1
|
Ghasemahmad Z, Mrvelj A, Panditi R, Sharma B, Perumal KD, Wenstrup JJ. Emotional vocalizations alter behaviors and neurochemical release into the amygdala. eLife 2024; 12:RP88838. [PMID: 39008352 PMCID: PMC11249735 DOI: 10.7554/elife.88838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/16/2024] Open
Abstract
The basolateral amygdala (BLA), a brain center of emotional expression, contributes to acoustic communication by first interpreting the meaning of social sounds in the context of the listener's internal state, then organizing the appropriate behavioral responses. We propose that modulatory neurochemicals such as acetylcholine (ACh) and dopamine (DA) provide internal-state signals to the BLA while an animal listens to social vocalizations. We tested this in a vocal playback experiment utilizing highly affective vocal sequences associated with either mating or restraint, then sampled and analyzed fluids within the BLA for a broad range of neurochemicals and observed behavioral responses of adult male and female mice. In male mice, playback of restraint vocalizations increased ACh release and usually decreased DA release, while playback of mating sequences evoked the opposite neurochemical release patterns. In non-estrus female mice, patterns of ACh and DA release with mating playback were similar to males. Estrus females, however, showed increased ACh, associated with vigilance, as well as increased DA, associated with reward-seeking. Experimental groups that showed increased ACh release also showed the largest increases in an aversive behavior. These neurochemical release patterns and several behavioral responses depended on a single prior experience with the mating and restraint behaviors. Our results support a model in which ACh and DA provide contextual information to sound analyzing BLA neurons that modulate their output to downstream brain regions controlling behavioral responses to social vocalizations.
Collapse
Affiliation(s)
- Zahra Ghasemahmad
- Department of Anatomy and Neurobiology and Hearing Research Group, Northeast Ohio Medical UniversityRootstownUnited States
- School of Biomedical Sciences, Kent State UniversityKentUnited States
- Brain Health Research Institute, Kent State UniversityKentUnited States
| | - Aaron Mrvelj
- Department of Anatomy and Neurobiology and Hearing Research Group, Northeast Ohio Medical UniversityRootstownUnited States
| | - Rishitha Panditi
- Department of Anatomy and Neurobiology and Hearing Research Group, Northeast Ohio Medical UniversityRootstownUnited States
| | - Bhavya Sharma
- Department of Anatomy and Neurobiology and Hearing Research Group, Northeast Ohio Medical UniversityRootstownUnited States
| | - Karthic Drishna Perumal
- Department of Anatomy and Neurobiology and Hearing Research Group, Northeast Ohio Medical UniversityRootstownUnited States
| | - Jeffrey J Wenstrup
- Department of Anatomy and Neurobiology and Hearing Research Group, Northeast Ohio Medical UniversityRootstownUnited States
- School of Biomedical Sciences, Kent State UniversityKentUnited States
- Brain Health Research Institute, Kent State UniversityKentUnited States
| |
Collapse
|
2
|
Cronin EM, Schneider AC, Nadim F, Bucher D. Modulation by Neuropeptides with Overlapping Targets Results in Functional Overlap in Oscillatory Circuit Activation. J Neurosci 2024; 44:e1201232023. [PMID: 37968117 PMCID: PMC10851686 DOI: 10.1523/jneurosci.1201-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 10/18/2023] [Accepted: 10/24/2023] [Indexed: 11/17/2023] Open
Abstract
Neuromodulation lends flexibility to neural circuit operation but the general notion that different neuromodulators sculpt neural circuit activity into distinct and characteristic patterns is complicated by interindividual variability. In addition, some neuromodulators converge onto the same signaling pathways, with similar effects on neurons and synapses. We compared the effects of three neuropeptides on the rhythmic pyloric circuit in the stomatogastric ganglion of male crabs, Cancer borealis Proctolin (PROC), crustacean cardioactive peptide (CCAP), and red pigment concentrating hormone (RPCH) activate the same modulatory inward current, I MI, and have convergent actions on synapses. However, while PROC targets all four neuron types in the core pyloric circuit, CCAP and RPCH target the same subset of only two neurons. After removal of spontaneous neuromodulator release, none of the neuropeptides restored the control cycle frequency, but all restored the relative timing between neuron types. Consequently, differences between neuropeptide effects were mainly found in the spiking activity of different neuron types. We performed statistical comparisons using the Euclidean distance in the multidimensional space of normalized output attributes to obtain a single measure of difference between modulatory states. Across preparations, the circuit output in PROC was distinguishable from CCAP and RPCH, but CCAP and RPCH were not distinguishable from each other. However, we argue that even between PROC and the other two neuropeptides, population data overlapped enough to prevent reliable identification of individual output patterns as characteristic for a specific neuropeptide. We confirmed this notion by showing that blind classifications by machine learning algorithms were only moderately successful.Significance Statement It is commonly assumed that distinct behaviors or circuit activities can be elicited by different neuromodulators. Yet it is unknown to what extent these characteristic actions remain distinct across individuals. We use a well-studied circuit model of neuromodulation to examine the effects of three neuropeptides, each known to produce a distinct activity pattern in controlled studies. We find that, when compared across individuals, the three peptides elicit activity patterns that are either statistically indistinguishable or show too much overlap to be labeled characteristic. We ascribe this to interindividual variability and overlapping subcellular actions of the modulators. Because both factors are common in all neural circuits, these findings have broad significance for understanding chemical neuromodulatory actions while considering interindividual variability.
Collapse
Affiliation(s)
- Elizabeth M Cronin
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, Newark, New Jersey 07102
| | - Anna C Schneider
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, Newark, New Jersey 07102
| | - Farzan Nadim
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, Newark, New Jersey 07102
| | - Dirk Bucher
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, Newark, New Jersey 07102
| |
Collapse
|
3
|
Carlos-Lima E, Higa GSV, Viana FJC, Tamais AM, Cruvinel E, Borges FDS, Francis-Oliveira J, Ulrich H, De Pasquale R. Serotonergic Modulation of the Excitation/Inhibition Balance in the Visual Cortex. Int J Mol Sci 2023; 25:519. [PMID: 38203689 PMCID: PMC10778629 DOI: 10.3390/ijms25010519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 12/18/2023] [Accepted: 12/28/2023] [Indexed: 01/12/2024] Open
Abstract
Serotonergic neurons constitute one of the main systems of neuromodulators, whose diffuse projections regulate the functions of the cerebral cortex. Serotonin (5-HT) is known to play a crucial role in the differential modulation of cortical activity related to behavioral contexts. Some features of the 5-HT signaling organization suggest its possible participation as a modulator of activity-dependent synaptic changes during the critical period of the primary visual cortex (V1). Cells of the serotonergic system are among the first neurons to differentiate and operate. During postnatal development, ramifications from raphe nuclei become massively distributed in the visual cortical area, remarkably increasing the availability of 5-HT for the regulation of excitatory and inhibitory synaptic activity. A substantial amount of evidence has demonstrated that synaptic plasticity at pyramidal neurons of the superficial layers of V1 critically depends on a fine regulation of the balance between excitation and inhibition (E/I). 5-HT could therefore play an important role in controlling this balance, providing the appropriate excitability conditions that favor synaptic modifications. In order to explore this possibility, the present work used in vitro intracellular electrophysiological recording techniques to study the effects of 5-HT on the E/I balance of V1 layer 2/3 neurons, during the critical period. Serotonergic action on the E/I balance has been analyzed on spontaneous activity, evoked synaptic responses, and long-term depression (LTD). Our results pointed out that the predominant action of 5-HT implies a reduction in the E/I balance. 5-HT promoted LTD at excitatory synapses while blocking it at inhibitory synaptic sites, thus shifting the Hebbian alterations of synaptic strength towards lower levels of E/I balance.
Collapse
Affiliation(s)
- Estevão Carlos-Lima
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo 05508-000, SP, Brazil; (E.C.-L.); (G.S.V.H.); (E.C.); (J.F.-O.)
| | - Guilherme Shigueto Vilar Higa
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo 05508-000, SP, Brazil; (E.C.-L.); (G.S.V.H.); (E.C.); (J.F.-O.)
- Departamento de Bioquímica, Instituto de Química (USP), São Paulo 05508-900, SP, Brazil;
- Laboratório de Neurogenética, Universidade Federal do ABC, São Bernardo do Campo 09210-580, SP, Brazil
| | - Felipe José Costa Viana
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo 05508-000, SP, Brazil; (E.C.-L.); (G.S.V.H.); (E.C.); (J.F.-O.)
| | - Alicia Moraes Tamais
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo 05508-000, SP, Brazil; (E.C.-L.); (G.S.V.H.); (E.C.); (J.F.-O.)
| | - Emily Cruvinel
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo 05508-000, SP, Brazil; (E.C.-L.); (G.S.V.H.); (E.C.); (J.F.-O.)
| | - Fernando da Silva Borges
- Department of Physiology & Pharmacology, SUNY Downstate Health Sciences University, New York, NY 11203, USA;
| | - José Francis-Oliveira
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo 05508-000, SP, Brazil; (E.C.-L.); (G.S.V.H.); (E.C.); (J.F.-O.)
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Henning Ulrich
- Departamento de Bioquímica, Instituto de Química (USP), São Paulo 05508-900, SP, Brazil;
| | - Roberto De Pasquale
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo 05508-000, SP, Brazil; (E.C.-L.); (G.S.V.H.); (E.C.); (J.F.-O.)
| |
Collapse
|
4
|
Schecter RW, Jensen CM, Gavornik JP. Sex and estrous cycle affect experience-dependent plasticity in mouse primary visual cortex. PLoS One 2023; 18:e0282349. [PMID: 37068089 PMCID: PMC10109517 DOI: 10.1371/journal.pone.0282349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 02/13/2023] [Indexed: 04/18/2023] Open
Abstract
Sex hormones can affect cellular physiology and modulate synaptic plasticity, but it is not always clear whether or how sex-dependent differences identified in vitro express themselves as functional dimorphisms in the brain. Historically, most experimental neuroscience has been conducted using only male animals and the literature is largely mute about whether including female mice in will introduce variability due to inherent sex differences or endogenous estrous cycles. Though this is beginning to change following an NIH directive that sex should be included as a factor in vertebrate research, the lack of information raises practical issues around how to design experimental controls and apply existing knowledge to more heterogeneous populations. Various lines of research suggest that visual processing can be affected by sex and estrous cycle stage. For these reasons, we performed a series of in vivo electrophysiological experiments to characterize baseline visual function and experience-dependent plasticity in the primary visual cortex (V1) of male and female mice. We find that sex and estrous stage have no statistically significant effect on baseline acuity measurements, but that both sex and estrous stage have can modulate two mechanistically distinct forms of experience dependent cortical plasticity. We also demonstrate that resulting variability can be largely controlled with appropriate normalizations. These findings suggest that V1 plasticity can be used for mechanistic studies focusing on how sex hormones effect experience dependent plasticity in the mammalian cortex.
Collapse
Affiliation(s)
- Rachel W. Schecter
- Center for Systems Neuroscience, Biology Department, Boston University, Boston, MA, United States of America
| | - Cambria M. Jensen
- Center for Systems Neuroscience, Biology Department, Boston University, Boston, MA, United States of America
| | - Jeffrey P. Gavornik
- Center for Systems Neuroscience, Biology Department, Boston University, Boston, MA, United States of America
| |
Collapse
|
5
|
Ribeiro FM, Castelo-Branco M, Gonçalves J, Martins J. Visual Cortical Plasticity: Molecular Mechanisms as Revealed by Induction Paradigms in Rodents. Int J Mol Sci 2023; 24:ijms24054701. [PMID: 36902131 PMCID: PMC10003432 DOI: 10.3390/ijms24054701] [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: 01/31/2023] [Revised: 02/24/2023] [Accepted: 02/26/2023] [Indexed: 03/05/2023] Open
Abstract
Assessing the molecular mechanism of synaptic plasticity in the cortex is vital for identifying potential targets in conditions marked by defective plasticity. In plasticity research, the visual cortex represents a target model for intense investigation, partly due to the availability of different in vivo plasticity-induction protocols. Here, we review two major protocols: ocular-dominance (OD) and cross-modal (CM) plasticity in rodents, highlighting the molecular signaling pathways involved. Each plasticity paradigm has also revealed the contribution of different populations of inhibitory and excitatory neurons at different time points. Since defective synaptic plasticity is common to various neurodevelopmental disorders, the potentially disrupted molecular and circuit alterations are discussed. Finally, new plasticity paradigms are presented, based on recent evidence. Stimulus-selective response potentiation (SRP) is one of the paradigms addressed. These options may provide answers to unsolved neurodevelopmental questions and offer tools to repair plasticity defects.
