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Tarhan M, Hartl T, Shchyglo O, Colitti-Klausnitzer J, Kuhla A, Breuer TM, Manahan-Vaughan D. Changes in hippocampal volume, synaptic plasticity and amylin sensitivity in an animal model of type 2 diabetes are associated with increased vulnerability to amyloid-beta in advancing age. Front Aging Neurosci 2024; 16:1373477. [PMID: 38974903 PMCID: PMC11224464 DOI: 10.3389/fnagi.2024.1373477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 05/28/2024] [Indexed: 07/09/2024] Open
Abstract
Type-2 diabetes (T2D) is a metabolic disorder that is considered a risk factor for Alzheimer's disease (AD). Cognitive impairment can arise due to hypoglycemia associated with T2D, and hyperamylinemia associated with insulin resistance can enhance AD pathology. We explored whether changes occur in the hippocampus in aging (6-12 months old) female V-Lep○b-/- transgenic (tg) mice, comprising an animal model of T2D. We also investigated whether an increase in vulnerability to Aβ (1-42), a known pathological hallmark of AD, is evident. Using magnetic resonance imaging we detected significant decreases in hippocampal brain volume in female tg-mice compared to wild-type (wt) littermates. Long-term potentiation (LTP) was impaired in tg compared to wt mice. Treatment of the hippocampus with Aβ (1-42) elicited a stronger debilitation of LTP in tg compared to wt mice. Treatment with an amylin antagonist (AC187) significantly enhanced LTP in wt and tg mice, and rescued LTP in Aβ (1-42)-treated tg mice. Taken together our data indicate that a T2D-like state results in an increased vulnerability of the hippocampus to the debilitating effects of Aβ (1-42) and that effects are mediated in part by changes in amylin receptor signaling.
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Affiliation(s)
- Melih Tarhan
- Department of Neurophysiology, Institute of Physiology, Ruhr University Bochum, Bochum, Germany
- International Graduate School of Neuroscience, Bochum, Germany
| | - Tim Hartl
- Department of Neurophysiology, Institute of Physiology, Ruhr University Bochum, Bochum, Germany
- International Graduate School of Neuroscience, Bochum, Germany
| | - Olena Shchyglo
- Department of Neurophysiology, Institute of Physiology, Ruhr University Bochum, Bochum, Germany
| | | | - Angela Kuhla
- Rudolf Zenker Institute for Experimental Surgery, Rostock University Medical Center, Rostock, Germany
| | | | - Denise Manahan-Vaughan
- Department of Neurophysiology, Institute of Physiology, Ruhr University Bochum, Bochum, Germany
- International Graduate School of Neuroscience, Bochum, Germany
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2
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Su C, Mendes-Platt RF, Alonso JM, Swadlow HA, Bereshpolova Y. Visual Corticotectal Neurons in Awake Rabbits: Receptive Fields and Driving Monosynaptic Thalamocortical Inputs. J Neurosci 2024; 44:e1945232024. [PMID: 38485258 PMCID: PMC11079980 DOI: 10.1523/jneurosci.1945-23.2024] [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: 10/13/2023] [Revised: 02/25/2024] [Accepted: 02/27/2024] [Indexed: 03/26/2024] Open
Abstract
The superior colliculus receives powerful synaptic inputs from corticotectal neurons in the visual cortex. The function of these corticotectal neurons remains largely unknown due to a limited understanding of their response properties and connectivity. Here, we use antidromic methods to identify corticotectal neurons in awake male and female rabbits, and measure their axonal conduction times, thalamic inputs and receptive field properties. All corticotectal neurons responded to sinusoidal drifting gratings with a nonlinear (nonsinusoidal) increase in mean firing rate but showed pronounced differences in their ON-OFF receptive field structures that we classified into three groups, Cx, S2, and S1. Cx receptive fields had highly overlapping ON and OFF subfields as classical complex cells, S2 had largely separated ON and OFF subfields as classical simple cells, and S1 had a single ON or OFF subfield. Thus, all corticotectal neurons are homogeneous in their nonlinear spatial summation but very heterogeneous in their spatial integration of ON and OFF inputs. The Cx type had the fastest conducting axons, the highest spontaneous activity, and the strongest and fastest visual responses. The S2 type had the highest orientation selectivity, and the S1 type had the slowest conducting axons. Moreover, our cross-correlation analyses found that a subpopulation of corticotectal neurons with very fast conducting axons and high spontaneous firing rates (largely "Cx" type) receives monosynaptic input from retinotopically aligned thalamic neurons. This previously unrecognized fast-conducting thalamic-mediated corticotectal pathway may provide specialized information to superior colliculus and prime recipient neurons for subsequent corticotectal or retinal synaptic input.
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Affiliation(s)
- Chuyi Su
- Department of Psychological Sciences, University of Connecticut, Storrs, Connecticut
| | | | - Jose-Manuel Alonso
- Department of Psychological Sciences, University of Connecticut, Storrs, Connecticut
- Department of Biological Sciences, SUNY-Optometry, New York, New York
| | - Harvey A Swadlow
- Department of Psychological Sciences, University of Connecticut, Storrs, Connecticut
- Department of Biological Sciences, SUNY-Optometry, New York, New York
| | - Yulia Bereshpolova
- Department of Psychological Sciences, University of Connecticut, Storrs, Connecticut
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Tian C, Reyes I, Masurkar AV. Impact of dendritic spine loss on excitability of hippocampal CA1 pyramidal neurons: a computational study of early Alzheimer disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.20.576500. [PMID: 38328155 PMCID: PMC10849489 DOI: 10.1101/2024.01.20.576500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Synaptic spine loss is an early pathophysiologic hallmark of Alzheimer disease (AD) that precedes overt loss of dendritic architecture and frank neurodegeneration. While spine loss signifies a decreased engagement of postsynaptic neurons by presynaptic targets, the degree to which loss of spines and their passive components impacts the excitability of postsynaptic neurons and responses to surviving synaptic inputs is unclear. Using passive multicompartmental models of CA1 pyramidal neurons (PNs), implicated in early AD, we find that spine loss alone drives a boosting of remaining inputs to their proximal and distal dendrites, targeted by CA3 and entorhinal cortex (EC), respectively. This boosting effect is higher in distal versus proximal dendrites and can be mediated by spine loss restricted to the distal compartment, enough to impact synaptic input integration and somatodendritic backpropagation. This has particular relevance to very early stages of AD in which pathophysiology extends from EC to CA1.
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Damiani F, Cornuti S, Tognini P. The gut-brain connection: Exploring the influence of the gut microbiota on neuroplasticity and neurodevelopmental disorders. Neuropharmacology 2023; 231:109491. [PMID: 36924923 DOI: 10.1016/j.neuropharm.2023.109491] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 02/22/2023] [Accepted: 03/05/2023] [Indexed: 03/17/2023]
Abstract
Neuroplasticity refers to the ability of brain circuits to reorganize and change the properties of the network, resulting in alterations in brain function and behavior. It is traditionally believed that neuroplasticity is influenced by external stimuli, learning, and experience. Intriguingly, there is new evidence suggesting that endogenous signals from the body's periphery may play a role. The gut microbiota, a diverse community of microorganisms living in harmony with their host, may be able to influence plasticity through its modulation of the gut-brain axis. Interestingly, the maturation of the gut microbiota coincides with critical periods of neurodevelopment, during which neural circuits are highly plastic and potentially vulnerable. As such, dysbiosis (an imbalance in the gut microbiota composition) during early life may contribute to the disruption of normal developmental trajectories, leading to neurodevelopmental disorders. This review aims to examine the ways in which the gut microbiota can affect neuroplasticity. It will also discuss recent research linking gastrointestinal issues and bacterial dysbiosis to various neurodevelopmental disorders and their potential impact on neurological outcomes.
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Affiliation(s)
| | - Sara Cornuti
- Laboratory of Biology, Scuola Normale Superiore, Pisa, Italy
| | - Paola Tognini
- Laboratory of Biology, Scuola Normale Superiore, Pisa, Italy; Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.
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Zarei F, Moazedi AA, Salimi Z, Pourmotabbed A, Yousofvand N, Farshad M, Akrami MR. Activation of androgen receptors alters hippocampal synaptic plasticity and memory retention through modulation of L-type calcium channels. Life Sci 2023; 314:121155. [PMID: 36379312 DOI: 10.1016/j.lfs.2022.121155] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 10/27/2022] [Accepted: 11/02/2022] [Indexed: 11/15/2022]
Abstract
AIMS It has been revealed that membrane androgen receptor activation modulates avoidance memory and synaptic plasticity. In a previous study, we showed that Calcineurin, a calcium dependent phosphatase, could be a potential mediator of these AR effects. Also, it is reported that AR activation leads to L-type calcium channel activation. The aim of the current study is to test whether L-type calcium channels are downstream of AR and whether this signal pathway mediates the impairment effect of androgenic steroids on passive avoidance memory and synaptic plasticity. MATERIALS AND METHODS We measured the effect of Nandrolone Decanoate (AR agonist), AR antagonist (Nilutamide) plus ND or L-type calcium channel inhibitor (Nifedipine) plus ND on passive avoidance performance of adolescent male rats. For extracellular field potential recordings hippocampal slices were perfused with ND, Nilutamide-ND or Nifedipine-ND. KEY FINDINGS Our results clarified that AR activation by ND could impair avoidance behavior as step through latency decreased in ND-treated group while application of both Nilutamide and Nifedipine reestablished normal avoidance behavior. Also, LTP induction in the CA1 area of hippocampus was diminished by ND perfusion and both AR antagonist and L-type calcium channel inhibitor application lead to normal LTP. These findings support our hypothesis that activation of L-type calcium channels are involved in ARs mechanism effects on both avoidance behavior and hippocampal synaptic plasticity. SIGNIFICANCE Understanding the biological effects of AR agonists on cognitive processes and its cellular mechanism may be a new/supplementary way to treating fear-related disorders.
