuronal activity and movement size. The photostimulation of the rhythmic domain also induced nonrhythmic, lever-pull movement, when the lever was present. Thus, the motor cortex has functional modules with distinct dynamics, and each module retains flexibility for adaptation to different environments.
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Abstract
Distinct subsets of sensory nerve fibres are involved in mediating mechanical and thermal pain hypersensitivity. They may also differentially respond to analgesics. Heat-sensitive C-fibres, for example, are thought to respond to μ-opioid receptor (MOR) activation while mechanoreceptive fibres are supposedly sensitive to δ-opioid receptor (DOR) or GABAB receptor (GABABR) activation. The suggested differential distribution of inhibitory neurotransmitter receptors on different subsets of sensory fibres is, however, heavily debated. In this study, we quantitatively compared the degree of presynaptic inhibition exerted by opioids and the GABABR agonist baclofen on (1) vesicular glutamate transporter subtype 3-positive (VGluT3) non-nociceptive primary afferent fibres and (2) putative nociceptive C-fibres. To investigate VGluT3 sensory fibres, we evoked excitatory postsynaptic currents with blue light at the level of the dorsal root ganglion (DRG) in spinal cord slices of mice, expressing channelrhodopsin-2. Putative nociceptive C-fibres were explored in VGluT3-knockout mice through electrical stimulation. The MOR agonist DAMGO strongly inhibited both VGluT3 and VGluT3 C-fibres innervating lamina I neurons but generally had less influence on fibres innervating lamina II neurons. The DOR agonist SNC80 did not have any pronounced effect on synaptic transmission in any fibre type tested. Baclofen, in striking contrast, powerfully inhibited all fibre populations investigated. In summary, we report optogenetic stimulation of DRG neurons in spinal slices as a capable approach for the subtype-selective investigation of primary afferent nerve fibres. Overall, pharmacological accessibility of different subtypes of sensory fibres considerably overlaps, indicating that MOR, DOR, and GABABR expressions are not substantially segregated between heat and mechanosensitive fibres.
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40
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Avants BW, Murphy DB, Dapello JA, Robinson JT. NeuroPG: open source software for optical pattern generation and data acquisition. FRONTIERS IN NEUROENGINEERING 2015; 8:1. [PMID: 25784873 PMCID: PMC4345891 DOI: 10.3389/fneng.2015.00001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 02/09/2015] [Indexed: 11/29/2022]
Abstract
Patterned illumination using a digital micromirror device (DMD) is a powerful tool for optogenetics. Compared to a scanning laser, DMDs are inexpensive and can easily create complex illumination patterns. Combining these complex spatiotemporal illumination patterns with optogenetics allows DMD-equipped microscopes to probe neural circuits by selectively manipulating the activity of many individual cells or many subcellular regions at the same time. To use DMDs to study neural activity, scientists must develop specialized software to coordinate optical stimulation patterns with the acquisition of electrophysiological and fluorescence data. To meet this growing need we have developed an open source optical pattern generation software for neuroscience—NeuroPG—that combines, DMD control, sample visualization, and data acquisition in one application. Built on a MATLAB platform, NeuroPG can also process, analyze, and visualize data. The software is designed specifically for the Mightex Polygon400; however, as an open source package, NeuroPG can be modified to incorporate any data acquisition, imaging, or illumination equipment that is compatible with MATLAB’s Data Acquisition and Image Acquisition toolboxes.
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Affiliation(s)
- Benjamin W Avants
- Department of Electrical and Computer Engineering, Rice University Houston, TX, USA
| | - Daniel B Murphy
- Department of Electrical and Computer Engineering, Rice University Houston, TX, USA
| | | | - Jacob T Robinson
- Department of Electrical and Computer Engineering, Rice University Houston, TX, USA ; Department of Bioengineering, Rice University Houston, TX, USA ; Department of Neuroscience, Baylor College of Medicine Houston, TX, USA
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41
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Su CTE, Yoon SI, Marcy G, Chin EWM, Augustine GJ, Goh ELK. An optogenetic approach for assessing formation of neuronal connections in a co-culture system. J Vis Exp 2015:e52408. [PMID: 25742527 PMCID: PMC4354644 DOI: 10.3791/52408] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Here we describe a protocol to generate a co-culture consisting of 2 different neuronal populations. Induced pluripotent stem cells (iPSCs) are reprogrammed from human fibroblasts using episomal vectors. Colonies of iPSCs can be observed 30 days after initiation of fibroblast reprogramming. Pluripotent colonies are manually picked and grown in neural induction medium to permit differentiation into neural progenitor cells (NPCs). iPSCs rapidly convert into neuroepithelial cells within 1 week and retain the capability to self-renew when maintained at a high culture density. Primary mouse NPCs are differentiated into astrocytes by exposure to a serum-containing medium for 7 days and form a monolayer upon which embryonic day 18 (E18) rat cortical neurons (transfected with channelrhodopsin-2 (ChR2)) are added. Human NPCs tagged with the fluorescent protein, tandem dimer Tomato (tdTomato), are then seeded onto the astrocyte/cortical neuron culture the following day and allowed to differentiate for 28 to 35 days. We demonstrate that this system forms synaptic connections between iPSC-derived neurons and cortical neurons, evident from an increase in the frequency of synaptic currents upon photostimulation of the cortical neurons. This co-culture system provides a novel platform for evaluating the ability of iPSC-derived neurons to create synaptic connections with other neuronal populations.
