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Sanetra AM, Jeczmien-Lazur JS, Pradel K, Klich JD, Palus-Chramiec K, Janik ME, Bajkacz S, Izowit G, Nathan C, Piggins HD, Delogu A, Belle MD, Lewandowski MH, Chrobok L. A novel developmental critical period of orexinergic signaling in the primary visual thalamus. iScience 2024; 27:110352. [PMID: 39055917 PMCID: PMC11269934 DOI: 10.1016/j.isci.2024.110352] [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: 01/12/2024] [Revised: 04/15/2024] [Accepted: 06/20/2024] [Indexed: 07/28/2024] Open
Abstract
The orexinergic system of the lateral hypothalamus plays crucial roles in arousal, feeding behavior, and reward modulation. Most research has focused on adult rodents, overlooking orexins' potential role in the nervous system development. This study, using electrophysiological and molecular tools, highlights importance of orexinergic signaling in the postnatal development of the rodent dorsolateral geniculate nucleus (DLG), a primary visual thalamic center. Orexin activation of DLG thalamocortical neurons occurs in a brief seven-day window around eye-opening, concurrent to transient OX2 receptor expression. Blocking OX2 receptors during this period reduces sensitivity of DLG neurons to green and blue light and lowers spontaneous firing rates in adulthood. This research reveals critical and temporally confined role of orexin signaling in postnatal brain development, emphasizing its contribution to experience-dependent refinement in the DLG and its long-term impact on visual function.
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Affiliation(s)
- Anna M. Sanetra
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University in Krakow, Krakow, Poland
| | - Jagoda S. Jeczmien-Lazur
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University in Krakow, Krakow, Poland
| | - Kamil Pradel
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University in Krakow, Krakow, Poland
- Institute for Systems Physiology, University of Cologne, Cologne, Germany
| | - Jasmin D. Klich
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University in Krakow, Krakow, Poland
- Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Katarzyna Palus-Chramiec
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University in Krakow, Krakow, Poland
| | - Marcelina E. Janik
- Department of Glycoconjugate Biochemistry, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University in Krakow, Krakow, Poland
| | - Sylwia Bajkacz
- Department of Inorganic Chemistry, Analytical Chemistry and Electrochemistry, Faculty of Chemistry, Silesian University of Technology, Gliwice, Poland
- The Biotechnology Centre, Silesian University of Technology, Gliwice, Poland
| | - Gabriela Izowit
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University in Krakow, Krakow, Poland
| | - Christian Nathan
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
- University of Exeter Medical School, Hatherly Labs, Streatham Campus, Prince of Wales Road, Exeter, Devon, UK
| | - Hugh D. Piggins
- School of Physiology, Pharmacology, and Neuroscience, Faculty of Health and Life Sciences, University of Bristol, Bristol, UK
| | - Alessio Delogu
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
| | - Mino D.C. Belle
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
- University of Exeter Medical School, Hatherly Labs, Streatham Campus, Prince of Wales Road, Exeter, Devon, UK
| | - Marian H. Lewandowski
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University in Krakow, Krakow, Poland
| | - Lukasz Chrobok
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University in Krakow, Krakow, Poland
- School of Physiology, Pharmacology, and Neuroscience, Faculty of Health and Life Sciences, University of Bristol, Bristol, UK
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Martini FJ, Guillamón-Vivancos T, Moreno-Juan V, Valdeolmillos M, López-Bendito G. Spontaneous activity in developing thalamic and cortical sensory networks. Neuron 2021; 109:2519-2534. [PMID: 34293296 DOI: 10.1016/j.neuron.2021.06.026] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 05/05/2021] [Accepted: 06/23/2021] [Indexed: 11/19/2022]
Abstract
Developing sensory circuits exhibit different patterns of spontaneous activity, patterns that are related to the construction and refinement of functional networks. During the development of different sensory modalities, spontaneous activity originates in the immature peripheral sensory structures and in the higher-order central structures, such as the thalamus and cortex. Certainly, the perinatal thalamus exhibits spontaneous calcium waves, a pattern of activity that is fundamental for the formation of sensory maps and for circuit plasticity. Here, we review our current understanding of the maturation of early (including embryonic) patterns of spontaneous activity and their influence on the assembly of thalamic and cortical sensory networks. Overall, the data currently available suggest similarities between the developmental trajectory of brain activity in experimental models and humans, which in the future may help to improve the early diagnosis of developmental disorders.