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Affiliation(s)
- Fatemeh Zarei
- Department of Physiology, Kermanshah University of Medical Sciences, Kermanshah, Iran; Fertility and Infertility Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran; Department of Biology, Shahid Chamran University of Ahvaz, Ahvaz, Iran; Department of Biology, Faculty of Sciences, Razi University, Kermanshah, Iran.
| | - Ahmad Ali Moazedi
- Department of Biology, Shahid Chamran University of Ahvaz, Ahvaz, Iran; Stem Cell and Transgenic Technology Research Center, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Zahra Salimi
- Department of Physiology, Kermanshah University of Medical Sciences, Kermanshah, Iran; Fertility and Infertility Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran; Department of Biology, Centre for Biomedical Research, University of Victoria, Victoria, BC V8P 5C2, Canada; Department of Biology, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Ali Pourmotabbed
- Department of Physiology, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Namdar Yousofvand
- Department of Biology, Centre for Biomedical Research, University of Victoria, Victoria, BC V8P 5C2, Canada
| | - Moradpour Farshad
- Department of Physiology, Kermanshah University of Medical Sciences, Kermanshah, Iran; Fertility and Infertility Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran; Department of Biology, Centre for Biomedical Research, University of Victoria, Victoria, BC V8P 5C2, Canada
| | - Mohammad Reza Akrami
- Department of Neurosurgery, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
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Dendritic Morphology Affects the Velocity and Amplitude of Back-propagating Action Potentials. Neurosci Bull 2022; 38:1330-1346. [PMID: 35984622 PMCID: PMC9672184 DOI: 10.1007/s12264-022-00931-9] [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: 03/03/2022] [Accepted: 05/20/2022] [Indexed: 11/30/2022] Open
Abstract
The back-propagating action potential (bpAP) is crucial for neuronal signal integration and synaptic plasticity in dendritic trees. Its properties (velocity and amplitude) can be affected by dendritic morphology. Due to limited spatial resolution, it has been difficult to explore the specific propagation process of bpAPs along dendrites and examine the influence of dendritic morphology, such as the dendrite diameter and branching pattern, using patch-clamp recording. By taking advantage of Optopatch, an all-optical electrophysiological method, we made detailed recordings of the real-time propagation of bpAPs in dendritic trees. We found that the velocity of bpAPs was not uniform in a single dendrite, and the bpAP velocity differed among distinct dendrites of the same neuron. The velocity of a bpAP was positively correlated with the diameter of the dendrite on which it propagated. In addition, when bpAPs passed through a dendritic branch point, their velocity decreased significantly. Similar to velocity, the amplitude of bpAPs was also positively correlated with dendritic diameter, and the attenuation patterns of bpAPs differed among different dendrites. Simulation results from neuron models with different dendritic morphology corresponded well with the experimental results. These findings indicate that the dendritic diameter and branching pattern significantly influence the properties of bpAPs. The diversity among the bpAPs recorded in different neurons was mainly due to differences in dendritic morphology. These results may inspire the construction of neuronal models to predict the propagation of bpAPs in dendrites with enormous variation in morphology, to further illuminate the role of bpAPs in neuronal communication.
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7
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Noise-induced properties of active dendrites. Proc Natl Acad Sci U S A 2021; 118:2023381118. [PMID: 34413187 DOI: 10.1073/pnas.2023381118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dendrites play an essential role in the integration of highly fluctuating input in vivo into neurons across all nervous systems. Yet, they are often studied under conditions where inputs to dendrites are sparse. The dynamic properties of active dendrites facing in vivo-like fluctuating input thus remain elusive. In this paper, we uncover dynamics in a canonical model of a dendritic compartment with active calcium channels, receiving in vivo-like fluctuating input. In a single-compartment model of the active dendrite with fast calcium activation, we show noise-induced nonmonotonic behavior in the relationship of the membrane potential output, and mean input emerges. In contrast, noise can induce bistability in the input-output relation in the system with slowly activating calcium channels. Both phenomena are absent in a noiseless condition. Furthermore, we show that timescales of the emerging stochastic bistable dynamics extend far beyond a deterministic system due to stochastic switching between the solutions. A numerical simulation of a multicompartment model neuron shows that in the presence of in vivo-like synaptic input, the bistability uncovered in our analysis persists. Our results reveal that realistic synaptic input contributes to sustained dendritic nonlinearities, and synaptic noise is a significant component of dendritic input integration.
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8
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Kawato M, Ohmae S, Hoang H, Sanger T. 50 Years Since the Marr, Ito, and Albus Models of the Cerebellum. Neuroscience 2020; 462:151-174. [PMID: 32599123 DOI: 10.1016/j.neuroscience.2020.06.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/10/2020] [Accepted: 06/15/2020] [Indexed: 12/18/2022]
Abstract
Fifty years have passed since David Marr, Masao Ito, and James Albus proposed seminal models of cerebellar functions. These models share the essential concept that parallel-fiber-Purkinje-cell synapses undergo plastic changes, guided by climbing-fiber activities during sensorimotor learning. However, they differ in several important respects, including holistic versus complementary roles of the cerebellum, pattern recognition versus control as computational objectives, potentiation versus depression of synaptic plasticity, teaching signals versus error signals transmitted by climbing-fibers, sparse expansion coding by granule cells, and cerebellar internal models. In this review, we evaluate different features of the three models based on recent computational and experimental studies. While acknowledging that the three models have greatly advanced our understanding of cerebellar control mechanisms in eye movements and classical conditioning, we propose a new direction for computational frameworks of the cerebellum, that is, hierarchical reinforcement learning with multiple internal models.
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Affiliation(s)
- Mitsuo Kawato
- Brain Information Communication Research Group, Advanced Telecommunications Research Institutes International (ATR), Hikaridai 2-2-2, "Keihanna Science City", Kyoto 619-0288, Japan; Center for Advanced Intelligence Project (AIP), RIKEN, Nihonbashi Mitsui Building, 1-4-1 Nihonbashi, Chuo-ku, Tokyo 103-0027, Japan.
| | - Shogo Ohmae
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA
| | - Huu Hoang
- Brain Information Communication Research Group, Advanced Telecommunications Research Institutes International (ATR), Hikaridai 2-2-2, "Keihanna Science City", Kyoto 619-0288, Japan
| | - Terry Sanger
- Department of Electrical Engineering, University of California, Irvine, 4207 Engineering Hall, Irvine CA 92697-2625, USA; Children's Hospital of Orange County, 1201 W La Veta Ave, Orange, CA 92868, USA.
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9
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Somatodendritic consistency check for temporal feature segmentation. Nat Commun 2020; 11:1554. [PMID: 32214100 PMCID: PMC7096495 DOI: 10.1038/s41467-020-15367-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 03/06/2020] [Indexed: 11/08/2022] Open
Abstract
The brain identifies potentially salient features within continuous information streams to process hierarchical temporal events. This requires the compression of information streams, for which effective computational principles are yet to be explored. Backpropagating action potentials can induce synaptic plasticity in the dendrites of cortical pyramidal neurons. By analogy with this effect, we model a self-supervising process that increases the similarity between dendritic and somatic activities where the somatic activity is normalized by a running average. We further show that a family of networks composed of the two-compartment neurons performs a surprisingly wide variety of complex unsupervised learning tasks, including chunking of temporal sequences and the source separation of mixed correlated signals. Common methods applicable to these temporal feature analyses were previously unknown. Our results suggest the powerful ability of neural networks with dendrites to analyze temporal features. This simple neuron model may also be potentially useful in neural engineering applications. The authors propose a learning rule for a neuron model with dendrite. In their model, somatodendritic interaction implements self-supervised learning applicable to a wide range of sequence learning tasks, including spike pattern detection, chunking temporal input and blind source separation.
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10
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Johansson F. Intrinsic memory of temporal intervals in cerebellar Purkinje cells. Neurobiol Learn Mem 2019; 166:107103. [PMID: 31648018 DOI: 10.1016/j.nlm.2019.107103] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 10/15/2019] [Accepted: 10/20/2019] [Indexed: 11/30/2022]
Abstract
The general consensus for learning and memory, including in the cerebellum, is that modification of synaptic strength via long-term potentiation (LTP) or long-term depression (LTD) are the primary mechanisms for the formation of memories. Recent findings suggest additional cellular mechanisms - referred to as 'intrinsic plasticity' - where a neuron's membrane excitability intrinsically changes. These mechanisms act like a dimmer and alter neuronal responsiveness by adjusting response amplitudes and spike thresholds. Here, I argue that classical conditioning of cerebellar Purkinje cell responses reveals yet another cell-intrinsic learning mechanism which significantly differs from both changes in synaptic strength and changes in membrane excitability. When the conditional (CS) and unconditional stimuli (US) are delivered directly to the Purkinje cell's immediate pre-synaptic afferents, the parallel fibres and the climbing fibre, the cell learns to respond to the CS with a pause in its spontaneous firing that reflects the interval between the two stimuli. The pause response has a delayed onset and adaptively timed maximum, offset and duration, determined by the previously experienced CS-US interval. The timing is not dependent on any network-generated time-varying input. This implies the existence of a timing mechanism and a memory substrate that encodes the duration of the CS-US interval inside the Purkinje cell. Such temporal interval learning is not simply a change that causes more or less firing in response to an input. Here, I review these findings in relation to the standard theory of synaptic strength changes and the network interactions believed to be necessary for generating time codes.
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Affiliation(s)
- Fredrik Johansson
- Associative Learning Group, Department of Experimental Medical Science, Lund University, Sweden; Department of Neuroscience, Physiology and Pharmacology, University College London, UK.
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11
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Jia X, Siegle JH, Bennett C, Gale SD, Denman DJ, Koch C, Olsen SR. High-density extracellular probes reveal dendritic backpropagation and facilitate neuron classification. J Neurophysiol 2019; 121:1831-1847. [PMID: 30840526 DOI: 10.1152/jn.00680.2018] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Different neuron types serve distinct roles in neural processing. Extracellular electrical recordings are extensively used to study brain function but are typically blind to cell identity. Morphoelectrical properties of neurons measured on spatially dense electrode arrays have the potential to distinguish neuron types. We used high-density silicon probes to record from cortical and subcortical regions of the mouse brain. Extracellular waveforms of each neuron were detected across many channels and showed distinct spatiotemporal profiles among brain regions. Classification of neurons by brain region was improved with multichannel compared with single-channel waveforms. In visual cortex, unsupervised clustering identified the canonical regular-spiking (RS) and fast-spiking (FS) classes but also indicated a subclass of RS units with unidirectional backpropagating action potentials (BAPs). Moreover, BAPs were observed in many hippocampal RS cells. Overall, waveform analysis of spikes from high-density probes aids neuron identification and can reveal dendritic backpropagation. NEW & NOTEWORTHY It is challenging to identify neuron types with extracellular electrophysiology in vivo. We show that spatiotemporal action potentials measured on high-density electrode arrays can capture cell type-specific morphoelectrical properties, allowing classification of neurons across brain structures and within the cortex. Moreover, backpropagating action potentials are reliably detected in vivo from subpopulations of cortical and hippocampal neurons. Together, these results enhance the utility of dense extracellular electrophysiology for cell-type interrogation of brain network function.
