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Schilling K. Revisiting the development of cerebellar inhibitory interneurons in the light of single-cell genetic analyses. Histochem Cell Biol 2024; 161:5-27. [PMID: 37940705 PMCID: PMC10794478 DOI: 10.1007/s00418-023-02251-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2023] [Indexed: 11/10/2023]
Abstract
The present review aims to provide a short update of our understanding of the inhibitory interneurons of the cerebellum. While these cells constitute but a minority of all cerebellar neurons, their functional significance is increasingly being recognized. For one, inhibitory interneurons of the cerebellar cortex are now known to constitute a clearly more diverse group than their traditional grouping as stellate, basket, and Golgi cells suggests, and this diversity is now substantiated by single-cell genetic data. The past decade or so has also provided important information about interneurons in cerebellar nuclei. Significantly, developmental studies have revealed that the specification and formation of cerebellar inhibitory interneurons fundamentally differ from, say, the cortical interneurons, and define a mode of diversification critically dependent on spatiotemporally patterned external signals. Last, but not least, in the past years, dysfunction of cerebellar inhibitory interneurons could also be linked with clinically defined deficits. I hope that this review, however fragmentary, may stimulate interest and help focus research towards understanding the cerebellum.
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Affiliation(s)
- Karl Schilling
- Anatomisches Institut - Anatomie und Zellbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Nussallee 10, 53115, Bonn, Germany.
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2
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Structured cerebellar connectivity supports resilient pattern separation. Nature 2023; 613:543-549. [PMID: 36418404 DOI: 10.1038/s41586-022-05471-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 10/20/2022] [Indexed: 11/25/2022]
Abstract
The cerebellum is thought to help detect and correct errors between intended and executed commands1,2 and is critical for social behaviours, cognition and emotion3-6. Computations for motor control must be performed quickly to correct errors in real time and should be sensitive to small differences between patterns for fine error correction while being resilient to noise7. Influential theories of cerebellar information processing have largely assumed random network connectivity, which increases the encoding capacity of the network's first layer8-13. However, maximizing encoding capacity reduces the resilience to noise7. To understand how neuronal circuits address this fundamental trade-off, we mapped the feedforward connectivity in the mouse cerebellar cortex using automated large-scale transmission electron microscopy and convolutional neural network-based image segmentation. We found that both the input and output layers of the circuit exhibit redundant and selective connectivity motifs, which contrast with prevailing models. Numerical simulations suggest that these redundant, non-random connectivity motifs increase the resilience to noise at a negligible cost to the overall encoding capacity. This work reveals how neuronal network structure can support a trade-off between encoding capacity and redundancy, unveiling principles of biological network architecture with implications for the design of artificial neural networks.
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3
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Tavosanis G. Dendrite enlightenment. Curr Opin Neurobiol 2021; 69:222-230. [PMID: 34134010 DOI: 10.1016/j.conb.2021.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/04/2021] [Accepted: 05/05/2021] [Indexed: 12/18/2022]
Abstract
Neuronal dendrites acquire complex morphologies during development. These are not just the product of cell-intrinsic developmental programs; rather they are defined in close interaction with the cellular environment. Thus, to understand the molecular cascades that yield appropriate morphologies, it is essential to investigate them in vivo, in the actual complex tissue environment encountered by the differentiating neuron in the developing animal. Particularly, genetic approaches have pointed to factors controlling dendrite differentiation in vivo. These suggest that localized and transient molecular cascades might underlie the formation and stabilization of dendrite branches with neuron type-specific characteristics. Here, I highlight the need for studies of neuronal dendrite differentiation in the animal, the challenges provided by such an approach, and the promising pathways that have recently opened.
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Affiliation(s)
- Gaia Tavosanis
- German Center for Neurodegenerative Diseases (DZNE), Venusberg-Campus 1/99, Bonn, 53127, Germany; LIMES Institute, University of Bonn, Carl-Troll-Str. 3, Bonn, 53115, Germany.
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4
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Chan U, Gautam D, West AE. Utilizing In Vivo Postnatal Electroporation to Study Cerebellar Granule Neuron Morphology and Synapse Development. J Vis Exp 2021:10.3791/62568. [PMID: 34180898 PMCID: PMC10476226 DOI: 10.3791/62568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Neurons undergo dynamic changes in their structure and function during brain development to form appropriate connections with other cells. The rodent cerebellum is an ideal system to track the development and morphogenesis of a single cell type, the cerebellar granule neuron (CGN), across time. Here, in vivo electroporation of granule neuron progenitors in the developing mouse cerebellum was employed to sparsely label cells for subsequent morphological analyses. The efficacy of this technique is demonstrated in its ability to showcase key developmental stages of CGN maturation, with a specific focus on the formation of dendritic claws, which are specialized structures where these cells receive the majority of their synaptic inputs. In addition to providing snapshots of CGN synaptic structures throughout cerebellar development, this technique can be adapted to genetically manipulate granule neurons in a cell-autonomous manner to study the role of any gene of interest and its effect on CGN morphology, claw development, and synaptogenesis.
