1
|
Jamal T, Yan X, Lantyer ADS, Ter Horst JG, Celikel T. Experience-dependent regulation of dopaminergic signaling in the somatosensory cortex. Prog Neurobiol 2024; 239:102630. [PMID: 38834131 DOI: 10.1016/j.pneurobio.2024.102630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 05/04/2024] [Accepted: 05/10/2024] [Indexed: 06/06/2024]
Abstract
Dopamine critically influences reward processing, sensory perception, and motor control. Yet, the modulation of dopaminergic signaling by sensory experiences is not fully delineated. Here, by manipulating sensory experience using bilateral single-row whisker deprivation, we demonstrated that gene transcription in the dopaminergic signaling pathway (DSP) undergoes experience-dependent plasticity in both granular and supragranular layers of the primary somatosensory (barrel) cortex (S1). Sensory experience and deprivation compete for the regulation of DSP transcription across neighboring cortical columns, and sensory deprivation-induced changes in DSP are topographically constrained. These changes in DSP extend beyond cortical map plasticity and influence neuronal information processing. Pharmacological regulation of D2 receptors, a key component of DSP, revealed that D2 receptor activation suppresses excitatory neuronal excitability, hyperpolarizes the action potential threshold, and reduces the instantaneous firing rate. These findings suggest that the dopaminergic drive originating from midbrain dopaminergic neurons, targeting the sensory cortex, is subject to experience-dependent regulation and might create a regulatory feedback loop for modulating sensory processing. Finally, using topological gene network analysis and mutual information, we identify the molecular hubs of experience-dependent plasticity of DSP. These findings provide new insights into the mechanisms by which sensory experience shapes dopaminergic signaling in the brain and might help unravel the sensory deficits observed after dopamine depletion.
Collapse
Affiliation(s)
- Tousif Jamal
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
| | - Xuan Yan
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
| | | | - Judith G Ter Horst
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
| | - Tansu Celikel
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands; School of Psychology, Georgia Institute of Technology, Atlanta, GA, USA.
| |
Collapse
|
2
|
Yang J, Prescott SA. Homeostatic regulation of neuronal function: importance of degeneracy and pleiotropy. Front Cell Neurosci 2023; 17:1184563. [PMID: 37333893 PMCID: PMC10272428 DOI: 10.3389/fncel.2023.1184563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 05/16/2023] [Indexed: 06/20/2023] Open
Abstract
Neurons maintain their average firing rate and other properties within narrow bounds despite changing conditions. This homeostatic regulation is achieved using negative feedback to adjust ion channel expression levels. To understand how homeostatic regulation of excitability normally works and how it goes awry, one must consider the various ion channels involved as well as the other regulated properties impacted by adjusting those channels when regulating excitability. This raises issues of degeneracy and pleiotropy. Degeneracy refers to disparate solutions conveying equivalent function (e.g., different channel combinations yielding equivalent excitability). This many-to-one mapping contrasts the one-to-many mapping described by pleiotropy (e.g., one channel affecting multiple properties). Degeneracy facilitates homeostatic regulation by enabling a disturbance to be offset by compensatory changes in any one of several different channels or combinations thereof. Pleiotropy complicates homeostatic regulation because compensatory changes intended to regulate one property may inadvertently disrupt other properties. Co-regulating multiple properties by adjusting pleiotropic channels requires greater degeneracy than regulating one property in isolation and, by extension, can fail for additional reasons such as solutions for each property being incompatible with one another. Problems also arise if a perturbation is too strong and/or negative feedback is too weak, or because the set point is disturbed. Delineating feedback loops and their interactions provides valuable insight into how homeostatic regulation might fail. Insofar as different failure modes require distinct interventions to restore homeostasis, deeper understanding of homeostatic regulation and its pathological disruption may reveal more effective treatments for chronic neurological disorders like neuropathic pain and epilepsy.
Collapse
Affiliation(s)
- Jane Yang
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Steven A. Prescott
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
3
|
Ahmadian Y, Miller KD. What is the dynamical regime of cerebral cortex? Neuron 2021; 109:3373-3391. [PMID: 34464597 PMCID: PMC9129095 DOI: 10.1016/j.neuron.2021.07.031] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 07/05/2021] [Accepted: 07/30/2021] [Indexed: 01/13/2023]
Abstract
Many studies have shown that the excitation and inhibition received by cortical neurons remain roughly balanced across many conditions. A key question for understanding the dynamical regime of cortex is the nature of this balancing. Theorists have shown that network dynamics can yield systematic cancellation of most of a neuron's excitatory input by inhibition. We review a wide range of evidence pointing to this cancellation occurring in a regime in which the balance is loose, meaning that the net input remaining after cancellation of excitation and inhibition is comparable in size with the factors that cancel, rather than tight, meaning that the net input is very small relative to the canceling factors. This choice of regime has important implications for cortical functional responses, as we describe: loose balance, but not tight balance, can yield many nonlinear population behaviors seen in sensory cortical neurons, allow the presence of correlated variability, and yield decrease of that variability with increasing external stimulus drive as observed across multiple cortical areas.
Collapse
Affiliation(s)
- Yashar Ahmadian
- Computational and Biological Learning Lab, Department of Engineering, University of Cambridge, Cambridge, UK.
| | - Kenneth D Miller
- Center for Theoretical Neuroscience, Swartz Program in Theoretical Neuroscience, Kavli Institute for Brain Science, and Department of Neuroscience, College of Physicians and Surgeons and Morton B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA.
