1
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Srivastava HK, Bandyopadhyay S. Parallel Lemniscal and Non-Lemniscal Sources Control Auditory Responses in the Orbitofrontal Cortex (OFC). eNeuro 2020; 7:ENEURO.0121-20.2020. [PMID: 32753369 PMCID: PMC7545433 DOI: 10.1523/eneuro.0121-20.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 04/29/2020] [Accepted: 05/10/2020] [Indexed: 12/14/2022] Open
Abstract
The orbitofrontal cortex (OFC) controls flexible behavior through stimulus value updating based on stimulus outcome associations, allowing seamless navigation in dynamic sensory environments with changing contingencies. Sensory cue driven responses, primarily studied through behavior, exist in the OFC. However, OFC neurons' sensory response properties, particularly auditory, are unknown in the mouse, a genetically tractable animal. We show that mouse OFC single neurons have unique auditory response properties showing pure oddball detection and long timescales of adaptation resulting in stimulus-history dependence. Further, we show that OFC auditory responses are shaped by two parallel sources in the auditory thalamus, lemniscal and non-lemniscal. The latter underlies a large component of the observed oddball detection and additionally controls persistent activity in the OFC through the amygdala. The deviant selectivity can serve as a signal for important changes in the auditory environment. Such signals, if coupled with persistent activity, obtained by disinhibitory control from the non-lemniscal auditory thalamus or amygdala, will allow for associations with a delayed outcome related signal, like reward prediction error, and potentially forms the basis of updating stimulus outcome associations in the OFC. Thus, the baseline sensory responses allow the behavioral requirement-based response modification through relevant inputs from other structures related to reward, punishment, or memory. Thus, alterations in these responses in neurologic disorders can lead to behavioral deficits.
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Affiliation(s)
- Hemant K Srivastava
- Advanced Technology Development Centre, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Sharba Bandyopadhyay
- Advanced Technology Development Centre, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
- Department of Electronics and Electrical Communication Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
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2
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Pham BN, Luo J, Anand H, Kola O, Salcedo P, Nguyen C, Gaunt S, Zhong H, Garfinkel A, Tillakaratne N, Edgerton VR. Redundancy and multifunctionality among spinal locomotor networks. J Neurophysiol 2020; 124:1469-1479. [PMID: 32966757 DOI: 10.1152/jn.00338.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
c-Fos is used to identify system-wide neural activation with cellular resolution in vivo. However, c-Fos can only capture neural activation of one event. Targeted recombination in active populations (TRAP) allows the capture of two different c-Fos activation patterns in the same animal. So far, TRAP has only been used to examine brain circuits. This study uses TRAP to investigate spinal circuit activation during resting and stepping, giving novel insights of network activation during these events. The level of colabeled (c-Fos+ and TRAP+) neurons observed after performing two bouts of stepping suggests that there is a probabilistic-like phenomenon that can recruit many combinations of neural populations (synapses) when repetitively generating many step cycles. Between two 30-min bouts of stepping, each consisting of thousands of steps, only ∼20% of the neurons activated from the first bout of stepping were also activated by the second bout. We also show colabeling of interneurons that have been active during stepping and resting. The use of the FosTRAP methodology in the spinal cord provides a new tool to compare the engagement of different populations of spinal interneurons in vivo under different motor tasks or under different conditions.NEW & NOTEWORTHY The results are consistent with there being an extensive amount of redundancy among spinal locomotor circuits. Using the newly developed FosTRAP mouse model, only ∼20% of neurons that were active (labeled by Fos-linked tdTomato expression) during a first bout of 30-min stepping were also labeled for c-Fos during a second bout of stepping. This finding suggests variability of neural networks that enables selection of many combinations of neurons (synapses) when generating each step cycle.
