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Benbenishty A, Peled-Hajaj S, Krishnaswamy VR, Har-Gil H, Havusha-Laufer S, Ruggiero A, Slutsky I, Blinder P, Sagi I. Longitudinal in vivo imaging of perineuronal nets. NEUROPHOTONICS 2023; 10:015008. [PMID: 36970015 PMCID: PMC10037344 DOI: 10.1117/1.nph.10.1.015008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
SIGNIFICANCE Perineuronal nets (PNNs) are extracellular matrix structures implicated in learning, memory, information processing, synaptic plasticity, and neuroprotection. However, our understanding of mechanisms governing the evidently important contribution of PNNs to central nervous system function is lacking. A primary cause for this gap of knowledge is the absence of direct experimental tools to study their role in vivo. AIM We introduce a robust approach for quantitative longitudinal imaging of PNNs in brains of awake mice at subcellular resolution. APPROACH We label PNNs in vivo with commercially available compounds and monitor their dynamics with two-photon imaging. RESULTS Using our approach, we show that it is possible to longitudinally follow the same PNNs in vivo while monitoring degradation and reconstitution of PNNs. We demonstrate the compatibility of our method to simultaneously monitor neuronal calcium dynamics in vivo and compare the activity of neurons with and without PNNs. CONCLUSION Our approach is tailored for studying the intricate role of PNNs in vivo, while paving the road for elucidating their role in different neuropathological conditions.
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Affiliation(s)
- Amit Benbenishty
- The Weizmann Institute of Science, Department of Immunology and Regenerative Biology, Rehovot, Israel
| | - Shany Peled-Hajaj
- Tel Aviv University, Neurobiology, Biochemistry, and Biophysics School, Tel Aviv, Israel
- Tel Aviv University, Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv, Israel
| | | | - Hagai Har-Gil
- Tel Aviv University, Neurobiology, Biochemistry, and Biophysics School, Tel Aviv, Israel
- Tel Aviv University, Sagol School of Neuroscience, Tel Aviv, Israel
| | - Sapir Havusha-Laufer
- The Weizmann Institute of Science, Department of Immunology and Regenerative Biology, Rehovot, Israel
| | - Antonella Ruggiero
- Tel Aviv University, Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv, Israel
| | - Inna Slutsky
- Tel Aviv University, Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv, Israel
- Tel Aviv University, Sagol School of Neuroscience, Tel Aviv, Israel
| | - Pablo Blinder
- Tel Aviv University, Neurobiology, Biochemistry, and Biophysics School, Tel Aviv, Israel
- Tel Aviv University, Sagol School of Neuroscience, Tel Aviv, Israel
| | - Irit Sagi
- The Weizmann Institute of Science, Department of Immunology and Regenerative Biology, Rehovot, Israel
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2
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Qi G, Yang D, Ding C, Feldmeyer D. Unveiling the Synaptic Function and Structure Using Paired Recordings From Synaptically Coupled Neurons. Front Synaptic Neurosci 2020; 12:5. [PMID: 32116641 PMCID: PMC7026682 DOI: 10.3389/fnsyn.2020.00005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 01/22/2020] [Indexed: 11/24/2022] Open
Abstract
Synaptic transmission between neurons is the basic mechanism for information processing in cortical microcircuits. To date, paired recording from synaptically coupled neurons is the most widely used method which allows a detailed functional characterization of unitary synaptic transmission at the cellular and synaptic level in combination with a structural characterization of both pre- and postsynaptic neurons at the light and electron microscopic level. In this review, we will summarize the many applications of paired recordings to investigate synaptic function and structure. Paired recordings have been used to study the detailed electrophysiological and anatomical properties of synaptically coupled cell pairs within a synaptic microcircuit; this is critical in order to understand the connectivity rules and dynamic properties of synaptic transmission. Paired recordings can also be adopted for quantal analysis of an identified synaptic connection and to study the regulation of synaptic transmission by neuromodulators such as acetylcholine, the monoamines, neuropeptides, and adenosine etc. Taken together, paired recordings from synaptically coupled neurons will remain a very useful approach for a detailed characterization of synaptic transmission not only in the rodent brain but also that of other species including humans.