| |
Collapse
|
4
|
Modulation of Coordinated Activity across Cortical Layers by Plasticity of Inhibitory Synapses. Cell Rep 2021; 30:630-641.e5. [PMID: 31968242 PMCID: PMC6988114 DOI: 10.1016/j.celrep.2019.12.052] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 11/21/2019] [Accepted: 12/13/2019] [Indexed: 11/25/2022] Open
Abstract
In the neocortex, synaptic inhibition shapes all forms of spontaneous and sensory evoked activity. Importantly, inhibitory transmission is highly plastic, but the functional role of inhibitory synaptic plasticity is unknown. In the mouse barrel cortex, activation of layer (L) 2/3 pyramidal neurons (PNs) elicits strong feedforward inhibition (FFI) onto L5 PNs. We find that FFI involving parvalbumin (PV)-expressing cells is strongly potentiated by postsynaptic PN burst firing. FFI plasticity modifies the PN excitation-to-inhibition (E/I) ratio, strongly modulates PN gain, and alters information transfer across cortical layers. Moreover, our LTPi-inducing protocol modifies firing of L5 PNs and alters the temporal association of PN spikes to γ-oscillations both in vitro and in vivo. All of these effects are captured by unbalancing the E/I ratio in a feedforward inhibition circuit model. Altogether, our results indicate that activity-dependent modulation of perisomatic inhibitory strength effectively influences the participation of single principal cortical neurons to cognition-relevant network activity. Feedforward inhibition (FFI) of layer 5 pyramidal neurons (PNs) is highly plastic Long-term potentiation of FFI modulates spiking activity of layer 5 PNs LTPi affects information transfer across cortical layers The strength of LTPi determines the phase locking of PN firing to γ-oscillations
Collapse
|
5
|
Deleuze C, Bhumbra GS, Pazienti A, Lourenço J, Mailhes C, Aguirre A, Beato M, Bacci A. Strong preference for autaptic self-connectivity of neocortical PV interneurons facilitates their tuning to γ-oscillations. PLoS Biol 2019; 17:e3000419. [PMID: 31483783 PMCID: PMC6726197 DOI: 10.1371/journal.pbio.3000419] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 08/05/2019] [Indexed: 12/23/2022] Open
Abstract
Parvalbumin (PV)-positive interneurons modulate cortical activity through highly specialized connectivity patterns onto excitatory pyramidal neurons (PNs) and other inhibitory cells. PV cells are autoconnected through powerful autapses, but the contribution of this form of fast disinhibition to cortical function is unknown. We found that autaptic transmission represents the most powerful inhibitory input of PV cells in neocortical layer V. Autaptic strength was greater than synaptic strength onto PNs as a result of a larger quantal size, whereas autaptic and heterosynaptic PV-PV synapses differed in the number of release sites. Overall, single-axon autaptic transmission contributed to approximately 40% of the global inhibition (mostly perisomatic) that PV interneurons received. The strength of autaptic transmission modulated the coupling of PV-cell firing with optogenetically induced γ-oscillations, preventing high-frequency bursts of spikes. Autaptic self-inhibition represents an exceptionally large and fast disinhibitory mechanism, favoring synchronization of PV-cell firing during cognitive-relevant cortical network activity. Parvalbumin-positive interneurons modulate cortical activity via highly specialized connections to excitatory pyramidal neurons and other inhibitory cells. However, this study shows that fast autaptic self-inhibition is the major output of parvalbumin-positive basket cells in the neocortex and serves to modulate phase-locking of these interneurons during gamma-oscillations.
Collapse
Affiliation(s)
- Charlotte Deleuze
- ICM-Institut du Cerveau et de la Moelle épinière, Inserm U1127, CNRS UMR 7225, Sorbonne Université, Paris, France
| | - Gary S Bhumbra
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | | | - Joana Lourenço
- ICM-Institut du Cerveau et de la Moelle épinière, Inserm U1127, CNRS UMR 7225, Sorbonne Université, Paris, France
| | - Caroline Mailhes
- ICM-Institut du Cerveau et de la Moelle épinière, Inserm U1127, CNRS UMR 7225, Sorbonne Université, Paris, France
| | - Andrea Aguirre
- ICM-Institut du Cerveau et de la Moelle épinière, Inserm U1127, CNRS UMR 7225, Sorbonne Université, Paris, France
| | - Marco Beato
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Alberto Bacci
- ICM-Institut du Cerveau et de la Moelle épinière, Inserm U1127, CNRS UMR 7225, Sorbonne Université, Paris, France
| |
Collapse
|
6
|
Hennequin G, Ahmadian Y, Rubin DB, Lengyel M, Miller KD. The Dynamical Regime of Sensory Cortex: Stable Dynamics around a Single Stimulus-Tuned Attractor Account for Patterns of Noise Variability. Neuron 2019; 98:846-860.e5. [PMID: 29772203 PMCID: PMC5971207 DOI: 10.1016/j.neuron.2018.04.017] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 02/14/2018] [Accepted: 04/12/2018] [Indexed: 12/16/2022]
Abstract
Correlated variability in cortical activity is ubiquitously quenched following stimulus onset, in a stimulus-dependent manner. These modulations have been attributed to circuit dynamics involving either multiple stable states (“attractors”) or chaotic activity. Here we show that a qualitatively different dynamical regime, involving fluctuations about a single, stimulus-driven attractor in a loosely balanced excitatory-inhibitory network (the stochastic “stabilized supralinear network”), best explains these modulations. Given the supralinear input/output functions of cortical neurons, increased stimulus drive strengthens effective network connectivity. This shifts the balance from interactions that amplify variability to suppressive inhibitory feedback, quenching correlated variability around more strongly driven steady states. Comparing to previously published and original data analyses, we show that this mechanism, unlike previous proposals, uniquely accounts for the spatial patterns and fast temporal dynamics of variability suppression. Specifying the cortical operating regime is key to understanding the computations underlying perception. A simple network model explains stimulus-tuning of cortical variability suppression Inhibition stabilizes recurrently interacting neurons with supralinear I/O functions Stimuli strengthen inhibitory stabilization around a stable state, quenching variability Single-trial V1 data are compatible with this model and rules out competing proposals
Collapse
Affiliation(s)
- Guillaume Hennequin
- Computational and Biological Learning Lab, Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK.