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Affiliation(s)
- Bau N Pham
- Department of Bioengineering, University of California, Los Angeles, California
| | - Jiangyuan Luo
- Department of Neuroscience, University of California, Los Angeles, California
| | - Harnadar Anand
- Institute for Society and Genetics, University of California, Los Angeles, California
| | - Olivia Kola
- Department of Neuroscience, University of California, Los Angeles, California
| | - Pia Salcedo
- Department of Psychobiology, University of California, Los Angeles, California
| | - Connie Nguyen
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California
| | - Sarah Gaunt
- Department of Molecular Cellular and Developmental Biology, University of California, Los Angeles, California
| | - Hui Zhong
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California
| | - Alan Garfinkel
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California
| | - Niranjala Tillakaratne
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California.,Brain Research Institute, University of California, Los Angeles, California
| | - V Reggie Edgerton
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California.,Brain Research Institute, University of California, Los Angeles, California.,Department of Neurobiology, University of California, Los Angeles, California.,Department of Neurosurgery, University of California, Los Angeles, California.,Institut Guttmann, Hospital de Neurorehabilitació, Universitat Autònoma de Barcelona, Badalona, Spain.,Centre for Neuroscience and Regenerative Medicine, Faculty of Science, University of Technology Sydney, Ultimo, Australia
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3
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Campelo T, Augusto E, Chenouard N, de Miranda A, Kouskoff V, Camus C, Choquet D, Gambino F. AMPAR-Dependent Synaptic Plasticity Initiates Cortical Remapping and Adaptive Behaviors during Sensory Experience. Cell Rep 2020; 32:108097. [PMID: 32877679 PMCID: PMC7487777 DOI: 10.1016/j.celrep.2020.108097] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/30/2020] [Accepted: 08/11/2020] [Indexed: 11/28/2022] Open
Abstract
Cortical plasticity improves behaviors and helps recover lost functions after injury. However, the underlying synaptic mechanisms remain unclear. In mice, we show that trimming all but one whisker enhances sensory responses from the spared whisker in the barrel cortex and occludes whisker-mediated synaptic potentiation (w-Pot) in vivo. In addition, whisker-dependent behaviors that are initially impaired by single-whisker experience (SWE) rapidly recover when associated cortical regions remap. Cross-linking the surface GluA2 subunit of AMPA receptors (AMPARs) suppresses the expression of w-Pot, presumably by blocking AMPAR surface diffusion, in mice with all whiskers intact, indicating that synaptic potentiation in vivo requires AMPAR trafficking. We use this approach to demonstrate that w-Pot is required for SWE-mediated strengthening of synaptic inputs and initiates the recovery of previously learned skills during the early phases of SWE. Taken together, our data reveal that w-Pot mediates cortical remapping and behavioral improvement upon partial sensory deafferentation.
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Affiliation(s)
- Tiago Campelo
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Elisabete Augusto
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Nicolas Chenouard
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Aron de Miranda
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Vladimir Kouskoff
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Come Camus
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Daniel Choquet
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France; University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4, 33000 Bordeaux, France.
| | - Frédéric Gambino
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France.
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4
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Geramita MA, Wen JA, Rannals MD, Urban NN. Decreased amplitude and reliability of odor-evoked responses in two mouse models of autism. J Neurophysiol 2019; 123:1283-1294. [PMID: 31891524 DOI: 10.1152/jn.00277.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Sensory processing deficits are increasingly recognized as core symptoms of autism spectrum disorders (ASDs). However the molecular and circuit mechanisms that lead to sensory deficits are unknown. We show that two molecularly disparate mouse models of autism display similar deficits in sensory-evoked responses in the mouse olfactory system. We find that both Cntnap2- and Shank3-deficient mice of both sexes exhibit reduced response amplitude and trial-to-trial reliability during repeated odor presentation. Mechanistically, we show that both mouse models have weaker and fewer synapses between olfactory sensory nerve (OSN) terminals and olfactory bulb tufted cells and weaker synapses between OSN terminals and inhibitory periglomerular cells. Consequently, deficits in sensory processing provide an excellent candidate phenotype for analysis in ASDs.NEW & NOTEWORTHY The genetics of autism spectrum disorder (ASD) are complex. How the many risk genes generate the similar sets of symptoms that define the disorder is unknown. In particular, little is understood about the functional consequences of these genetic alterations. Sensory processing deficits are important aspects of the ASD diagnosis and may be due to unreliable neural circuits. We show that two mouse models of autism, Cntnap2- and Shank3-deficient mice, display reduced odor-evoked response amplitudes and reliability. These data suggest that altered sensory-evoked responses may constitute a circuit phenotype in ASDs.
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Affiliation(s)
- Matthew A Geramita
- Department of Neurobiology, Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Jing A Wen
- Department of Neurobiology, Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Biology, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Matthew D Rannals
- Department of Neurobiology, Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Nathan N Urban
- Department of Biology, Carnegie Mellon University, Pittsburgh, Pennsylvania
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5
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Barth AL, Ray A. Progressive Circuit Changes during Learning and Disease. Neuron 2019; 104:37-46. [PMID: 31600514 DOI: 10.1016/j.neuron.2019.09.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/23/2019] [Accepted: 09/19/2019] [Indexed: 02/07/2023]
Abstract
A critical step toward understanding cognition, learning, and brain dysfunction will be identification of the underlying cellular computations that occur in and across discrete brain areas, as well as how they are progressively altered by experience or disease. These computations will be revealed by targeted analyses of the neurons that perform these calculations, defined not only by their firing properties but also by their molecular identity and how they are wired within the local and broad-scale network of the brain. New studies that take advantage of sophisticated genetic tools for cell-type-specific identification and control are revealing how learning and neurological disorders initiate and successively change the properties of defined neural circuits. Understanding the temporal sequence of adaptive or pathological synaptic changes across multiple synapses within a network will shed light into how small-scale neural circuits contribute to higher cognitive functions during learning and disease.