Collapse
Affiliation(s)
- Francisco M. Ribeiro
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), University of Coimbra, 3000-548 Coimbra, Portugal
- Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Miguel Castelo-Branco
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), University of Coimbra, 3000-548 Coimbra, Portugal
- Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, 3000-548 Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Joana Gonçalves
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), University of Coimbra, 3000-548 Coimbra, Portugal
- Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, 3000-548 Coimbra, Portugal
- Correspondence:
| | - João Martins
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), University of Coimbra, 3000-548 Coimbra, Portugal
- Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, 3000-548 Coimbra, Portugal
| |
Collapse
|
6
|
Lee HK. Metaplasticity framework for cross-modal synaptic plasticity in adults. Front Synaptic Neurosci 2023; 14:1087042. [PMID: 36685084 PMCID: PMC9853192 DOI: 10.3389/fnsyn.2022.1087042] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 12/19/2022] [Indexed: 01/09/2023] Open
Abstract
Sensory loss leads to widespread adaptation of neural circuits to mediate cross-modal plasticity, which allows the organism to better utilize the remaining senses to guide behavior. While cross-modal interactions are often thought to engage multisensory areas, cross-modal plasticity is often prominently observed at the level of the primary sensory cortices. One dramatic example is from functional imaging studies in humans where cross-modal recruitment of the deprived primary sensory cortex has been observed during the processing of the spared senses. In addition, loss of a sensory modality can lead to enhancement and refinement of the spared senses, some of which have been attributed to compensatory plasticity of the spared sensory cortices. Cross-modal plasticity is not restricted to early sensory loss but is also observed in adults, which suggests that it engages or enables plasticity mechanisms available in the adult cortical circuit. Because adult cross-modal plasticity is observed without gross anatomical connectivity changes, it is thought to occur mainly through functional plasticity of pre-existing circuits. The underlying cellular and molecular mechanisms involve activity-dependent homeostatic and Hebbian mechanisms. A particularly attractive mechanism is the sliding threshold metaplasticity model because it innately allows neurons to dynamically optimize their feature selectivity. In this mini review, I will summarize the cellular and molecular mechanisms that mediate cross-modal plasticity in the adult primary sensory cortices and evaluate the metaplasticity model as an effective framework to understand the underlying mechanisms.
Collapse
|
7
|
Scott DN, Frank MJ. Adaptive control of synaptic plasticity integrates micro- and macroscopic network function. Neuropsychopharmacology 2023; 48:121-144. [PMID: 36038780 PMCID: PMC9700774 DOI: 10.1038/s41386-022-01374-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 06/23/2022] [Accepted: 06/24/2022] [Indexed: 11/09/2022]
Abstract
Synaptic plasticity configures interactions between neurons and is therefore likely to be a primary driver of behavioral learning and development. How this microscopic-macroscopic interaction occurs is poorly understood, as researchers frequently examine models within particular ranges of abstraction and scale. Computational neuroscience and machine learning models offer theoretically powerful analyses of plasticity in neural networks, but results are often siloed and only coarsely linked to biology. In this review, we examine connections between these areas, asking how network computations change as a function of diverse features of plasticity and vice versa. We review how plasticity can be controlled at synapses by calcium dynamics and neuromodulatory signals, the manifestation of these changes in networks, and their impacts in specialized circuits. We conclude that metaplasticity-defined broadly as the adaptive control of plasticity-forges connections across scales by governing what groups of synapses can and can't learn about, when, and to what ends. The metaplasticity we discuss acts by co-opting Hebbian mechanisms, shifting network properties, and routing activity within and across brain systems. Asking how these operations can go awry should also be useful for understanding pathology, which we address in the context of autism, schizophrenia and Parkinson's disease.
Collapse
Affiliation(s)
- Daniel N Scott
- Cognitive Linguistic, and Psychological Sciences, Brown University, Providence, RI, USA.
- Carney Institute for Brain Science, Brown University, Providence, RI, USA.
| | - Michael J Frank
- Cognitive Linguistic, and Psychological Sciences, Brown University, Providence, RI, USA.
- Carney Institute for Brain Science, Brown University, Providence, RI, USA.
| |
Collapse
|
8
|
Butcher JB, Sims RE, Ngum NM, Bazzari AH, Jenkins SI, King M, Hill EJ, Nagel DA, Fox K, Parri HR, Glazewski S. A requirement for astrocyte IP3R2 signaling for whisker experience-dependent depression and homeostatic upregulation in the mouse barrel cortex. Front Cell Neurosci 2022; 16:905285. [PMID: 36090792 PMCID: PMC9452848 DOI: 10.3389/fncel.2022.905285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 07/06/2022] [Indexed: 11/19/2022] Open
Abstract
Changes to sensory experience result in plasticity of synapses in the cortex. This experience-dependent plasticity (EDP) is a fundamental property of the brain. Yet, while much is known about neuronal roles in EDP, very little is known about the role of astrocytes. To address this issue, we used the well-described mouse whiskers-to-barrel cortex system, which expresses a number of forms of EDP. We found that all-whisker deprivation induced characteristic experience-dependent Hebbian depression (EDHD) followed by homeostatic upregulation in L2/3 barrel cortex of wild type mice. However, these changes were not seen in mutant animals (IP3R2–/–) that lack the astrocyte-expressed IP3 receptor subtype. A separate paradigm, the single-whisker experience, induced potentiation of whisker-induced response in both wild-type (WT) mice and IP3R2–/– mice. Recordings in ex vivo barrel cortex slices reflected the in vivo results so that long-term depression (LTD) could not be elicited in slices from IP3R2–/– mice, but long-term potentiation (LTP) could. Interestingly, 1 Hz stimulation inducing LTD in WT paradoxically resulted in NMDAR-dependent LTP in slices from IP3R2–/– animals. The LTD to LTP switch was mimicked by acute buffering astrocytic [Ca2+]i in WT slices. Both WT LTD and IP3R2–/– 1 Hz LTP were mediated by non-ionotropic NMDAR signaling, but only WT LTD was P38 MAPK dependent, indicating an underlying mechanistic switch. These results demonstrate a critical role for astrocytic [Ca2+]i in several EDP mechanisms in neocortex.
Collapse
Affiliation(s)
- John B. Butcher
- School of Life Sciences, Keele University, Keele, United Kingdom
- College of Health and Life Sciences, Aston University, Birmingham, United Kingdom
| | - Robert E. Sims
- College of Health and Life Sciences, Aston University, Birmingham, United Kingdom
| | - Neville M. Ngum
- College of Health and Life Sciences, Aston University, Birmingham, United Kingdom
| | - Amjad H. Bazzari
- College of Health and Life Sciences, Aston University, Birmingham, United Kingdom
| | - Stuart I. Jenkins
- Neural Tissue Engineering Group, Institute for Science and Technology in Medicine (ISTM), Keele University, Keele, United Kingdom
| | - Marianne King
- College of Health and Life Sciences, Aston University, Birmingham, United Kingdom
| | - Eric J. Hill
- College of Health and Life Sciences, Aston University, Birmingham, United Kingdom
| | - David A. Nagel
- Aston Medical School, Aston Medical Research Institute, Aston University, Birmingham, United Kingdom
| | - Kevin Fox
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - H. Rheinallt Parri
- College of Health and Life Sciences, Aston University, Birmingham, United Kingdom
- *Correspondence: H. Rheinallt Parri,
| | - Stanislaw Glazewski
- School of Life Sciences, Keele University, Keele, United Kingdom
- Stanislaw Glazewski,
| |
Collapse
|
9
|
Hong SZ, Mesik L, Grossman CD, Cohen JY, Lee B, Severin D, Lee HK, Hell JW, Kirkwood A. Norepinephrine potentiates and serotonin depresses visual cortical responses by transforming eligibility traces. Nat Commun 2022; 13:3202. [PMID: 35680879 PMCID: PMC9184610 DOI: 10.1038/s41467-022-30827-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 05/19/2022] [Indexed: 11/18/2022] Open
Abstract
Reinforcement allows organisms to learn which stimuli predict subsequent biological relevance. Hebbian mechanisms of synaptic plasticity are insufficient to account for reinforced learning because neuromodulators signaling biological relevance are delayed with respect to the neural activity associated with the stimulus. A theoretical solution is the concept of eligibility traces (eTraces), silent synaptic processes elicited by activity which upon arrival of a neuromodulator are converted into a lasting change in synaptic strength. Previously we demonstrated in visual cortical slices the Hebbian induction of eTraces and their conversion into LTP and LTD by the retroactive action of norepinephrine and serotonin Here we show in vivo in mouse V1 that the induction of eTraces and their conversion to LTP/D by norepinephrine and serotonin respectively potentiates and depresses visual responses. We also show that the integrity of this process is crucial for ocular dominance plasticity, a canonical model of experience-dependent plasticity.
Collapse
Affiliation(s)
- Su Z Hong
- Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Lukas Mesik
- Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Cooper D Grossman
- Department of Neuroscience, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Jeremiah Y Cohen
- Department of Neuroscience, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Boram Lee
- Department of Pharmacology, University of California at Davis, Davis, CA, 95616, USA
| | - Daniel Severin
- Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Hey-Kyoung Lee
- Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, 21218, USA
- Department of Neuroscience, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Johannes W Hell
- Department of Pharmacology, University of California at Davis, Davis, CA, 95616, USA
| | - Alfredo Kirkwood
- Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, 21218, USA.
- Department of Neuroscience, Johns Hopkins University, Baltimore, MD, 21205, USA.
| |
Collapse
|
10
|
Brinkman BAW, Yan H, Maffei A, Park IM, Fontanini A, Wang J, La Camera G. Metastable dynamics of neural circuits and networks. APPLIED PHYSICS REVIEWS 2022; 9:011313. [PMID: 35284030 PMCID: PMC8900181 DOI: 10.1063/5.0062603] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 01/31/2022] [Indexed: 05/14/2023]
Abstract
Cortical neurons emit seemingly erratic trains of action potentials or "spikes," and neural network dynamics emerge from the coordinated spiking activity within neural circuits. These rich dynamics manifest themselves in a variety of patterns, which emerge spontaneously or in response to incoming activity produced by sensory inputs. In this Review, we focus on neural dynamics that is best understood as a sequence of repeated activations of a number of discrete hidden states. These transiently occupied states are termed "metastable" and have been linked to important sensory and cognitive functions. In the rodent gustatory cortex, for instance, metastable dynamics have been associated with stimulus coding, with states of expectation, and with decision making. In frontal, parietal, and motor areas of macaques, metastable activity has been related to behavioral performance, choice behavior, task difficulty, and attention. In this article, we review the experimental evidence for neural metastable dynamics together with theoretical approaches to the study of metastable activity in neural circuits. These approaches include (i) a theoretical framework based on non-equilibrium statistical physics for network dynamics; (ii) statistical approaches to extract information about metastable states from a variety of neural signals; and (iii) recent neural network approaches, informed by experimental results, to model the emergence of metastable dynamics. By discussing these topics, we aim to provide a cohesive view of how transitions between different states of activity may provide the neural underpinnings for essential functions such as perception, memory, expectation, or decision making, and more generally, how the study of metastable neural activity may advance our understanding of neural circuit function in health and disease.
Collapse
Affiliation(s)
| | - H. Yan
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, People's Republic of China
| | | | | | | | - J. Wang
- Authors to whom correspondence should be addressed: and
| | - G. La Camera
- Authors to whom correspondence should be addressed: and
| |
Collapse
|
11
|
Frost Nylen J, Hjorth JJJ, Grillner S, Hellgren Kotaleski J. Dopaminergic and Cholinergic Modulation of Large Scale Networks in silico Using Snudda. Front Neural Circuits 2021; 15:748989. [PMID: 34744638 PMCID: PMC8568057 DOI: 10.3389/fncir.2021.748989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/16/2021] [Indexed: 11/25/2022] Open
Abstract
Neuromodulation is present throughout the nervous system and serves a critical role for circuit function and dynamics. The computational investigations of neuromodulation in large scale networks require supportive software platforms. Snudda is a software for the creation and simulation of large scale networks of detailed microcircuits consisting of multicompartmental neuron models. We have developed an extension to Snudda to incorporate neuromodulation in large scale simulations. The extended Snudda framework implements neuromodulation at the level of single cells incorporated into large-scale microcircuits. We also developed Neuromodcell, a software for optimizing neuromodulation in detailed multicompartmental neuron models. The software adds parameters within the models modulating the conductances of ion channels and ionotropic receptors. Bath application of neuromodulators is simulated and models which reproduce the experimentally measured effects are selected. In Snudda, we developed an extension to accommodate large scale simulations of neuromodulation. The simulator has two modes of simulation – denoted replay and adaptive. In the replay mode, transient levels of neuromodulators can be defined as a time-varying function which modulates the receptors and ion channels within the network in a cell-type specific manner. In the adaptive mode, spiking neuromodulatory neurons are connected via integrative modulating mechanisms to ion channels and receptors. Both modes of simulating neuromodulation allow for simultaneous modulation by several neuromodulators that can interact dynamically with each other. Here, we used the Neuromodcell software to simulate dopaminergic and muscarinic modulation of neurons from the striatum. We also demonstrate how to simulate different neuromodulatory states with dopamine and acetylcholine using Snudda. All software is freely available on Github, including tutorials on Neuromodcell and Snudda-neuromodulation.