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Affiliation(s)
- Xiaoxuan Jia
- Allen Institute for Brain Science , Seattle, Washington
| | | | | | - Samuel D Gale
- Allen Institute for Brain Science , Seattle, Washington
| | | | - Christof Koch
- Allen Institute for Brain Science , Seattle, Washington
| | - Shawn R Olsen
- Allen Institute for Brain Science , Seattle, Washington
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12
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Divakaruni SS, Van Dyke AM, Chandra R, LeGates TA, Contreras M, Dharmasri PA, Higgs HN, Lobo MK, Thompson SM, Blanpied TA. Long-Term Potentiation Requires a Rapid Burst of Dendritic Mitochondrial Fission during Induction. Neuron 2018; 100:860-875.e7. [PMID: 30318410 DOI: 10.1016/j.neuron.2018.09.025] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 08/09/2018] [Accepted: 09/14/2018] [Indexed: 12/22/2022]
Abstract
Synaptic transmission is bioenergetically demanding, and the diverse processes underlying synaptic plasticity elevate these demands. Therefore, mitochondrial functions, including ATP synthesis and Ca2+ handling, are likely essential for plasticity. Although axonal mitochondria have been extensively analyzed, LTP is predominantly induced postsynaptically, where mitochondria are understudied. Additionally, though mitochondrial fission is essential for their function, signaling pathways that regulate fission in neurons remain poorly understood. We found that NMDAR-dependent LTP induction prompted a rapid burst of dendritic mitochondrial fission and elevations of mitochondrial matrix Ca2+. The fission burst was triggered by cytosolic Ca2+ elevation and required CaMKII, actin, and Drp1, as well as dynamin 2. Preventing fission impaired mitochondrial matrix Ca2+ elevations, structural LTP in cultured neurons, and electrophysiological LTP in hippocampal slices. These data illustrate a novel pathway whereby synaptic activity controls mitochondrial fission and show that dynamic control of fission regulates plasticity induction, perhaps by modulating mitochondrial Ca2+ handling.
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Affiliation(s)
- Sai Sachin Divakaruni
- Medical Scientist Training Program, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Adam M Van Dyke
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Ramesh Chandra
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Tara A LeGates
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Minerva Contreras
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Poorna A Dharmasri
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Henry N Higgs
- Department of Biochemistry, Geisel School of Medicine at Dartmouth College, Hanover, NH 03755, USA
| | - Mary Kay Lobo
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Scott M Thompson
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Thomas A Blanpied
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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13
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Normann C, Frase S, Haug V, von Wolff G, Clark K, Münzer P, Dorner A, Scholliers J, Horn M, Vo Van T, Seifert G, Serchov T, Biber K, Nissen C, Klugbauer N, Bischofberger J. Antidepressants Rescue Stress-Induced Disruption of Synaptic Plasticity via Serotonin Transporter-Independent Inhibition of L-Type Calcium Channels. Biol Psychiatry 2018; 84:55-64. [PMID: 29174591 DOI: 10.1016/j.biopsych.2017.10.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 09/29/2017] [Accepted: 10/11/2017] [Indexed: 12/19/2022]
Abstract
BACKGROUND Long-term synaptic plasticity is a basic ability of the brain to dynamically adapt to external stimuli and regulate synaptic strength and ultimately network function. It is dysregulated by behavioral stress in animal models of depression and in humans with major depressive disorder. Antidepressants have been shown to restore disrupted synaptic plasticity in both animal models and humans; however, the underlying mechanism is unclear. METHODS We examined modulation of synaptic plasticity by selective serotonin reuptake inhibitors (SSRIs) in hippocampal brain slices from wild-type rats and serotonin transporter (SERT) knockout mice. Recombinant voltage-gated calcium (Ca2+) channels in heterologous expression systems were used to determine the modulation of Ca2+ channels by SSRIs. We tested the behavioral effects of SSRIs in the chronic behavioral despair model of depression both in the presence and in the absence of SERT. RESULTS SSRIs selectively inhibited hippocampal long-term depression. The inhibition of long-term depression by SSRIs was mediated by a direct block of voltage-activated L-type Ca2+ channels and was independent of SERT. Furthermore, SSRIs protected both wild-type and SERT knockout mice from behavioral despair induced by chronic stress. Finally, long-term depression was facilitated in animals subjected to the behavioral despair model, which was prevented by SSRI treatment. CONCLUSIONS These results showed that antidepressants protected synaptic plasticity and neuronal circuitry from the effects of stress via a modulation of Ca2+ channels and synaptic plasticity independent of SERT. Thus, L-type Ca2+ channels might constitute an important signaling hub for stress response and for pathophysiology and treatment of depression.
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Affiliation(s)
- Claus Normann
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany.
| | - Sibylle Frase
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Verena Haug
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Gregor von Wolff
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Kristin Clark
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Patrick Münzer
- Institute of Biology, University of Freiburg, Freiburg, Germany
| | - Alexandra Dorner
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Jonas Scholliers
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Max Horn
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Tanja Vo Van
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Gabriel Seifert
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Tsvetan Serchov
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Knut Biber
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Christoph Nissen
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Norbert Klugbauer
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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14
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Recent insights into antidepressant therapy: Distinct pathways and potential common mechanisms in the treatment of depressive syndromes. Neurosci Biobehav Rev 2018; 88:63-72. [DOI: 10.1016/j.neubiorev.2018.03.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 02/07/2018] [Accepted: 03/13/2018] [Indexed: 12/13/2022]
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15
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Medan V, Mäki-Marttunen T, Sztarker J, Preuss T. Differential processing in modality-specific Mauthner cell dendrites. J Physiol 2017; 596:667-689. [PMID: 29148564 DOI: 10.1113/jp274861] [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: 07/01/2017] [Accepted: 11/11/2017] [Indexed: 12/23/2022] Open
Abstract
KEY POINTS The present study examines dendritic integrative processes that occur in many central neurons but have been challenging to study in vivo in the vertebrate brain. The Mauthner cell of goldfish receives auditory and visual information via two separate dendrites, providing a privileged scenario for in vivo examination of dendritic integration. The results show differential attenuation properties in the Mauthner cell dendrites arising at least partly from differences in cable properties and the nonlinear behaviour of the respective dendritic membranes. In addition to distinct modality-dependent membrane specialization in neighbouring dendrites of the Mauthner cell, we report cross-modal dendritic interactions via backpropagating postsynaptic potentials. Broadly, the results of the present study provide an exceptional example for the processing power of single neurons. ABSTRACT Animals process multimodal information for adaptive behavioural decisions. In fish, evasion of a diving bird that breaks the water surface depends on integrating visual and auditory stimuli with very different characteristics. How do neurons process such differential sensory inputs at the dendritic level? For that, we studied the Mauthner cells (M-cells) in the goldfish startle circuit, which receive visual and auditory inputs via two separate dendrites, both accessible for in vivo recordings. We investigated whether electrophysiological membrane properties and dendrite morphology, studied in vivo, play a role in selective sensory processing in the M-cell. The results obtained show that anatomical and electrophysiological differences between the dendrites combine to produce stronger attenuation of visually evoked postsynaptic potentials (PSPs) than to auditory evoked PSPs. Interestingly, our recordings showed also cross-modal dendritic interaction because auditory evoked PSPs invade the ventral dendrite (VD), as well as the opposite where visual PSPs invade the lateral dendrite (LD). However, these interactions were asymmetrical, with auditory PSPs being more prominent in the VD than visual PSPs in the LD. Modelling experiments imply that this asymmetry is caused by active conductances expressed in the proximal segments of the VD. The results obtained in the present study suggest modality-dependent membrane specialization in M-cell dendrites suited for processing stimuli of different time domains and, more broadly, provide a compelling example of information processing in single neurons.
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Affiliation(s)
- Violeta Medan
- Department of Psychology, Hunter College, City University of New York, New York, NY, USA.,Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
| | - Tuomo Mäki-Marttunen
- Department of Signal Processing, Tampere University of Technology, Tampere, Finland.,Institute of Clinical Medicine, University of Oslo, OUS, Nydalen, Oslo, Norway.,Simula Research Laboratory, Lysaker, Norway
| | - Julieta Sztarker
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
| | - Thomas Preuss
- Department of Psychology, Hunter College, City University of New York, New York, NY, USA
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16
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Yang Z, Chen N, Ge R, Qian H, Wang JH. Functional compatibility between Purkinje cell axon branches and their target neurons in the cerebellum. Oncotarget 2017; 8:72424-72437. [PMID: 29069799 PMCID: PMC5641142 DOI: 10.18632/oncotarget.19770] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 06/28/2017] [Indexed: 01/10/2023] Open
Abstract
A neuron sprouts an axon, and its branches to innervate many target neurons that are divergent in their functions. In order to efficiently regulate the diversified cells, the axon branches should differentiate functionally to be compatible with their target neurons, i.e., a function compatibility between presynaptic and postsynaptic partners. We have examined this hypothesis by using electrophysiological method in the cerebellum, in which the main axon of Purkinje cell projected to deep nucleus cells and the recurrent axons innervated the adjacent Purkinje cells. The fidelity of spike propagation is superior in the recurrent branches than the main axon. The capabilities of encoding spikes and processing GABAergic inputs are advanced in Purkinje cells versus deep nucleus cells. The functional differences among Purkinje's axonal branches and their postsynaptic neurons are preset by the variable dynamics of their voltage-gated sodium channels. In addition, activity strengths between presynaptic and postsynaptic partners are proportionally correlated, i.e., active axonal branches innervate active target neurons, or vice versa. The physiological impact of the functional compatibility is to make the neurons in their circuits to be activated appropriately. In conclusion, each cerebellar Purkinje cell sprouts the differentiated axon branches to be compatible with the diversified target cells in their functions, in order to construct the homeostatic and efficient units for their coordinated activity in neural circuits.