| | - Yashar Ahmadian
- Center for Theoretical Neuroscience, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Swartz Program in Theoretical Neuroscience, Kavli Institute for Brain Science, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Centre de Neurophysique, Physiologie, et Pathologie, CNRS, 75270 Paris Cedex 06, France; Institute of Neuroscience, Department of Biology and Mathematics, University of Oregon, Eugene, OR 97403, USA
| | - Daniel B Rubin
- Center for Theoretical Neuroscience, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Neurology, Massachusetts General Hospital and Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Máté Lengyel
- Computational and Biological Learning Lab, Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK; Department of Cognitive Science, Central European University, 1051 Budapest, Hungary
| | - Kenneth D Miller
- Center for Theoretical Neuroscience, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Swartz Program in Theoretical Neuroscience, Kavli Institute for Brain Science, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| |
Collapse
|
7
|
Rapid Disinhibition by Adjustment of PV Intrinsic Excitability during Whisker Map Plasticity in Mouse S1. J Neurosci 2018; 38:4749-4761. [PMID: 29678876 DOI: 10.1523/jneurosci.3628-17.2018] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 03/27/2018] [Accepted: 04/10/2018] [Indexed: 01/11/2023] Open
Abstract
Rapid plasticity of layer (L) 2/3 inhibitory circuits is an early step in sensory cortical map plasticity, but its cellular basis is unclear. We show that, in mice of either sex, 1 d whisker deprivation drives the rapid loss of L4-evoked feedforward inhibition and more modest loss of feedforward excitation in L2/3 pyramidal (PYR) cells, increasing the excitation-inhibition conductance ratio. Rapid disinhibition was due to reduced L4-evoked spiking by L2/3 parvalbumin (PV) interneurons, caused by reduced PV intrinsic excitability. This included elevated PV spike threshold, which is associated with an increase in low-threshold, voltage-activated delayed rectifier (presumed Kv1) and A-type potassium currents. Excitatory synaptic input and unitary inhibitory output of PV cells were unaffected. Functionally, the loss of feedforward inhibition and excitation was precisely coordinated in L2/3 PYR cells, so that peak feedforward synaptic depolarization remained stable. Thus, the rapid plasticity of PV intrinsic excitability offsets early weakening of excitatory circuits to homeostatically stabilize synaptic potentials in PYR cells of sensory cortex.SIGNIFICANCE STATEMENT Inhibitory circuits in cerebral cortex are highly plastic, but the cellular mechanisms and functional importance of this plasticity are incompletely understood. We show that brief (1 d) sensory deprivation rapidly weakens parvalbumin (PV) inhibitory circuits by reducing the intrinsic excitability of PV neurons. This involved a rapid increase in voltage-gated potassium conductances that control near-threshold spiking excitability. Functionally, the loss of PV-mediated feedforward inhibition in L2/3 pyramidal cells was precisely balanced with the separate loss of feedforward excitation, resulting in a net homeostatic stabilization of synaptic potentials. Thus, rapid plasticity of PV intrinsic excitability implements network-level homeostasis to stabilize synaptic potentials in sensory cortex.
Collapse
|
8
|
Hakim R, Shamardani K, Adesnik H. A neural circuit for gamma-band coherence across the retinotopic map in mouse visual cortex. eLife 2018; 7:28569. [PMID: 29480803 PMCID: PMC5826269 DOI: 10.7554/elife.28569] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 02/15/2018] [Indexed: 11/13/2022] Open
Abstract
Cortical gamma oscillations have been implicated in a variety of cognitive, behavioral, and circuit-level phenomena. However, the circuit mechanisms of gamma-band generation and synchronization across cortical space remain uncertain. Using optogenetic patterned illumination in acute brain slices of mouse visual cortex, we define a circuit composed of layer 2/3 (L2/3) pyramidal cells and somatostatin (SOM) interneurons that phase-locks ensembles across the retinotopic map. The network oscillations generated here emerge from non-periodic stimuli, and are stimulus size-dependent, coherent across cortical space, narrow band (30 Hz), and depend on SOM neuron but not parvalbumin (PV) neuron activity; similar to visually induced gamma oscillations observed in vivo. Gamma oscillations generated in separate cortical locations exhibited high coherence as far apart as 850 μm, and lateral gamma entrainment depended on SOM neuron activity. These data identify a circuit that is sufficient to mediate long-range gamma-band coherence in the primary visual cortex.
Collapse
Affiliation(s)
- Richard Hakim
- Department of Molecular and Cell Biology, University of California, Berkeley, United States.,Helen Wills Neuroscience Institute, University of California, Berkeley, United States
| | - Kiarash Shamardani
- Department of Molecular and Cell Biology, University of California, Berkeley, United States.,Helen Wills Neuroscience Institute, University of California, Berkeley, United States
| | - Hillel Adesnik
- Department of Molecular and Cell Biology, University of California, Berkeley, United States.,Helen Wills Neuroscience Institute, University of California, Berkeley, United States
| |
Collapse
|
9
|
Adesnik H. Layer-specific excitation/inhibition balances during neuronal synchronization in the visual cortex. J Physiol 2018; 596:1639-1657. [PMID: 29313982 DOI: 10.1113/jp274986] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 01/02/2018] [Indexed: 01/21/2023] Open
Abstract
KEY POINTS Understanding the balance between synaptic excitation and inhibition in cortical circuits in the brain, and how this contributes to cortical rhythms, is fundamental to explaining information processing in the cortex. This study used cortical layer-specific optogenetic activation in mouse cortex to show that excitatory neurons in any cortical layer can drive powerful gamma rhythms, while inhibition balances excitation. The net impact of this is to keep activity within each layer in check, but simultaneously to promote the propagation of activity to downstream layers. The data show that rhythm-generating circuits exist in all principle layers of the cortex, and provide layer-specific balances of excitation and inhibition that affect the flow of information across the layers. ABSTRACT Rhythmic activity can synchronize neural ensembles within and across cortical layers. While gamma band rhythmicity has been observed in all layers, the laminar sources and functional impacts of neuronal synchronization in the cortex remain incompletely understood. Here, layer-specific optogenetic stimulation demonstrates that populations of excitatory neurons in any cortical layer of the mouse's primary visual cortex are sufficient to powerfully entrain neuronal oscillations in the gamma band. Within each layer, inhibition balances excitation and keeps activity in check. Across layers, translaminar output overcomes inhibition and drives downstream firing. These data establish that rhythm-generating circuits exist in all principle layers of the cortex, but provide layer-specific balances of excitation and inhibition that may dynamically shape the flow of information through cortical circuits. These data might help explain how excitation/inhibition (E/I) balances across cortical layers shape information processing, and shed light on the diverse nature and functional impacts of cortical gamma rhythms.
Collapse
Affiliation(s)
- Hillel Adesnik
- Department of Molecular and Cell Biology, University of California, Berkeley, USA.,Helen Wills Neuroscience Institute, University of California, Berkeley, USA
| |
Collapse
|
10
|
Abstract
Somatosensory areas containing topographic maps of the body surface are a major feature of parietal cortex. In primates, parietal cortex contains four somatosensory areas, each with its own map, with the primary cutaneous map in area 3b. Rodents have at least three parietal somatosensory areas. Maps are not isomorphic to the body surface, but magnify behaviorally important skin regions, which include the hands and face in primates, and the whiskers in rodents. Within each map, intracortical circuits process tactile information, mediate spatial integration, and support active sensation. Maps may also contain fine-scale representations of touch submodalities, or direction of tactile motion. Functional representations are more overlapping than suggested by textbook depictions of map topography. The whisker map in rodent somatosensory cortex is a canonic system for studying cortical microcircuits, sensory coding, and map plasticity. Somatosensory maps are plastic throughout life in response to altered use or injury. This chapter reviews basic principles and recent findings in primate, human, and rodent somatosensory maps.