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Affiliation(s)
- Alison L Barth
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | - Ajit Ray
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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6
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Camon J, Hugues S, Erlandson MA, Robbe D, Lagoun S, Marouane E, Bureau I. The Timing of Sensory-Guided Behavioral Response is Represented in the Mouse Primary Somatosensory Cortex. Cereb Cortex 2019; 29:3034-3047. [PMID: 30060069 DOI: 10.1093/cercor/bhy169] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 06/01/2018] [Accepted: 06/25/2018] [Indexed: 11/13/2022] Open
Abstract
Whisker-guided decision making in mice is thought to critically depend on information processing occurring in the primary somatosensory cortex. However, it is not clear if neuronal activity in this "early" sensory region contains information about the timing and speed of motor response. To address this question we designed a new task in which freely moving mice learned to associate a whisker stimulus to reward delivery. The task was tailored in such a way that a wide range of delays between whisker stimulation and reward collection were observed due to differences of motivation and perception. After training, mice were anesthetized and neuronal responses evoked by stimulating trained and untrained whiskers were recorded across several cortical columns of barrel cortex. We found a strong correlation between the delay of the mouse behavioral response and the timing of multiunit activity evoked by the trained whisker, outside its principal cortical column, in layers 4 and 5A but not in layer 2/3. Circuit mapping ex vivo revealed this effect was associated with a weakening of layer 4 to layer 2/3 projection. We conclude that the processes controlling the propagation of key sensory inputs to naive cortical columns and the timing of sensory-guided action are linked.
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Affiliation(s)
- Jérémy Camon
- INMED, INSERM U1249, Université Aix-Marseille, Marseille, France
| | - Sandrine Hugues
- INMED, INSERM U1249, Université Aix-Marseille, Marseille, France
| | | | - David Robbe
- INMED, INSERM U1249, Université Aix-Marseille, Marseille, France
| | - Sabria Lagoun
- INMED, INSERM U1249, Université Aix-Marseille, Marseille, France
| | - Emna Marouane
- INMED, INSERM U1249, Université Aix-Marseille, Marseille, France
| | - Ingrid Bureau
- INMED, INSERM U1249, Université Aix-Marseille, Marseille, France
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7
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Carrillo-Medina JL, Latorre R. Detection of Activation Sequences in Spiking-Bursting Neurons by means of the Recognition of Intraburst Neural Signatures. Sci Rep 2018; 8:16726. [PMID: 30425274 PMCID: PMC6233224 DOI: 10.1038/s41598-018-34757-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 10/24/2018] [Indexed: 11/18/2022] Open
Abstract
Bursting activity is present in many cells of different nervous systems playing important roles in neural information processing. Multiple assemblies of bursting neurons act cooperatively to produce coordinated spatio-temporal patterns of sequential activity. A major goal in neuroscience is unveiling the mechanisms underlying neural information processing based on this sequential dynamics. Experimental findings have revealed the presence of precise cell-type-specific intraburst firing patterns in the activity of some bursting neurons. This characteristic neural signature coexists with the information encoded in other aspects of the spiking-bursting signals, and its functional meaning is still unknown. We investigate the ability of a neuron conductance-based model to detect specific presynaptic activation sequences taking advantage of intraburst fingerprints identifying the source of the signals building up a sequential pattern of activity. Our simulations point out that a reader neuron could use this information to contextualize incoming signals and accordingly compute a characteristic response by relying on precise phase relationships among the activity of different emitters. This would provide individual neurons enhanced capabilities to control and negotiate sequential dynamics. In this regard, we discuss the possible implications of the proposed contextualization mechanism for neural information processing.
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Affiliation(s)
- José Luis Carrillo-Medina
- Departamento de Eléctrica y Electrónica, Universidad de las Fuerzas Armadas - ESPE, Sangolquí, Ecuador
| | - Roberto Latorre
- Grupo de Neurocomputación Biológica, Dpto. Ingeniería Informática, Universidad Autónoma de Madrid, 28049, Madrid, Spain.
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8
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Audette NJ, Urban-Ciecko J, Matsushita M, Barth AL. POm Thalamocortical Input Drives Layer-Specific Microcircuits in Somatosensory Cortex. Cereb Cortex 2018; 28:1312-1328. [PMID: 28334225 PMCID: PMC6093433 DOI: 10.1093/cercor/bhx044] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 02/03/2017] [Indexed: 12/11/2022] Open
Abstract
Higher-order thalamic nuclei, such as the posterior medial nucleus (POm) in the somatosensory system or the pulvinar in the visual system, densely innervate the cortex and can influence perception and plasticity. To systematically evaluate how higher-order thalamic nuclei can drive cortical circuits, we investigated cell-type selective responses to POm stimulation in mouse primary somatosensory (barrel) cortex, using genetically targeted whole-cell recordings in acute brain slices. We find that ChR2-evoked thalamic input selectively targets specific cell types in the neocortex, revealing layer-specific modules for the summation and processing of POm input. Evoked activity in pyramidal neurons from deep layers is fast and synchronized by rapid feedforward inhibition from GABAergic parvalbumin-expressing neurons, and activity in superficial layers is weaker and prolonged, facilitated by slow inhibition from GABAergic neurons expressing the 5HT3a receptor. Somatostatin-expressing GABAergic neurons do not receive direct input in either layer and their spontaneous activity is suppressed during POm stimulation. This novel pattern of weak, delayed, thalamus-evoked inhibition in layer 2 suggests a longer integration window for incoming sensory information and may facilitate stimulus detection and plasticity in superficial pyramidal neurons.