Collapse
Affiliation(s)
| | - Jarl Jacob Johannes Hjorth
- Science for Life Laboratory, School of Electrical Engineering and Computer Science, Royal Institute of Technology, Stockholm, Sweden
| | - Sten Grillner
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Jeanette Hellgren Kotaleski
- Science for Life Laboratory, School of Electrical Engineering and Computer Science, Royal Institute of Technology, Stockholm, Sweden
| |
Collapse
|
12
|
Tseng CT, Gaulding SJ, Dancel CLE, Thorn CA. Local activation of α2 adrenergic receptors is required for vagus nerve stimulation induced motor cortical plasticity. Sci Rep 2021; 11:21645. [PMID: 34737352 PMCID: PMC8568982 DOI: 10.1038/s41598-021-00976-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 10/20/2021] [Indexed: 11/09/2022] Open
Abstract
Vagus nerve stimulation (VNS) paired with rehabilitation training is emerging as a potential treatment for improving recovery of motor function following stroke. In rats, VNS paired with skilled forelimb training results in significant reorganization of the somatotopic cortical motor map; however, the mechanisms underlying this form of VNS-dependent plasticity remain unclear. Recent studies have shown that VNS-driven cortical plasticity is dependent on noradrenergic innervation of the neocortex. In the central nervous system, noradrenergic α2 receptors (α2-ARs) are widely expressed in the motor cortex and have been critically implicated in synaptic communication and plasticity. In current study, we examined whether activation of cortical α2-ARs is necessary for VNS-driven motor cortical reorganization to occur. Consistent with previous studies, we found that VNS paired with motor training enlarges the map representation of task-relevant musculature in the motor cortex. Infusion of α2-AR antagonists into M1 blocked VNS-driven motor map reorganization from occurring. Our results suggest that local α2-AR activation is required for VNS-induced cortical reorganization to occur, providing insight into the mechanisms that may underlie the neuroplastic effects of VNS therapy.
Collapse
Affiliation(s)
- Ching-Tzu Tseng
- School of Behavioral and Brain Sciences, University of Texas at Dallas, 800 W. Campbell Rd, Richardson, TX, 75080, USA
| | - Solomon J Gaulding
- School of Behavioral and Brain Sciences, University of Texas at Dallas, 800 W. Campbell Rd, Richardson, TX, 75080, USA
| | - Canice Lei E Dancel
- School of Behavioral and Brain Sciences, University of Texas at Dallas, 800 W. Campbell Rd, Richardson, TX, 75080, USA
| | - Catherine A Thorn
- School of Behavioral and Brain Sciences, University of Texas at Dallas, 800 W. Campbell Rd, Richardson, TX, 75080, USA.
| |
Collapse
|
13
|
Mihalas S, Ardiles A, He K, Palacios A, Kirkwood A. A Multisubcellular Compartment Model of AMPA Receptor Trafficking for Neuromodulation of Hebbian Synaptic Plasticity. Front Synaptic Neurosci 2021; 13:703621. [PMID: 34456706 PMCID: PMC8385783 DOI: 10.3389/fnsyn.2021.703621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/05/2021] [Indexed: 11/13/2022] Open
Abstract
Neuromodulation can profoundly impact the gain and polarity of postsynaptic changes in Hebbian synaptic plasticity. An emerging pattern observed in multiple central synapses is a pull–push type of control in which activation of receptors coupled to the G-protein Gs promote long-term potentiation (LTP) at the expense of long-term depression (LTD), whereas receptors coupled to Gq promote LTD at the expense of LTP. Notably, coactivation of both Gs- and Gq-coupled receptors enhances the gain of both LTP and LTD. To account for these observations, we propose a simple kinetic model in which AMPA receptors (AMPARs) are trafficked between multiple subcompartments in and around the postsynaptic spine. In the model AMPARs in the postsynaptic density compartment (PSD) are the primary contributors to synaptic conductance. During LTP induction, AMPARs are trafficked to the PSD primarily from a relatively small perisynaptic (peri-PSD) compartment. Gs-coupled receptors promote LTP by replenishing peri-PSD through increased AMPAR exocytosis from a pool of endocytic AMPAR. During LTD induction AMPARs are trafficked in the reverse direction, from the PSD to the peri-PSD compartment, and Gq-coupled receptors promote LTD by clearing the peri-PSD compartment through increased AMPAR endocytosis. We claim that the model not only captures essential features of the pull–push neuromodulation of synaptic plasticity, but it is also consistent with other actions of neuromodulators observed in slice experiments and is compatible with the current understanding of AMPAR trafficking.
Collapse
Affiliation(s)
- Stefan Mihalas
- Allen Institute for Brain Science, Seattle, WA, United States
| | - Alvaro Ardiles
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.,Centro de Neurología Traslacional, Facultad de Medicina, Universidad de Valparaíso, Valparaíso, Chile
| | - Kaiwen He
- Mind Brain Institute, Johns Hopkins University, Baltimore, MD, United States
| | - Adrian Palacios
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Alfredo Kirkwood
- Mind Brain Institute, Johns Hopkins University, Baltimore, MD, United States
| |
Collapse
|
14
|
Dolzer J, Schröder K, Stengl M. Cyclic nucleotide-dependent ionic currents in olfactory receptor neurons of the hawkmoth Manduca sexta suggest pull-push sensitivity modulation. Eur J Neurosci 2021; 54:4804-4826. [PMID: 34128265 DOI: 10.1111/ejn.15346] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 06/02/2021] [Accepted: 06/04/2021] [Indexed: 11/27/2022]
Abstract
Olfactory receptor neurons (ORNs) of the hawkmoth Manduca sexta sensitize via cAMP- and adapt via cGMP-dependent mechanisms. Perforated patch clamp recordings distinguished 11 currents in these ORNs. Derivatives of cAMP and/or cGMP antagonistically affected three of five K+ currents and two non-specific cation currents. The Ca2+ -dependent K+ current IK(Ca 2+ ) and the sensitive pheromone-dependent K+ current IK(cGMP-) , which both express fast kinetics, were inhibited by 8bcGMP, while a slow K+ current, IK(cGMP+) , was activated by 8bcGMP. Furthermore, application of 8bcAMP blocked slowly activating, zero mV-reversing, non-specific cation currents, ILL and Icat(PKC?) , which remained activated in the presence of 8bcGMP. Their activations pull the membrane potential towards their 0-mV reversal potentials, in addition to increasing intracellular Ca2+ levels voltage- and ILL -dependently. Twenty minutes after application, 8bcGMP blocked a TEA-independent K+ current, IK(noTEA) , and a fast cation current, Icat(nRP) , which both shift the membrane potential to negative values. We conclude that conditions of sensitization are maintained at high levels of cAMP, via specific opening/closure of ion channels that allow for fast kinetics, hyperpolarized membrane potentials, and low intracellular Ca2+ levels. In contrast, adaptation is supported via cGMP, which antagonizes cAMP, opening Ca2+ -permeable channels with slow kinetics that stabilize depolarized resting potentials. The antagonistic modulation of peripheral sensory neurons by cAMP or cGMP is reminiscent of pull-push mechanisms of neuromodulation at central synapses underlying metaplasticity.
Collapse
Affiliation(s)
- Jan Dolzer
- Biologie, Tierphysiologie, Philipps-Universität Marburg, Marburg, Germany.,Institut für Zoologie, Universität Regensburg, Regensburg, Germany
| | - Katrin Schröder
- Animal Physiology/Neuroethology, Biology, FB 10, University of Kassel, Kassel, Germany
| | - Monika Stengl
- Biologie, Tierphysiologie, Philipps-Universität Marburg, Marburg, Germany.,Institut für Zoologie, Universität Regensburg, Regensburg, Germany.,Animal Physiology/Neuroethology, Biology, FB 10, University of Kassel, Kassel, Germany
| |
Collapse
|
15
|
Ewall G, Parkins S, Lin A, Jaoui Y, Lee HK. Cortical and Subcortical Circuits for Cross-Modal Plasticity Induced by Loss of Vision. Front Neural Circuits 2021; 15:665009. [PMID: 34113240 PMCID: PMC8185208 DOI: 10.3389/fncir.2021.665009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 04/14/2021] [Indexed: 11/29/2022] Open
Abstract
Cortical areas are highly interconnected both via cortical and subcortical pathways, and primary sensory cortices are not isolated from this general structure. In primary sensory cortical areas, these pre-existing functional connections serve to provide contextual information for sensory processing and can mediate adaptation when a sensory modality is lost. Cross-modal plasticity in broad terms refers to widespread plasticity across the brain in response to losing a sensory modality, and largely involves two distinct changes: cross-modal recruitment and compensatory plasticity. The former involves recruitment of the deprived sensory area, which includes the deprived primary sensory cortex, for processing the remaining senses. Compensatory plasticity refers to plasticity in the remaining sensory areas, including the spared primary sensory cortices, to enhance the processing of its own sensory inputs. Here, we will summarize potential cellular plasticity mechanisms involved in cross-modal recruitment and compensatory plasticity, and review cortical and subcortical circuits to the primary sensory cortices which can mediate cross-modal plasticity upon loss of vision.
Collapse
Affiliation(s)
- Gabrielle Ewall
- Solomon H. Snyder Department of Neuroscience, Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Samuel Parkins
- Cell, Molecular, Developmental Biology and Biophysics (CMDB) Graduate Program, Johns Hopkins University, Baltimore, MD, United States
| | - Amy Lin
- Solomon H. Snyder Department of Neuroscience, Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Yanis Jaoui
- Solomon H. Snyder Department of Neuroscience, Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Hey-Kyoung Lee
- Solomon H. Snyder Department of Neuroscience, Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins School of Medicine, Baltimore, MD, United States.,Cell, Molecular, Developmental Biology and Biophysics (CMDB) Graduate Program, Johns Hopkins University, Baltimore, MD, United States.,Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, United States
| |
Collapse
|
16
|
Hong SZ, Huang S, Severin D, Kirkwood A. Pull-push neuromodulation of cortical plasticity enables rapid bi-directional shifts in ocular dominance. eLife 2020; 9:e54455. [PMID: 32432545 PMCID: PMC7239653 DOI: 10.7554/elife.54455] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 05/01/2020] [Indexed: 02/06/2023] Open
Abstract
Neuromodulatory systems are essential for remodeling glutamatergic connectivity during experience-dependent cortical plasticity. This permissive/enabling function of neuromodulators has been associated with their capacity to facilitate the induction of Hebbian forms of long-term potentiation (LTP) and depression (LTD) by affecting cellular and network excitability. In vitro studies indicate that neuromodulators also affect the expression of Hebbian plasticity in a pull-push manner: receptors coupled to the G-protein Gs promote the expression of LTP at the expense of LTD, and Gq-coupled receptors promote LTD at the expense of LTP. Here we show that pull-push mechanisms can be recruited in vivo by pairing brief monocular stimulation with pharmacological or chemogenetical activation of Gs- or Gq-coupled receptors to respectively enhance or reduce neuronal responses in primary visual cortex. These changes were stable, inducible in adults after the termination of the critical period for ocular dominance plasticity, and can rescue deficits induced by prolonged monocular deprivation.