Collapse
Affiliation(s)
- Samuel Harding-Forrester
- Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, CA, United States
| | - Daniel E Feldman
- Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, CA, United States.
| |
Collapse
|
11
|
Gainey MA, Feldman DE. Multiple shared mechanisms for homeostatic plasticity in rodent somatosensory and visual cortex. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0157. [PMID: 28093551 DOI: 10.1098/rstb.2016.0157] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2016] [Indexed: 12/17/2022] Open
Abstract
We compare the circuit and cellular mechanisms for homeostatic plasticity that have been discovered in rodent somatosensory (S1) and visual (V1) cortex. Both areas use similar mechanisms to restore mean firing rate after sensory deprivation. Two time scales of homeostasis are evident, with distinct mechanisms. Slow homeostasis occurs over several days, and is mediated by homeostatic synaptic scaling in excitatory networks and, in some cases, homeostatic adjustment of pyramidal cell intrinsic excitability. Fast homeostasis occurs within less than 1 day, and is mediated by rapid disinhibition, implemented by activity-dependent plasticity in parvalbumin interneuron circuits. These processes interact with Hebbian synaptic plasticity to maintain cortical firing rates during learned adjustments in sensory representations.This article is part of the themed issue 'Integrating Hebbian and homeostatic plasticity'.
Collapse
Affiliation(s)
- Melanie A Gainey
- Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720-3200, USA
| | - Daniel E Feldman
- Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720-3200, USA
| |
Collapse
|
12
|
Yee AX, Hsu YT, Chen L. A metaplasticity view of the interaction between homeostatic and Hebbian plasticity. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0155. [PMID: 28093549 DOI: 10.1098/rstb.2016.0155] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/25/2016] [Indexed: 01/25/2023] Open
Abstract
Hebbian and homeostatic plasticity are two major forms of plasticity in the nervous system: Hebbian plasticity provides a synaptic basis for associative learning, whereas homeostatic plasticity serves to stabilize network activity. While achieving seemingly very different goals, these two types of plasticity interact functionally through overlapping elements in their respective mechanisms. Here, we review studies conducted in the mammalian central nervous system, summarize known circuit and molecular mechanisms of homeostatic plasticity, and compare these mechanisms with those that mediate Hebbian plasticity. We end with a discussion of 'local' homeostatic plasticity and the potential role of local homeostatic plasticity as a form of metaplasticity that modulates a neuron's future capacity for Hebbian plasticity.This article is part of the themed issue 'Integrating Hebbian and homeostatic plasticity'.
Collapse
Affiliation(s)
- Ada X Yee
- Departments of Neurosurgery, Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305-5453, USA
| | - Yu-Tien Hsu
- Departments of Neurosurgery, Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305-5453, USA
| | - Lu Chen
- Departments of Neurosurgery, Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305-5453, USA
| |
Collapse
|
13
|
Tuning neural circuits by turning the interneuron knob. Curr Opin Neurobiol 2017; 42:144-151. [DOI: 10.1016/j.conb.2016.12.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 12/09/2016] [Accepted: 12/22/2016] [Indexed: 01/23/2023]
|
14
|
Zhang JB, Chen L, Lv ZM, Niu XY, Shao CC, Zhang C, Pruski M, Huang Y, Qi CC, Song NN, Lang B, Ding YQ. Oxytocin is implicated in social memory deficits induced by early sensory deprivation in mice. Mol Brain 2016; 9:98. [PMID: 27964753 PMCID: PMC5155398 DOI: 10.1186/s13041-016-0278-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 12/01/2016] [Indexed: 12/04/2022] Open
Abstract
Early-life sensory input plays a crucial role in brain development. Although deprivation of orofacial sensory input at perinatal stages disrupts the establishment of the barrel cortex and relevant callosal connections, its long-term effect on adult behavior remains elusive. In this study, we investigated the behavioral phenotypes in adult mice with unilateral transection of the infraorbital nerve (ION) at postnatal day 3 (P3). Although ION-transected mice had normal locomotor activity, motor coordination, olfaction, anxiety-like behaviors, novel object memory, preference for social novelty and sociability, they presented deficits in social memory and spatial memory compared with control mice. In addition, the social memory deficit was associated with reduced oxytocin (OXT) levels in the hypothalamus and could be partially restored by intranasal administration of OXT. Thus, early sensory deprivation does result in behavioral alterations in mice, some of which may be associated with the disruption of oxytocin signaling.
Collapse
Affiliation(s)
- Jin-Bao Zhang
- Department of Histology and Embryology, Institute of Neuroscience, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, People's Republic of China
| | - Ling Chen
- Key Laboratory of Arrhythmias, Ministry of Education of China, East Hospital, Shanghai, 200092, People's Republic of China.,Department of Anatomy and Neurobiology, Collaborative Innovation Center for Brain Science, Tongji University School of Medicine, Shanghai, 200092, People's Republic of China
| | - Zhu-Man Lv
- Department of Histology and Embryology, Institute of Neuroscience, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, People's Republic of China
| | - Xue-Yuan Niu
- Department of Histology and Embryology, Institute of Neuroscience, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, People's Republic of China
| | - Can-Can Shao
- Department of Histology and Embryology, Institute of Neuroscience, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, People's Republic of China
| | - Chan Zhang
- Department of Histology and Embryology, Institute of Neuroscience, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, People's Republic of China
| | - Michal Pruski
- Key Laboratory of Arrhythmias, Ministry of Education of China, East Hospital, Shanghai, 200092, People's Republic of China.,Department of Anatomy and Neurobiology, Collaborative Innovation Center for Brain Science, Tongji University School of Medicine, Shanghai, 200092, People's Republic of China.,School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, Scotland, UK
| | - Ying Huang
- Key Laboratory of Arrhythmias, Ministry of Education of China, East Hospital, Shanghai, 200092, People's Republic of China.,Department of Anatomy and Neurobiology, Collaborative Innovation Center for Brain Science, Tongji University School of Medicine, Shanghai, 200092, People's Republic of China
| | - Cong-Cong Qi
- Key Laboratory of Arrhythmias, Ministry of Education of China, East Hospital, Shanghai, 200092, People's Republic of China.,Department of Anatomy and Neurobiology, Collaborative Innovation Center for Brain Science, Tongji University School of Medicine, Shanghai, 200092, People's Republic of China
| | - Ning-Ning Song
- Key Laboratory of Arrhythmias, Ministry of Education of China, East Hospital, Shanghai, 200092, People's Republic of China.,Department of Anatomy and Neurobiology, Collaborative Innovation Center for Brain Science, Tongji University School of Medicine, Shanghai, 200092, People's Republic of China
| | - Bing Lang
- Key Laboratory of Arrhythmias, Ministry of Education of China, East Hospital, Shanghai, 200092, People's Republic of China.,Department of Anatomy and Neurobiology, Collaborative Innovation Center for Brain Science, Tongji University School of Medicine, Shanghai, 200092, People's Republic of China.,School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, Scotland, UK
| | - Yu-Qiang Ding
- Department of Histology and Embryology, Institute of Neuroscience, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, People's Republic of China. .,Key Laboratory of Arrhythmias, Ministry of Education of China, East Hospital, Shanghai, 200092, People's Republic of China. .,Department of Anatomy and Neurobiology, Collaborative Innovation Center for Brain Science, Tongji University School of Medicine, Shanghai, 200092, People's Republic of China.