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Affiliation(s)
- Nicholas J Audette
- Department of Biological Sciences and Center for the Neural Basis of Cognition, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA, USA
| | - Joanna Urban-Ciecko
- Department of Biological Sciences and Center for the Neural Basis of Cognition, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA, USA
| | - Megumi Matsushita
- Department of Biological Sciences and Center for the Neural Basis of Cognition, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA, USA
| | - Alison L Barth
- Department of Biological Sciences and Center for the Neural Basis of Cognition, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA, USA
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9
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Blake DT. Network Supervision of Adult Experience and Learning Dependent Sensory Cortical Plasticity. Compr Physiol 2017. [DOI: 10.1002/cphy.c160036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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10
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Maisel B, Lindenberg K. Channel noise effects on first spike latency of a stochastic Hodgkin-Huxley neuron. Phys Rev E 2017; 95:022414. [PMID: 28297877 DOI: 10.1103/physreve.95.022414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Indexed: 06/06/2023]
Abstract
While it is widely accepted that information is encoded in neurons via action potentials or spikes, it is far less understood what specific features of spiking contain encoded information. Experimental evidence has suggested that the timing of the first spike may be an energy-efficient coding mechanism that contains more neural information than subsequent spikes. Therefore, the biophysical features of neurons that underlie response latency are of considerable interest. Here we examine the effects of channel noise on the first spike latency of a Hodgkin-Huxley neuron receiving random input from many other neurons. Because the principal feature of a Hodgkin-Huxley neuron is the stochastic opening and closing of channels, the fluctuations in the number of open channels lead to fluctuations in the membrane voltage and modify the timing of the first spike. Our results show that when a neuron has a larger number of channels, (i) the occurrence of the first spike is delayed and (ii) the variation in the first spike timing is greater. We also show that the mean, median, and interquartile range of first spike latency can be accurately predicted from a simple linear regression by knowing only the number of channels in the neuron and the rate at which presynaptic neurons fire, but the standard deviation (i.e., neuronal jitter) cannot be predicted using only this information. We then compare our results to another commonly used stochastic Hodgkin-Huxley model and show that the more commonly used model overstates the first spike latency but can predict the standard deviation of first spike latencies accurately. We end by suggesting a more suitable definition for the neuronal jitter based upon our simulations and comparison of the two models.
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Affiliation(s)
- Brenton Maisel
- Department of Chemistry and Biochemistry, and BioCircuits Institute, University of California San Diego, La Jolla, California 92093-0340, USA
| | - Katja Lindenberg
- Department of Chemistry and Biochemistry, and BioCircuits Institute, University of California San Diego, La Jolla, California 92093-0340, USA
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11
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Unbiased, High-Throughput Electron Microscopy Analysis of Experience-Dependent Synaptic Changes in the Neocortex. J Neurosci 2016; 35:16450-62. [PMID: 26674870 DOI: 10.1523/jneurosci.1573-15.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Neocortical circuits can be altered by sensory and motor experience, with experimental evidence supporting both anatomical and electrophysiological changes in synaptic properties. Previous studies have focused on changes in specific neurons or pathways-for example, the thalamocortical circuitry, layer 4-3 (L4-L3) synapses, or in the apical dendrites of L5 neurons- but a broad-scale analysis of experience-induced changes across the cortical column has been lacking. Without this comprehensive approach, a full understanding of how cortical circuits adapt during learning or altered sensory input will be impossible. Here we adapt an electron microscopy technique that selectively labels synapses, in combination with a machine-learning algorithm for semiautomated synapse detection, to perform an unbiased analysis of developmental and experience-dependent changes in synaptic properties across an entire cortical column in mice. Synapse density and length were compared across development and during whisker-evoked plasticity. Between postnatal days 14 and 18, synapse density significantly increases most in superficial layers, and synapse length increases in L3 and L5B. Removal of all but a single whisker row for 24 h led to an apparent increase in synapse density in L2 and a decrease in L6, and a significant increase in length in L3. Targeted electrophysiological analysis of changes in miniature EPSC and IPSC properties in L2 pyramidal neurons showed that mEPSC frequency nearly doubled in the whisker-spared column, a difference that was highly significant. Together, this analysis shows that data-intensive analysis of column-wide changes in synapse properties can generate specific and testable hypotheses about experience-dependent changes in cortical organization. SIGNIFICANCE STATEMENT Development and sensory experience can change synapse properties in the neocortex. Here we use a semiautomated analysis of electron microscopy images for an unbiased, column-wide analysis of synapse changes. This analysis reveals new loci for synaptic change that can be verified by targeted electrophysiological investigation. This method can be used as a platform for generating new hypotheses about synaptic changes across different brain areas and experimental conditions.