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Affiliation(s)
- Colin T E Su
- Neuroscience & Behavioral Disorders, Duke-NUS Graduate Medical School
| | - Su-In Yoon
- Lee Kong Chian School of Medicine, Nanyang Technological University
| | - Guillaume Marcy
- Neuroscience & Behavioral Disorders, Duke-NUS Graduate Medical School
| | - Eunice W M Chin
- Neuroscience & Behavioral Disorders, Duke-NUS Graduate Medical School
| | | | - Eyleen L K Goh
- Neuroscience & Behavioral Disorders, Duke-NUS Graduate Medical School;
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Abstract
Quality sleep is critical for daily functions of human beings and thus the timing and duration of sleep are tightly controlled. However, rare genetic variants affecting sleep regulatory mechanisms can result in sleep phenotypes of extremely deviated sleep/wake onset time or duration. Using genetic analyses in families with multiple members expressing particular sleep phenotypes, these sleep-associated genetic variants can be identified. Deciphering the nature of these genetic variants using animal models or biochemical methods helps further our understanding of sleep processes. In this chapter, we describe the methods for studying genetics of human sleep behavioral phenotypes.
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Affiliation(s)
- Pei-Ken Hsu
- Department of Neurology, University of California, San Francisco, San Francisco, California, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, USA
| | - Louis J Ptáček
- Department of Neurology, University of California, San Francisco, San Francisco, California, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, USA.
| | - Ying-Hui Fu
- Department of Neurology, University of California, San Francisco, San Francisco, California, USA.
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43
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Wouterlood FG, Bloem B, Mansvelder HD, Luchicchi A, Deisseroth K. A fourth generation of neuroanatomical tracing techniques: exploiting the offspring of genetic engineering. J Neurosci Methods 2014; 235:331-48. [PMID: 25107853 DOI: 10.1016/j.jneumeth.2014.07.021] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 07/28/2014] [Accepted: 07/29/2014] [Indexed: 11/18/2022]
Abstract
The first three generations of neuroanatomical tract-tracing methods include, respectively, techniques exploiting degeneration, retrograde cellular transport and anterograde cellular transport. This paper reviews the most recent development in third-generation tracing, i.e., neurochemical fingerprinting based on BDA tracing, and continues with an emerging tracing technique called here 'selective fluorescent protein expression' that in our view belongs to an entirely new 'fourth-generation' class. Tracing techniques in this class lean on gene expression technology designed to 'label' projections exclusively originating from neurons expressing a very specific molecular phenotype. Genetically engineered mice that express cre-recombinase in a neurochemically specific neuronal population receive into a brain locus of interest an injection of an adeno-associated virus (AAV) carrying a double-floxed promoter-eYFP DNA sequence. After transfection this sequence is expressed only in neurons metabolizing recombinase protein. These particular neurons promptly start manufacturing the fluorescent protein which then accumulates and labels to full detail all the neuronal processes, including fibers and terminal arborizations. All other neurons remain optically 'dark'. The AAV is not replicated by the neurons, prohibiting intracerebral spread of 'infection'. The essence is that the fiber projections of discrete subpopulations of neurochemically specific neurons can be traced in full detail. One condition is that the transgenic mouse strain is recombinase-perfect. We illustrate selective fluorescent protein expression in parvalbumin-cre (PV-cre) mice and choline acetyltransferase-cre (ChAT-cre) mice. In addition we compare this novel tracing technique with observations in brains of native PV mice and ChAT-GFP mice. We include a note on tracing techniques using viruses.
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Affiliation(s)
- Floris G Wouterlood
- Department of Anatomy and Neurosciences, Neuroscience Campus Amsterdam, Vrije University Medical Center, Amsterdam, The Netherlands.
| | - Bernard Bloem
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research (CNCR), Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands; Department of Brain and Cognitive Sciences, McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Huibert D Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research (CNCR), Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Antonio Luchicchi
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research (CNCR), Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Karl Deisseroth
- Bioengineering Department, James E. Clark Center, Stanford University, Stanford, CA, USA
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44
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Abstract
Cerebellar research has focused principally on adult motor function. However, the cerebellum also maintains abundant connections with nonmotor brain regions throughout postnatal life. Here we review evidence that the cerebellum may guide the maturation of remote nonmotor neural circuitry and influence cognitive development, with a focus on its relationship with autism. Specific cerebellar zones influence neocortical substrates for social interaction, and we propose that sensitive-period disruption of such internal brain communication can account for autism's key features.