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Affiliation(s)
- Urann Chan
- Department of Neurobiology, Duke University Medical Center
| | - Diwas Gautam
- Department of Neurobiology, Duke University Medical Center
| | - Anne E West
- Department of Neurobiology, Duke University Medical Center;
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5
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Iwasato T. In vivo imaging of neural circuit formation in the neonatal mouse barrel cortex. Dev Growth Differ 2020; 62:476-486. [DOI: 10.1111/dgd.12693] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 09/13/2020] [Accepted: 09/27/2020] [Indexed: 01/21/2023]
Affiliation(s)
- Takuji Iwasato
- Laboratory of Mammalian Neural Circuits National Institute of Genetics Mishima Japan
- Department of Genetics SOKENDAI Mishima Japan
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6
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Barnes JL, Mohr C, Ritchey CR, Erikson CM, Shiina H, Rossi DJ. Developmentally Transient CB1Rs on Cerebellar Afferents Suppress Afferent Input, Downstream Synaptic Excitation, and Signaling to Migrating Neurons. J Neurosci 2020; 40:6133-6145. [PMID: 32631938 PMCID: PMC7406284 DOI: 10.1523/jneurosci.1931-19.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 06/15/2020] [Accepted: 06/20/2020] [Indexed: 01/13/2023] Open
Abstract
The endocannabinoid system plays important roles in brain development, but mechanistic studies have focused on neuronal differentiation, migration, and synaptogenesis, with less attention to transcellular interactions that coordinate neurodevelopmental processes across developing neural networks. We determined that, in the developing rodent cerebellar cortex (of both sexes), there is a transient window when the dominant brain cannabinoid receptor, CB1R, is expressed on afferent terminals instead of output neuron Purkinje cell synapses that dominate the adult cerebellum. Activation of these afferent CB1Rs suppresses synaptic transmission onto developing granule cells, and consequently also suppresses excitation of downstream neurons in the developing cortical network, including nonsynaptic, migrating neurons. Application of a CB1R antagonist during afferent stimulation trains and depolarizing voltage steps caused a significant, sustained potentiation of synaptic amplitude. Our data demonstrate that transiently expressed afferent CB1Rs regulate afferent synaptic strength during synaptogenesis, which enables coordinated dampening of transcortical developmental signals.SIGNIFICANCE STATEMENT The endogenous cannabinoid system plays diverse roles in brain development, which, combined with the rapidly changing legal and medical status of cannabis-related compounds, makes understanding how exogenous cannabinoids affect brain development an important biomedical objective. The cerebellum is a key brain region in a variety of neurodevelopmental disorders, and the adult cerebellum has one of the highest expression levels of CB1R, but little is known about CB1R in the developing cerebellum. Here we report a developmentally distinct expression and function of CB1R in the cerebellum, in which endogenous or exogenous activation of CB1Rs modifies afferent synaptic strength and coordinated downstream network signaling. These findings have implications for recreational and medical use of exogenous cannabinoids by pregnant and breastfeeding women.
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MESH Headings
- Action Potentials
- Animals
- Cannabinoid Receptor Antagonists/pharmacology
- Cell Movement
- Excitatory Postsynaptic Potentials
- Female
- Male
- Mice
- Mice, Inbred C57BL
- Neurogenesis
- Neurons, Afferent/drug effects
- Neurons, Afferent/metabolism
- Neurons, Afferent/physiology
- Purkinje Cells/drug effects
- Purkinje Cells/metabolism
- Purkinje Cells/physiology
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Synapses/metabolism
- Synapses/physiology
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Affiliation(s)
- Jesse L Barnes
- Washington State University, Integrative Physiology and Neuroscience, Pullman, Washington 99164
| | - Claudia Mohr
- Washington State University, Integrative Physiology and Neuroscience, Pullman, Washington 99164
| | - Caitlin R Ritchey
- Washington State University, Integrative Physiology and Neuroscience, Pullman, Washington 99164
| | - Chloe M Erikson
- Washington State University, Integrative Physiology and Neuroscience, Pullman, Washington 99164
| | - Hiroko Shiina
- Washington State University, Integrative Physiology and Neuroscience, Pullman, Washington 99164
| | - David J Rossi
- Washington State University, Integrative Physiology and Neuroscience, Pullman, Washington 99164
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7
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Straub I, Witter L, Eshra A, Hoidis M, Byczkowicz N, Maas S, Delvendahl I, Dorgans K, Savier E, Bechmann I, Krueger M, Isope P, Hallermann S. Gradients in the mammalian cerebellar cortex enable Fourier-like transformation and improve storing capacity. eLife 2020; 9:e51771. [PMID: 32022688 PMCID: PMC7002074 DOI: 10.7554/elife.51771] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 12/20/2019] [Indexed: 12/28/2022] Open
Abstract
Cerebellar granule cells (GCs) make up the majority of all neurons in the vertebrate brain, but heterogeneities among GCs and potential functional consequences are poorly understood. Here, we identified unexpected gradients in the biophysical properties of GCs in mice. GCs closer to the white matter (inner-zone GCs) had higher firing thresholds and could sustain firing with larger current inputs than GCs closer to the Purkinje cell layer (outer-zone GCs). Dynamic Clamp experiments showed that inner- and outer-zone GCs preferentially respond to high- and low-frequency mossy fiber inputs, respectively, enabling dispersion of the mossy fiber input into its frequency components as performed by a Fourier transformation. Furthermore, inner-zone GCs have faster axonal conduction velocity and elicit faster synaptic potentials in Purkinje cells. Neuronal network modeling revealed that these gradients improve spike-timing precision of Purkinje cells and decrease the number of GCs required to learn spike-sequences. Thus, our study uncovers biophysical gradients in the cerebellar cortex enabling a Fourier-like transformation of mossy fiber inputs.