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12
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Abstract
Synaptic neurotransmission is modified at cortical connections throughout life. Varying the amplitude of the postsynaptic response is one mechanism that generates flexible signaling in neural circuits. The timing of the synaptic response may also play a role. Here, we investigated whether weakening and loss of an entire connection between excitatory cortical neurons was foreshadowed in the timing of the postsynaptic response. We made electrophysiological recordings in rat primary somatosensory cortex that was undergoing experience-dependent loss of complete local excitatory connections. The synaptic latency of pyramid-pyramid connections, which typically comprise multiple synapses, was longer and more variable. Connection strength and latency were not correlated. Instead, prolonged latency was more closely related to progression of connection loss. The action potential waveform and axonal conduction velocity were unaffected, suggesting that the altered timing of neurotransmission was attributable to a synaptic mechanism. Modeling studies indicated that increasing the latency and jitter at a subset of synapses reduced the number of action potentials fired by a postsynaptic neuron. We propose that prolonged synaptic latency and diminished temporal precision of neurotransmission are hallmarks of impending loss of a cortical connection.
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13
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Astrocyte and Neuronal Plasticity in the Somatosensory System. Neural Plast 2015; 2015:732014. [PMID: 26345481 PMCID: PMC4539490 DOI: 10.1155/2015/732014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/09/2015] [Indexed: 11/17/2022] Open
Abstract
Changing the whisker complement on a rodent's snout can lead to two forms of experience-dependent plasticity (EDP) in the neurons of the barrel cortex, where whiskers are somatotopically represented. One form, termed coding plasticity, concerns changes in synaptic transmission and connectivity between neurons. This is thought to underlie learning and memory processes and so adaptation to a changing environment. The second, called homeostatic plasticity, serves to maintain a restricted dynamic range of neuronal activity thus preventing its saturation or total downregulation. Current explanatory models of cortical EDP are almost exclusively neurocentric. However, in recent years, increasing evidence has emerged on the role of astrocytes in brain function, including plasticity. Indeed, astrocytes appear as necessary partners of neurons at the core of the mechanisms of coding and homeostatic plasticity recorded in neurons. In addition to neuronal plasticity, several different forms of astrocytic plasticity have recently been discovered. They extend from changes in receptor expression and dynamic changes in morphology to alteration in gliotransmitter release. It is however unclear how astrocytic plasticity contributes to the neuronal EDP. Here, we review the known and possible roles for astrocytes in the barrel cortex, including its plasticity.
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14
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Glazewski S, Barth AL. Stimulus intensity determines experience-dependent modifications in neocortical neuron firing rates. Eur J Neurosci 2014; 41:410-9. [PMID: 25546174 PMCID: PMC4331261 DOI: 10.1111/ejn.12805] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 11/12/2014] [Accepted: 11/18/2014] [Indexed: 11/27/2022]
Abstract
Although subthreshold inputs of neocortical sensory neurons are broadly tuned, the spiking output is more restricted. These subthreshold inputs provide a substrate for stimulus intensity-dependent changes their spiking output, as well as for experience-dependent plasticity to alter firing properties. Here we investigated how different stimulus intensities modified the firing output of individual neurons in layer 2/3 of the mouse barrel cortex. Decreasing stimulus intensity over a 30-fold range lowered the firing rates evoked by principal whisker stimulation and reduced the overall size of the responding ensemble in whisker-undeprived animals. We then examined how these responses were changed after single-whisker experience (SWE). After 7 days of SWE, the mean magnitude of response to spared whisker stimulation at the highest stimulus intensity was not altered. However, lower-intensity whisker stimulation revealed a more than 10-fold increase in mean firing output compared with control animals. Also, under control conditions, only ∽15% of neurons showed any firing at low stimulus intensity, compared with more than 70% of neurons after SWE. However, response changes measured in the immediately surrounding representations were detected only for the highest stimulus intensity. Overall, these data showed that the measurement of experience-dependent changes in the spike output of neocortical neurons was highly dependent upon stimulus intensity.