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Affiliation(s)
- Francisco J Martini
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), Sant Joan d'Alacant, Spain.
| | - Teresa Guillamón-Vivancos
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), Sant Joan d'Alacant, Spain
| | - Verónica Moreno-Juan
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), Sant Joan d'Alacant, Spain
| | - Miguel Valdeolmillos
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), Sant Joan d'Alacant, Spain
| | - Guillermina López-Bendito
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), Sant Joan d'Alacant, Spain.
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Tikidji-Hamburyan RA, Colonnese MT. Polynomial, piecewise-Linear, Step (PLS): A Simple, Scalable, and Efficient Framework for Modeling Neurons. Front Neuroinform 2021; 15:642933. [PMID: 34025382 PMCID: PMC8134741 DOI: 10.3389/fninf.2021.642933] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/29/2021] [Indexed: 01/04/2023] Open
Abstract
Biological neurons can be modeled with different levels of biophysical/biochemical details. The accuracy with which a model reflects the actual physiological processes and ultimately the information function of a neuron, can range from very detailed to a schematic phenomenological representation. This range exists due to the common problem: one needs to find an optimal trade-off between the level of details needed to capture the necessary information processing in a neuron and the computational load needed to compute 1 s of model time. An increase in modeled network size or model-time, for which the solution should be obtained, makes this trade-off pivotal in model development. Numerical simulations become incredibly challenging when an extensive network with a detailed representation of each neuron needs to be modeled over a long time interval to study slow evolving processes, e.g., development of the thalamocortical circuits. Here we suggest a simple, powerful and flexible approach in which we approximate the right-hand sides of differential equations by combinations of functions from three families: Polynomial, piecewise-Linear, Step (PLS). To obtain a single coherent framework, we provide four core principles in which PLS functions should be combined. We show the rationale behind each of the core principles. Two examples illustrate how to build a conductance-based or phenomenological model using the PLS-framework. We use the first example as a benchmark on three different computational platforms: CPU, GPU, and mobile system-on-chip devices. We show that the PLS-framework speeds up computations without increasing the memory footprint and maintains high model fidelity comparable to the fully-computed model or with lookup-table approximation. We are convinced that the full range of neuron models: from biophysical to phenomenological and even to abstract models, may benefit from using the PLS-framework.
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Affiliation(s)
| | - Matthew T Colonnese
- School of Medicine and Health Sciences, George Washington University, Washington, DC, United States
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Murata Y, Colonnese MT. Thalamic inhibitory circuits and network activity development. Brain Res 2019; 1706:13-23. [PMID: 30366019 PMCID: PMC6363901 DOI: 10.1016/j.brainres.2018.10.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 09/30/2018] [Accepted: 10/22/2018] [Indexed: 02/06/2023]
Abstract
Inhibitory circuits in thalamus and cortex shape the major activity patterns observed by electroencephalogram (EEG) in the adult brain. Their delayed maturation and circuit integration, relative to excitatory neurons, suggest inhibitory neuronal development could be responsible for the onset of mature thalamocortical activity. Indeed, the immature brain lacks many inhibition-dependent activity patterns, such as slow-waves, delta oscillations and sleep-spindles, and instead expresses other unique oscillatory activities in multiple species including humans. Thalamus contributes significantly to the generation of these early oscillations. Compared to the abundance of studies on the development of inhibition in cortex, however, the maturation of thalamic inhibition is poorly understood. Here we review developmental changes in the neuronal and circuit properties of the thalamic relay and its interconnected inhibitory thalamic reticular nucleus (TRN) both in vitro and in vivo, and discuss their potential contribution to early network activity and its maturation. While much is unknown, we argue that weak inhibitory function in the developing thalamus allows for amplification of thalamocortical activity that supports the generation of early oscillations. The available evidence suggests that the developmental acquisition of critical thalamic oscillations such as slow-waves and sleep-spindles is driven by maturation of the TRN. Further studies to elucidate thalamic GABAergic circuit formation in relation to thalamocortical network function would help us better understand normal as well as pathological brain development.