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Affiliation(s)
- Isabelle Straub
- Carl-Ludwig-Institute for Physiology, Medical FacultyLeipzig UniversityLeipzigGermany
| | - Laurens Witter
- Carl-Ludwig-Institute for Physiology, Medical FacultyLeipzig UniversityLeipzigGermany
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research (CNCR)VU UniversityAmsterdamNetherlands
| | - Abdelmoneim Eshra
- Carl-Ludwig-Institute for Physiology, Medical FacultyLeipzig UniversityLeipzigGermany
| | - Miriam Hoidis
- Carl-Ludwig-Institute for Physiology, Medical FacultyLeipzig UniversityLeipzigGermany
| | - Niklas Byczkowicz
- Carl-Ludwig-Institute for Physiology, Medical FacultyLeipzig UniversityLeipzigGermany
| | - Sebastian Maas
- Carl-Ludwig-Institute for Physiology, Medical FacultyLeipzig UniversityLeipzigGermany
| | - Igor Delvendahl
- Carl-Ludwig-Institute for Physiology, Medical FacultyLeipzig UniversityLeipzigGermany
| | - Kevin Dorgans
- Institut des Neurosciences Cellulaires et IntégrativesCNRS, Université de StrasbourgStrasbourgFrance
| | - Elise Savier
- Institut des Neurosciences Cellulaires et IntégrativesCNRS, Université de StrasbourgStrasbourgFrance
| | - Ingo Bechmann
- Institute of Anatomy, Medical FacultyLeipzig UniversityLeipzigGermany
| | - Martin Krueger
- Institute of Anatomy, Medical FacultyLeipzig UniversityLeipzigGermany
| | - Philippe Isope
- Institut des Neurosciences Cellulaires et IntégrativesCNRS, Université de StrasbourgStrasbourgFrance
| | - Stefan Hallermann
- Carl-Ludwig-Institute for Physiology, Medical FacultyLeipzig UniversityLeipzigGermany
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8
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Cembran A, Bruggeman KF, Williams RJ, Parish CL, Nisbet DR. Biomimetic Materials and Their Utility in Modeling the 3-Dimensional Neural Environment. iScience 2020; 23:100788. [PMID: 31954980 PMCID: PMC6970178 DOI: 10.1016/j.isci.2019.100788] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 10/30/2019] [Accepted: 12/13/2019] [Indexed: 02/06/2023] Open
Abstract
The brain is a complex 3-dimensional structure, the organization of which provides a local environment that directly influences the survival, proliferation, differentiation, migration, and plasticity of neurons. To probe the effects of damage and disease on these cells, a synthetic environment is needed. Three-dimensional culturing of stem cells, neural progenitors, and neurons within fabricated biomaterials has demonstrated superior biomimetic properties over conventional 2-dimensional cultureware, offering direct recapitulation of both cell-cell and cell-extracellular matrix interactions. Within this review we address the benefits of deploying biomaterials as advanced cell culture tools capable of influencing neuronal fate and as in vitro models of the native in vivo microenvironment. We highlight recent and promising biomaterials approaches toward understanding neural network and their function relevant to neurodevelopment and provide our perspective on how these materials can be engineered and programmed to study both the healthy and diseased nervous system.
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Affiliation(s)
- Arianna Cembran
- Laboratory of Advanced Biomaterials, Research School of Electrical, Energy and Materials Engineering, The Australian National University, Canberra, ACT 2600, Australia
| | - Kiara F Bruggeman
- Laboratory of Advanced Biomaterials, Research School of Electrical, Energy and Materials Engineering, The Australian National University, Canberra, ACT 2600, Australia
| | | | - Clare L Parish
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Melbourne, VIC 3010, Australia.
| | - David R Nisbet
- Laboratory of Advanced Biomaterials, Research School of Electrical, Energy and Materials Engineering, The Australian National University, Canberra, ACT 2600, Australia.
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