Collapse
Affiliation(s)
- Su Z Hong
- Mind/Brain Institute, Johns Hopkins UniversityBaltimoreUnited States
| | - Shiyong Huang
- Mind/Brain Institute, Johns Hopkins UniversityBaltimoreUnited States
| | - Daniel Severin
- Mind/Brain Institute, Johns Hopkins UniversityBaltimoreUnited States
| | - Alfredo Kirkwood
- Mind/Brain Institute, Johns Hopkins UniversityBaltimoreUnited States
- Department of Neuroscience, Johns Hopkins UniversityBaltimoreUnited States
| |
Collapse
|
17
|
Souza RR, Robertson NM, Mathew E, Tabet MN, Bucksot JE, Pruitt DT, Rennaker RL, Hays SA, McIntyre CK, Kilgard MP. Efficient parameters of vagus nerve stimulation to enhance extinction learning in an extinction-resistant rat model of PTSD. Prog Neuropsychopharmacol Biol Psychiatry 2020; 99:109848. [PMID: 31863872 DOI: 10.1016/j.pnpbp.2019.109848] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 12/11/2019] [Accepted: 12/16/2019] [Indexed: 12/20/2022]
Abstract
Vagus nerve stimulation (VNS) has shown promise as an adjuvant treatment for posttraumatic stress disorder (PTSD), as it enhances fear extinction and reduces anxiety symptoms in multiple rat models of this condition. Yet, identification of the optimal stimulation paradigm is needed to facilitate clinical translation of this potential therapy. Using an extinction-resistant rat model of PTSD, we tested whether varying VNS intensity and duration could maximize extinction learning while minimizing the total amount of stimulation. We confirmed that sham rats failed to extinguish after a week of extinction training. Delivery of the standard LONG VNS trains (30 s) at 0.4 mA enhanced extinction and reduced anxiety but did not prevent fear return. Increasing the intensity of LONG VNS trains to 0.8 mA prevented fear return and attenuated anxiety symptoms. Interestingly, delivering 1, 4 or 16 SHORT VNS bursts (0.5 s) at 0.8 mA during each cue presentation in extinction training also enhanced extinction. LONG VNS trains or multiple SHORT VNS bursts at 0.8 mA attenuated fear renewal and reinstatement, promoted extinction generalization and reduced generalized anxiety. Delivering 16 SHORT VNS bursts also facilitated extinction in fewer trials. This study provides the first evidence that brief bursts of VNS can enhance extinction training, reduce relapse and support symptom remission using much less VNS than previous protocols. These findings suggest that VNS parameters can be adjusted in order to minimize total charge delivery and maximize therapeutic effectiveness.
Collapse
Affiliation(s)
- Rimenez R Souza
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America; School of Behavioral Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America.
| | - Nicole M Robertson
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America
| | - Ezek Mathew
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America; School of Behavioral Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America
| | - Michel N Tabet
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America; School of Behavioral Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America
| | - Jesse E Bucksot
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America; Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America
| | - David T Pruitt
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America; School of Behavioral Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America; Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America
| | - Robert L Rennaker
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America; School of Behavioral Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America; Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America
| | - Seth A Hays
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America; Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America
| | - Christa K McIntyre
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America; School of Behavioral Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America
| | - Michael P Kilgard
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America; School of Behavioral Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, United States of America
| |
Collapse
|
18
|
Lee HK, Kirkwood A. Mechanisms of Homeostatic Synaptic Plasticity in vivo. Front Cell Neurosci 2019; 13:520. [PMID: 31849610 PMCID: PMC6901705 DOI: 10.3389/fncel.2019.00520] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 11/06/2019] [Indexed: 11/13/2022] Open
Abstract
Synapses undergo rapid activity-dependent plasticity to store information, which when left uncompensated can lead to destabilization of neural function. It has been well documented that homeostatic changes, which operate at a slower time scale, are required to maintain stability of neural networks. While there are many mechanisms that can endow homeostatic control, sliding threshold and synaptic scaling are unique in that they operate by providing homeostatic control of synaptic strength. The former mechanism operates by adjusting the threshold for synaptic plasticity, while the latter mechanism directly alters the gain of synapses. Both modes of homeostatic synaptic plasticity have been studied across various preparations from reduced in vitro systems, such as neuronal cultures, to in vivo intact circuitry. While most of the cellular and molecular mechanisms of homeostatic synaptic plasticity have been worked out using reduced preparations, there are unique challenges present in intact circuitry in vivo, which deserve further consideration. For example, in an intact circuit, neurons receive distinct set of inputs across their dendritic tree which carry unique information. Homeostatic synaptic plasticity in vivo needs to operate without compromising processing of these distinct set of inputs to preserve information processing while maintaining network stability. In this mini review, we will summarize unique features of in vivo homeostatic synaptic plasticity, and discuss how sliding threshold and synaptic scaling may act across different activity regimes to provide homeostasis.
Collapse
Affiliation(s)
- Hey-Kyoung Lee
- Department of Neuroscience, Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, United States.,Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, United States
| | - Alfredo Kirkwood
- Department of Neuroscience, Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, United States
| |
Collapse
|
19
|
Disruption of NMDAR Function Prevents Normal Experience-Dependent Homeostatic Synaptic Plasticity in Mouse Primary Visual Cortex. J Neurosci 2019; 39:7664-7673. [PMID: 31413075 DOI: 10.1523/jneurosci.2117-18.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 08/07/2019] [Accepted: 08/08/2019] [Indexed: 12/21/2022] Open
Abstract
Homeostatic regulation of synaptic strength allows for maintenance of neural activity within a dynamic range for proper circuit function. There are largely two distinct modes of synaptic plasticity that allow for homeostatic adaptation of cortical circuits: synaptic scaling and sliding threshold (BCM theory). Previous findings suggest that the induction of synaptic scaling is not prevented by blocking NMDARs, whereas the sliding threshold model posits that the synaptic modification threshold of LTP and LTD readjusts with activity and thus the outcome of synaptic plasticity is NMDAR dependent. Although synaptic scaling and sliding threshold have been considered two distinct mechanisms, there are indications from recent studies that these two modes of homeostatic plasticity may interact or that they may operate under two distinct activity regimes. Here, we report using both sexes of mouse that acute genetic knock-out of the obligatory subunit of NMDAR or acute pharmacological block of NMDAR prevents experience-dependent homeostatic regulation of AMPAR-mediated miniature EPSCs in layer 2/3 of visual cortex. This was not due to gross changes in postsynaptic neuronal activity with inhibiting NMDAR function as determine by c-Fos expression and two-photon Ca2+ imaging in awake mice. Our results suggest that experience-dependent homeostatic regulation of intact cortical circuits is mediated by NMDAR-dependent plasticity mechanisms, which supports a sliding threshold model of homeostatic adaptation.SIGNIFICANCE STATEMENT Prolonged changes in sensory experience lead to homeostatic adaptation of excitatory synaptic strength in sensory cortices. Both sliding threshold and synaptic scaling models can account for the observed homeostatic synaptic plasticity. Here we report that visual experience-dependent homeostatic plasticity of excitatory synapses observed in superficial layers of visual cortex is dependent on NMDAR function. In particular, both strengthening of synapses induced by visual deprivation and the subsequent weakening by reinstatement of visual experience were prevented in the absence of functional NMDARs. Our results suggest that sensory experience-dependent homeostatic adaptation depends on NMDARs, which supports the sliding threshold model of plasticity and input-specific homeostatic control observed in vivo.
Collapse
|
20
|
Brzosko Z, Mierau SB, Paulsen O. Neuromodulation of Spike-Timing-Dependent Plasticity: Past, Present, and Future. Neuron 2019; 103:563-581. [DOI: 10.1016/j.neuron.2019.05.041] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 05/20/2019] [Accepted: 05/24/2019] [Indexed: 12/31/2022]
|
21
|
Burgos H, Hernández A, Constandil L, Ríos M, Flores O, Puentes G, Hernández K, Morgan C, Valladares L, Castillo A, Cofre C, Milla LA, Sáez-Briones P, Barra R. Early postnatal environmental enrichment restores neurochemical and functional plasticities of the cerebral cortex and improves learning performance in hidden-prenatally-malnourished young-adult rats. Behav Brain Res 2019; 363:182-190. [DOI: 10.1016/j.bbr.2019.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 01/11/2019] [Accepted: 02/01/2019] [Indexed: 01/28/2023]
|
22
|
Abstract
The corpus callosum is a large fiber bundle which connects contralateral brain regions. After unilateral perturbations such as stroke or amputation, interhemispheric connectivity is altered and often leads to bilateral somatomotor cortical hyperactivity in patients with poor recovery. This study reports that callosal targeting of deprived layer 5 neurons is maximally potentiated in mouse primary somatosensory barrel cortex after unilateral whisker denervation. These neurons also experience an increase in excitability and spontaneous excitatory amplitudes. These results should be relevant to the cortical responses observed in human patients after unilateral nerve transection, amputation, or stroke. Central or peripheral injury causes reorganization of the brain’s connections and functions. A striking change observed after unilateral stroke or amputation is a recruitment of bilateral cortical responses to sensation or movement of the unaffected peripheral area. The mechanisms underlying this phenomenon are described in a mouse model of unilateral whisker deprivation. Stimulation of intact whiskers yields a bilateral blood-oxygen-level−dependent fMRI response in somatosensory barrel cortex. Whole-cell electrophysiology demonstrated that the intact barrel cortex selectively strengthens callosal synapses to layer 5 neurons in the deprived cortex. These synapses have larger AMPA receptor- and NMDA receptor-mediated events. These factors contribute to a maximally potentiated callosal synapse. This potentiation occludes long-term potentiation, which could be rescued, to some extent, with prior long-term depression induction. Excitability and excitation/inhibition balance were altered in a manner consistent with cell-specific callosal changes and support a shift in the overall state of the cortex. This is a demonstration of a cell-specific, synaptic mechanism underlying interhemispheric cortical reorganization.
Collapse
|
23
|
Glutamate Receptor Trafficking and Protein Synthesis Mediate the Facilitation of LTP by Secreted Amyloid Precursor Protein-Alpha. J Neurosci 2019; 39:3188-3203. [PMID: 30804097 DOI: 10.1523/jneurosci.1826-18.2019] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 01/15/2019] [Accepted: 02/11/2019] [Indexed: 01/08/2023] Open
Abstract
Secreted amyloid precursor protein-alpha (sAPPα) has growth factor-like properties and can modulate long-term potentiation (LTP) and memory. Here, we demonstrate that exposure to sAPPα converts short-lasting LTP into protein-synthesis-dependent late LTP in hippocampal slices from male rats. sAPPβ had no discernable effect. We hypothesized that sAPPα facilitated LTP via regulated glutamate receptor trafficking and de novo protein synthesis. We found using a linear mixed model that sAPPα stimulated trafficking of GluA2-lacking AMPARs, as well as NMDARs to the extrasynaptic cell surface, in a calcium/calmodulin-dependent kinase II and protein kinase G-dependent manner. Both cell surface receptor accumulation and LTP facilitation were present even after sAPPα washout and inhibition of receptor trafficking or protein synthesis prevented all these effects. Direct visualization of newly synthesized proteins (FUNCAT-PLA) confirmed the ability of sAPPα to stimulate de novo protein synthesis and revealed GluA1 as one of the upregulated proteins. Therefore, sAPPα generates a coordinated synthesis and trafficking of glutamate receptors to the cell surface that facilitate LTP.SIGNIFICANCE STATEMENT Secreted amyloid precursor protein-alpha (sAPPα) is a neurotrophic and neuroprotective protein that can promote synaptic plasticity and memory, yet the molecular mechanisms underlying these effects are still not well understood. Here, we show that sAPPα facilitates long-term potentiation (LTP) in a concentration-dependent fashion through cellular processes involving de novo protein synthesis and trafficking of both GluA2-lacking AMPARs and NMDARs to the extrasynaptic cell surface. sAPPα also enhances GluA1, but not GluA2, synthesis. The trafficking effects, along with the LTP facilitation, persist after sAPPα washout, revealing a metaplastic capability of exogenous sAPPα administration. sAPPα thus facilitates LTP through coordinated activation of protein synthesis and trafficking of glutamate receptors to the cell surface, where they are positioned for priming LTP.
Collapse
|
24
|
Abraham WC, Jones OD, Glanzman DL. Is plasticity of synapses the mechanism of long-term memory storage? NPJ SCIENCE OF LEARNING 2019; 4:9. [PMID: 31285847 PMCID: PMC6606636 DOI: 10.1038/s41539-019-0048-y] [Citation(s) in RCA: 159] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 05/29/2019] [Indexed: 05/05/2023]
Abstract
It has been 70 years since Donald Hebb published his formalized theory of synaptic adaptation during learning. Hebb's seminal work foreshadowed some of the great neuroscientific discoveries of the following decades, including the discovery of long-term potentiation and other lasting forms of synaptic plasticity, and more recently the residence of memories in synaptically connected neuronal assemblies. Our understanding of the processes underlying learning and memory has been dominated by the view that synapses are the principal site of information storage in the brain. This view has received substantial support from research in several model systems, with the vast majority of studies on the topic corroborating a role for synapses in memory storage. Yet, despite the neuroscience community's best efforts, we are still without conclusive proof that memories reside at synapses. Furthermore, an increasing number of non-synaptic mechanisms have emerged that are also capable of acting as memory substrates. In this review, we address the key findings from the synaptic plasticity literature that make these phenomena such attractive memory mechanisms. We then turn our attention to evidence that questions the reliance of memory exclusively on changes at the synapse and attempt to integrate these opposing views.