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Affiliation(s)
- Samuel S-H Wang
- Princeton Neuroscience Institute and Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
| | - Alexander D Kloth
- Princeton Neuroscience Institute and Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Aleksandra Badura
- Princeton Neuroscience Institute and Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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45
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Ambrosi CM, Klimas A, Yu J, Entcheva E. Cardiac applications of optogenetics. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 115:294-304. [PMID: 25035999 DOI: 10.1016/j.pbiomolbio.2014.07.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 07/05/2014] [Indexed: 01/16/2023]
Abstract
In complex multicellular systems, such as the brain or the heart, the ability to selectively perturb and observe the response of individual components at the cellular level and with millisecond resolution in time, is essential for mechanistic understanding of function. Optogenetics uses genetic encoding of light sensitivity (by the expression of microbial opsins) to provide such capabilities for manipulation, recording, and control by light with cell specificity and high spatiotemporal resolution. As an optical approach, it is inherently scalable for remote and parallel interrogation of biological function at the tissue level; with implantable miniaturized devices, the technique is uniquely suitable for in vivo tracking of function, as illustrated by numerous applications in the brain. Its expansion into the cardiac area has been slow. Here, using examples from published research and original data, we focus on optogenetics applications to cardiac electrophysiology, specifically dealing with the ability to manipulate membrane voltage by light with implications for cardiac pacing, cardioversion, cell communication, and arrhythmia research, in general. We discuss gene and cell delivery methods of inscribing light sensitivity in cardiac tissue, functionality of the light-sensitive ion channels within different types of cardiac cells, utility in probing electrical coupling between different cell types, approaches and design solutions to all-optical electrophysiology by the combination of optogenetic sensors and actuators, and specific challenges in moving towards in vivo cardiac optogenetics.
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Affiliation(s)
- Christina M Ambrosi
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Aleksandra Klimas
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Jinzhu Yu
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Emilia Entcheva
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-8661, USA.
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46
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Abstract
Purkinje cells (PCs) of the cerebellar cortex are necessary for controlling movement with precision, but a mechanistic explanation of how the activity of these inhibitory neurons regulates motor output is still lacking. We used an optogenetic approach in awake mice to show for the first time that transiently suppressing spontaneous activity in a population of PCs is sufficient to cause discrete movements that can be systematically modulated in size, speed, and timing depending on how much and how long PC firing is suppressed. We further demonstrate that this fine control of movement kinematics is mediated by a graded disinhibition of target neurons in the deep cerebellar nuclei. Our results prove a long-standing model of cerebellar function and provide the first demonstration that suppression of inhibitory signals can act as a powerful mechanism for the precise control of behavior.
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47
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Ting JT, Daigle TL, Chen Q, Feng G. Acute brain slice methods for adult and aging animals: application of targeted patch clamp analysis and optogenetics. Methods Mol Biol 2014; 1183:221-42. [PMID: 25023312 DOI: 10.1007/978-1-4939-1096-0_14] [Citation(s) in RCA: 428] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The development of the living acute brain slice preparation for analyzing synaptic function roughly a half century ago was a pivotal achievement that greatly influenced the landscape of modern neuroscience. Indeed, many neuroscientists regard brain slices as the gold-standard model system for detailed cellular, molecular, and circuitry level analysis and perturbation of neuronal function. A critical limitation of this model system is the difficulty in preparing slices from adult and aging animals, and over the past several decades few substantial methodological improvements have emerged to facilitate patch clamp analysis in the mature adult stage. In this chapter we describe a robust and practical protocol for preparing brain slices from mature adult mice that are suitable for patch clamp analysis. This method reduces swelling and damage in superficial layers of the slices and improves the success rate for targeted patch clamp recordings, including recordings from fluorescently labeled populations in slices derived from transgenic mice. This adult brain slice method is suitable for diverse experimental applications, including both monitoring and manipulating neuronal activity with genetically encoded calcium indicators and optogenetic actuators, respectively. We describe the application of this adult brain slice platform and associated methods for screening kinetic properties of Channelrhodopsin (ChR) variants expressed in genetically defined neuronal subtypes.
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Affiliation(s)
- Jonathan T Ting
- Human Cell Types Department, Allen Institute for Brain Science, 551 N 34th Street, Seattle, WA, 98103, USA,
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