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Affiliation(s)
- Guanxiao Qi
- Institute of Neuroscience and Medicine, INM-10, Jülich Research Centre, Jülich, Germany
| | - Danqing Yang
- Institute of Neuroscience and Medicine, INM-10, Jülich Research Centre, Jülich, Germany
| | - Chao Ding
- Institute of Neuroscience and Medicine, INM-10, Jülich Research Centre, Jülich, Germany
| | - Dirk Feldmeyer
- Institute of Neuroscience and Medicine, INM-10, Jülich Research Centre, Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University Hospital, Aachen, Germany.,Jülich-Aachen Research Alliance, Translational Brain Medicine (JARA Brain), Aachen, Germany
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3
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Scala F, Kobak D, Shan S, Bernaerts Y, Laturnus S, Cadwell CR, Hartmanis L, Froudarakis E, Castro JR, Tan ZH, Papadopoulos S, Patel SS, Sandberg R, Berens P, Jiang X, Tolias AS. Layer 4 of mouse neocortex differs in cell types and circuit organization between sensory areas. Nat Commun 2019; 10:4174. [PMID: 31519874 PMCID: PMC6744474 DOI: 10.1038/s41467-019-12058-z] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 08/06/2019] [Indexed: 01/13/2023] Open
Abstract
Layer 4 (L4) of mammalian neocortex plays a crucial role in cortical information processing, yet a complete census of its cell types and connectivity remains elusive. Using whole-cell recordings with morphological recovery, we identified one major excitatory and seven inhibitory types of neurons in L4 of adult mouse visual cortex (V1). Nearly all excitatory neurons were pyramidal and all somatostatin-positive (SOM+) non-fast-spiking interneurons were Martinotti cells. In contrast, in somatosensory cortex (S1), excitatory neurons were mostly stellate and SOM+ interneurons were non-Martinotti. These morphologically distinct SOM+ interneurons corresponded to different transcriptomic cell types and were differentially integrated into the local circuit with only S1 neurons receiving local excitatory input. We propose that cell type specific circuit motifs, such as the Martinotti/pyramidal and non-Martinotti/stellate pairs, are used across the cortex as building blocks to assemble cortical circuits.
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Affiliation(s)
- Federico Scala
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Dmitry Kobak
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Shen Shan
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Yves Bernaerts
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Sophie Laturnus
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Cathryn Rene Cadwell
- Department of Anatomic Pathology, University of California San Francisco, San Francisco, CA, USA
| | - Leonard Hartmanis
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Emmanouil Froudarakis
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Jesus Ramon Castro
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Zheng Huan Tan
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Stelios Papadopoulos
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Saumil Surendra Patel
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Rickard Sandberg
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Philipp Berens
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Department of Computer Science, University of Tübingen, Tübingen, Germany
| | - Xiaolong Jiang
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA.
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA.
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA.
| | - Andreas Savas Tolias
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA.
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA.
- Department of Electrical and Computational Engineering, Rice University, Houston, TX, USA.
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4
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Yang D, Günter R, Qi G, Radnikow G, Feldmeyer D. Muscarinic and Nicotinic Modulation of Neocortical Layer 6A Synaptic Microcircuits Is Cooperative and Cell-Specific. Cereb Cortex 2019; 30:3528-3542. [PMID: 32026946 PMCID: PMC7233001 DOI: 10.1093/cercor/bhz324] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/02/2019] [Accepted: 12/05/2019] [Indexed: 12/27/2022] Open
Abstract
Acetylcholine (ACh) is known to regulate cortical activity during different behavioral states, for example, wakefulness and attention. Here we show a differential expression of muscarinic ACh receptors (mAChRs) and nicotinic ACh receptors (nAChRs) in different layer 6A (L6A) pyramidal cell (PC) types of somatosensory cortex. At low concentrations, ACh induced a persistent hyperpolarization in corticocortical (CC) but a depolarization in corticothalamic (CT) L6A PCs via M 4 and M1 mAChRs, respectively. At ~ 1 mM, ACh depolarized exclusively CT PCs via α4β2 subunit-containing nAChRs without affecting CC PCs. Miniature EPSC frequency in CC PCs was decreased by ACh but increased in CT PCs. In synaptic connections with a presynaptic CC PC, glutamate release was suppressed via M4 mAChR activation but enhanced by nAChRs via α4β2 nAChRs when the presynaptic neuron was a CT PC. Thus, in L6A, the interaction of mAChRs and nAChRs results in an altered excitability and synaptic release, effectively strengthening CT output while weakening CC synaptic signaling.