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Affiliation(s)
- Zhilai Yang
- Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,Department of Anesthesiology, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, China
| | - Na Chen
- Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Rongjing Ge
- Department of Physiology, Bengbu Medical College, Bengbu 233000, China
| | - Hao Qian
- Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Jin-Hui Wang
- Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China.,Qingdao University, School of Pharmacy, Shandong 266021, China.,Department of Physiology, Bengbu Medical College, Bengbu 233000, China
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17
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Neural plasticity and network remodeling: From concepts to pathology. Neuroscience 2017; 344:326-345. [PMID: 28069532 DOI: 10.1016/j.neuroscience.2016.12.048] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/24/2016] [Accepted: 12/27/2016] [Indexed: 11/22/2022]
Abstract
Neuroplasticity has been subject to a great deal of research in the last century. Recently, significant emphasis has been placed on the global effect of localized plastic changes throughout the central nervous system, and on how these changes integrate in a pathological context. Specifically, alterations of network functionality have been described in various pathological contexts to which corresponding structural alterations have been proposed. However, considering the amount of literature and the different pathological contexts, an integration of this information is still lacking. In this paper we will review the concepts of neural plasticity as well as their repercussions on network remodeling and provide a possible explanation to how these two concepts relate to each other. We will further examine how alterations in different pathological contexts may relate to each other and will discuss the concept of plasticity diseases, its models and implications.
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18
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Garrido JA, Luque NR, Tolu S, D’Angelo E. Oscillation-Driven Spike-Timing Dependent Plasticity Allows Multiple Overlapping Pattern Recognition in Inhibitory Interneuron Networks. Int J Neural Syst 2016; 26:1650020. [DOI: 10.1142/s0129065716500209] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The majority of operations carried out by the brain require learning complex signal patterns for future recognition, retrieval and reuse. Although learning is thought to depend on multiple forms of long-term synaptic plasticity, the way this latter contributes to pattern recognition is still poorly understood. Here, we have used a simple model of afferent excitatory neurons and interneurons with lateral inhibition, reproducing a network topology found in many brain areas from the cerebellum to cortical columns. When endowed with spike-timing dependent plasticity (STDP) at the excitatory input synapses and at the inhibitory interneuron–interneuron synapses, the interneurons rapidly learned complex input patterns. Interestingly, induction of plasticity required that the network be entrained into theta-frequency band oscillations, setting the internal phase-reference required to drive STDP. Inhibitory plasticity effectively distributed multiple patterns among available interneurons, thus allowing the simultaneous detection of multiple overlapping patterns. The addition of plasticity in intrinsic excitability made the system more robust allowing self-adjustment and rescaling in response to a broad range of input patterns. The combination of plasticity in lateral inhibitory connections and homeostatic mechanisms in the inhibitory interneurons optimized mutual information (MI) transfer. The storage of multiple complex patterns in plastic interneuron networks could be critical for the generation of sparse representations of information in excitatory neuron populations falling under their control.
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Affiliation(s)
- Jesús A. Garrido
- Department of Computer Architecture and Technology, University of Granada, Periodista Daniel Saucedo Aranda s/n, Granada, 18071, Spain
| | - Niceto R. Luque
- Institut National de la Santé et de la Recherche Médicale, U968 and Centre National de la Recherche Scientifique, UMR_7210, Institut de la Vision, rue Moreau, 17, Paris, F75012, France
- Sorbonne Universités, Université Pierre et Marie Curie Paris 06, UMR_S 968, Place Jussieu, 4, Paris, F75252, France
| | - Silvia Tolu
- Center for Playware, Department of Electrical Engineering, Technical University of Denmark, Richard Petersens Plads, Elektrovej, Building 326, Lyngby, Copenhagen, 2800, Denmark
| | - Egidio D’Angelo
- Department of Brain and Behavioral Sciences, University of Pavia, Via Forlanini, 6, Pavia, I27100, Italy
- Brain Connectivity Center, Istituto Neurologico IRCCS Fondazione Casimiro Mondino, Via Mondino, 2 Pavia, I27100, Italy
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19
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Sweatt JD. Neural plasticity and behavior - sixty years of conceptual advances. J Neurochem 2016; 139 Suppl 2:179-199. [PMID: 26875778 DOI: 10.1111/jnc.13580] [Citation(s) in RCA: 187] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 01/19/2016] [Accepted: 02/09/2016] [Indexed: 02/06/2023]
Abstract
This brief review summarizes 60 years of conceptual advances that have demonstrated a role for active changes in neuronal connectivity as a controller of behavior and behavioral change. Seminal studies in the first phase of the six-decade span of this review firmly established the cellular basis of behavior - a concept that we take for granted now, but which was an open question at the time. Hebbian plasticity, including long-term potentiation and long-term depression, was then discovered as being important for local circuit refinement in the context of memory formation and behavioral change and stabilization in the mammalian central nervous system. Direct demonstration of plasticity of neuronal circuit function in vivo, for example, hippocampal neurons forming place cell firing patterns, extended this concept. However, additional neurophysiologic and computational studies demonstrated that circuit development and stabilization additionally relies on non-Hebbian, homoeostatic, forms of plasticity, such as synaptic scaling and control of membrane intrinsic properties. Activity-dependent neurodevelopment was found to be associated with cell-wide adjustments in post-synaptic receptor density, and found to occur in conjunction with synaptic pruning. Pioneering cellular neurophysiologic studies demonstrated the critical roles of transmembrane signal transduction, NMDA receptor regulation, regulation of neural membrane biophysical properties, and back-propagating action potential in critical time-dependent coincidence detection in behavior-modifying circuits. Concerning the molecular mechanisms underlying these processes, regulation of gene transcription was found to serve as a bridge between experience and behavioral change, closing the 'nature versus nurture' divide. Both active DNA (de)methylation and regulation of chromatin structure have been validated as crucial regulators of gene transcription during learning. The discovery of protein synthesis dependence on the acquisition of behavioral change was an influential discovery in the neurochemistry of behavioral modification. Higher order cognitive functions such as decision making and spatial and language learning were also discovered to hinge on neural plasticity mechanisms. The role of disruption of these processes in intellectual disabilities, memory disorders, and drug addiction has recently been clarified based on modern genetic techniques, including in the human. The area of neural plasticity and behavior has seen tremendous advances over the last six decades, with many of those advances being specifically in the neurochemistry domain. This review provides an overview of the progress in the area of neuroplasticity and behavior over the life-span of the Journal of Neurochemistry. To organize the broad literature base, the review collates progress into fifteen broad categories identified as 'conceptual advances', as viewed by the author. The fifteen areas are delineated in the figure above. This article is part of the 60th Anniversary special issue.
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Affiliation(s)
- J David Sweatt
- Department of Neurobiology, Evelyn F. McKnight Brain Institute and Civitan International Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA.
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20
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Kneussel M, Hausrat TJ. Postsynaptic Neurotransmitter Receptor Reserve Pools for Synaptic Potentiation. Trends Neurosci 2016; 39:170-182. [PMID: 26833258 DOI: 10.1016/j.tins.2016.01.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 01/06/2016] [Accepted: 01/07/2016] [Indexed: 11/18/2022]
Abstract
At excitatory and inhibitory synapses, an immediate transfer of additional neurotransmitter receptors from non-synaptic positions to the synapse mediates synaptic long-term potentiation (LTP). Different types of non-synaptic reserve pools permit the rapid supply of transmembrane neurotransmitter receptors. Recycling endosomes (REs) serve as an intracellular reservoir of receptors that is delivered to the plasma membrane on LTP induction. Furthermore, AMPA receptors at the non-synaptic plasma membrane provide an extrasynaptic reserve pool that is also important to potentiate synapse function. Finally, bidirectional synaptic versus extrasynaptic trapping of freely diffusing plasma membrane GABAA receptors (GABAARs) by scaffolding proteins modulates synaptic transmission. Here we discuss novel findings regarding neurotransmitter receptor reservoirs and potential reserve pool mechanisms for synaptic potentiation.
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Affiliation(s)
- Matthias Kneussel
- Department of Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251 Hamburg, Germany.
| | - Torben Johann Hausrat
- Department of Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251 Hamburg, Germany
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21
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Mapelli L, Pagani M, Garrido JA, D'Angelo E. Integrated plasticity at inhibitory and excitatory synapses in the cerebellar circuit. Front Cell Neurosci 2015; 9:169. [PMID: 25999817 PMCID: PMC4419603 DOI: 10.3389/fncel.2015.00169] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 04/16/2015] [Indexed: 12/25/2022] Open
Abstract
The way long-term potentiation (LTP) and depression (LTD) are integrated within the different synapses of brain neuronal circuits is poorly understood. In order to progress beyond the identification of specific molecular mechanisms, a system in which multiple forms of plasticity can be correlated with large-scale neural processing is required. In this paper we take as an example the cerebellar network, in which extensive investigations have revealed LTP and LTD at several excitatory and inhibitory synapses. Cerebellar LTP and LTD occur in all three main cerebellar subcircuits (granular layer, molecular layer, deep cerebellar nuclei) and correspondingly regulate the function of their three main neurons: granule cells (GrCs), Purkinje cells (PCs) and deep cerebellar nuclear (DCN) cells. All these neurons, in addition to be excited, are reached by feed-forward and feed-back inhibitory connections, in which LTP and LTD may either operate synergistically or homeostatically in order to control information flow through the circuit. Although the investigation of individual synaptic plasticities in vitro is essential to prove their existence and mechanisms, it is insufficient to generate a coherent view of their impact on network functioning in vivo. Recent computational models and cell-specific genetic mutations in mice are shedding light on how plasticity at multiple excitatory and inhibitory synapses might regulate neuronal activities in the cerebellar circuit and contribute to learning and memory and behavioral control.