| |
Collapse
|
15
|
Functional and structural underpinnings of neuronal assembly formation in learning. Nat Neurosci 2016; 19:1553-1562. [PMID: 27749830 DOI: 10.1038/nn.4418] [Citation(s) in RCA: 141] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 09/14/2016] [Indexed: 02/07/2023]
Abstract
Learning and memory are associated with the formation and modification of neuronal assemblies: populations of neurons that encode what has been learned and mediate memory retrieval upon recall. Functional studies of neuronal assemblies have progressed dramatically thanks to recent technological advances. Here we discuss how a focus on assembly formation and consolidation has provided a powerful conceptual framework to relate mechanistic studies of synaptic and circuit plasticity to behaviorally relevant aspects of learning and memory. Neurons are likely recruited to particular learning-related assemblies as a function of their relative excitabilities and synaptic activation, followed by selective strengthening of pre-existing synapses, formation of new connections and elimination of outcompeted synapses to ensure memory formation. Mechanistically, these processes involve linking transcription to circuit modification. They include the expression of immediate early genes and specific molecular and cellular events, supported by network-wide activities that are shaped and modulated by local inhibitory microcircuits.
Collapse
|
16
|
Neske GT, Connors BW. Synchronized gamma-frequency inhibition in neocortex depends on excitatory-inhibitory interactions but not electrical synapses. J Neurophysiol 2016; 116:351-68. [PMID: 27121576 PMCID: PMC4969394 DOI: 10.1152/jn.00071.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 04/23/2016] [Indexed: 11/22/2022] Open
Abstract
Synaptic inhibition plays a crucial role in the precise timing of spiking activity in the cerebral cortex. Synchronized, rhythmic inhibitory activity in the gamma (30-80 Hz) range is thought to be especially important for the active, information-processing neocortex, but the circuit mechanisms that give rise to synchronized inhibition are uncertain. In particular, the relative contributions of reciprocal inhibitory connections, excitatory-inhibitory interactions, and electrical synapses to precise spike synchrony among inhibitory interneurons are not well understood. Here we describe experiments on mouse barrel cortex in vitro as it spontaneously generates slow (<1 Hz) oscillations (Up and Down states). During Up states, inhibitory postsynaptic currents (IPSCs) are generated at gamma frequencies and are more synchronized than excitatory postsynaptic currents (EPSCs) among neighboring pyramidal cells. Furthermore, spikes in homotypic pairs of interneurons are more synchronized than in pairs of pyramidal cells. Comparing connexin36 knockout and wild-type animals, we found that electrical synapses make a minimal contribution to synchronized inhibition during Up states. Estimations of the delays between EPSCs and IPSCs in single pyramidal cells showed that excitation often preceded inhibition by a few milliseconds. Finally, tonic optogenetic activation of different interneuron subtypes in the absence of excitation led to only weak synchrony of IPSCs in pairs of pyramidal neurons. Our results suggest that phasic excitatory inputs are indispensable for synchronized spiking in inhibitory interneurons during Up states and that electrical synapses play a minimal role.
Collapse
Affiliation(s)
- Garrett T Neske
- Department of Neuroscience, Brown University, Providence, Rhode Island
| | - Barry W Connors
- Department of Neuroscience, Brown University, Providence, Rhode Island
| |
Collapse
|
17
|
Yee AX, Chen L. Differential regulation of spontaneous and evoked inhibitory synaptic transmission in somatosensory cortex by retinoic acid. Synapse 2016; 70:445-52. [PMID: 27348405 DOI: 10.1002/syn.21921] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 06/23/2016] [Indexed: 11/08/2022]
Abstract
Retinoic acid (RA), a developmental morphogen, has emerged in recent studies as a novel synaptic signaling molecule that acts in mature hippocampal neurons to modulate excitatory and inhibitory synaptic transmission in the context of homeostatic synaptic plasticity. However, it is unclear whether RA is capable of modulating neural circuits outside of the hippocampus, and if so, whether the mode of RA's action at synapses is similar to that within the hippocampal network. Here we explore for the first time RA's synaptic function outside the hippocampus and uncover a novel function of all-trans retinoic acid at inhibitory synapses. Acute RA treatment increases spontaneous inhibitory synaptic transmission in L2/3 pyramidal neurons of the somatosensory cortex, and this effect requires expression of RA's receptor RARα both pre- and post-synaptically. Intriguingly, RA does not seem to affect evoked inhibitory transmission assayed with either extracellular stimulation or direct activation of action potentials in presynaptic interneurons at connected pairs of interneurons and pyramidal neurons. Taken together, these results suggest that RA's action at synapses is not monotonous, but is diverse depending on the type of synaptic connection (excitatory versus inhibitory) and circuit (hippocampal versus cortical). Thus, synaptic signaling of RA may mediate multi-faceted regulation of synaptic plasticity. In addition to its classic roles in brain development, retinoic acid (RA) has recently been shown to regulate excitatory and inhibitory transmission in the adult brain. Here, the authors show that in layer 2/3 (L2/3) of the somatosensory cortex (S1), acute RA induces increases in spontaneous but not action-potential evoked transmission, and that this requires retinoic acid receptor (RARα) both in presynaptic PV-positive interneurons and postsynaptic pyramidal (PN) neurons.