Collapse
Affiliation(s)
- Wickliffe C. Abraham
- Department of Psychology, Brain Health Research Centre, Brain Research New Zealand, University of Otago, Box 56, Dunedin, 9010 New Zealand
| | - Owen D. Jones
- Department of Psychology, Brain Health Research Centre, Brain Research New Zealand, University of Otago, Box 56, Dunedin, 9010 New Zealand
| | - David L. Glanzman
- Departments of Integrative Biology and Physiology, and Neurobiology, and the Brain Research Institute, University of California, Los Angeles, CA 90095 USA
| |
Collapse
|
25
|
Hackett TA. Adenosine A 1 Receptor mRNA Expression by Neurons and Glia in the Auditory Forebrain. Anat Rec (Hoboken) 2018; 301:1882-1905. [PMID: 30315630 PMCID: PMC6282551 DOI: 10.1002/ar.23907] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 12/05/2017] [Accepted: 01/10/2018] [Indexed: 12/30/2022]
Abstract
In the brain, purines such as ATP and adenosine can function as neurotransmitters and co‐transmitters, or serve as signals in neuron–glial interactions. In thalamocortical (TC) projections to sensory cortex, adenosine functions as a negative regulator of glutamate release via activation of the presynaptic adenosine A1 receptor (A1R). In the auditory forebrain, restriction of A1R‐adenosine signaling in medial geniculate (MG) neurons is sufficient to extend LTP, LTD, and tonotopic map plasticity in adult mice for months beyond the critical period. Interfering with adenosine signaling in primary auditory cortex (A1) does not contribute to these forms of plasticity, suggesting regional differences in the roles of A1R‐mediated adenosine signaling in the forebrain. To advance understanding of the circuitry, in situ hybridization was used to localize neuronal and glial cell types in the auditory forebrain that express A1R transcripts (Adora1), based on co‐expression with cell‐specific markers for neuronal and glial subtypes. In A1, Adora1 transcripts were concentrated in L3/4 and L6 of glutamatergic neurons. Subpopulations of GABAergic neurons, astrocytes, oligodendrocytes, and microglia expressed lower levels of Adora1. In MG, Adora1 was expressed by glutamatergic neurons in all divisions, and subpopulations of all glial classes. The collective findings imply that A1R‐mediated signaling broadly extends to all subdivisions of auditory cortex and MG. Selective expression by neuronal and glial subpopulations suggests that experimental manipulations of A1R‐adenosine signaling could impact several cell types, depending on their location. Strategies to target Adora1 in specific cell types can be developed from the data generated here. Anat Rec, 301:1882–1905, 2018. © 2018 The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.
Collapse
Affiliation(s)
- Troy A Hackett
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Department of Psychology, Vanderbilt University, Nashville, Tennessee, USA.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA.,Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee, USA
| |
Collapse
|
26
|
Frankiensztajn LM, Gur-Pollack R, Wagner S. A combinatorial modulation of synaptic plasticity in the rat medial amygdala by oxytocin, urocortin3 and estrogen. Psychoneuroendocrinology 2018; 92:95-102. [PMID: 29674171 DOI: 10.1016/j.psyneuen.2018.04.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/07/2018] [Accepted: 04/09/2018] [Indexed: 12/14/2022]
Abstract
The medial nucleus of the amygdala (MeA) plays a pivotal role in a variety of mammalian social behaviors. Specifically, activity of the hypothalamic pro-social neuropeptide oxytocin in the MeA was shown to be crucial for social recognition memory. The MeA is also a hub of neuroendocrine activity and expresses a large number of receptors of neuropeptides and hormones. These include oxytocin receptor, estrogen receptor alpha and corticotropin-releasing factor (CRF) receptor type 2 (CRFR2). In a previous study we found that intracerebroventricular (ICV) oxytocin application to anesthetized rats promotes long-term depression (LTD) of the MeA response to electrical stimulation of its main sensory input, the accessory olfactory bulb (AOB). We also reported that this type of synaptic plasticity contributes to long-term social recognition memory. Here we used similar methodology to examine the possibility that various neuromodulators pose a combinatorial effect on synaptic plasticity in the MeA. We found that ICV administration of the CRF-related peptide urocortin3 fifteen minutes before oxytocin, caused long-term potentiation (LTP), via CRFR2 activation. Similarly, ICV administration of 17β-estradiol forty-five minutes before oxytocin induced LTP, which was blocked by an antagonist of the estrogen receptors alpha and beta. Notably, none of these two neuromodulators had any effect on its own, suggesting that they both turn the oxytocin-mediated synaptic plasticity from LTD to LTP. Finally, we found that application of 17β-estradiol, forty-five minutes before urocortin3 also caused LTP in the MeA response to AOB stimulation, even without oxytocin application. We suggest that the combinatorial modulation of the bidirectional synaptic plasticity in the AOB-MeA pathway by oxytocin, 17β-estradiol and urocotin-3 serves to modify social information processing according to the animal's internal state.
Collapse
Affiliation(s)
- Linoy Mia Frankiensztajn
- Sagol Department of Neurobiology, The Integrated Brain and Behavior Research Center (IBBR), University of Haifa, Haifa 3498838, Israel
| | - Rotem Gur-Pollack
- Sagol Department of Neurobiology, The Integrated Brain and Behavior Research Center (IBBR), University of Haifa, Haifa 3498838, Israel
| | - Shlomo Wagner
- Sagol Department of Neurobiology, The Integrated Brain and Behavior Research Center (IBBR), University of Haifa, Haifa 3498838, Israel.
| |
Collapse
|
27
|
Tie X, Li S, Feng Y, Lai B, Liu S, Jiang B. Distinct Roles of NMDAR and mGluR5 in Light Exposure Reversal of Feedforward Synaptic Strength in V1 of Juvenile Mice after Binocular Vision Deprivation. Neuroscience 2018; 384:131-138. [PMID: 29859977 DOI: 10.1016/j.neuroscience.2018.05.034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 05/21/2018] [Accepted: 05/22/2018] [Indexed: 11/25/2022]
Abstract
In the visual cortex, sensory deprivation causes global augmentation of the amplitude of AMPA receptor-mediated miniature EPSCs in layer 2/3 pyramidal cells and enhancement of NMDA receptor-dependent long-term potentiation (LTP) in cells activated in layer 4, effects that are both rapidly reversed by light exposure. Layer 2/3 pyramidal cells receive both feedforward input from layer 4 and intra-cortical lateral input from the same layer, LTP is mainly induced by the former input. Whether feedforward excitatory synaptic strength is affected by visual deprivation and light exposure, how this synaptic strength correlates with the magnitude of LTP in this pathway, and the underlying mechanism have not been explored. Here, we showed that in juvenile mice, both dark rearing and dark exposure reduced the feedforward excitatory synaptic strength, and the effects can be reversed completely by 10-12 h and 6-8 h light exposure, respectively. However, inhibition of NMDA receptors by CPP or mGluR5 by MPEP, prevented the effect of light exposure on the mice reared in the dark from birth, while only inhibition of NMDAR prevented the effect of light exposure on dark-exposed mice. These results suggested that the activation of both NMDAR and mGluR5 are essential in the light exposure reversal of feedforward excitatory synaptic strength in the dark reared mice from birth; while in the dark exposed mice, only activation of NMDAR is required.
Collapse
Affiliation(s)
- Xiaoxiu Tie
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, China
| | - Shuo Li
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, China
| | - Yilin Feng
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, China
| | - Biqin Lai
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, China
| | - Sheng Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie South Road, Guangzhou 510080, China.
| | - Bin Jiang
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, China.
| |
Collapse
|
28
|
Edelmann E, Lessmann V. Dopaminergic innervation and modulation of hippocampal networks. Cell Tissue Res 2018; 373:711-727. [PMID: 29470647 DOI: 10.1007/s00441-018-2800-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 01/17/2018] [Indexed: 02/06/2023]
Abstract
The catecholamine dopamine plays an important role in hippocampus-dependent plasticity and related learning and memory processes. Dopamine secretion in the hippocampus is activated by, e.g., salient or novel stimuli, thereby helping to establish and to stabilize hippocampus-dependent memories. Disturbed dopaminergic function in the hippocampus leads to severe pathophysiological conditions. While the role and importance of dopaminergic modulation of hippocampal networks have been unequivocally proven, there is still a lack of detailed molecular and cellular mechanistic understanding of how dopamine orchestrates these hippocampal processes. In this chapter of the special issue "Hippocampal structure and function," we will discuss the current understanding of dopaminergic modulation of basal synaptic transmission and long-lasting, activity-dependent potentiation or depression.
Collapse
Affiliation(s)
- Elke Edelmann
- Institut für Physiologie, Otto-von-Guericke-Universität, Medizinische Fakultät, Leipziger Str. 44, 39120, Magdeburg, Germany. .,Center for Behavioral Brain Sciences, Otto-von-Guericke University, Universitätsplatz 2, 39106, Magdeburg, Germany.
| | - Volkmar Lessmann
- Institut für Physiologie, Otto-von-Guericke-Universität, Medizinische Fakultät, Leipziger Str. 44, 39120, Magdeburg, Germany. .,Center for Behavioral Brain Sciences, Otto-von-Guericke University, Universitätsplatz 2, 39106, Magdeburg, Germany.
| |
Collapse
|
29
|
Abstract
Schizophrenia is a complex disorder lacking an effective treatment option for the pervasive and debilitating cognitive impairments experienced by patients. Working memory is a core cognitive function impaired in schizophrenia that depends upon activation of distributed neural network, including the circuitry of the dorsolateral prefrontal cortex (DLPFC). Accordingly, individuals diagnosed with schizophrenia show reduced DLPFC activation while performing working-memory tasks. This lower DLPFC activation appears to be an integral part of the disease pathophysiology, and not simply a reflection of poor performance. Thus, the cellular and circuitry alterations that underlie lower DLPFC neuronal activity in schizophrenia must be determined in order to identify appropriate therapeutic targets. Studies using human postmortem brain tissue provide a robust way to investigate and characterize these cellular and circuitry alterations at multiple levels of resolution, and such studies provide essential information that cannot be obtained either through in vivo studies in humans or through experimental animal models. Studies examining neuronal morphology, protein expression and localization, and transcript levels indicate that a microcircuit composed of excitatory pyramidal cells and inhibitory interneurons containing the calcium-binding protein parvalbumin is altered in the DLPFC of subjects with schizophrenia and likely contributes to DLPFC dysfunction.
Collapse
Affiliation(s)
- Jill R Glausier
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States
| | - David A Lewis
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States.
| |
Collapse
|
30
|
Lisman J. Glutamatergic synapses are structurally and biochemically complex because of multiple plasticity processes: long-term potentiation, long-term depression, short-term potentiation and scaling. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0260. [PMID: 28093558 DOI: 10.1098/rstb.2016.0260] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/29/2016] [Indexed: 01/03/2023] Open
Abstract
Synapses are complex because they perform multiple functions, including at least six mechanistically different forms of plasticity. Here, I comment on recent developments regarding these processes. (i) Short-term potentiation (STP), a Hebbian process that requires small amounts of synaptic input, appears to make strong contributions to some forms of working memory. (ii) The rules for long-term potentiation (LTP) induction in CA3 have been clarified: induction does not depend obligatorily on backpropagating sodium spikes but, rather, on dendritic branch-specific N-methyl-d-aspartate (NMDA) spikes. (iii) Late LTP, a process that requires a dopamine signal (and is therefore neoHebbian), is mediated by trans-synaptic growth of the synapse, a growth that occurs about an hour after LTP induction. (iv) LTD processes are complex and include both homosynaptic and heterosynaptic forms. (v) Synaptic scaling produced by changes in activity levels are not primarily cell-autonomous, but rather depend on network activity. (vi) The evidence for distance-dependent scaling along the primary dendrite is firm, and a plausible structural-based mechanism is suggested.Ideas about the mechanisms of synaptic function need to take into consideration newly emerging data about synaptic structure. Recent super-resolution studies indicate that glutamatergic synapses are modular (module size 70-80 nm), as predicted by theoretical work. Modules are trans-synaptic structures and have high concentrations of postsynaptic density-95 (PSD-95) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor. These modules function as quasi-independent loci of AMPA-mediated transmission and may be independently modifiable, suggesting a new understanding of quantal transmission.This article is part of the themed issue 'Integrating Hebbian and homeostatic plasticity.'