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Affiliation(s)
- Stanislaw Glazewski
- Department of Biological Sciences and Center for the Neural Basis of Cognition, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA, 15213, USA; School of Life Sciences and Institute for Science and Technology in Medicine, Keele University, Keele, Staffordshire, UK
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15
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Li XY, Wang N, Wang YJ, Zuo ZX, Koga K, Luo F, Zhuo M. Long-term temporal imprecision of information coding in the anterior cingulate cortex of mice with peripheral inflammation or nerve injury. J Neurosci 2014; 34:10675-87. [PMID: 25100600 PMCID: PMC4122801 DOI: 10.1523/jneurosci.5166-13.2014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 06/13/2014] [Accepted: 06/30/2014] [Indexed: 12/23/2022] Open
Abstract
Temporal properties of spike firing in the central nervous system (CNS) are critical for neuronal coding and the precision of information storage. Chronic pain has been reported to affect cognitive and emotional functions, in addition to trigger long-term plasticity in sensory synapses and behavioral sensitization. Less is known about the possible changes in temporal precision of cortical neurons in chronic pain conditions. In the present study, we investigated the temporal precision of action potential firing in the anterior cingulate cortex (ACC) by using both in vivo and in vitro electrophysiological approaches. We found that peripheral inflammation caused by complete Freund's adjuvant (CFA) increased the standard deviation (SD) of spikes latency (also called jitter) of ∼51% of recorded neurons in the ACC of adult rats in vivo. Similar increases in jitter were found in ACC neurons using in vitro brain slices from adult mice with peripheral inflammation or nerve injury. Bath application of glutamate receptor antagonists CNQX and AP5 abolished the enhancement of jitter induced by CFA injection or nerve injury, suggesting that the increased jitter depends on the glutamatergic synaptic transmission. Activation of adenylyl cyclases (ACs) by bath application of forskolin increased jitter, whereas genetic deletion of AC1 abolished the change of jitter caused by CFA inflammation. Our study provides strong evidence for long-term changes of temporal precision of information coding in cortical neurons after peripheral injuries and explains neuronal mechanism for chronic pain caused cognitive and emotional impairment.
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Affiliation(s)
- Xiang-Yao Li
- Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China, Department of Physiology, Faculty of Medicine, University of Toronto, The Center for the study of Pain, Toronto, Ontario M5S 1A8, Canada, and
| | - Ning Wang
- Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yong-Jie Wang
- Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China
| | - Zhen-Xing Zuo
- Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China
| | - Kohei Koga
- Department of Physiology, Faculty of Medicine, University of Toronto, The Center for the study of Pain, Toronto, Ontario M5S 1A8, Canada, and
| | - Fei Luo
- Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China
| | - Min Zhuo
- Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China, Department of Physiology, Faculty of Medicine, University of Toronto, The Center for the study of Pain, Toronto, Ontario M5S 1A8, Canada, and
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16
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Initiation, labile, and stabilization phases of experience-dependent plasticity at neocortical synapses. J Neurosci 2013; 33:8483-93. [PMID: 23658185 DOI: 10.1523/jneurosci.3575-12.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Alteration of sensory input can change the strength of neocortical synapses. Selective activation of a subset of whiskers is sufficient to potentiate layer 4-layer 2/3 excitatory synapses in the mouse somatosensory (barrel) cortex, a process that is NMDAR dependent. By analyzing the time course of sensory-induced synaptic change, we have identified three distinct phases for synaptic strengthening in vivo. After an early, NMDAR-dependent phase where selective whisker activation is rapidly translated into increased synaptic strength, we identify a second phase where this potentiation is profoundly reduced by an input-specific, NMDAR-dependent depression. This labile phase is transient, lasting only a few hours, and may require ongoing sensory input for synaptic weakening. Residual synaptic strength is maintained in a third phase, the stabilization phase, which requires mGluR5 signaling. Identification of these three phases will facilitate a molecular dissection of the pathways that regulate synaptic lability and stabilization, and suggest potential approaches to modulate learning.
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17
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Goel A, Buonomano DV. Chronic electrical stimulation homeostatically decreases spontaneous activity, but paradoxically increases evoked network activity. J Neurophysiol 2013; 109:1824-36. [PMID: 23324317 DOI: 10.1152/jn.00612.2012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neural dynamics generated within cortical networks play a fundamental role in brain function. However, the learning rules that allow recurrent networks to generate functional dynamic regimes, and the degree to which these regimes are themselves plastic, are not known. In this study we examined plasticity of network dynamics in cortical organotypic slices in response to chronic changes in activity. Studies have typically manipulated network activity pharmacologically; we used chronic electrical stimulation to increase activity in in vitro cortical circuits in a more physiological manner. Slices were stimulated with "implanted" electrodes for 4 days. Chronic electrical stimulation or treatment with bicuculline decreased spontaneous activity as predicted by homeostatic learning rules. Paradoxically, however, whereas bicuculline decreased evoked network activity, chronic stimulation actually increased the likelihood that evoked stimulation elicited polysynaptic activity, despite a decrease in evoked monosynaptic strength. Furthermore, there was an inverse correlation between spontaneous and evoked activity, suggesting a homeostatic tradeoff between spontaneous and evoked activity. Within-slice experiments revealed that cells close to the stimulated electrode exhibited more evoked polysynaptic activity and less spontaneous activity than cells close to a control electrode. Collectively, our results establish that chronic stimulation changes the dynamic regimes of networks. In vitro studies of homeostatic plasticity typically lack any external input, and thus neurons must rely on "spontaneous" activity to reach homeostatic "set points." However, in the presence of external input we propose that homeostatic learning rules seem to shift networks from spontaneous to evoked regimes.