Collapse
Affiliation(s)
- Ada X Yee
- Department of Neurosurgery, Neurosciences Program, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA, 94305-5453.,Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA, 94305-5453
| | - Lu Chen
- Department of Neurosurgery, Neurosciences Program, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA, 94305-5453. .,Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA, 94305-5453.
| |
Collapse
|
18
|
Miller KD. Canonical computations of cerebral cortex. Curr Opin Neurobiol 2016; 37:75-84. [PMID: 26868041 DOI: 10.1016/j.conb.2016.01.008] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 01/14/2016] [Indexed: 12/23/2022]
Abstract
The idea that there is a fundamental cortical circuit that performs canonical computations remains compelling though far from proven. Here we review evidence for two canonical operations within sensory cortical areas: a feedforward computation of selectivity; and a recurrent computation of gain in which, given sufficiently strong external input, perhaps from multiple sources, intracortical input largely, but not completely, cancels this external input. This operation leads to many characteristic cortical nonlinearities in integrating multiple stimuli. The cortical computation must combine such local processing with hierarchical processing across areas. We point to important changes in moving from sensory cortex to motor and frontal cortex and the possibility of substantial differences between cortex in rodents vs. species with columnar organization of selectivity.
Collapse
Affiliation(s)
- Kenneth D Miller
- Center for Theoretical Neuroscience, Department of Neuroscience, Swartz Program in Theoretical Neuroscience, Kavli Institute for Brain Science, College of Physicians and Surgeons, Columbia University, New York, NY 10032-2695, United States.
| |
Collapse
|
19
|
Temporal Structure of Neuronal Activity among Cortical Neuron Subtypes during Slow Oscillations in Anesthetized Rats. J Neurosci 2015; 35:11988-2001. [PMID: 26311779 DOI: 10.1523/jneurosci.5074-14.2015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
UNLABELLED Slow-wave oscillations, the predominant brain rhythm during sleep, are composed of Up/Down cycles. Depolarizing Up-states involve activity in layer 5 (L5) of the neocortex, but it is unknown how diverse subtypes of neurons within L5 participate in generating and maintaining Up-states. Here we compare the in vivo firing patterns of corticopontine (CPn) pyramidal cells, crossed-corticostriatal (CCS) pyramidal cells, and fast-spiking (FS) GABAergic neurons in the rat frontal cortex, with those of thalamocortical neurons during Up/Down cycles in the anesthetized condition. During the transition from Down- to Up-states, increased activity in these neurons was highly temporally structured, with spiking occurring first in thalamocortical neurons, followed by cortical FS cells, CCS cells, and, finally, CPn cells. Activity in some FS, CCS, and CPn neurons occurred in phase with Up-nested gamma rhythms, with FS neurons showing phase delay relative to pyramidal neurons. These results suggest that thalamic and cortical pyramidal neurons are activated in a specific temporal sequence during Up/Down cycles, but cortical pyramidal cells are activated at a similar gamma phase. In addition to Up-state firing specificity, CCS and CPn cells exhibited differences in activity during cortical desynchronization, further indicating projection- and state-dependent information processing within L5. SIGNIFICANCE STATEMENT Patterned activity in neocortical electroencephalograms, including slow waves and gamma oscillations, is thought to reflect the organized activity of neocortical neurons that comprises many specialized neuron subtypes. We found that the timing of action potentials during slow waves in individual cortical neurons was correlated with their laminar positions and axonal targets. Within gamma cycles nested in the slow-wave depolarization, cortical pyramidal cells fired earlier than did interneurons. At the start of slow-wave depolarizations, activity in thalamic neurons receiving inhibition from the basal ganglia occurred earlier than activity in cortical neurons. Together, these findings reveal a temporally ordered pattern of output from diverse neuron subtypes in the frontal cortex and related thalamic nuclei during neocortical oscillations.
Collapse
|
20
|
Letzkus J, Wolff S, Lüthi A. Disinhibition, a Circuit Mechanism for Associative Learning and Memory. Neuron 2015; 88:264-76. [PMID: 26494276 DOI: 10.1016/j.neuron.2015.09.024] [Citation(s) in RCA: 240] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
21
|
DOP-2 D2-Like Receptor Regulates UNC-7 Innexins to Attenuate Recurrent Sensory Motor Neurons during C. elegans Copulation. J Neurosci 2015; 35:9990-10004. [PMID: 26156999 DOI: 10.1523/jneurosci.0940-15.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
UNLABELLED Neuromodulation of self-amplifying circuits directs context-dependent behavioral executions. Although recurrent networks are found throughout the Caenorhabditis elegans connectome, few reports describe the mechanisms that regulate reciprocal neural activity during complex behavior. We used C. elegans male copulation to dissect how a goal-oriented motor behavior is regulated by recurrently wired sensory-motor neurons. As the male tail presses against the hermaphrodite's vulva, cholinergic and glutamatergic reciprocal innervations of post cloaca sensilla (PCS) neurons (PCA, PCB, and PCC), hook neurons (HOA, HOB), and their postsynaptic sex muscles execute rhythmic copulatory spicule thrusts. These repetitive spicule movements continue until the male shifts off the vulva or genital penetration is accomplished. However, the signaling mechanism that temporally and spatially restricts repetitive intromission attempts to vulva cues was unclear. Here, we report that confinement of spicule insertion attempts to the vulva is facilitated by D2-like receptor modulation of gap-junctions between PCB and the hook sensillum. We isolated a missense mutation in the UNC-7(L) gap-junction isoform, which perturbs DOP-2 signaling in the PCB neuron and its electrical partner, HOA. The glutamate-gated chloride channel AVR-14 is expressed in HOA. Our analysis of the unc-7 mutant allele indicates that when DOP-2 promotes UNC-7 electrical communication, AVR-14-mediated inhibitory signals pass from HOA to PCB. As a consequence, PCB is less receptive to be stimulated by its recurrent synaptic partner, PCA. Behavioral observations suggest that dopamine neuromodulation of UNC-7 ensures attenuation of recursive intromission attempts when the male disengages or is dislodged from the hermaphrodite genitalia. SIGNIFICANCE STATEMENT Using C. elegans male copulation as a model, we found that the neurotransmitter dopamine stimulates D2-like receptors in two sensory circuits to terminate futile behavioral loops. The D2-like receptors promote inhibitory electrical junction activity between a chemosensory and a mechanosensory circuit. Therefore, both systems are attenuated and the animal ceases the recursive behavior.