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Affiliation(s)
- Lisa Mapelli
- Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy ; Museo Storico Della Fisica e Centro Studi e Ricerche Enrico Fermi Rome, Italy
| | - Martina Pagani
- Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy ; Institute of Pharmacology and Toxicology, University of Zurich Zurich, Switzerland
| | - Jesus A Garrido
- Brain Connectivity Center, C. Mondino National Neurological Institute Pavia, Italy ; Department of Computer Architecture and Technology, University of Granada Granada, Spain
| | - Egidio D'Angelo
- Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy ; Brain Connectivity Center, C. Mondino National Neurological Institute Pavia, Italy
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22
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Wójtowicz T, Mozrzymas JW. Diverse impact of neuronal activity at θ frequency on hippocampal long-term plasticity. J Neurosci Res 2015; 93:1330-44. [PMID: 25789967 DOI: 10.1002/jnr.23581] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/05/2015] [Accepted: 02/10/2015] [Indexed: 12/29/2022]
Abstract
Brain oscillatory activity is considered an essential aspect of brain function, and its frequency can vary from <1 Hz to >200 Hz, depending on the brain states and projection. Episodes of rhythmic activity accompany hippocampus-dependent learning and memory in vivo. Therefore, long-term synaptic potentiation (LTP) and long-term depression, which are considered viable substrates of learning and memory, are often experimentally studied in paradigms of patterned high-frequency (>50 Hz) and low-frequency (<5 Hz) stimulation. However, the impact of intermediate frequencies on neuronal plasticity remains less well understood. In particular, hippocampal neurons are specifically tuned for activity at θ frequency (4-8 Hz); this band contributes significantly to electroencephalographic signals, and it is likely to be involved in shaping synaptic strength in hippocampal circuits. Here, we review in vitro and in vivo studies showing that variation of θ-activity duration may affect long-term modification of synaptic strength and neuronal excitability in the hippocampus. Such θ-pulse-induced neuronal plasticity 1) is long-lasting, 2) may be built on previously stabilized potentiation in the synapse, 3) may produce opposite changes in synaptic strength, and 4) requires complex molecular machinery. Apparently innocuous episodes of low-frequency synaptic activity may have a profound impact on network signaling, thereby contributing to information processing in the hippocampus and beyond. In addition, θ-pulse-induced LTP might be an advantageous protocol in studies of specific molecular mechanisms of synaptic plasticity.
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Affiliation(s)
- Tomasz Wójtowicz
- Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University, Wroclaw, Poland
| | - Jerzy W Mozrzymas
- Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University, Wroclaw, Poland
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23
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Flores CE, Méndez P. Shaping inhibition: activity dependent structural plasticity of GABAergic synapses. Front Cell Neurosci 2014; 8:327. [PMID: 25386117 PMCID: PMC4209871 DOI: 10.3389/fncel.2014.00327] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 09/28/2014] [Indexed: 11/22/2022] Open
Abstract
Inhibitory transmission through the neurotransmitter γ-aminobutyric acid (GABA) shapes network activity in the mammalian cerebral cortex by filtering synaptic incoming information and dictating the activity of principal cells. The incredibly diverse population of cortical neurons that use GABA as neurotransmitter shows an equally diverse range of mechanisms that regulate changes in the strength of GABAergic synaptic transmission and allow them to dynamically follow and command the activity of neuronal ensembles. Similarly to glutamatergic synaptic transmission, activity-dependent functional changes in inhibitory neurotransmission are accompanied by alterations in GABAergic synapse structure that range from morphological reorganization of postsynaptic density to de novo formation and elimination of inhibitory contacts. Here we review several aspects of structural plasticity of inhibitory synapses, including its induction by different forms of neuronal activity, behavioral and sensory experience and the molecular mechanisms and signaling pathways involved. We discuss the functional consequences of GABAergic synapse structural plasticity for information processing and memory formation in view of the heterogenous nature of the structural plasticity phenomena affecting inhibitory synapses impinging on somatic and dendritic compartments of cortical and hippocampal neurons.
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Affiliation(s)
- Carmen E Flores
- Department of Basic Neuroscience, Geneva Medical Center, University of Geneva Geneva, Switzerland
| | - Pablo Méndez
- Department of Basic Neuroscience, Geneva Medical Center, University of Geneva Geneva, Switzerland
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24
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Memory trace and timing mechanism localized to cerebellar Purkinje cells. Proc Natl Acad Sci U S A 2014; 111:14930-4. [PMID: 25267641 DOI: 10.1073/pnas.1415371111] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The standard view of the mechanisms underlying learning is that they involve strengthening or weakening synaptic connections. Learned response timing is thought to combine such plasticity with temporally patterned inputs to the neuron. We show here that a cerebellar Purkinje cell in a ferret can learn to respond to a specific input with a temporal pattern of activity consisting of temporally specific increases and decreases in firing over hundreds of milliseconds without a temporally patterned input. Training Purkinje cells with direct stimulation of immediate afferents, the parallel fibers, and pharmacological blocking of interneurons shows that the timing mechanism is intrinsic to the cell itself. Purkinje cells can learn to respond not only with increased or decreased firing but also with an adaptively timed activity pattern.
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25
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Zhang C, Li S, Sun Y, Dong W, Piao F, Piao Y, liu S, Guan H, Yu S. Arsenic downregulates gene expression at the postsynaptic density in mouse cerebellum, including genes responsible for long-term potentiation and depression. Toxicol Lett 2014; 228:260-9. [DOI: 10.1016/j.toxlet.2014.05.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 04/23/2014] [Accepted: 05/02/2014] [Indexed: 01/25/2023]
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26
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He W, Huang K, Ning N, Ramanathan K, Li G, Jiang Y, Sze J, Shi L, Zhao R, Pei J. Enabling an integrated rate-temporal learning scheme on memristor. Sci Rep 2014; 4:4755. [PMID: 24755608 PMCID: PMC3996481 DOI: 10.1038/srep04755] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 04/02/2014] [Indexed: 11/18/2022] Open
Abstract
Learning scheme is the key to the utilization of spike-based computation and the emulation of neural/synaptic behaviors toward realization of cognition. The biological observations reveal an integrated spike time- and spike rate-dependent plasticity as a function of presynaptic firing frequency. However, this integrated rate-temporal learning scheme has not been realized on any nano devices. In this paper, such scheme is successfully demonstrated on a memristor. Great robustness against the spiking rate fluctuation is achieved by waveform engineering with the aid of good analog properties exhibited by the iron oxide-based memristor. The spike-time-dependence plasticity (STDP) occurs at moderate presynaptic firing frequencies and spike-rate-dependence plasticity (SRDP) dominates other regions. This demonstration provides a novel approach in neural coding implementation, which facilitates the development of bio-inspired computing systems.
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Affiliation(s)
- Wei He
- Data Storage Institute, Agency for Science, Technology and Research (A*STAR), 5 Engineering Drive 1, Singapore 117608
- These authors contributed equally to this work
| | - Kejie Huang
- Singapore University of Technology & Design, 20 Dover Drive, Singapore 138682
- These authors contributed equally to this work
| | - Ning Ning
- Data Storage Institute, Agency for Science, Technology and Research (A*STAR), 5 Engineering Drive 1, Singapore 117608
| | - Kiruthika Ramanathan
- Data Storage Institute, Agency for Science, Technology and Research (A*STAR), 5 Engineering Drive 1, Singapore 117608
| | - Guoqi Li
- Optical Memory National Engineering Research Center, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Yu Jiang
- Data Storage Institute, Agency for Science, Technology and Research (A*STAR), 5 Engineering Drive 1, Singapore 117608
| | - JiaYin Sze
- Data Storage Institute, Agency for Science, Technology and Research (A*STAR), 5 Engineering Drive 1, Singapore 117608
| | - Luping Shi
- Optical Memory National Engineering Research Center, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Rong Zhao
- Singapore University of Technology & Design, 20 Dover Drive, Singapore 138682
| | - Jing Pei
- Optical Memory National Engineering Research Center, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
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27
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Lee J, Favorov OV, Tommerdahl M, Lee CJ, Whitsel BL. Attenuated Glial K(+) Clearance Contributes to Long-Term Synaptic Potentiation Via Depolarizing GABA in Dorsal Horn Neurons of Rat Spinal Cord. Exp Neurobiol 2014; 23:53-64. [PMID: 24737940 PMCID: PMC3984957 DOI: 10.5607/en.2014.23.1.53] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 03/05/2014] [Accepted: 03/05/2014] [Indexed: 11/19/2022] Open
Abstract
It has been reported that long-term enhancement of superficial dorsal horn (DHs) excitatory synaptic transmission underlies central sensitization, secondary hyperalgesia, and persistent pain. We tested whether impaired clearance of K(+) and glutamate by glia in DHs may contribute to initiation and maintenance of the CNS pain circuit and sensorimotor abnormalities. Transient exposure of the spinal cord slice to fluorocitrate (FC) is shown to be accompanied by a protracted decrease of the DHs optical response to repetitive electrical stimulation of the ipsilateral dorsal root, and by a similarly protracted increase in the postsynaptic response of the DHs like LTP. It also is shown that LTPFC does not occur in the presence of APV, and becomes progressively smaller as [K(+)]o in the perfusion solution decreased from 3.0 mM to 0.0 mM. Interestingly LTPFC is reduced by bath application of Bic. Whole-cell patch recordings were carried out to evaluate the effects of FC on the response of DHs neurons to puffer-applied GABA. The observations reveal that transient exposure to FC is reliably accompanied by a prolonged (>1 hr) depolarizing shift of the equilibrium potential for the DHs neuron transmembrane ionic currents evoked by GABA. Considered collectively, the findings demonstrate that LTPFC involves (1) elevation of [K(+)]o in the DHs, (2) NMDAR activation, and (3) conversion of the effect of GABA on DHs neurons from inhibition to excitation. It is proposed that a transient impairment of astrocyte energy production can trigger the cascade of dorsal horn mechanisms that underlies hyperalgesia and persistent pain.
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Affiliation(s)
- Jaekwang Lee
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. ; WCI Center for Functional Connectomics, Institute of Science and Technology (KIST), Seoul, Korea
| | - Oleg V Favorov
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Mark Tommerdahl
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - C Justin Lee
- WCI Center for Functional Connectomics, Institute of Science and Technology (KIST), Seoul, Korea. ; KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Korea
| | - Barry L Whitsel
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. ; Department of Cell and Molecular Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Bratby P, Montgomery J, Sneyd J. A biophysical model of adaptive noise filtering in the shark brain. Bull Math Biol 2014; 76:455-75. [PMID: 24402471 DOI: 10.1007/s11538-013-9928-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Accepted: 12/10/2013] [Indexed: 10/25/2022]
Abstract
Sharks detect their prey using an extremely sensitive electrosensory system that is capable of distinguishing weak external stimuli from a relatively strong background noise generated by the animal itself. Experiments indicate that part of the shark's hindbrain, the dorsal octavolateralis nucleus (DON), is responsible for extracting the external stimulus using an adaptive filter mechanism to suppress signals correlated with the shark's breathing motion. The DON's principal neuron integrates input from afferents as well as many thousands of parallel fibres transmitting, inter alia, breathing-correlated motor command signals. There are a number of models in the literature, studying how this adaptive filtering mechanisms occurs, but most of them are based on a spike-train model approach.This paper presents a biophysically based computational simulation which demonstrates a mechanism for adaptive noise filtering in the DON. A spatial model of the neuron uses the Hodgkin-Huxley equations to simulate the propagation of action potentials along the dendrites. Synaptic inputs are modelled by applied currents at various positions along the dendrites, whose input conductances are varied according to a simple learning rule.Simulation results show that the model is able to demonstrate adaptive filtering in agreement with previous experimental and modelling studies. Furthermore, the spatial nature of the model does not greatly affect its learning properties, and in its present form is effectively equivalent to an isopotential model which does not incorporate a spatial element.