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Affiliation(s)
- Anubhuti Goel
- Dept. of Neurobiology and Psychology, Integrative Center for Learning and Memory, Univ. of California, Los Angeles, Los Angeles, CA 90095, USA
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18
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Developmental switch in spike timing-dependent plasticity at layers 4-2/3 in the rodent barrel cortex. J Neurosci 2013; 32:15000-11. [PMID: 23100422 DOI: 10.1523/jneurosci.2506-12.2012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Sensory deprivation during the critical period induces long-lasting changes in cortical maps. In the rodent somatosensory cortex (S1), its precise initiation mechanism is not known, yet spike timing-dependent plasticity (STDP) at layer 4 (L4)-L2/3 synapses are thought to be crucial. Whisker stimulation causes "L4 followed by L2/3" cell firings, while acute single whisker deprivation suddenly reverses the sequential order in L4 and L2/3 neurons in the deprived column (Celikel et al., 2004). Reversed spike sequence then leads to long-term depression through an STDP mechanism (timing-dependent long-term depression), known as deprivation-induced suppression at L4-L2/3 synapses (Bender et al., 2006a), an important first step in the map reorganization. Here we show that STDP properties change dramatically on postnatal day 13-15 (P13-P15) in mice S1. Before P13, timing-dependent long-term potentiation (t-LTP) was predominantly induced regardless of spiking order. The induction of t-LTP required postsynaptic influx of Ca(2+), an activation of protein kinase A, but not calcium/calmodulin-dependent protein kinase II. Consistent with the strong bias toward t-LTP, whisker deprivation (all whiskers in Row "D") from P7-P12 failed to induce synaptic depression at L4-L2/3 synapses in the deprived column, but clear depression was seen if deprivation occurred after P14. Random activation of L4, L2/3 cells, as may occur in response to whisker stimulation before P13 during network formation, led to potentiation under the immature STDP rule, as predicted from the bias toward t-LTP regardless of spiking order. These findings describe a developmental switch in the STDP rule that may underlie the transition from synapse formation to circuit reorganization at L4-L2/3 synapses, both in distinct activity-dependent manners.
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19
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Karayannis T, De Marco García NV, Fishell GJ. Functional adaptation of cortical interneurons to attenuated activity is subtype-specific. Front Neural Circuits 2012; 6:66. [PMID: 23015781 PMCID: PMC3449283 DOI: 10.3389/fncir.2012.00066] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 08/30/2012] [Indexed: 12/04/2022] Open
Abstract
Functional neuronal homeostasis has been studied in a variety of model systems and contexts. Many studies have shown that there are a number of changes that can be activated within individual cells or networks in order to compensate for perturbations or changes in levels of activity. Dissociating the cell autonomous from the network-mediated events has been complicated due to the difficulty of sparsely targeting specific populations of neurons in vivo. Here, we make use of a recent in vivo approach we developed that allows for the sparse labeling and manipulation of activity within superficial caudal ganglionic eminence (CGE)-derived GABAergic interneurons. Expression of the inward rectifying potassium channel Kir2.1 cell-autonomously reduced neuronal activity and lead to specific developmental changes in their intrinsic electrophysiological properties and the synaptic input they received. In contrast to previous studies on homeostatic scaling of pyramidal cells, we did not detect any of the typically observed compensatory mechanisms in these interneurons. Rather, we instead saw a specific alteration of the kinetics of excitatory synaptic events within the reelin-expressing subpopulation of interneurons. These results provide the first in vivo observations for the capacity of interneurons to cell-autonomously regulate their excitability.
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Affiliation(s)
- Theofanis Karayannis
- Smilow Neuroscience, NYU Langone Medical Center, Neuroscience Institute New York City, NY, USA
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20
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Benedetti BL, Takashima Y, Wen JA, Urban-Ciecko J, Barth AL. Differential wiring of layer 2/3 neurons drives sparse and reliable firing during neocortical development. ACTA ACUST UNITED AC 2012; 23:2690-9. [PMID: 22918982 DOI: 10.1093/cercor/bhs257] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Sensory information is transmitted with high fidelity across multiple synapses until it reaches the neocortex. There, individual neurons exhibit enormous variability in responses. The source of this diversity in output has been debated. Using transgenic mice expressing the green fluorescent protein coupled to the activity-dependent gene c-fos, we identified neurons with a history of elevated activity in vivo. Focusing on layer 4 to layer 2/3 connections, a site of strong excitatory drive at an initial stage of cortical processing, we find that fluorescently tagged neurons receive significantly greater excitatory and reduced inhibitory input compared with neighboring, unlabeled cells. Differential wiring of layer 2/3 neurons arises early in development and requires sensory input to be established. Stronger connection strength is not associated with evidence for recent synaptic plasticity, suggesting that these more active ensembles may not be generated over short time scales. Paired recordings show fosGFP+ neurons spike at lower stimulus thresholds than neighboring, fosGFP- neurons. These data indicate that differences in circuit construction can underlie response heterogeneity amongst neocortical neurons.