Collapse
Affiliation(s)
- John Lisman
- Biology Department, Brandeis University, Waltham, MA, USA
| |
Collapse
|
31
|
Social isolation suppresses actin dynamics and synaptic plasticity through ADF/cofilin inactivation in the developing rat barrel cortex. Sci Rep 2017; 7:8471. [PMID: 28814784 PMCID: PMC5559554 DOI: 10.1038/s41598-017-08849-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 07/19/2017] [Indexed: 02/08/2023] Open
Abstract
Exposure to a stressful environment early in life can cause psychiatric disorders by disrupting circuit formation. Actin plays central roles in regulating neuronal structure and protein trafficking. We have recently reported that neonatal isolation inactivated ADF/cofilin, the actin depolymerizing factor, resulted in a reduced actin dynamics at spines and an attenuation of synaptic α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor delivery in the juvenile rat medial prefrontal cortex (mPFC), leading to altered social behaviours. Here, we investigated the impact of neonatal social isolation in the developing rat barrel cortex. Similar to the mPFC study, we detected an increase in stable actin fraction in spines and this resulted in a decreased synaptic AMPA receptor delivery. Thus, we conclude that early life social isolation affects multiple cortical areas with common molecular changes.
Collapse
|
32
|
Park Y, Choi W, Paik SB. Symmetry of learning rate in synaptic plasticity modulates formation of flexible and stable memories. Sci Rep 2017; 7:5671. [PMID: 28720795 PMCID: PMC5516032 DOI: 10.1038/s41598-017-05929-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 06/06/2017] [Indexed: 01/06/2023] Open
Abstract
Spike-timing-dependent plasticity (STDP) is considered critical to learning and memory functions in the human brain. Across various types of synapse, STDP is observed as different profiles of Hebbian and anti-Hebbian learning rules. However, the specific roles of diverse STDP profiles in memory formation still remain elusive. Here, we show that the symmetry of the learning rate profile in STDP is crucial to determining the character of stored memory. Using computer simulations, we found that an asymmetric learning rate generates flexible memory that is volatile and easily overwritten by newly appended information. Moreover, a symmetric learning rate generates stable memory that can coexist with newly appended information. In addition, by combining these two conditions, we could realize a hybrid memory type that operates in a way intermediate between stable and flexible memory. Our results demonstrate that various attributes of memory functions may originate from differences in the synaptic stability.
Collapse
Affiliation(s)
- Youngjin Park
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Woochul Choi
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.,Program of Brain and Cognitive Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Se-Bum Paik
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea. .,Program of Brain and Cognitive Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
| |
Collapse
|
33
|
Monocular deprivation induces dendritic spine elimination in the developing mouse visual cortex. Sci Rep 2017; 7:4977. [PMID: 28694464 PMCID: PMC5504056 DOI: 10.1038/s41598-017-05337-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 06/08/2017] [Indexed: 12/24/2022] Open
Abstract
It is well established that visual deprivation has a profound impact on the responsiveness of neurons in the developing visual cortex. The effect of visual deprivation on synaptic connectivity remains unclear. Using transcranial two-photon microscopy, we examined the effect of visual deprivation and subsequent recovery on dendritic spine remodeling of layer 5 pyramidal neurons in the mouse primary visual cortex. We found that monocular deprivation (MD), but not binocular deprivation (BD), increased dendritic spine elimination over 3 days in the binocular region of 4-week-old adolescent mice. This MD-induced dendritic spine elimination persisted during subsequent 2-4 days of binocular recovery. Furthermore, we found that average dendritic spine sizes were decreased and increased following 3-day MD and BD, respectively. These spine size changes induced by MD or BD tended to be reversed during subsequent binocular recovery. Taken together, these findings reveal differential effects of MD and BD on synaptic connectivity of layer 5 pyramidal neurons and underscore the persistent impact of MD on synapse loss in the developing visual cortex.
Collapse
|
34
|
Guo Y, Zhang W, Chen X, Fu J, Cheng W, Song D, Qu X, Yang Z, Zhao K. Timing-dependent LTP and LTD in mouse primary visual cortex following different visual deprivation models. PLoS One 2017; 12:e0176603. [PMID: 28520739 PMCID: PMC5435181 DOI: 10.1371/journal.pone.0176603] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 04/13/2017] [Indexed: 11/23/2022] Open
Abstract
Visual deprivation during the critical period induces long-lasting changes in cortical circuitry by adaptively modifying neuro-transmission and synaptic connectivity at synapses. Spike timing-dependent plasticity (STDP) is considered a strong candidate for experience-dependent changes. However, the visual deprivation forms that affect timing-dependent long-term potentiation(LTP) and long-term depression(LTD) remain unclear. Here, we demonstrated the temporal window changes of tLTP and tLTD, elicited by coincidental pre- and post-synaptic firing, following different modes of 6-day visual deprivation. Markedly broader temporal windows were found in robust tLTP and tLTD in the V1M of the deprived visual cortex in mice after 6-day MD and DE. The underlying mechanism for the changes seen with visual deprivation in juvenile mice using 6 days of dark exposure or monocular lid suture involves an increased fraction of NR2b-containing NMDAR and the consequent prolongation of NMDAR-mediated response duration. Moreover, a decrease in NR2A protein expression at the synapse is attributable to the reduction of the NR2A/2B ratio in the deprived cortex.
Collapse
Affiliation(s)
- Yatu Guo
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
- * E-mail: (YG); (KXZ)
| | - Wei Zhang
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
| | - Xia Chen
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
| | - Junhong Fu
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
- Department of Ophthalmology, The TEDA International Hospital, Tianjin, China
| | - Wenbo Cheng
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
- Department of Ophthalmology, The TEDA International Hospital, Tianjin, China
| | - Desheng Song
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
- Department of Ophthalmology, The TEDA International Hospital, Tianjin, China
| | - Xiaolei Qu
- Department of Ophthalmology, the Second People’s Hospital of Jinan, Shandong, China
| | - Zhuo Yang
- Key Laboratory of Bioactive Materials, Ministry of Education, College of Life Science, Nankai University, Tianjin, China
- College of Medicine, Nankai University, Tianjin, China
| | - Kanxing Zhao
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
- * E-mail: (YG); (KXZ)
| |
Collapse
|
35
|
Tatti R, Haley MS, Swanson O, Tselha T, Maffei A. Neurophysiology and Regulation of the Balance Between Excitation and Inhibition in Neocortical Circuits. Biol Psychiatry 2017; 81:821-831. [PMID: 27865453 PMCID: PMC5374043 DOI: 10.1016/j.biopsych.2016.09.017] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 08/25/2016] [Accepted: 09/15/2016] [Indexed: 12/18/2022]
Abstract
Brain function relies on the ability of neural networks to maintain stable levels of activity, while experiences sculpt them. In the neocortex, the balance between activity and stability relies on the coregulation of excitatory and inhibitory inputs onto principal neurons. Shifts of excitation or inhibition result in altered excitability impaired processing of incoming information. In many neurodevelopmental and neuropsychiatric disorders, the excitability of local circuits is altered, suggesting that their pathophysiology may involve shifts in synaptic excitation, inhibition, or both. Most studies focused on identifying the cellular and molecular mechanisms controlling network excitability to assess whether they may be altered in animal models of disease. The impact of changes in excitation/inhibition balance on local circuit and network computations is not clear. Here we report findings on the integration of excitatory and inhibitory inputs in healthy cortical circuits and discuss how shifts in excitation/inhibition balance may relate to pathological phenotypes.
Collapse
Affiliation(s)
- Roberta Tatti
- Dept. of Neurobiology and Behavior, SUNY-Stony Brook, Stony Brook, NY 11794
| | - Melissa S. Haley
- Dept. of Neurobiology and Behavior, SUNY-Stony Brook, Stony Brook, NY 11794
| | - Olivia Swanson
- Dept. of Neurobiology and Behavior, SUNY-Stony Brook, Stony Brook, NY 11794
| | - Tenzin Tselha
- Dept. of Neurobiology and Behavior, SUNY-Stony Brook, Stony Brook, NY 11794
| | - Arianna Maffei
- Department of Neurobiology and Behavior, Stony Brook University, The State University of New York, Stony Brook, New York.
| |
Collapse
|
36
|
Li YH, Han L, Wu KLK, Chan YS. Activation of 5-HT 7 receptors reverses NMDA-R-dependent LTD by activating PKA in medial vestibular neurons. Neuropharmacology 2017; 123:242-248. [PMID: 28483393 DOI: 10.1016/j.neuropharm.2017.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 04/07/2017] [Accepted: 05/04/2017] [Indexed: 11/30/2022]
Abstract
The medial vestibular nucleus (MVN) is a major output station for neurons that project to the vestibulo-spinal pathway. MVN neurons show capacity for long-term depression (LTD) during the juvenile period. We investigated LTD of MVN neurons using whole-cell patch-clamp recordings. High frequency stimulation (HFS) robustly induced LTD in 90% of type B neurons in the MVN, while only 10% of type A neurons were responsive, indicating that type B neurons are the major contributors to LTD in the MVN. The neuromodulator serotonin (5-HT) is known to modulate LTD in neural circuits of the cerebral cortex and the hippocampus. We therefore aim to determine the action of 5-HT on the LTD of type B MVN neurons and elucidate the relevant 5-HT receptor subtypes responsible for its action. Using specific agonists and antagonists of 5-HT receptors, we found that selective activation of 5-HT7 receptor in type B neurons in the MVN of juvenile (P13-16) rats completely abolished NMDA-receptor-mediated LTD in a protein kinase A (PKA)-dependent manner. Our finding that 5-HT restricts plasticity of type B MVN neurons via 5-HT7 receptors offers a mechanism whereby vestibular tuning contributes to the maturation of the vestibulo-spinal circuit and highlights the role of 5-HT in postural control.
Collapse
Affiliation(s)
- Yan-Hai Li
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Research Center of Rehabilitation Science and Technology, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, PR China; School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, Hong Kong, PR China
| | - Lei Han
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, Hong Kong, PR China
| | - Kenneth Lap Kei Wu
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, Hong Kong, PR China
| | - Ying-Shing Chan
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, Hong Kong, PR China; State Key Laboratory of Brain and Congnitive Sciences, The University of Hong Kong, Hong Kong, PR China.
| |
Collapse
|
37
|
Tada H, Miyazaki T, Takemoto K, Takase K, Jitsuki S, Nakajima W, Koide M, Yamamoto N, Komiya K, Suyama K, Sano A, Taguchi A, Takahashi T. Neonatal isolation augments social dominance by altering actin dynamics in the medial prefrontal cortex. Proc Natl Acad Sci U S A 2016; 113:E7097-E7105. [PMID: 27791080 PMCID: PMC5111648 DOI: 10.1073/pnas.1606351113] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Social separation early in life can lead to the development of impaired interpersonal relationships and profound social disorders. However, the underlying cellular and molecular mechanisms involved are largely unknown. Here, we found that isolation of neonatal rats induced glucocorticoid-dependent social dominance over nonisolated control rats in juveniles from the same litter. Furthermore, neonatal isolation inactivated the actin-depolymerizing factor (ADF)/cofilin in the juvenile medial prefrontal cortex (mPFC). Isolation-induced inactivation of ADF/cofilin increased stable actin fractions at dendritic spines in the juvenile mPFC, decreasing glutamate synaptic AMPA receptors. Expression of constitutively active ADF/cofilin in the mPFC rescued the effect of isolation on social dominance. Thus, neonatal isolation affects spines in the mPFC by reducing actin dynamics, leading to altered social behavior later in life.