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Affiliation(s)
- Peter Bratby
- Department of Mathematics, University of Auckland, Auckland, New Zealand,
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Hesslow G, Jirenhed DA, Rasmussen A, Johansson F. Classical conditioning of motor responses: What is the learning mechanism? Neural Netw 2013; 47:81-7. [DOI: 10.1016/j.neunet.2013.03.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 03/20/2013] [Accepted: 03/20/2013] [Indexed: 10/27/2022]
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Piochon C, Kruskal P, Maclean J, Hansel C. Non-Hebbian spike-timing-dependent plasticity in cerebellar circuits. Front Neural Circuits 2013; 6:124. [PMID: 23335888 PMCID: PMC3542521 DOI: 10.3389/fncir.2012.00124] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 12/26/2012] [Indexed: 11/16/2022] Open
Abstract
Spike-timing-dependent plasticity (STDP) provides a cellular implementation of the Hebb postulate, which states that synapses, whose activity repeatedly drives action potential firing in target cells, are potentiated. At glutamatergic synapses onto hippocampal and neocortical pyramidal cells, synaptic activation followed by spike firing in the target cell causes long-term potentiation (LTP)—as predicted by Hebb—whereas excitatory postsynaptic potentials (EPSPs) evoked after a spike elicit long-term depression (LTD)—a phenomenon that was not specifically addressed by Hebb. In both instances the action potential in the postsynaptic target neuron is an instructive signal that is capable of supporting synaptic plasticity. STDP generally relies on the propagation of Na+ action potentials that are initiated in the axon hillhock back into the dendrite, where they cause depolarization and boost local calcium influx. However, recent studies in CA1 hippocampal pyramidal neurons have suggested that local calcium spikes might provide a more efficient trigger for LTP induction than backpropagating action potentials. Dendritic calcium spikes also play a role in an entirely different type of STDP that can be observed in cerebellar Purkinje cells. These neurons lack backpropagating Na+ spikes. Instead, plasticity at parallel fiber (PF) to Purkinje cell synapses depends on the relative timing of PF-EPSPs and activation of the glutamatergic climbing fiber (CF) input that causes dendritic calcium spikes. Thus, the instructive signal in this system is externalized. Importantly when EPSPs are elicited before CF activity, PF-LTD is induced rather than LTP. Thus, STDP in the cerebellum follows a timing rule that is opposite to its hippocampal/neocortical counterparts. Regardless, a common motif in plasticity is that LTD/LTP induction depends on the relative timing of synaptic activity and regenerative dendritic spikes which are driven by the instructive signal.
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Affiliation(s)
- Claire Piochon
- Department of Neurobiology, University of Chicago Chicago, IL, USA
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Hu Y, Zhou J, Fang L, Liu H, Zhan Q, Luo D, Zhou C, Chen J, Li Q, Xie P. Hippocampal synaptic dysregulation of exo/endocytosis-associated proteins induced in a chronic mild-stressed rat model. Neuroscience 2013; 230:1-12. [DOI: 10.1016/j.neuroscience.2012.08.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 08/04/2012] [Accepted: 08/14/2012] [Indexed: 10/28/2022]
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Bunday KL, Perez MA. Motor recovery after spinal cord injury enhanced by strengthening corticospinal synaptic transmission. Curr Biol 2012. [PMID: 23200989 DOI: 10.1016/j.cub.2012.10.046] [Citation(s) in RCA: 152] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The corticospinal tract is an important target for motor recovery after spinal cord injury (SCI) in animals and humans. Voluntary motor output depends on the efficacy of synapses between corticospinal axons and spinal motoneurons, which can be modulated by the precise timing of neuronal spikes. Using noninvasive techniques, we developed tailored protocols for precise timing of the arrival of descending and peripheral volleys at corticospinal-motoneuronal synapses of an intrinsic finger muscle in humans with chronic incomplete SCI. We found that arrival of presynaptic volleys prior to motoneuron discharge enhanced corticospinal transmission and hand voluntary motor output. The reverse order of volley arrival and sham stimulation did not affect or decreased voluntary motor output and electrophysiological outcomes. These findings are the first demonstration that spike timing-dependent plasticity of residual corticospinal-motoneuronal synapses provides a mechanism to improve motor function after SCI. Modulation of residual corticospinal-motoneuronal synapses may present a novel therapeutic target for enhancing voluntary motor output in motor disorders affecting the corticospinal tract.
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Affiliation(s)
- Karen L Bunday
- Department of Physical Medicine and Rehabilitation, Center for the Neural Basis of Cognition, and Systems Neuroscience Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
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Villamar MF, Santos Portilla A, Fregni F, Zafonte R. Noninvasive brain stimulation to modulate neuroplasticity in traumatic brain injury. Neuromodulation 2012; 15:326-38. [PMID: 22882244 DOI: 10.1111/j.1525-1403.2012.00474.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
OBJECTIVE To review the use of noninvasive brain stimulation (NBS) as a therapeutic tool to enhance neuroplasticity following traumatic brain injury (TBI). MATERIALS AND METHODS Based on a literature search, we describe the pathophysiological events following TBI and the rationale for the use of transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) in this setting. RESULTS The pathophysiological mechanisms occurring after TBI vary across time and therefore require differential interventions. Theoretically, given the neurophysiological effects of both TMS and tDCS, these tools may: 1) decrease cortical hyperexcitability acutely after TBI; 2) modulate long-term synaptic plasticity as to avoid maladaptive consequences; and 3) combined with physical and behavioral therapy, facilitate cortical reorganization and consolidation of learning in specific neural networks. All of these interventions may help decrease the burden of disabling sequelae after brain injury. CONCLUSIONS Evidence from animal and human studies reveals the potential benefit of NBS in decreasing the extent of injury and enhancing plastic changes to facilitate learning and recovery of function in lesioned neural tissue. However, this evidence is mainly theoretical at this point. Given safety constraints, studies in TBI patients are necessary to address the role of NBS in this condition as well as to further elucidate its therapeutic effects and define optimal stimulation parameters.
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Affiliation(s)
- Mauricio Fernando Villamar
- Laboratory of Neuromodulation, Department of Physical Medicine & Rehabilitation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
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Zhao C, Wang L, Netoff T, Yuan LL. Dendritic mechanisms controlling the threshold and timing requirement of synaptic plasticity. Hippocampus 2012; 21:288-97. [PMID: 20087888 DOI: 10.1002/hipo.20748] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Active conductances located and operating on neuronal dendrites are expected to regulate synaptic integration and plasticity. We investigate how Kv4.2-mediated A-type K(+) channels and Ca(2+) -activated K(+) channels are involved in the induction process of Hebbian-type plasticity that requires correlated pre- and postsynaptic activities. In CA1 pyramidal neurons, robust long-term potentiation (LTP) induced by a theta burst pairing protocol usually occurred within a narrow window during which incoming synaptic potentials coincided with postsynaptic depolarization. Elimination of dendritic A-type K(+) currents in Kv4.2(-/-) mice, however, resulted in an expanded time window, making the induction of synaptic potentiation less dependent on the temporal relation of pre- and postsynaptic activity. For the other type of synaptic plasticity, long-term depression, the threshold was significantly increased in Kv4.2(-/-) mice. This shift in depression threshold was restored to normal when the appropriate amount of internal free calcium was chelated during induction. In concert with A-type channels, Ca(2+) -activated K(+) channels also exerted a sliding effect on synaptic plasticity. Blocking these channels in Kv4.2(-/-) mice resulted in an even larger potentiation while by contrast, the depression threshold was shifted further. In conclusion, dendritic A-type and Ca(2+) -activated K(+) channels dually regulate the timing-dependence and thresholds of synaptic plasticity in an additive way.
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Affiliation(s)
- Cuiping Zhao
- Department of Neuroscience, University of Minnesota, Minneapolis, USA
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Malik R, Chattarji S. Enhanced intrinsic excitability and EPSP-spike coupling accompany enriched environment-induced facilitation of LTP in hippocampal CA1 pyramidal neurons. J Neurophysiol 2012; 107:1366-78. [DOI: 10.1152/jn.01009.2011] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Environmental enrichment (EE) is a well-established paradigm for studying naturally occurring changes in synaptic efficacy in the hippocampus that underlie experience-induced modulation of learning and memory in rodents. Earlier research on the effects of EE on hippocampal plasticity focused on long-term potentiation (LTP). Whereas many of these studies investigated changes in synaptic weight, little is known about potential contributions of neuronal excitability to EE-induced plasticity. Here, using whole-cell recordings in hippocampal slices, we address this gap by analyzing the impact of EE on both synaptic plasticity and intrinsic excitability of hippocampal CA1 pyramidal neurons. Consistent with earlier reports, EE increased contextual fear memory and dendritic spine density on CA1 cells. Furthermore, EE facilitated LTP at Schaffer collateral inputs to CA1 pyramidal neurons. Analysis of the underlying causes for enhanced LTP shows EE to increase the frequency but not amplitude of miniature excitatory postsynaptic currents. However, presynaptic release probability, assayed using paired-pulse ratios and use-dependent block of N-methyl-d-aspartate receptor currents, was not affected. Furthermore, CA1 neurons fired more action potentials (APs) in response to somatic depolarization, as well as during the induction of LTP. EE also reduced spiking threshold and after-hyperpolarization amplitude. Strikingly, this EE-induced increase in excitability caused the same-sized excitatory postsynaptic potential to fire more APs. Together, these findings suggest that EE may enhance the capacity for plasticity in CA1 neurons, not only by strengthening synapses but also by enhancing their efficacy to fire spikes—and the two combine to act as an effective substrate for amplifying LTP.