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Affiliation(s)
- Brett L Benedetti
- Department of Biological Sciences and Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, PA, USA
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21
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Natural movies evoke spike trains with low spike time variability in cat primary visual cortex. J Neurosci 2011; 31:15844-60. [PMID: 22049428 DOI: 10.1523/jneurosci.5153-10.2011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Neuronal responses in primary visual cortex have been found to be highly variable. This has led to the widespread notion that neuronal responses have to be averaged over large numbers of neurons to obtain suitably invariant responses that can be used to reliably encode or represent external stimuli. However, it is possible that the high variability of neuronal responses may result from the use of simple, artificial stimuli and that the visual cortex may respond differently to dynamic, naturalistic images. To investigate this question, we recorded the responses of primary visual cortical neurons in the anesthetized cat under stimulation with time-varying natural movies. We found that cortical neurons on the whole exhibited a high degree of spike count variability, but a surprisingly low degree of spike time variability. The spike count variability was further reduced when all but the first spike in a burst were removed. We also found that responses exhibiting low spike time variability exhibited low spike count variability, suggesting that rate coding and temporal coding might be more compatible than previously thought. In addition, we found the spike time variability to be significantly lower when stimulated by natural movies as compared with stimulation using drifting gratings. Our results indicate that response variability in primary visual cortex is stimulus dependent and significantly lower than previous measurements have indicated.
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22
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Kaliszewska A, Bijata M, Kaczmarek L, Kossut M. Experience-Dependent Plasticity of the Barrel Cortex in Mice Observed with 2-DG Brain Mapping and c-Fos: Effects of MMP-9 KO. Cereb Cortex 2011; 22:2160-70. [DOI: 10.1093/cercor/bhr303] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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Input-specific critical periods for experience-dependent plasticity in layer 2/3 pyramidal neurons. J Neurosci 2011; 31:4456-65. [PMID: 21430146 DOI: 10.1523/jneurosci.6042-10.2011] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Critical periods for experience-dependent plasticity have been well characterized within sensory cortex, in which the ability of altered sensory input to drive firing rate changes has been demonstrated across brain areas. Here we show that rapid experience-dependent changes in the strength of excitatory synapses within mouse primary somatosensory cortex exhibit a critical period that is input specific and mechanistically distinct in layer 2/3 pyramidal neurons. Removal of all but a single whisker [single whisker experience (SWE)] can trigger the strengthening of individual glutamatergic synaptic contacts onto layer 2/3 neurons only during a short window during the second and third postnatal week. At both layer 4 and putative 2/3 inputs, SWE-triggered plasticity has a discrete onset, before which it cannot be induced. SWE synaptic strengthening is concluded at both inputs after the beginning of the third postnatal week, indicating that both types of inputs display a critical period for experience-dependent plasticity. Importantly, the timing of this critical period is both delayed and prolonged for layer 2/3-2/3 versus layer 4-2/3 excitatory synapses. Furthermore, plasticity at layer 2/3 inputs does not invoke the trafficking of calcium-permeable, GluR2-lacking AMPA receptors, whereas it sometimes does at layer 4 inputs. The dissociation of critical period timing and plasticity mechanisms at layer 4 and layer 2/3 synapses, despite the close apposition of these inputs along the dendrite, suggests remarkable specificity for the developmental regulation of plasticity in vivo.
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24
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Clem RL, Anggono V, Huganir RL. PICK1 regulates incorporation of calcium-permeable AMPA receptors during cortical synaptic strengthening. J Neurosci 2010; 30:6360-6. [PMID: 20445062 PMCID: PMC2897179 DOI: 10.1523/jneurosci.6276-09.2010] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 03/08/2010] [Accepted: 03/21/2010] [Indexed: 01/05/2023] Open
Abstract
While AMPA-type glutamate receptors (AMPARs) found at principal neuron excitatory synapses typically contain the GluR2 subunit, several forms of behavioral experience have been linked to the de novo synaptic insertion of calcium-permeable (CP) AMPARs, defined by their lack of GluR2. In particular, whisker experience drives synaptic potentiation as well as the incorporation of CP-AMPARs in the neocortex. Previous studies implicate PICK1 (protein interacting with C kinase-1) in activity-dependent internalization of GluR2, suggesting one potential mechanism leading to the subsequent accumulation of synaptic CP-AMPARs and increased synaptic strength. Here we test this hypothesis by using a whisker stimulation paradigm in PICK1 knock-out mice. We demonstrate that PICK1 facilitates the surface expression of CP-AMPARs and is indispensable for their experience-dependent synaptic insertion. However, the failure to incorporate CP-AMPARs in PICK1 knock-outs does not preclude sensory-induced enhancement of synaptic currents. Our results indicate that synaptic strengthening in the early postnatal cortex does not require PICK1 or the addition of GluR2-lacking AMPARs. Instead, PICK1 permits changes in AMPAR subunit composition to occur in conjunction with synaptic potentiation.
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Affiliation(s)
- Roger L. Clem
- Department of Neuroscience and
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Victor Anggono
- Department of Neuroscience and
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Richard L. Huganir
- Department of Neuroscience and
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
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