Collapse
|
22
|
Rubin DB, Van Hooser SD, Miller KD. The stabilized supralinear network: a unifying circuit motif underlying multi-input integration in sensory cortex. Neuron 2015; 85:402-17. [PMID: 25611511 DOI: 10.1016/j.neuron.2014.12.026] [Citation(s) in RCA: 179] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2014] [Indexed: 01/09/2023]
Abstract
Neurons in sensory cortex integrate multiple influences to parse objects and support perception. Across multiple cortical areas, integration is characterized by two neuronal response properties: (1) surround suppression--modulatory contextual stimuli suppress responses to driving stimuli; and (2) "normalization"--responses to multiple driving stimuli add sublinearly. These depend on input strength: for weak driving stimuli, contextual influences facilitate or more weakly suppress and summation becomes linear or supralinear. Understanding the circuit operations underlying integration is critical to understanding cortical function and disease. We present a simple, general theory. A wealth of integrative properties, including the above, emerge robustly from four cortical circuit properties: (1) supralinear neuronal input/output functions; (2) sufficiently strong recurrent excitation; (3) feedback inhibition; and (4) simple spatial properties of intracortical connections. Integrative properties emerge dynamically as circuit properties, with excitatory and inhibitory neurons showing similar behaviors. In new recordings in visual cortex, we confirm key model predictions.
Collapse
Affiliation(s)
- Daniel B Rubin
- Center for Theoretical Neuroscience, Doctoral Program in Neurobiology and Behavior, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Stephen D Van Hooser
- Department of Biology, Swartz Center for Theoretical Biology, Brandeis University, Waltham, MA 02454, USA
| | - Kenneth D Miller
- Center for Theoretical Neuroscience, Doctoral Program in Neurobiology and Behavior, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Swartz Program in Theoretical Neuroscience, Kavli Institute for Brain Science, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
| |
Collapse
|
23
|
Siegle JH, Pritchett DL, Moore CI. Gamma-range synchronization of fast-spiking interneurons can enhance detection of tactile stimuli. Nat Neurosci 2014; 17:1371-9. [PMID: 25151266 PMCID: PMC4229565 DOI: 10.1038/nn.3797] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 07/29/2014] [Indexed: 12/15/2022]
Abstract
We tested the sensory impact of repeated synchronization of fast-spiking interneurons (FS), an activity pattern thought to underlie neocortical gamma oscillations. We optogenetically drove 'FS-gamma' while mice detected naturalistic vibrissal stimuli and found enhanced detection of less salient stimuli and impaired detection of more salient ones. Prior studies have predicted that the benefit of FS-gamma is generated when sensory neocortical excitation arrives in a specific temporal window 20-25 ms after FS synchronization. To systematically test this prediction, we aligned periodic tactile and optogenetic stimulation. We found that the detection of less salient stimuli was improved only when peripheral drive led to the arrival of excitation 20-25 ms after synchronization and that other temporal alignments either had no effects or impaired detection. These results provide causal evidence that FS-gamma can enhance processing of less salient stimuli, those that benefit from the allocation of attention.
Collapse
Affiliation(s)
- Joshua H Siegle
- 1] Department of Neuroscience and Institute for Brain Science, Brown University, Providence, Rhode Island, USA. [2] Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Dominique L Pritchett
- 1] Department of Neuroscience and Institute for Brain Science, Brown University, Providence, Rhode Island, USA. [2] Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA. [3]
| | - Christopher I Moore
- Department of Neuroscience and Institute for Brain Science, Brown University, Providence, Rhode Island, USA
| |
Collapse
|
24
|
Khakhalin AS, Koren D, Gu J, Xu H, Aizenman CD. Excitation and inhibition in recurrent networks mediate collision avoidance in Xenopus tadpoles. Eur J Neurosci 2014; 40:2948-62. [PMID: 24995793 DOI: 10.1111/ejn.12664] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 04/23/2014] [Accepted: 05/28/2014] [Indexed: 01/24/2023]
Abstract
Information processing in the vertebrate brain is thought to be mediated through distributed neural networks, but it is still unclear how sensory stimuli are encoded and detected by these networks, and what role synaptic inhibition plays in this process. Here we used a collision avoidance behavior in Xenopus tadpoles as a model for stimulus discrimination and recognition. We showed that the visual system of the tadpole is selective for behaviorally relevant looming stimuli, and that the detection of these stimuli first occurs in the optic tectum. By comparing visually guided behavior, optic nerve recordings, excitatory and inhibitory synaptic currents, and the spike output of tectal neurons, we showed that collision detection in the tadpole relies on the emergent properties of distributed recurrent networks within the tectum. We found that synaptic inhibition was temporally correlated with excitation, and did not actively sculpt stimulus selectivity, but rather it regulated the amount of integration between direct inputs from the retina and recurrent inputs from the tectum. Both pharmacological suppression and enhancement of synaptic inhibition disrupted emergent selectivity for looming stimuli. Taken together these findings suggested that, by regulating the amount of network activity, inhibition plays a critical role in maintaining selective sensitivity to behaviorally-relevant visual stimuli.
Collapse
Affiliation(s)
- Arseny S Khakhalin
- Department of Neuroscience, Brown University, Box G-LN, Providence, RI, 02912, USA
| | | | | | | | | |
Collapse
|
25
|
Elstrott J, Clancy KB, Jafri H, Akimenko I, Feldman DE. Cellular mechanisms for response heterogeneity among L2/3 pyramidal cells in whisker somatosensory cortex. J Neurophysiol 2014; 112:233-48. [PMID: 24740854 DOI: 10.1152/jn.00848.2013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Whisker deflection evokes sparse, low-probability spiking among L2/3 pyramidal cells in rodent somatosensory cortex (S1), with spiking distributed nonuniformly between more and less responsive cells. The cellular and local circuit factors that determine whisker responsiveness across neurons are unclear. To identify these factors, we used two-photon calcium imaging and loose-seal recording to identify more and less responsive L2/3 neurons in S1 slices in vitro, during feedforward recruitment of the L2/3 network by L4 stimulation. We observed a broad gradient of spike recruitment thresholds within local L2/3 populations, with low- and high-threshold cells intermixed. This recruitment gradient was significantly correlated across different L4 stimulation sites, and between L4-evoked and whisker-evoked responses in vivo, indicating that a substantial component of responsiveness is independent of tuning to specific feedforward inputs. Low- and high-threshold L2/3 pyramidal cells differed in L4-evoked excitatory synaptic conductance and intrinsic excitability, including spike threshold and the likelihood of doublet spike bursts. A gradient of intrinsic excitability was observed across neurons. Cells that spiked most readily to L4 stimulation received the most synaptic excitation but had the lowest intrinsic excitability. Low- and high-threshold cells did not differ in dendritic morphology, passive membrane properties, or L4-evoked inhibitory conductance. Thus multiple gradients of physiological properties exist across L2/3 pyramidal cells, with excitatory synaptic input strength best predicting overall spiking responsiveness during network recruitment.