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Affiliation(s)
- Ruchi Malik
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Sumantra Chattarji
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
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Kawato M, Kuroda S, Schweighofer N. Cerebellar supervised learning revisited: biophysical modeling and degrees-of-freedom control. Curr Opin Neurobiol 2011; 21:791-800. [PMID: 21665461 DOI: 10.1016/j.conb.2011.05.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 05/19/2011] [Accepted: 05/20/2011] [Indexed: 11/18/2022]
Abstract
The biophysical models of spike-timing-dependent plasticity have explored dynamics with molecular basis for such computational concepts as coincidence detection, synaptic eligibility trace, and Hebbian learning. They overall support different learning algorithms in different brain areas, especially supervised learning in the cerebellum. Because a single spine is physically very small, chemical reactions at it are essentially stochastic, and thus sensitivity-longevity dilemma exists in the synaptic memory. Here, the cascade of excitable and bistable dynamics is proposed to overcome this difficulty. All kinds of learning algorithms in different brain regions confront with difficult generalization problems. For resolution of this issue, the control of the degrees-of-freedom can be realized by changing synchronicity of neural firing. Especially, for cerebellar supervised learning, the triangle closed-loop circuit consisting of Purkinje cells, the inferior olive nucleus, and the cerebellar nucleus is proposed as a circuit to optimally control synchronous firing and degrees-of-freedom in learning.
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Affiliation(s)
- Mitsuo Kawato
- ATR Computational Neuroscience Laboratories, 2-2-2 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-0288, Japan.
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37
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Tsanov M, Wright N, Vann SD, Erichsen JT, Aggleton JP, O'Mara SM. Hippocampal inputs mediate theta-related plasticity in anterior thalamus. Neuroscience 2011; 187:52-62. [PMID: 21459129 DOI: 10.1016/j.neuroscience.2011.03.055] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 03/24/2011] [Accepted: 03/24/2011] [Indexed: 10/18/2022]
Abstract
Hippocampally-driven oscillatory activity at theta frequency is found in the diencephalon, but an understanding of the fundamental role of theta in the hippocampo-diencephalic circuit remains elusive. An important strategy in determining how activity modifies oscillatory properties of hippocampo-diencephalic circuitry comprises investigations of anterior thalamic responses to their main inputs: the descending dorsal fornix and the ascending mammillothalamic tract. Here, we show that the amplitude of thalamic theta spectral power selectively increases after plasticity-inducing stimulation of the dorsal fornix, but not of the mammillothalamic tract in urethane-anaesthetized young male rats. Furthermore, we show that low-frequency stimulation (LFS) significantly augments the fornix-driven theta ratio (theta over delta power, T-ratio), in parallel with depressing thalamic synaptic responses. However, the mammillothalamic synaptic response after LFS did not correlate with the slow band of theta oscillation (low T-ratio), but did correlate positively with the fast band of theta oscillation (high T-ratio). Our data demonstrate that the descending direct fornix projection is a pathway that modulates theta rhythm in the hippocampo-diencephalic circuit, resulting in dynamic augmentation of thalamic neuronal responsiveness. These findings suggest that hippocampal theta differentially affects synaptic integration in the different structures with which the hippocampus is reciprocally connected.
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Affiliation(s)
- M Tsanov
- Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland; School of Psychology, Trinity College Dublin, Ireland
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38
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Zhang Y, Shi Z, Magnus G, Meek J, Han VZ, Qiao JT. Functional circuitry of a unique cerebellar specialization: the valvula cerebelli of a mormyrid fish. Neuroscience 2011; 182:11-31. [PMID: 21414387 DOI: 10.1016/j.neuroscience.2011.03.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 03/06/2011] [Accepted: 03/08/2011] [Indexed: 10/18/2022]
Abstract
The valvula cerebelli of the mormyrid electric fish is a useful site for the study of cerebellar function. The valvula forms a part of the electrosensory-electromotor system of this fish, a system that offers many possibilities for the study of sensory-motor integration. The valvula also has a number of histological features not present in mammals which facilitate investigation of cerebellar circuitry and its plasticity. This initial study characterizes the basic physiology and pharmacology of cells in the valvula using an in vitro slice preparation. Intrinsic properties and synaptic responses of Purkinje cells and other cell types were examined. We found that Purkinje cells fire a small narrow Na(+) spike and a large broad Ca(2+) spike, generated in the axon initial segment and dendritic-soma region, respectively. Purkinje cells respond to parallel fiber inputs with graded excitatory postsynaptic potentials (EPSPs) and to climbing fiber inputs with all-or-none EPSPs. Efferent cells, Golgi cells, and deep stellate cells all fire a single type of large narrow spike and respond only to parallel fiber inputs. Both parallel fiber and climbing fiber responses in Purkinje cells appear to be entirely mediated by AMPA-type glutamate receptors, whereas parallel fiber responses in efferent cells and stellate cells include AMPA and NMDA components. In addition, a strong synaptic inhibition was uncovered in both Purkinje cells and efferent cells in response to the focal stimulation of parallel fibers. Dual cell recordings indicate that deep stellate cells contribute at least partially to this inhibition. We conclude that despite its unique histology, the local functional circuitry of the mormyrid valvula cerebelli is largely similar to that of the mammalian cerebellum. Thus, what is learned concerning the functioning of the mormyrid valvula cerebelli may be expected to be informative about cerebellar function in general.
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Affiliation(s)
- Y Zhang
- Department of Pediatrics and Neurosciences, Xijing Hospital, the Fourth Military Medical University, Xi'an, Shaanxi, PR China
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Synaptic plasticity and addiction: learning mechanisms gone awry. Neuropharmacology 2011; 61:1052-9. [PMID: 21277315 DOI: 10.1016/j.neuropharm.2011.01.036] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 01/18/2011] [Accepted: 01/19/2011] [Indexed: 01/21/2023]
Abstract
Experience-dependent changes in synaptic strength, or synaptic plasticity, may underlie many learning processes. In the reward circuit for example, synaptic plasticity may serve as a cellular substrate for goal-directed behaviors. Addictive drugs, through a surge of dopamine released from neurons of the ventral tegmental area, induce widespread synaptic adaptations within this neuronal circuit. Such drug-evoked synaptic plasticity may constitute an early cellular mechanism eventually causing compulsive drug-seeking behavior in some drug users. In the present review we will discuss how different classes of addictive drugs cause an increase of dopamine release and describe their effects on synapses within the mesolimbic dopamine system. We will emphasize the early synaptic changes in the ventral tegmental area common to all additive drugs and go on to show how these adaptations may reorganize neuronal circuits, eventually leading to behaviors that define addiction.
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40
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Pell GS, Roth Y, Zangen A. Modulation of cortical excitability induced by repetitive transcranial magnetic stimulation: Influence of timing and geometrical parameters and underlying mechanisms. Prog Neurobiol 2011; 93:59-98. [DOI: 10.1016/j.pneurobio.2010.10.003] [Citation(s) in RCA: 223] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Revised: 10/14/2010] [Accepted: 10/20/2010] [Indexed: 01/10/2023]
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D'Errico A, Prestori F, D'Angelo E. Differential induction of bidirectional long-term changes in neurotransmitter release by frequency-coded patterns at the cerebellar input. J Physiol 2010; 587:5843-57. [PMID: 19858226 DOI: 10.1113/jphysiol.2009.177162] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Sensory stimulation conveys spike discharges of variable frequency and duration along the mossy fibres of cerebellum raising the question of whether and how these patterns determine plastic changes at the mossy fibre-granule cell synapse. Although various combinations of high-frequency bursts and membrane depolarization can induce NMDA receptor-dependent long-term depression (LTD) and long-term potentiation (LTP), the effect of different discharge frequencies remained unknown. Here we show that low-frequency mossy fibre stimulation (100 impulses1 Hz) induces mGlu receptor-dependent LTD. For various burst frequencies, the plasticity-[Ca(2+)](i) relationship was U-shaped resembling the Bienenstok-Cooper-Munro (BCM) learning rule. Moreover, LTD expression was associated with increased paired-pulse ratio, coefficient of variation and failure rate, and with a decrease in release probability, therefore showing changes opposite to those characterizing LTP. The plasticity-[Ca(2+)](i) relationship and the changes in neurotransmitter release measured by varying induction frequencies were indistinguishable from those obtained by varying high-frequency burst duration. These results suggest that different glutamate receptors converge onto a final common mechanism translating the frequency and duration of mossy fibre discharges into a regulation of the LTP/LTD balance, which may play an important role in adapting spatio-temporal signal transformations at the cerebellar input stage.
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Affiliation(s)
- Anna D'Errico
- Universitá di Pavia, Istituto di Fisiologia Generale, Via Forlanini 6, Pavia I-27100, Italy
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42
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Harnett MT, Bernier BE, Ahn KC, Morikawa H. Burst-timing-dependent plasticity of NMDA receptor-mediated transmission in midbrain dopamine neurons. Neuron 2009; 62:826-38. [PMID: 19555651 DOI: 10.1016/j.neuron.2009.05.011] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Revised: 12/16/2008] [Accepted: 05/07/2009] [Indexed: 10/20/2022]
Abstract
Bursts of spikes triggered by sensory stimuli in midbrain dopamine neurons evoke phasic release of dopamine in target brain areas, driving reward-based reinforcement learning and goal-directed behavior. NMDA-type glutamate receptors (NMDARs) play a critical role in the generation of these bursts. Here we report LTP of NMDAR-mediated excitatory transmission onto dopamine neurons in the substantia nigra. Induction of LTP requires burst-evoked Ca2+ signals amplified by preceding metabotropic neurotransmitter inputs in addition to the activation of NMDARs themselves. PKA activity gates LTP induction by regulating the magnitude of Ca2+ signal amplification. This form of plasticity is associative, input specific, reversible, and depends on the relative timing of synaptic input and postsynaptic bursting in a manner analogous to the timing rule for cue-reward learning paradigms in behaving animals. NMDAR plasticity might thus represent a potential neural substrate for conditioned dopamine neuron burst responses to environmental stimuli acquired during reward-based learning.
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Affiliation(s)
- Mark T Harnett
- Institute for Neuroscience, University of Texas at Austin, Austin, TX 78712, USA
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Urakubo H, Honda M, Tanaka K, Kuroda S. Experimental and computational aspects of signaling mechanisms of spike-timing-dependent plasticity. HFSP JOURNAL 2009; 3:240-54. [PMID: 20119481 DOI: 10.2976/1.3137602] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 04/27/2009] [Indexed: 11/19/2022]
Abstract
STDP (spike-timing-dependent synaptic plasticity) is thought to be a synaptic learning rule that embeds spike-timing information into a specific pattern of synaptic strengths in neuronal circuits, resulting in a memory. STDP consists of bidirectional long-term changes in synaptic strengths. This process includes long-term potentiation and long-term depression, which are dependent on the timing of presynaptic and postsynaptic spikings. In this review, we focus on computational aspects of signaling mechanisms that induce and maintain STDP as a key step toward the definition of a general synaptic learning rule. In addition, we discuss the temporal and spatial aspects of STDP, and the requirement of a homeostatic mechanism of STDP in vivo.