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Affiliation(s)
- Yasunobu Murata
- Department of Pharmacology and Physiology, and Institute for Neuroscience, George Washington University, 2300 Eye Street NW, Washington, DC 20037, USA.
| | - Matthew T Colonnese
- Department of Pharmacology and Physiology, and Institute for Neuroscience, George Washington University, 2300 Eye Street NW, Washington, DC 20037, USA.
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Guido W. Development, form, and function of the mouse visual thalamus. J Neurophysiol 2018; 120:211-225. [PMID: 29641300 PMCID: PMC6093956 DOI: 10.1152/jn.00651.2017] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 04/04/2018] [Accepted: 04/04/2018] [Indexed: 12/16/2022] Open
Abstract
The dorsal lateral geniculate nucleus (dLGN) of the thalamus is the exclusive relay of retinal information en route to the visual cortex. Although much of our understanding about dLGN comes from studies done in higher mammals, such as the cat and primate, the mouse as a model organism has moved to the forefront as a tractable experimental platform to examine cell type-specific relations. This review highlights our current knowledge about the development, structure, and function of the mouse dLGN.
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Affiliation(s)
- William Guido
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine , Louisville, Kentucky
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6
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Abstract
The thalamocortical (TC) relay neuron of the dorsoLateral Geniculate Nucleus (dLGN) has borne its imprecise label for many decades in spite of strong evidence that its role in visual processing transcends the implied simplicity of the term "relay". The retinogeniculate synapse is the site of communication between a retinal ganglion cell and a TC neuron of the dLGN. Activation of retinal fibers in the optic tract causes reliable, rapid, and robust postsynaptic potentials that drive postsynaptics spikes in a TC neuron. Cortical and subcortical modulatory systems have been known for decades to regulate retinogeniculate transmission. The dynamic properties that the retinogeniculate synapse itself exhibits during and after developmental refinement further enrich the role of the dLGN in the transmission of the retinal signal. Here we consider the structural and functional substrates for retinogeniculate synaptic transmission and plasticity, and reflect on how the complexity of the retinogeniculate synapse imparts a novel dynamic and influential capacity to subcortical processing of visual information.
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Affiliation(s)
- Elizabeth Y Litvina
- Department of Neurology,F.M. Kirby Neurobiology Center,Children's Hospital, Boston,Boston,Massachusetts 02115
| | - Chinfei Chen
- Department of Neurology,F.M. Kirby Neurobiology Center,Children's Hospital, Boston,Boston,Massachusetts 02115
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7
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El-Danaf RN, Krahe TE, Dilger EK, Bickford ME, Fox MA, Guido W. Developmental remodeling of relay cells in the dorsal lateral geniculate nucleus in the absence of retinal input. Neural Dev 2015; 10:19. [PMID: 26174426 PMCID: PMC4502538 DOI: 10.1186/s13064-015-0046-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 07/01/2015] [Indexed: 12/01/2022] Open
Abstract
Background The dorsal lateral geniculate nucleus (dLGN) of the mouse has been an important experimental model for understanding thalamic circuit development. The developmental remodeling of retinal projections has been the primary focus, however much less is known about the maturation of their synaptic targets, the relay cells of the dLGN. Here we examined the growth and maturation of relay cells during the first few weeks of life and addressed whether early retinal innervation affects their development. To accomplish this we utilized the math5 null (math5−/−) mouse, a mutant lacking retinal ganglion cells and central projections. Results The absence of retinogeniculate axon innervation led to an overall shrinkage of dLGN and disrupted the pattern of dendritic growth among developing relay cells. 3-D reconstructions of biocytin filled neurons from math5−/− mice showed that in the absence of retinal input relay cells undergo a period of exuberant dendritic growth and branching, followed by branch elimination and an overall attenuation in dendritic field size. However, math5−/− relay cells retained a sufficient degree of complexity and class specificity, as well as their basic membrane properties and spike firing characteristics. Conclusions Retinal innervation plays an important trophic role in dLGN development. Additional support perhaps arising from non-retinal innervation and signaling is likely to contribute to the stabilization of their dendritic form and function.
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Affiliation(s)
- Rana N El-Danaf
- Departments of Neuroscience, Neurobiology Section in the Division of Biological Sciences, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Thomas E Krahe
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, Richmond, VA, 23298, USA.
| | | | - Martha E Bickford
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY, 40292, USA.
| | - Michael A Fox
- Virginia Tech Carilion Research Institute, Roanoke, VA, 24016, USA. .,Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA.
| | - William Guido
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY, 40292, USA.