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Affiliation(s)
- Danqing Yang
- Institute of Neuroscience and Medicine (INM-10), Function of Neuronal Microcircuits, Research Centre Jülich, D-52425 Jülich, Germany
| | - Robert Günter
- Institute of Neuroscience and Medicine (INM-10), Function of Neuronal Microcircuits, Research Centre Jülich, D-52425 Jülich, Germany
| | - Guanxiao Qi
- Institute of Neuroscience and Medicine (INM-10), Function of Neuronal Microcircuits, Research Centre Jülich, D-52425 Jülich, Germany
| | - Gabriele Radnikow
- Institute of Neuroscience and Medicine (INM-10), Function of Neuronal Microcircuits, Research Centre Jülich, D-52425 Jülich, Germany
| | - Dirk Feldmeyer
- Institute of Neuroscience and Medicine (INM-10), Function of Neuronal Microcircuits, Research Centre Jülich, D-52425 Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, D-52074 Aachen, Germany.,Jülich Aachen Research Alliance, Translational Brain Medicine (JARA Brain), D-52074 Aachen, Germany
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5
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Deitcher Y, Eyal G, Kanari L, Verhoog MB, Atenekeng Kahou GA, Mansvelder HD, de Kock CPJ, Segev I. Comprehensive Morpho-Electrotonic Analysis Shows 2 Distinct Classes of L2 and L3 Pyramidal Neurons in Human Temporal Cortex. Cereb Cortex 2018; 27:5398-5414. [PMID: 28968789 PMCID: PMC5939232 DOI: 10.1093/cercor/bhx226] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Indexed: 12/31/2022] Open
Abstract
There have been few quantitative characterizations of the morphological, biophysical, and cable properties of neurons in the human neocortex. We employed feature-based statistical methods on a rare data set of 60 3D reconstructed pyramidal neurons from L2 and L3 in the human temporal cortex (HL2/L3 PCs) removed after brain surgery. Of these cells, 25 neurons were also characterized physiologically. Thirty-two morphological features were analyzed (e.g., dendritic surface area, 36 333 ± 18 157 μm2; number of basal trees, 5.55 ± 1.47; dendritic diameter, 0.76 ± 0.28 μm). Eighteen features showed a significant gradual increase with depth from the pia (e.g., dendritic length and soma radius). The other features showed weak or no correlation with depth (e.g., dendritic diameter). The basal dendritic terminals in HL2/L3 PCs are particularly elongated, enabling multiple nonlinear processing units in these dendrites. Unlike the morphological features, the active biophysical features (e.g., spike shapes and rates) and passive/cable features (e.g., somatic input resistance, 47.68 ± 15.26 MΩ, membrane time constant, 12.03 ± 1.79 ms, average dendritic cable length, 0.99 ± 0.24) were depth-independent. A novel descriptor for apical dendritic topology yielded 2 distinct classes, termed hereby as “slim-tufted” and “profuse-tufted” HL2/L3 PCs; the latter class tends to fire at higher rates. Thus, our morpho-electrotonic analysis shows 2 distinct classes of HL2/L3 PCs.