Collapse
Affiliation(s)
- Hirobumi Tada
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Tomoyuki Miyazaki
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Kiwamu Takemoto
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
- Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Saitama 332-0012, Japan
| | - Kenkichi Takase
- Laboratory of Psychology, Jichi Medical University, Tochigi 329-0498, Japan
| | - Susumu Jitsuki
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Waki Nakajima
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Mayu Koide
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Naoko Yamamoto
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Kasane Komiya
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Kumiko Suyama
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Akane Sano
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Akiko Taguchi
- Department of Integrative Aging Neuroscience, National Center for Geriatrics and Gerontology, Aichi 474-8511, Japan
| | - Takuya Takahashi
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan;
| |
Collapse
|
38
|
Clewett D, Sakaki M, Nielsen S, Petzinger G, Mather M. Noradrenergic mechanisms of arousal's bidirectional effects on episodic memory. Neurobiol Learn Mem 2016; 137:1-14. [PMID: 27815214 DOI: 10.1016/j.nlm.2016.10.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 10/27/2016] [Accepted: 10/31/2016] [Indexed: 01/20/2023]
Abstract
Arousal's selective effects on cognition go beyond the simple enhancement of emotional stimuli, sometimes enhancing and other times impairing processing of proximal neutral information. Past work shows that arousal impairs encoding of subsequent neutral stimuli regardless of their top-down priority via the engagement of β-adrenoreceptors. In contrast, retrograde amnesia induced by emotional arousal can flip to enhancement when preceding neutral items are prioritized in top-down attention. Whether β-adrenoreceptors also contribute to this retrograde memory enhancement of goal-relevant neutral stimuli is unclear. In this pharmacological study, we administered 40mg of propranolol or 40mg of placebo to healthy young adults to examine whether emotional arousal's bidirectional effects on declarative memory relies on β-adrenoreceptor activation. Following pill intake, participants completed an emotional oddball task in which they were asked to prioritize a neutral object appearing just before an emotional or neutral oddball image within a sequence of 7 neutral objects. Under placebo, emotional oddballs impaired memory for lower priority oddball+1 objects but had no effect on memory for high priority oddball-1 objects. Propranolol blocked this anterograde amnesic effect of arousal. Emotional oddballs also enhanced selective memory trade-offs significantly more in the placebo than drug condition, such that high priority oddball-1 objects were more likely to be remembered at the cost of their corresponding lower priority oddball+1 objects under arousal. Lastly, those who recalled more high priority oddball-1 objects preceding an emotional versus neutral oddball image showed greater increases in salivary alpha-amylase, a biomarker of noradrenergic system activation, across the task. Together these findings suggest that different noradrenergic mechanisms contribute to the anterograde and retrograde mnemonic effects of arousal on proximal neutral memoranda.
Collapse
Affiliation(s)
- David Clewett
- Neuroscience Graduate Program, University of Southern California, USA.
| | - Michiko Sakaki
- School of Psychology and Clinical Language Sciences, University of Reading, UK
| | - Shawn Nielsen
- Davis School of Gerontology, University of Southern California, USA
| | - Giselle Petzinger
- Neuroscience Graduate Program, University of Southern California, USA; Department of Neurology, University of Southern California, USA
| | - Mara Mather
- Neuroscience Graduate Program, University of Southern California, USA; Davis School of Gerontology, University of Southern California, USA
| |
Collapse
|
39
|
Fields DP, Mitchell GS. Divergent cAMP signaling differentially regulates serotonin-induced spinal motor plasticity. Neuropharmacology 2016; 113:82-88. [PMID: 27663700 DOI: 10.1016/j.neuropharm.2016.09.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 09/11/2016] [Accepted: 09/19/2016] [Indexed: 12/29/2022]
Abstract
Spinal metabotropic serotonin receptors encode transient experiences into long-lasting changes in motor behavior (i.e. motor plasticity). While interactions between serotonin receptor subtypes are known to regulate plasticity, the significance of molecular divergence in downstream G protein coupled receptor signaling is not well understood. Here we tested the hypothesis that distinct cAMP dependent signaling pathways differentially regulate serotonin-induced phrenic motor facilitation (pMF); a well-studied model of spinal motor plasticity. Specifically, we studied the capacity of cAMP-dependent protein kinase A (PKA) and exchange protein activated by cAMP (EPAC) to regulate 5-HT2A receptor-induced pMF within adult male rats. Although spinal PKA, EPAC and 5-HT2A each elicit pMF when activated alone, concurrent PKA and 5-HT2A activation interact via mutual inhibition thereby blocking pMF expression. Conversely, concurrent EPAC and 5-HT2A activation enhance pMF expression reflecting additive contributions from both mechanisms. Thus, we demonstrate that distinct downstream cAMP signaling pathways enable differential regulation of 5-HT2A-induced pMF. Conditional activation of independent signaling mechanisms may explain experience amendable changes in plasticity expression (i.e. metaplasticity), an emerging concept thought to enable flexible motor control within the adult central nervous system.
Collapse
Affiliation(s)
- D P Fields
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI 53706, USA
| | - G S Mitchell
- Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
| |
Collapse
|
40
|
Phillips WA, Larkum ME, Harley CW, Silverstein SM. The effects of arousal on apical amplification and conscious state. Neurosci Conscious 2016; 2016:niw015. [PMID: 29877512 PMCID: PMC5934888 DOI: 10.1093/nc/niw015] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 06/28/2016] [Accepted: 08/08/2016] [Indexed: 01/19/2023] Open
Abstract
Neocortical pyramidal cells can integrate two classes of input separately and use one to modulate response to the other. Their tuft dendrites are electrotonically separated from basal dendrites and soma by the apical dendrite, and apical hyperpolarization-activated currents (Ih) further isolate subthreshold integration of tuft inputs. When apical depolarization exceeds a threshold, however, it can enhance response to the basal inputs that specify the cell's selective sensitivity. This process is referred to as apical amplification (AA). We review evidence suggesting that, by regulating Ih in the apical compartments, adrenergic arousal controls the coupling between apical and somatic integration zones thus modifying cognitive capabilities closely associated with consciousness. Evidence relating AA to schizophrenia, sleep, and anesthesia is reviewed, and we assess theories that emphasize the relevance of AA to consciousness. Implications for theories of neocortical computation that emphasize context-sensitive modulation are summarized. We conclude that the findings concerning AA and its regulation by arousal offer a new perspective on states of consciousness, the function and evolution of neocortex, and psychopathology. Many issues worthy of closer examination arise.
Collapse
Affiliation(s)
- W. A. Phillips
- School of Natural Sciences, University of Stirling, Scotland FK9 4LA, UK
| | - M. E. Larkum
- Neurocure Cluster of Excellence, Department of Biology, Humboldt University,
Charitéplatz 1, Berlin 10117, Germany
| | - C. W. Harley
- Psychology Department, Memorial University of Newfoundland, St. John's, NL A1C 5S7,
P.O. Box 4200, Canada
| | | |
Collapse
|
41
|
Abstract
Regulation of AMPA receptor (AMPAR) function is a fundamental mechanism controlling synaptic strength during long-term potentiation/depression and homeostatic scaling. AMPAR function and membrane trafficking is controlled by protein-protein interactions, as well as by posttranslational modifications. Phosphorylation of the GluA1 AMPAR subunit at S845 and S831 play especially important roles during synaptic plasticity. Recent controversy has emerged regarding the extent to which GluA1 phosphorylation may contribute to synaptic plasticity. Here we used a variety of methods to measure the population of phosphorylated GluA1-containing AMPARs in cultured primary neurons and mouse forebrain. Phosphorylated GluA1 represents large fractions from 12% to 50% of the total population under basal and stimulated conditions in vitro and in vivo. Furthermore, a large fraction of synapses are positive for phospho-GluA1-containing AMPARs. Our results support the large body of research indicating a prominent role of GluA1 phosphorylation in synaptic plasticity.
Collapse
|
42
|
Abstract
Tonic inhibition mediated by extrasynaptic GABA(A) receptors (GABARs) sensing ambient levels of GABA can profoundly alter the membrane input resistance to affect cellular excitability. Therefore, regulation of tonic inhibition is an attractive mechanism to control the levels of cortical firing. In cortical pyramidal cells, tonic inhibition is regulated by age and several neurotransmitters and is affected by stroke and epilepsy. However, the possible role of sensory experience has not been examined. Here, we report that a brief 2-day exposure to dark reduces by 1/3 the inhibitory tonic conductance recorded in layer II/III pyramidal cells of the mouse juvenile (postnatal day 12-27) visual cortex. In these cells, tonic inhibition is carried primarily by GABARs containing the δ subunit. Consistently, the dark exposure reduction in conductance was associated with a reduction in δ subunit levels, which were not affected in control frontal cortex. We propose that a deprivation-induced reduction in tonic inhibition might serve a homeostatic function by increasing the firing levels of cells in deprived cortical circuits.
Collapse
|
43
|
Kimoto S, Glausier JR, Fish KN, Volk DW, Bazmi HH, Arion D, Datta D, Lewis DA. Reciprocal Alterations in Regulator of G Protein Signaling 4 and microRNA16 in Schizophrenia. Schizophr Bull 2016; 42:396-405. [PMID: 26424323 PMCID: PMC4753606 DOI: 10.1093/schbul/sbv139] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
N-methyl-d-aspartate receptor (NMDAR) hypofunction in the dorsolateral prefrontal cortex (DLPFC) has been implicated in the pathology of schizophrenia. NMDAR activity is negatively regulated by some G protein-coupled receptors (GPCRs). Signaling through these GPCRs is reduced by Regulator of G protein Signaling 4 (RGS4). Thus, lower levels of RGS4 would enhance GPCR-mediated reductions in NMDAR activity and could contribute to NMDAR hypofunction in schizophrenia. In this study, we quantified RGS4 mRNA and protein levels at several levels of resolution in the DLPFC from subjects with schizophrenia and matched healthy comparison subjects. To investigate molecular mechanisms that could contribute to altered RGS4 levels, we quantified levels of small noncoding RNAs, known as microRNAs (miRs), which regulate RGS4 mRNA integrity after transcription. RGS4 mRNA and protein levels were significantly lower in schizophrenia subjects and were positively correlated across all subjects. The RGS4 mRNA deficit was present in pyramidal neurons of DLPFC layers 3 and 5 of the schizophrenia subjects. In contrast, levels of miR16 were significantly higher in the DLPFC of schizophrenia subjects, and higher miR16 levels predicted lower RGS4 mRNA levels. These findings provide convergent evidence of lower RGS4 mRNA and protein levels in schizophrenia that may result from increased expression of miR16. Given the role of RGS4 in regulating GPCRs, and consequently the strength of NMDAR signaling, these findings could contribute to the molecular substrate for NMDAR hypofunction in DLPFC pyramidal cells in schizophrenia.
Collapse
Affiliation(s)
- Sohei Kimoto
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA; Department of Psychiatry, Nara Medical University, Nara, Japan
| | - Jill R Glausier
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - Kenneth N Fish
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - David W Volk
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - H Holly Bazmi
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - Dominique Arion
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - Dibyadeep Datta
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - David A Lewis
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA; Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA
| |
Collapse
|
44
|
Emerging Link between Alzheimer's Disease and Homeostatic Synaptic Plasticity. Neural Plast 2016; 2016:7969272. [PMID: 27019755 PMCID: PMC4785275 DOI: 10.1155/2016/7969272] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 01/31/2016] [Indexed: 01/14/2023] Open
Abstract
Alzheimer's disease (AD) is an irreversible brain disorder characterized by progressive cognitive decline and neurodegeneration of brain regions that are crucial for learning and memory. Although intracellular neurofibrillary tangles and extracellular senile plaques, composed of insoluble amyloid-β (Aβ) peptides, have been the hallmarks of postmortem AD brains, memory impairment in early AD correlates better with pathological accumulation of soluble Aβ oligomers and persistent weakening of excitatory synaptic strength, which is demonstrated by inhibition of long-term potentiation, enhancement of long-term depression, and loss of synapses. However, current, approved interventions aiming to reduce Aβ levels have failed to retard disease progression; this has led to a pressing need to identify and target alternative pathogenic mechanisms of AD. Recently, it has been suggested that the disruption of Hebbian synaptic plasticity in AD is due to aberrant metaplasticity, which is a form of homeostatic plasticity that tunes the magnitude and direction of future synaptic plasticity based on previous neuronal or synaptic activity. This review examines emerging evidence for aberrant metaplasticity in AD. Putative mechanisms underlying aberrant metaplasticity in AD will also be discussed. We hope this review inspires future studies to test the extent to which these mechanisms contribute to the etiology of AD and offer therapeutic targets.