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Hauser JL, Liu X, Litvina EY, Chen C. Prolonged synaptic currents increase relay neuron firing at the developing retinogeniculate synapse. J Neurophysiol 2014; 112:1714-28. [PMID: 24966302 DOI: 10.1152/jn.00451.2014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The retinogeniculate synapse, the connection between retinal ganglion cells (RGC) and thalamic relay neurons, undergoes robust changes in connectivity over development. This process of synapse elimination and strengthening of remaining inputs is thought to require synapse specificity. Here we show that glutamate spillover and asynchronous release are prominent features of retinogeniculate synaptic transmission during this period. The immature excitatory postsynaptic currents exhibit a slow decay time course that is sensitive to low-affinity glutamate receptor antagonists and extracellular calcium concentrations, consistent with glutamate spillover. Furthermore, we uncover and characterize a novel, purely spillover-mediated AMPA receptor current from immature relay neurons. The isolation of this current strongly supports the presence of spillover between boutons of different RGCs. In addition, fluorescence measurements of presynaptic calcium transients suggest that prolonged residual calcium contributes to both glutamate spillover and asynchronous release. These data indicate that, during development, far more RGCs contribute to relay neuron firing than would be expected based on predictions from anatomy alone.
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Affiliation(s)
- Jessica L Hauser
- Department of Neurology, F. M. Kirby Neurobiology Center, Children's Hospital, Boston, Massachusetts; and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts
| | - Xiaojin Liu
- Department of Neurology, F. M. Kirby Neurobiology Center, Children's Hospital, Boston, Massachusetts; and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts
| | - Elizabeth Y Litvina
- Department of Neurology, F. M. Kirby Neurobiology Center, Children's Hospital, Boston, Massachusetts; and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts
| | - Chinfei Chen
- Department of Neurology, F. M. Kirby Neurobiology Center, Children's Hospital, Boston, Massachusetts; and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts
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Venkataraman Y, Bartlett EL. Postnatal development of auditory central evoked responses and thalamic cellular properties. Dev Neurobiol 2013; 74:541-55. [PMID: 24214269 DOI: 10.1002/dneu.22148] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 10/23/2013] [Accepted: 11/04/2013] [Indexed: 01/04/2023]
Abstract
During development, the sense of hearing changes rapidly with age, especially around hearing onset. During this period, auditory structures are highly sensitive to alterations of the acoustic environment, such as hearing loss or background noise. This sensitivity includes auditory temporal processing, which is important for processing complex sounds, and for acquiring reading and language skills. Developmental changes can be observed at multiple levels of brain organization-from behavioral responses to cellular responses, and at every auditory nucleus. Neuronal properties and sound processing change dramatically in auditory cortex neurons after hearing onset. However, development of its primary source, the auditory thalamus, or medial geniculate body (MGB), has not been well studied over this critical time window. Furthermore, to understand how temporal processing develops, it is important to determine the relative maturation of temporal processing not only in the MGB, but also in its inputs. Cellular properties of rat MGB neurons were studied using in vitro whole-cell patch-clamp recordings, at ages postnatal day (P) 7-9; P15-17, and P22-32. Auditory evoked potentials were measured in P14-17 and P22-32 rats. MGB action potentials became about five times faster, and the ability to generate spike trains increased with age, particularly at frequencies of 50 Hz and higher. Evoked potential responses, including auditory brainstem responses (ABR), middle latency responses (MLR), and amplitude modulation following responses, showed increased amplitudes with age, and ABRs and MLRs additionally showed decreased latencies with age. Overall, temporal processing at subthalamic nuclei is concurrently maturing with MGB cellular properties.