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Affiliation(s)
- Yair Deitcher
- Department of Neurobiology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.,Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Guy Eyal
- Department of Neurobiology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Lida Kanari
- Blue Brain Project, Ecole Polytechnique Fédérale de Lausanne, Campus Biotech, Chemin de Mines, 9, Geneva 1202, Switzerland
| | - Matthijs B Verhoog
- Department of Integrative Neurophysiology, Centre for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam NL-1081 HV, The Netherlands
| | - Guy Antoine Atenekeng Kahou
- Blue Brain Project, Ecole Polytechnique Fédérale de Lausanne, Campus Biotech, Chemin de Mines, 9, Geneva 1202, Switzerland
| | - Huibert D Mansvelder
- Department of Integrative Neurophysiology, Centre for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam NL-1081 HV, The Netherlands
| | - Christiaan P J de Kock
- Department of Integrative Neurophysiology, Centre for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam NL-1081 HV, The Netherlands
| | - Idan Segev
- Department of Neurobiology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.,Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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6
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Qi G, van Aerde K, Abel T, Feldmeyer D. Adenosine Differentially Modulates Synaptic Transmission of Excitatory and Inhibitory Microcircuits in Layer 4 of Rat Barrel Cortex. Cereb Cortex 2018; 27:4411-4422. [PMID: 27522071 DOI: 10.1093/cercor/bhw243] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 07/15/2016] [Indexed: 12/27/2022] Open
Abstract
Adenosine is considered to be a key regulator of sleep homeostasis by promoting slow-wave sleep through inhibition of the brain's arousal centers. However, little is known about the effect of adenosine on neuronal network activity at the cellular level in the neocortex. Here, we show that adenosine differentially modulates synaptic transmission between different types of neurons in cortical layer 4 (L4) through activation of pre- and/or postsynaptically located adenosine A1 receptors. In recurrent excitatory connections between L4 spiny neurons, adenosine suppresses synaptic transmission through activation of both pre- and postsynaptic A1 receptors. In reciprocal excitatory and inhibitory connections between L4 spiny neurons and interneurons, adenosine strongly suppresses excitatory transmission via activating presynaptic A1 receptors but only slightly suppresses inhibitory transmission via activating postsynaptic A1 receptors. Adenosine has no effect on inhibitory transmission between L4 interneurons. The effect of adenosine is concentration dependent and first visible at a concentration of 1 μM. The effect of adenosine is blocked by the specific A1 receptor antagonist, 8-cyclopentyltheophylline or the nonspecific adenosine receptor antagonist, caffeine. By differentially affecting excitatory and inhibitory synaptic transmission, adenosine changes the excitation-inhibition balance and causes an overall shift to lower excitability in L4 primary somatosensory (barrel) cortical microcircuits.
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Affiliation(s)
- Guanxiao Qi
- Institute of Neuroscience and Medicine, INM-2, Research Centre Jülich, D-52425 Jülich, Germany
| | - Karlijn van Aerde
- Institute of Neuroscience and Medicine, INM-2, Research Centre Jülich, D-52425 Jülich, Germany.,Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands
| | - Ted Abel
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Dirk Feldmeyer
- Institute of Neuroscience and Medicine, INM-2, Research Centre Jülich, D-52425 Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, D-52074 Aachen, Germany.,Jülich-Aachen Research Alliance-Brain, Translational Brain Medicine, D-52074 Aachen, Germany
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7
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Weiler S, Bauer J, Hübener M, Bonhoeffer T, Rose T, Scheuss V. High-yield in vitro recordings from neurons functionally characterized in vivo. Nat Protoc 2018; 13:1275-1293. [DOI: 10.1038/nprot.2018.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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8
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Ting JT, Lee BR, Chong P, Soler-Llavina G, Cobbs C, Koch C, Zeng H, Lein E. Preparation of Acute Brain Slices Using an Optimized N-Methyl-D-glucamine Protective Recovery Method. J Vis Exp 2018. [PMID: 29553547 DOI: 10.3791/53825] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
This protocol is a practical guide to the N-methyl-D-glucamine (NMDG) protective recovery method of brain slice preparation. Numerous recent studies have validated the utility of this method for enhancing neuronal preservation and overall brain slice viability. The implementation of this technique by early adopters has facilitated detailed investigations into brain function using diverse experimental applications and spanning a wide range of animal ages, brain regions, and cell types. Steps are outlined for carrying out the protective recovery brain slice technique using an optimized NMDG artificial cerebrospinal fluid (aCSF) media formulation and enhanced procedure to reliably obtain healthy brain slices for patch clamp electrophysiology. With this updated approach, a substantial improvement is observed in the speed and reliability of gigaohm seal formation during targeted patch clamp recording experiments while maintaining excellent neuronal preservation, thereby facilitating challenging experimental applications. Representative results are provided from multi-neuron patch clamp recording experiments to assay synaptic connectivity in neocortical brain slices prepared from young adult transgenic mice and mature adult human neurosurgical specimens. Furthermore, the optimized NMDG protective recovery method of brain slicing is compatible with both juvenile and adult animals, thus resolving a limitation of the original methodology. In summary, a single media formulation and brain slicing procedure can be implemented across various species and ages to achieve excellent viability and tissue preservation.