Collapse
|
45
|
Salgado H, Treviño M, Atzori M. Layer- and area-specific actions of norepinephrine on cortical synaptic transmission. Brain Res 2016; 1641:163-76. [PMID: 26820639 DOI: 10.1016/j.brainres.2016.01.033] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 01/08/2016] [Accepted: 01/20/2016] [Indexed: 12/20/2022]
Abstract
The cerebral cortex is a critical target of the central noradrenergic system. The importance of norepinephrine (NE) in the regulation of cortical activity is underscored by clinical findings that involve this catecholamine and its receptor subtypes in the regulation of a large number of emotional and cognitive functions and illnesses. In this review, we highlight diverse effects of the LC/NE system in the mammalian cortex. Indeed, electrophysiological, pharmacological, and behavioral studies in the last few decades reveal that NE elicits a mixed repertoire of excitatory, inhibitory, and biphasic effects on the firing activity and transmitter release of cortical neurons. At the intrinsic cellular level, NE can produce a series of effects similar to those elicited by other monoamines or acetylcholine, associated with systemic arousal. At the synaptic level, NE induces numerous acute changes in synaptic function, and ׳gates' the induction of long-term plasticity of glutamatergic synapses, consisting in an enhancement of engaged and relevant cortical synapses and/or depression of unengaged synapses. Equally important in shaping cortical function, in many cortical areas NE promotes a characteristic, most often reversible, increase in the gain of local inhibitory synapses, whose extent and temporal properties vary between different areas and sometimes even between cortical layers of the same area. While we are still a long way from a comprehensive theory of the function of the LC/NE system, its cellular, synaptic, and plastic effects are consistent with the hypothesis that noradrenergic modulation is critical in coordinating the activity of cortical and subcortical circuits for the integration of sensory activity and working memory. This article is part of a Special Issue entitled SI: Noradrenergic System.
Collapse
Affiliation(s)
| | | | - Marco Atzori
- Universidad Autónoma de San Luis Potosí, México.
| |
Collapse
|
46
|
Abstract
UNLABELLED Much of the molecular understanding of synaptic pathology in Alzheimer's disease (AD) comes from studies of various mouse models that express familial AD (FAD)-linked mutations, often in combinations. Most studies compare the absolute magnitudes of long-term potentiation (LTP) and long-term depression (LTD) to assess deficits in bidirectional synaptic plasticity accompanying FAD-linked mutations. However, LTP and LTD are not static, but their induction threshold is adjusted by overall neural activity via metaplasticity. Hence LTP/LTD changes in AD mouse models may reflect defects in metaplasticity processes. To determine this, we examined the LTP/LTD induction threshold in APPswe;PS1ΔE9 transgenic (Tg) mice across two different ages. We found that in young Tg mice (1 month), LTP is enhanced at the expense of LTD, but in adults (6 months), the phenotype is reversed to promote LTD and reduce LTP, compared to age-matched wild-type (WT) littermates. The apparent opposite phenotype across age was due to an initial offset in the induction threshold to favor LTP and the inability to undergo developmental metaplasticity in Tg mice. In WTs, the synaptic modification threshold decreased over development to favor LTP and diminish LTD in adults. However, in Tg mice, the magnitudes of LTP and LTD stayed constant across development. The initial offset in LTP/LTD threshold in young Tg mice did not accompany changes in the LTP/LTD induction mechanisms, but altered AMPA receptor phosphorylation and appearance of Ca(2+)-permeable AMPA receptors. We propose that the main synaptic defect in AD mouse models is due to their inability to undergo developmental metaplasticity. SIGNIFICANCE STATEMENT This work offers a new insight that metaplasticity defects are central to synaptic dysfunctions seen in AD mouse models. In particular, we demonstrate that the apparent differences in LTP/LTD magnitude seen across ages in AD transgenic mouse models reflect the inability to undergo a normal developmental shift in metaplasticity.
Collapse
|
47
|
He K, Huertas M, Hong SZ, Tie X, Hell JW, Shouval H, Kirkwood A. Distinct Eligibility Traces for LTP and LTD in Cortical Synapses. Neuron 2015; 88:528-38. [PMID: 26593091 DOI: 10.1016/j.neuron.2015.09.037] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 09/01/2015] [Accepted: 09/18/2015] [Indexed: 10/22/2022]
Abstract
In reward-based learning, synaptic modifications depend on a brief stimulus and a temporally delayed reward, which poses the question of how synaptic activity patterns associate with a delayed reward. A theoretical solution to this so-called distal reward problem has been the notion of activity-generated "synaptic eligibility traces," silent and transient synaptic tags that can be converted into long-term changes in synaptic strength by reward-linked neuromodulators. Here we report the first experimental demonstration of eligibility traces in cortical synapses. We demonstrate the Hebbian induction of distinct traces for LTP and LTD and their subsequent timing-dependent transformation into lasting changes by specific monoaminergic receptors anchored to postsynaptic proteins. Notably, the temporal properties of these transient traces allow stable learning in a recurrent neural network that accurately predicts the timing of the reward, further validating the induction and transformation of eligibility traces for LTP and LTD as a plausible synaptic substrate for reward-based learning.
Collapse
Affiliation(s)
- Kaiwen He
- Mind/Brain Institute, Johns Hopkins University, 3400 North Charles Street, 350 Dunning Hall, Baltimore, MD 21218, USA
| | - Marco Huertas
- Department of Neurobiology and Anatomy, University of Texas at Houston, 6431 Fannin Street, Suite MSB 7.046, Houston, TX 77030, USA
| | - Su Z Hong
- Mind/Brain Institute, Johns Hopkins University, 3400 North Charles Street, 350 Dunning Hall, Baltimore, MD 21218, USA
| | - XiaoXiu Tie
- Mind/Brain Institute, Johns Hopkins University, 3400 North Charles Street, 350 Dunning Hall, Baltimore, MD 21218, USA
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, 1544 Newton Court, Davis, CA 95618, USA
| | - Harel Shouval
- Department of Neurobiology and Anatomy, University of Texas at Houston, 6431 Fannin Street, Suite MSB 7.046, Houston, TX 77030, USA
| | - Alfredo Kirkwood
- Mind/Brain Institute, Johns Hopkins University, 3400 North Charles Street, 350 Dunning Hall, Baltimore, MD 21218, USA.
| |
Collapse
|
48
|
Metabotropic glutamate receptor signaling is required for NMDA receptor-dependent ocular dominance plasticity and LTD in visual cortex. Proc Natl Acad Sci U S A 2015; 112:12852-7. [PMID: 26417096 DOI: 10.1073/pnas.1512878112] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A feature of early postnatal neocortical development is a transient peak in signaling via metabotropic glutamate receptor 5 (mGluR5). In visual cortex, this change coincides with increased sensitivity of excitatory synapses to monocular deprivation (MD). However, loss of visual responsiveness after MD occurs via mechanisms revealed by the study of long-term depression (LTD) of synaptic transmission, which in layer 4 is induced by acute activation of NMDA receptors (NMDARs) rather than mGluR5. Here we report that chronic postnatal down-regulation of mGluR5 signaling produces coordinated impairments in both NMDAR-dependent LTD in vitro and ocular dominance plasticity in vivo. The data suggest that ongoing mGluR5 signaling during a critical period of postnatal development establishes the biochemical conditions that are permissive for activity-dependent sculpting of excitatory synapses via the mechanism of NMDAR-dependent LTD.
Collapse
|
49
|
Zhou L, Qin SJ, Gao X, Han JP, Hu B, Li M, Wu YQ, Ma X, Gu SL, Ma TF. Dexmedetomidine prevents post-ischemic LTP via presynaptic and postsynaptic mechanisms. Brain Res 2015; 1622:308-20. [PMID: 26168895 DOI: 10.1016/j.brainres.2015.06.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 05/03/2015] [Accepted: 06/24/2015] [Indexed: 11/19/2022]
Abstract
Increasing evidence indicates that dexmedetomidine (DEX), a selective α2-adrenergic receptor agonist, has a neuroprotective effect against cerebral injury. However, it remains unknown whether and how DEX functionally prevents the pathological form of synaptic plasticity caused by ischemia in the hippocampal CA1 neurons. To address this issue, we analyzed the role of DEX using a model of brain ischemia (oxygen and glucose deprivation, OGD) referred to as post-ischemic LTP (i-LTP). We found that DEX could reduce i-LTP by selectively activating α2 receptors. To clarify its detailed mechanisms, the presynaptic and postsynaptic roles of DEX were investigated. The activation of the α2 receptors of DEX decreased the frequency spontaneous mEPSCs, which exerted its presynaptic mechanisms. In addition, DEX also decreased the amplitude of mEPSCs and prevented the depolarization of postsynaptic membranes during OGD treatment, which exerted its postsynaptic mechanisms. More importantly, our results indicate that postsynaptic β receptors, not α1 receptors, participated in i-LTP. Therefore, these results demonstrated that decreasing β receptors activation by DEX-medicated pre- and post-synaptic α2 receptors activation is responsible for i-LTP. Because of the NMDARs required for i-LTP, we further examined the critical roles of postsynaptic β receptors downstream PKA regulation of NMDA receptor-mediated EPSCs (NMDA EPSC). We clarified that it is attributable to the direct effect of DEX on NMDA EPSC as mediated by PKA inactivation. These findings suggest that DEX can protect neurons from functional damage caused by a relatively mild degree of transient cerebral ischemia, and this effect is mediated by both presynaptic reduction of NE and glutamate release and postsynaptic suppression of NMDAR activation by β receptors and downstream PKA regulation.
Collapse
Affiliation(s)
- Li Zhou
- Department of Anaesthesiology, The Affiliated Hospital of XuZhou Medical College, XuZhou 221002, Jiangsu, China; Key Laboratory for Anesthesiology of Jiangsu Province Xuzhou, XuZhou 221004, Jiangsu, China
| | - Shou-Jun Qin
- Department of Pharmacology, Xuzhou Medical College, Jiangsu Key Laboratory of Target Drug and Clinical Application, XuZhou 221004, Jiangsu, China
| | - Xin Gao
- Department of Pharmacology, Xuzhou Medical College, Jiangsu Key Laboratory of Target Drug and Clinical Application, XuZhou 221004, Jiangsu, China
| | - Jun-Ping Han
- Department of Pharmacology, Xuzhou Medical College, Jiangsu Key Laboratory of Target Drug and Clinical Application, XuZhou 221004, Jiangsu, China
| | - Bin Hu
- Department of Pharmacology, Xuzhou Medical College, Jiangsu Key Laboratory of Target Drug and Clinical Application, XuZhou 221004, Jiangsu, China
| | - Mei Li
- Department of Pharmacology, Xuzhou Medical College, Jiangsu Key Laboratory of Target Drug and Clinical Application, XuZhou 221004, Jiangsu, China
| | - Yu-Qing Wu
- Key Laboratory for Anesthesiology of Jiangsu Province Xuzhou, XuZhou 221004, Jiangsu, China
| | - Xing Ma
- Department of Pharmacology, Xuzhou Medical College, Jiangsu Key Laboratory of Target Drug and Clinical Application, XuZhou 221004, Jiangsu, China
| | - Shu-Ling Gu
- Department of Pharmacology, Xuzhou Medical College, Jiangsu Key Laboratory of Target Drug and Clinical Application, XuZhou 221004, Jiangsu, China
| | - Teng-Fei Ma
- Department of Pharmacology, Xuzhou Medical College, Jiangsu Key Laboratory of Target Drug and Clinical Application, XuZhou 221004, Jiangsu, China.
| |
Collapse
|
50
|
Norepinephrine ignites local hotspots of neuronal excitation: How arousal amplifies selectivity in perception and memory. Behav Brain Sci 2015; 39:e200. [PMID: 26126507 DOI: 10.1017/s0140525x15000667] [Citation(s) in RCA: 311] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Emotional arousal enhances perception and memory of high-priority information but impairs processing of other information. Here, we propose that, under arousal, local glutamate levels signal the current strength of a representation and interact with norepinephrine (NE) to enhance high priority representations and out-compete or suppress lower priority representations. In our "glutamate amplifies noradrenergic effects" (GANE) model, high glutamate at the site of prioritized representations increases local NE release from the locus coeruleus (LC) to generate "NE hotspots." At these NE hotspots, local glutamate and NE release are mutually enhancing and amplify activation of prioritized representations. In contrast, arousal-induced LC activity inhibits less active representations via two mechanisms: 1) Where there are hotspots, lateral inhibition is amplified; 2) Where no hotspots emerge, NE levels are only high enough to activate low-threshold inhibitory adrenoreceptors. Thus, LC activation promotes a few hotspots of excitation in the context of widespread suppression, enhancing high priority representations while suppressing the rest. Hotspots also help synchronize oscillations across neural ensembles transmitting high-priority information. Furthermore, brain structures that detect stimulus priority interact with phasic NE release to preferentially route such information through large-scale functional brain networks. A surge of NE before, during, or after encoding enhances synaptic plasticity at NE hotspots, triggering local protein synthesis processes that enhance selective memory consolidation. Together, these noradrenergic mechanisms promote selective attention and memory under arousal. GANE not only reconciles apparently contradictory findings in the emotion-cognition literature but also extends previous influential theories of LC neuromodulation by proposing specific mechanisms for how LC-NE activity increases neural gain.
Collapse
|