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Affiliation(s)
- Yamini Venkataraman
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana
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Venkataraman Y, Bartlett EL. Postnatal development of synaptic properties of the GABAergic projection from the inferior colliculus to the auditory thalamus. J Neurophysiol 2013; 109:2866-82. [PMID: 23536710 DOI: 10.1152/jn.00021.2013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The development of auditory temporal processing is important for processing complex sounds as well as for acquiring reading and language skills. Neuronal properties and sound processing change dramatically in auditory cortex neurons after the onset of hearing. However, the development of the auditory thalamus or medial geniculate body (MGB) has not been well studied over this critical time window. Since synaptic inhibition has been shown to be crucial for auditory temporal processing, this study examined the development of a feedforward, GABAergic connection to the MGB from the inferior colliculus (IC), which is also the source of sensory glutamatergic inputs to the MGB. IC-MGB inhibition was studied using whole cell patch-clamp recordings from rat brain slices in current-clamp and voltage-clamp modes at three age groups: a prehearing group [postnatal day (P)7-P9], an immediate posthearing group (P15-P17), and a juvenile group (P22-P32) whose neuronal properties are largely mature. Membrane properties matured substantially across the ages studied. GABAA and GABAB inhibitory postsynaptic potentials were present at all ages and were similar in amplitude. Inhibitory postsynaptic potentials became faster to single shocks, showed less depression to train stimuli at 5 and 10 Hz, and were overall more efficacious in controlling excitability with age. Overall, IC-MGB inhibition becomes faster and more precise during a time period of rapid changes across the auditory system due to the codevelopment of membrane properties and synaptic properties.
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Affiliation(s)
- Yamini Venkataraman
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
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Morphologically distinct classes of relay cells exhibit regional preferences in the dorsal lateral geniculate nucleus of the mouse. J Neurosci 2012; 31:17437-48. [PMID: 22131405 DOI: 10.1523/jneurosci.4370-11.2011] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A fundamental feature of the mammalian visual system is the presence of separate channels that work in parallel to efficiently extract and analyze specific elements of a visual scene. Despite the extensive use of the mouse as a model system, it is not clear whether such parallel organization extends beyond the retina to subcortical structures, such as the dorsal lateral geniculate (dLGN) of thalamus. To begin to address this, we examined the morphology of biocytin-filled relay cells recorded in dLGN of mice. Based on a quantitative assessment of their dendritic architecture, we found that even at early postnatal ages relay cells could be readily classified as X-like (biconical), Y-like (symmetrical), or W-like (hemispheric) and that each cell type was regionally specified in dLGN. X-like cells were confined primarily to the monocular ventral region of dLGN. Y-like cells occupied a central core that also contained ipsilateral eye projections, whereas W-like cells were found along the perimeter of dLGN. Similar to cat, Y-like cells were more prevalent than X- and W-like cells, and X-like cells tended to be smaller than other cell types. However, the dendritic fields of X- and W-like cells did not exhibit an orientation bias with respect to optic tract or boundaries of dLGN. Although we found clear morphological differences among relay cells, an analysis of their electrophysiological properties did not reveal any additional distinguishing characteristics. Overall, these data coupled with recent observations in the retina suggest that the mouse has many of the hallmark features of a system-wide parallel organization.
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12
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Wijesinghe R, Camp AJ. Intrinsic neuronal excitability: implications for health and disease. Biomol Concepts 2011; 2:247-59. [PMID: 25962033 DOI: 10.1515/bmc.2011.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 05/30/2011] [Indexed: 11/15/2022] Open
Abstract
The output of a single neuron depends on both synaptic connectivity and intrinsic membrane properties. Changes in both synaptic and intrinsic membrane properties have been observed during homeostatic processes (e.g., vestibular compensation) as well as in several central nervous system (CNS) disorders. Although changes in synaptic properties have been extensively studied, particularly with regard to learning and memory, the contribution of intrinsic membrane properties to either physiological or pathological processes is much less clear. Recent research, however, has shown that alterations in the number, location or properties of voltage- and ligand-gated ion channels can underlie both normal and abnormal physiology, and that these changes arise via a diverse suite of molecular substrates. The literature reviewed here shows that changes in intrinsic neuronal excitability (presumably in concert with synaptic plasticity) can fundamentally modify the output of neurons, and that these modifications can subserve both homeostatic mechanisms and the pathogenesis of CNS disorders including epilepsy, migraine, and chronic pain.