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Affiliation(s)
| | - Brian R Lee
- Cell Types Program, Allen Institute for Brain Science
| | - Peter Chong
- Cell Types Program, Allen Institute for Brain Science
| | | | - Charles Cobbs
- The Ben and Catherine Ivy Center for Advanced Brain Tumor Treatment, Swedish Neuroscience Institute
| | - Christof Koch
- Cell Types Program, Allen Institute for Brain Science
| | - Hongkui Zeng
- Cell Types Program, Allen Institute for Brain Science
| | - Ed Lein
- Cell Types Program, Allen Institute for Brain Science
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9
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Magdesian MH, Anthonisen M, Lopez-Ayon GM, Chua XY, Rigby M, Grütter P. Rewiring Neuronal Circuits: A New Method for Fast Neurite Extension and Functional Neuronal Connection. J Vis Exp 2017. [PMID: 28654038 DOI: 10.3791/55697] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Brain and spinal cord injury may lead to permanent disability and death because it is still not possible to regenerate neurons over long distances and accurately reconnect them with an appropriate target. Here a procedure is described to rapidly initiate, elongate, and precisely connect new functional neuronal circuits over long distances. The extension rates achieved reach over 1.2 mm/h, 30-60 times faster than the in vivo rates of the fastest growing axons from the peripheral nervous system (0.02 to 0.04 mm/h)28 and 10 times faster than previously reported for the same neuronal type at an earlier stage of development4. First, isolated populations of rat hippocampal neurons are grown for 2-3 weeks in microfluidic devices to precisely position the cells, enabling easy micromanipulation and experimental reproducibility. Next, beads coated with poly-D-lysine (PDL) are placed on neurites to form adhesive contacts and pipette micromanipulation is used to move the resulting bead-neurite complex. As the bead is moved, it pulls out a new neurite that can be extended over hundreds of micrometers and functionally connected to a target cell in less than 1 h. This process enables experimental reproducibility and ease of manipulation while bypassing slower chemical strategies to induce neurite growth. Preliminary measurements presented here demonstrate a neuronal growth rate far exceeding physiological ones. Combining these innovations allows for the precise establishment of neuronal networks in culture with an unprecedented degree of control. It is a novel method that opens the door to a plethora of information and insights into signal transmission and communication within the neuronal network as well as being a playground in which to explore the limits of neuronal growth. The potential applications and experiments are widespread with direct implications for therapies that aim to reconnect neuronal circuits after trauma or in neurodegenerative diseases.
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Affiliation(s)
- Margaret H Magdesian
- Department of Physics, McGill University; Department of Neurology and Neurosurgery, Montreal Neurological Institute; Ananda Devices
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10
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Swietek B, Gupta A, Proddutur A, Santhakumar V. Immunostaining of Biocytin-filled and Processed Sections for Neurochemical Markers. J Vis Exp 2016:54880. [PMID: 28117774 PMCID: PMC5264554 DOI: 10.3791/54880] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Electrophysiological recordings of cells using the patch clamp technique have allowed for the identification of different neuronal types based on firing patterns. The inclusion of biocytin/neurobiotin in the recording electrode permits post-hoc recovery of morphological details, which are necessary to determine the dendritic arborization and the regions targeted by the axons of the recorded neurons. However, given the presence of morphologically similar neurons with distinct neurochemical identities and functions, immunohistochemical staining for cell-type-specific proteins is essential to definitively identify neurons. To maintain network connectivity, brain sections for physiological recordings are prepared at a thickness of 300 µm or greater. However, this thickness often hinders immunohistological postprocessing due to issues with antibody penetration, necessitating the resectioning of the tissue. Resectioning of slices is a challenging art, often resulting in the loss of tissue and morphology of the cells from which electrophysiological data was obtained, rendering the data unusable. Since recovery of morphology would limit data loss and guide in the selection of neuronal markers, we have adopted a strategy of recovering cell morphology first, followed by secondary immunostaining. We introduce a practical approach to biocytin filling during physiological recordings and subsequent serial immunostaining for the recovery of morphology, followed by the restaining of sections to determine the neurochemical identity. We report that sections that were filled with biocytin, fixed with paraformaldehyde (PFA), stained, and coverslipped can be removed and restained with a second primary antibody days later. This restaining involves the removal of the coverslip, the washing of sections in a buffer solution, and the incubation of primary and secondary antibodies to reveal the neurochemical identity. The method is advantageous for eliminating data loss due to an inability to recover morphology and for narrowing down the neurochemical markers to be tested based on morphology.