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44
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Thickbroom GW, Mastaglia FL. Plasticity in neurological disorders and challenges for noninvasive brain stimulation (NBS). J Neuroeng Rehabil 2009; 6:4. [PMID: 19222843 PMCID: PMC2649147 DOI: 10.1186/1743-0003-6-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Accepted: 02/17/2009] [Indexed: 12/01/2022] Open
Abstract
There has been considerable interest in trialing NBS in a range of neurological conditions, and in parallel the range of NBS techniques available continues to expand. Underpinning this is the idea that NBS modulates neuroplasticity and that plasticity is an important contributor to functional recovery after brain injury and to the pathophysiology of neurological disorders. However while the evidence for neuroplasticity and its varied mechanisms is strong, the relationship to functional outcome is less clear and the clinical indications remain to be determined. To be maximally effective, the application of NBS techniques will need to be refined to take into account the diversity of neurological symptoms, the fundamental differences between acute, longstanding and chronic progressive disease processes, and the differential part played by functional and dysfunctional plasticity in diseases of the brain and spinal cord.
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Affiliation(s)
- Gary W Thickbroom
- Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Western Australia, Australia.
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45
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Kabaso D, Coskren PJ, Henry BI, Hof PR, Wearne SL. The electrotonic structure of pyramidal neurons contributing to prefrontal cortical circuits in macaque monkeys is significantly altered in aging. Cereb Cortex 2009; 19:2248-68. [PMID: 19150923 DOI: 10.1093/cercor/bhn242] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Whereas neuronal numbers are largely preserved in normal aging, subtle morphological changes occur in dendrites and spines, whose electrotonic consequences remain unexplored. We examined age-related morphological alterations in 2 types of pyramidal neurons contributing to working memory circuits in the macaque prefrontal cortex (PFC): neurons in the superior temporal cortex forming "long" projections to the PFC and "local" projection neurons within the PFC. Global dendritic mass homeostasis, measured by 3-dimensional scaling analysis, was conserved with aging in both neuron types. Spine densities, dendrite diameters, lengths, and branching complexity were all significantly reduced in apical dendrites of long projection neurons with aging, but only spine parameters were altered in local projection neurons. Despite these differences, voltage attenuation due to passive electrotonic structure, assuming equivalent cable parameters, was significantly reduced with aging in the apical dendrites of both neuron classes. Confirming the electrotonic analysis, simulated passive backpropagating action potential efficacy was significantly higher in apical but not basal dendrites of old neurons. Unless compensated by changes in passive cable parameters, active membrane properties, or altered synaptic properties, these effects will increase the excitability of pyramidal neurons, compromising the precisely tuned activity required for working memory, ultimately resulting in age-related PFC dysfunction.
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Affiliation(s)
- Doron Kabaso
- Department of Neuroscience, Mount Sinai School of Medicine, New York, NY 10029, USA
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46
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Acker CD, Antic SD. Quantitative assessment of the distributions of membrane conductances involved in action potential backpropagation along basal dendrites. J Neurophysiol 2008; 101:1524-41. [PMID: 19118105 DOI: 10.1152/jn.00651.2007] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Basal dendrites of prefrontal cortical neurons receive strong synaptic drive from recurrent excitatory synaptic inputs. Synaptic integration within basal dendrites is therefore likely to play an important role in cortical information processing. Both synaptic integration and synaptic plasticity depend crucially on dendritic membrane excitability and the backpropagation of action potentials. We carried out multisite voltage-sensitive dye imaging of membrane potential transients from thin basal branches of prefrontal cortical pyramidal neurons before and after application of channel blockers. We found that backpropagating action potentials (bAPs) are predominantly controlled by voltage-gated sodium and A-type potassium channels. In contrast, pharmacologically blocking the delayed rectifier potassium, voltage-gated calcium, or I(h) conductance had little effect on dendritic AP propagation. Optically recorded bAP waveforms were quantified and multicompartmental modeling was used to link the observed behavior with the underlying biophysical properties. The best-fit model included a nonuniform sodium channel distribution with decreasing conductance with distance from the soma, together with a nonuniform (increasing) A-type potassium conductance. AP amplitudes decline with distance in this model, but to a lesser extent than previously thought. We used this model to explore the mechanisms underlying two sets of published data involving high-frequency trains of APs and the local generation of sodium spikelets. We also explored the conditions under which I(A) down-regulation would produce branch strength potentiation in the proposed model. Finally, we discuss the hypothesis that a fraction of basal branches may have different membrane properties compared with sister branches in the same dendritic tree.
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Affiliation(s)
- Corey D Acker
- Department of Neuroscience, UConn Health Center, Farmington, CT 06030, USA
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Abstract
The remarkable versatility of the mammalian brain is made possible by a huge diversity of cellular plasticity mechanisms. These include long-term potentiation and depression at both excitatory and inhibitory synapses, as well as a variety of intrinsic and homeostatic plasticity mechanisms. A fundamental challenge for the field is to assemble our detailed knowledge of these specific mechanisms into a coherent picture of how plasticity within cortical circuits works to tune network properties.
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Affiliation(s)
- Sacha B Nelson
- Department of Biology and National Center for Behavioral Genomics, Brandeis University, MS 008, 415 South Street, Waltham, Massachusetts 02454-9110, USA
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48
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D'Angelo E, De Zeeuw CI. Timing and plasticity in the cerebellum: focus on the granular layer. Trends Neurosci 2008; 32:30-40. [PMID: 18977038 DOI: 10.1016/j.tins.2008.09.007] [Citation(s) in RCA: 221] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2008] [Revised: 09/12/2008] [Accepted: 09/15/2008] [Indexed: 02/02/2023]
Abstract
Two of the most striking properties of the cerebellum are its control in timing of motor operations and its ability to adapt behavior to new sensorimotor associations. Here, we propose a 'time-window matching' hypothesis for granular layer processing. Our hypothesis states that mossy fiber inputs to the granular layer are transformed into well-timed spike bursts by intrinsic granule cell processing, that feedforward Golgi cell inhibition sets a limit to the duration of such bursts and that these activities are spread over particular fields in the granular layer so as to generate ongoing time-windows for proper control of interacting motor domains. The role of synaptic plasticity would be that of fine-tuning pre-wired circuits favoring activation of specific granule cell groups in relation to particular time windows. This concept has wide implications for processing in the olivo-cerebellar system as a whole.
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Affiliation(s)
- Egidio D'Angelo
- Department of Cellular and Molecular Physiological and Pharmacological Sciences, University of Pavia and CNISM, Via Forlanini 6, I-27100 Pavia, Italy.
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49
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Huber R, Määttä S, Esser SK, Sarasso S, Ferrarelli F, Watson A, Ferreri F, Peterson MJ, Tononi G. Measures of cortical plasticity after transcranial paired associative stimulation predict changes in electroencephalogram slow-wave activity during subsequent sleep. J Neurosci 2008; 28:7911-8. [PMID: 18667623 PMCID: PMC2809373 DOI: 10.1523/jneurosci.1636-08.2008] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Revised: 06/11/2008] [Accepted: 06/12/2008] [Indexed: 12/25/2022] Open
Abstract
Sleep slow-wave activity (SWA) is thought to reflect sleep need, increasing in proportion to the previous time awake and decreasing during sleep, although the underlying mechanisms are unclear. Recent studies have shown that procedures presumably leading to local plastic changes in the cerebral cortex can lead to local changes in SWA during subsequent sleep. To further investigate the connection between cortical plasticity and sleep SWA, in this study we used a paired associative stimulation (PAS) protocol, in which median nerve stimuli were followed at different intervals (25 or 10 ms) by transcranial magnetic stimulation (TMS) pulses to the contralateral cortical hand area. As expected, such a protocol led to a sustained increase (long-term potentiation-like) or decrease (long-term depression-like) of cortical excitability as measured by motor evoked potentials. By using a TMS-compatible high-density electroencephalographic (EEG) system, we also found that, in individual subjects, TMS-evoked cortical responses over sensorimotor cortex changed with different interstimulus intervals. Moreover, during subsequent sleep, SWA increased locally in subjects whose TMS-evoked cortical responses had increased after PAS, and decreased in subjects whose cortical responses had decreased. Changes in TMS-evoked cortical EEG response and change in sleep SWA were localized to similar cortical regions and were positively correlated. Together, these results suggest that changes in cortical excitability in opposite directions lead to corresponding changes in local sleep regulation, as reflected by SWA, providing evidence for a tight relationship between cortical plasticity and sleep intensity.
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Affiliation(s)
- Reto Huber
- Department of Psychiatry, University of Wisconsin–Madison, Madison, Wisconsin 53719
- University Children's Hospital Zurich, CH-8032 Zurich, Switzerland, and
| | - Sara Määttä
- Department of Psychiatry, University of Wisconsin–Madison, Madison, Wisconsin 53719
| | - Steve K. Esser
- Department of Psychiatry, University of Wisconsin–Madison, Madison, Wisconsin 53719
| | - Simone Sarasso
- Department of Psychiatry, University of Wisconsin–Madison, Madison, Wisconsin 53719
| | - Fabio Ferrarelli
- Department of Psychiatry, University of Wisconsin–Madison, Madison, Wisconsin 53719
| | - Adam Watson
- Department of Psychiatry, University of Wisconsin–Madison, Madison, Wisconsin 53719
| | - Florinda Ferreri
- Department of Neurology, University Campus Biomedico, I-00155 Rome, Italy
| | - Michael J. Peterson
- Department of Psychiatry, University of Wisconsin–Madison, Madison, Wisconsin 53719
| | - Giulio Tononi
- Department of Psychiatry, University of Wisconsin–Madison, Madison, Wisconsin 53719
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50
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Clark K, Normann C. Induction mechanisms and modulation of bidirectional burst stimulation-induced synaptic plasticity in the hippocampus. Eur J Neurosci 2008; 28:279-87. [DOI: 10.1111/j.1460-9568.2008.06337.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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