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13
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Dilger EK, Shin HS, Guido W. Requirements for synaptically evoked plateau potentials in relay cells of the dorsal lateral geniculate nucleus of the mouse. J Physiol 2010; 589:919-37. [PMID: 21173075 DOI: 10.1113/jphysiol.2010.202499] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
In developing cells of the mouse dorsal lateral geniculate nucleus (dLGN), synaptic responses evoked by optic tract (OT) stimulation give rise to long-lasting, high-amplitude depolarizations known as plateau potentials. These events are mediated by L-type Ca2+ channels and occur during early postnatal life, a time when retinogeniculate connections are remodelling. To better understand the relationship between L-type activity and dLGN development we used an in vitro thalamic slice preparation which preserves the retinal connections and intrinsic circuitry in dLGN and examined how synaptic responses evoked by OT stimulation lead to the activation of plateau potentials. By varying the strength and temporal frequency of OT stimulation we identified at least three factors that contribute to the developmental regulation of plateau activity: the degree of retinal convergence, the temporal pattern of retinal stimulation and the emergence of feed-forward inhibition. Before natural eye opening (postnatal day 14), the excitatory synaptic responses of relay cells receiving multiple retinal inputs summated in both the spatial and temporal domains to produce depolarizations sufficient to activate L-type activity. After eye opening, when inhibitory responses are fully developed, plateau activity was rarely evoked even with high temporal rates of OT stimulation. When the bulk of this inhibition was blocked by bath application of bicuculline, the incidence of plateau activity increased significantly. We also made use of a transgenic mouse that lacks the β3 subunit of the L-type Ca2+ channel. These mutants have far fewer membrane-bound Ca2+ channels and attenuated L-type activity. In β3 nulls, L-type plateau activity was rarely observed even at young ages when plateau activity prevails. Thus, in addition to the changing patterns of synaptic connectivity and retinal activity, the expression of L-type Ca2+ channels is a requisite component in the manifestation of plateau activity.
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Affiliation(s)
- Emily K Dilger
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Centre, Sanger Hall, 1101 E. Marshall St, Richmond, VA 23298, USA
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14
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Guido W. A shout out to immature synapses. Focus on "different roles for AMPA and NMDA receptors in transmission at the immature retinogeniculate synapse". J Neurophysiol 2007; 99:411-2. [PMID: 18057105 DOI: 10.1152/jn.01288.2007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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15
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Liu X, Chen C. Different roles for AMPA and NMDA receptors in transmission at the immature retinogeniculate synapse. J Neurophysiol 2007; 99:629-43. [PMID: 18032559 DOI: 10.1152/jn.01171.2007] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The relay of information at the retinogeniculate synapse, the connection between retina and visual thalamus, begins days before eye opening and is thought to play an important role in the maturation of neural circuits in the thalamus and visual cortex. Remarkably, during this period of development, the retinogeniculate synapse is immature, with single retinal ganglion cell inputs evoking an average peak excitatory postsynaptic current (EPSC) of only about 40 pA compared with 800 pA in mature synapses. Yet, at the mature synapse, EPSCs >400 pA are needed to drive relay neuron firing. This raises the question of how small-amplitude EPSCs can drive transmission at the immature retinogeniculate synapse. Here we find that several features of the immature synapse, compared with the mature synapse, contribute to synaptic transmission. First, although the peak amplitude of EPSC is small, the decay time course of both alpha-amino-3-hydroxy-5-methyl-4isoxazolepropionic acid receptor (AMPAR) and N-methyl-d-aspartate receptor (NMDAR) currents is significantly slower. The prolonged time course of NMDAR currents is a result of the presence of both NR2B and NR2C/D subunits. In addition, the extended presence of neurotransmitter released prolongs the synaptic current time course. Second, reduced sensitivity to magnesium block results in significantly greater synaptic charge transfer through NMDAR. Third, AMPAR currents contribute to the spike latency, but not to temporal precision, at the immature synapse. Furthermore, intrinsic excitability is greater. These properties enable immature synapses with predominantly NMDARs and little or no AMPARs to contribute to the relay of information from retina to visual cortex.