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Affiliation(s)
- Bogumila Swietek
- Graduate School of Biomedical Sciences, Rutgers New Jersey Medical School
| | - Akshay Gupta
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School
| | - Archana Proddutur
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School
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11
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LSPS/Optogenetics to Improve Synaptic Connectivity Mapping: Unmasking the Role of Basket Cell-Mediated Feedforward Inhibition. eNeuro 2016; 3:eN-MNT-0142-15. [PMID: 27517089 PMCID: PMC4976301 DOI: 10.1523/eneuro.0142-15.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 06/28/2016] [Accepted: 07/15/2016] [Indexed: 12/20/2022] Open
Abstract
Neocortical pyramidal cells (PYRs) receive synaptic inputs from many types of GABAergic interneurons. Connections between parvalbumin (PV)-positive, fast-spiking interneurons (“PV cells”) and PYRs are characterized by perisomatic synapses and high-amplitude, short-latency IPSCs. Here, we present novel methods to study the functional influence of PV cells on layer 5 PYRs using optogenetics combined with laser-scanning photostimulation (LSPS). First, we examined the strength and spatial distribution of PV-to-PYR inputs. To that end, the fast channelrhodopsin variant AAV5-EF1α-DIO-hChR2(E123T)-eYFP (ChETA) was expressed in PV cells in somatosensory cortex of mice using an adeno-associated virus-based viral construct. Focal blue illumination (100–150 µm half-width) was directed through the microscope objective to excite PV cells along a spatial grid covering layers 2–6, while IPSCs were recorded in layer 5 PYRs. The resulting optogenetic input maps showed evoked PV cell inputs originating from an ∼500-μm-diameter area surrounding the recorded PYR. Evoked IPSCs had the short-latency/high-amplitude characteristic of PV cell inputs. Second, we investigated how PV cell activity modulates PYR output in response to synaptic excitation. We expressed halorhodopsin (eNpHR3.0) in PV cells using the same strategy as for ChETA. Yellow illumination hyperpolarized eNpHR3.0-expressing PV cells, effectively preventing action potential generation and thus decreasing the inhibition of downstream targets. Synaptic input maps onto layer 5 PYRs were acquired using standard glutamate-photolysis LSPS either with or without full-field yellow illumination to silence PV cells. The resulting IPSC input maps selectively lacked short-latency perisomatic inputs, while EPSC input maps showed increased connectivity, particularly from upper layers. This indicates that glutamate uncaging LSPS-based excitatory synaptic maps will consistently underestimate connectivity.
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12
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Qi G, Feldmeyer D. Dendritic Target Region-Specific Formation of Synapses Between Excitatory Layer 4 Neurons and Layer 6 Pyramidal Cells. Cereb Cortex 2015; 26:1569-1579. [PMID: 25595180 DOI: 10.1093/cercor/bhu334] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Excitatory connections between neocortical layer 4 (L4) and L6 are part of the corticothalamic feedback microcircuitry. Here we studied the intracortical element of this feedback loop, the L4 spiny neuron-to-L6 pyramidal cell connection. We found that the distribution of synapses onto both putative corticothalamic (CT) and corticocortical (CC) L6 pyramidal cells (PCs) depends on the presynaptic L4 neuron type but is independent of the postsynaptic L6 PC type. L4 spiny stellate cells establish synapses on distal apical tuft dendrites of L6 PCs and elicit slow unitary excitatory postsynaptic potentials (uEPSPs) in L6 somata. In contrast, the majority of L4 star pyramidal neurons target basal and proximal apical oblique dendrites of L6 PCs and show fast uEPSPs. Compartmental modeling suggests that the slow uEPSP time course is primarily the result of dendritic filtering. This suggests that the dendritic target specificity of the 2 L4 spiny neuron types is due to their different axonal projection patterns across cortical layers. The preferential dendritic targeting by different L4 neuron types may facilitate the generation of dendritic Ca(2+) or Na(+) action potentials in L6 PCs; this could play a role in synaptic gain modulation in the corticothalamic pathway.
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Affiliation(s)
- Guanxiao Qi
- Institute of Neuroscience and Medicine, INM-2, Research Centre Jülich, D-52425 Jülich, Germany
| | - Dirk Feldmeyer
- Institute of Neuroscience and Medicine, INM-2, Research Centre Jülich, D-52425 Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, D-52074 Aachen, Germany.,Jülich-Aachen Research Alliance-Brain, Translational Brain Medicine, D-52074 Aachen, Germany
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