Collapse
Affiliation(s)
- Justin Elstrott
- Department of Molecular and Cellular Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, California; and
| | - Kelly B Clancy
- Biophysics PhD Program, University of California, Berkeley, California
| | - Haani Jafri
- Department of Molecular and Cellular Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, California; and
| | - Igor Akimenko
- Department of Molecular and Cellular Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, California; and
| | - Daniel E Feldman
- Department of Molecular and Cellular Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, California; and
| |
Collapse
|
26
|
Griffen TC, Maffei A. GABAergic synapses: their plasticity and role in sensory cortex. Front Cell Neurosci 2014; 8:91. [PMID: 24723851 PMCID: PMC3972456 DOI: 10.3389/fncel.2014.00091] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 03/12/2014] [Indexed: 12/17/2022] Open
Abstract
The mammalian neocortex is composed of a variety of cell types organized in a highly interconnected circuit. GABAergic neurons account for only about 20% of cortical neurons. However, they show widespread connectivity and a high degree of diversity in morphology, location, electrophysiological properties and gene expression. In addition, distinct populations of inhibitory neurons have different sensory response properties, capacities for plasticity and sensitivities to changes in sensory experience. In this review we summarize experimental evidence regarding the properties of GABAergic neurons in primary sensory cortex. We will discuss how distinct GABAergic neurons and different forms of GABAergic inhibitory plasticity may contribute to shaping sensory cortical circuit activity and function.
Collapse
Affiliation(s)
- Trevor C Griffen
- SUNY Eye Research Consortium Buffalo, NY, USA ; Program in Neuroscience, SUNY - Stony Brook Stony Brook, NY, USA ; Medical Scientist Training Program, SUNY - Stony Brook Stony Brook, NY, USA
| | - Arianna Maffei
- SUNY Eye Research Consortium Buffalo, NY, USA ; Department of Neurobiology and Behavior, SUNY - Stony Brook Stony Brook, NY, USA
| |
Collapse
|
27
|
Abstract
How homeostatic processes contribute to map plasticity and stability in sensory cortex is not well-understood. Classically, sensory deprivation first drives rapid Hebbian weakening of spiking responses to deprived inputs, which is followed days later by a slow homeostatic increase in spiking responses mediated by excitatory synaptic scaling. Recently, more rapid homeostasis by inhibitory circuit plasticity has been discovered in visual cortex, but whether this process occurs in other brain areas is not known. We tested for rapid homeostasis in layer 2/3 (L2/3) of rodent somatosensory cortex, where D-row whisker deprivation drives Hebbian weakening of whisker-evoked spiking responses after an unexplained initial delay, but no homeostasis of deprived whisker responses is known. We hypothesized that the delay reflects rapid homeostasis through disinhibition, which masks the onset of Hebbian weakening of L2/3 excitatory input. We found that deprivation (3 d) transiently increased whisker-evoked spiking responses in L2/3 single units before classical Hebbian weakening (≥5 d), whereas whisker-evoked synaptic input was reduced during both periods. This finding suggests a transient homeostatic increase in L2/3 excitability. In whole-cell recordings from L2/3 neurons in vivo, brief deprivation decreased whisker-evoked inhibition more than excitation and increased the excitation-inhibition ratio. In contrast, synaptic scaling and increased intrinsic excitability were absent. Thus, disinhibition is a rapid homeostatic plasticity mechanism in rodent somatosensory cortex that transiently maintains whisker-evoked spiking in L2/3, despite the onset of Hebbian weakening of excitatory input.
Collapse
|
28
|
Chen CC, Bajnath A, Brumberg JC. The impact of development and sensory deprivation on dendritic protrusions in the mouse barrel cortex. ACTA ACUST UNITED AC 2014; 25:1638-53. [PMID: 24408954 DOI: 10.1093/cercor/bht415] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Dendritic protrusions (spines and filopodia) are structural indicators of synapses that have been linked to neuronal learning and memory through their morphological alterations induced by development and experienced-dependent activities. Although previous studies have demonstrated that depriving sensory experience leads to structural changes in neocortical organization, the more subtle effects on dendritic protrusions remain unclear, mostly due to focus on only one specific cell type and/or age of manipulation. Here, we show that sensory deprivation induced by whisker trimming influences the dendritic protrusions of basilar dendrites located in thalamocortical recipient lamina (IV and VI) of the mouse barrel cortex in a layer-specific manner. Following 1 month of whisker trimming after birth, the density of dendritic protrusions increased in layer IV, but decreased in layer VI. Whisker regrowth for 1 month returned protrusion densities to comparable level of age-matched controls in layer VI, but not in layer IV. In adults, chronic sensory deprivation led to an increase in protrusion densities in layer IV, but not in layer VI. In addition, chronic pharmacological blockade of N-methyl-d-aspartate receptors (NMDARs) increased protrusion density in both layers IV and VI, which returned to the control level after 1 month of drug withdrawal. Our data reveal that different cortical layers respond to chronic sensory deprivation in different ways, with more pronounced effects during developmental critical periods than adulthood. We also show that chronically blocking NMDARs activity during developmental critical period also influences the protrusion density and morphology in the cerebral cortex.
Collapse
Affiliation(s)
| | - Adesh Bajnath
- Neuroscience Program, The Graduate Center, CUNY, New York, NY 10016, USA
| | - Joshua C Brumberg
- Neuropsychology Subprogram Neuroscience Program, The Graduate Center, CUNY, New York, NY 10016, USA Department of Psychology, Queens College, CUNY, Flushing, NY 11367, USA
| |
Collapse
|