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Affiliation(s)
- Xiaojin Liu
- Neurobiology Program, Division in Neuroscience, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA
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Postnatal maturational properties of rat parafascicular thalamic neurons recorded in vitro. ACTA ACUST UNITED AC 2006; 3:89-113. [PMID: 19305519 DOI: 10.1017/s1472928805000105] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Thalamic relay neurons have homogeneous, adult-like firing properties and similar morphology by 12 days postnatally (PN 12). Parafascicular (Pf) neurons have a different morphology compared with typical thalamic relay neurons, but the development of their electrophysiological properties is not well studied. Intracellular recordings in PN 12-50 Pf neurons revealed several heterogeneous firing patterns different from those in thalamic relay neurons. Two types of cells were identified: Type I cells displayed a fast afterhyperpolarization (AHP) followed by a large-amplitude, slow AHP; whereas Type II cells had only a fast AHP. These cell types had overlapping membrane properties but differences in excitability. Some properties of Pf neurons were adult-like by PN 12, but, unlike thalamic relay neurons, there were significant maturational changes thereafter, including decreased action potential (AP) duration, increased fast AHP amplitude and increased excitability. Pf neurons did not exhibit rhythmic bursting and generally lacked low-threshold spike (LTS) responses that characterize thalamic relay neurons. Pf neurons exhibited nonlinear I-V relationships, and only a third of the cells expressed the time and voltage-dependent hyperpolarization activated (Ih) current, which declined with age. These results indicate that the morphological differences between Pf neurons and typical thalamic relay neurons are paralleled by electrophysiological differences, and that Pf membrane properties change during postnatal development.
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17
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Lo FS, Erzurumlu RS. Neonatal deafferentation does not alter membrane properties of trigeminal nucleus principalis neurons. J Neurophysiol 2001; 85:1088-96. [PMID: 11247979 PMCID: PMC3676675 DOI: 10.1152/jn.2001.85.3.1088] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the brain stem trigeminal complex of rats and mice, presynaptic afferent arbors and postsynaptic target cells form discrete modules ("barrelettes"), the arrangement of which duplicates the patterned distribution of whiskers and sinus hairs on the ipsilateral snout. Within the barrelette region of the nucleus principalis of the trigeminal nerve (PrV), neurons participating in barrelettes and those with dendritic spans covering multiple barrelettes (interbarrelette neurons) can be identified by their morphological and electrophysiological characteristics as early as postnatal day 1. Barrelette cells have focal dendritic processes, are characterized by a transient K(+) conductance (I(A)), whereas interbarrelette cells with larger soma and extensive dendritic fields characteristically exhibit low-threshold T-type Ca(2+) spikes (LTS). In this study, we surveyed membrane properties of barrelette and interbarrelette neurons during and after consolidation of barrelettes in the PrV and effects of peripheral deafferentation on these properties. During postnatal development (PND1-13), there were no changes in the resting potential, composition of active conductances and Na(+) spikes of both barrelette and interbarrelette cells. The only notable changes were a decline in input resistance and a slight increase in the amplitude of LTS. The infraorbital (IO) branch of the trigeminal nerve provides the sole afferent input source to the whisker pad. IO nerve transection at birth abolishes barrelette formation as well as whisker-related neuronal patterns all the way to the neocortex. Surprisingly this procedure had no effect on membrane properties of PrV neurons. The results of the present study demonstrate that distinct membrane properties of barrelette and interbarrelette cells are maintained even in the absence of input from the whiskers during the critical period of pattern formation.
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Affiliation(s)
- F S Lo
- Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA.
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Black CJ, Johnston AR, Fraser JR, MacLeod N. Electrophysiological properties of dorsal lateral geniculate neurons in brain slices from ME7 scrapie-infected mice. Exp Neurol 1998; 149:253-61. [PMID: 9454635 DOI: 10.1006/exnr.1997.6713] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Electrophysiological recordings using conventional intracellular techniques were obtained from dorsal lateral geniculate nucleus (dLGN) neurons in brain slices from ME7 scrapie-infected mice at specific time points throughout the incubation period of the disease. Comparisons were made with age-matched control mice. A number of dLGN neurons from control and scrapie-infected mice were injected with biocytin in order to examine their cellular morphology. Mice were infected with ME7 scrapie by an intraocular route and the mean (+/- SEM) incubation period of the disease was 276 +/- 3.5 days. Our results indicate that there were no differences in the electrophysiological or morphological parameters of neurons recorded in ME7 scrapie-infected and age-matched control mice at any stage of the disease up to 240 days postinoculation. After this time, however, no detectable electrical activity was recorded in the dLGN. This study demonstrates that in the ME7 scrapie-infected dLGN, relay neurons with normal physiological and morphological properties are present even at an advanced stage of the disease at a time when the dLGN is known to be subject to marked pathological changes and a profound neuronal loss.
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Affiliation(s)
- C J Black
- Department of Physiology, University Medical School, Edinburgh, United Kingdom
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