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Fan Y, Wei X, Lu M, Wang J, Yi G. State-dependent modulation of low-threshold-current-regulated dendritic Ca 2+ response in thalamic reticular neurons with extracellular electric fields. Sci Rep 2023; 13:16485. [PMID: 37779115 PMCID: PMC10543533 DOI: 10.1038/s41598-023-43611-y] [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: 07/06/2023] [Accepted: 09/26/2023] [Indexed: 10/03/2023] Open
Abstract
Deep brain stimulation (DBS) in thalamic reticular nucleus (TRN) neuron provides a novel treatment for drug-resistant epilepsy via the induced electrical field (EFs). However, the mechanisms underlying EF effects remain unclear. This paper investigated how EFs regulate low-threshold dendritic Ca2+ (dCa) response and thus contribute to the input-output relationship of TRN cell. Our results showed that EFs modulate firing modes differently in a neuronal state-dependent manner. At the depolarized state, EFs only regulate the spike timing of a somatic stimulus-evoked single action potential (AP) with less contribution in the regulation of dCa response but could induce the transition between a dendritic stimulus-evoked single AP and a tonic burst of APs via the moderate regulation of dCa response. At the hyperpolarized state, EFs have significant effects on the dCa response, which modulate the large dCa response-dependent burst discharge and even cause a transition from this type of burst discharge to a single AP with less dCa response. Moreover, EF effects on stimulation threshold of somatic spiking prominently depend on EF-regulated dCa responses and the onset time differences between the stimulus and EF give rise to the distinct effect in the EF regulation of dCa responses. Finally, the larger neuronal axial resistance tends to result in the dendritic stimulus-evoked dCa response independent of somatic state. Interestingly, in this case, the EF application could reproduce the similar somatic state-dependent dCa response to dendritic stimulus which occurs in the case of lower axial resistance. These results suggest that the influence of EF on neuronal activities depends on neuronal intrinsic properties, which provides insight into understanding how DBS in TRN neuron modulates epilepsy from the point of view of biophysics.
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Affiliation(s)
- Yaqin Fan
- Tianjin Key Laboratory of Process Measurement and Control, School of Electrical and Information Engineering, Tianjin University, Tianjin, China
| | - Xile Wei
- Tianjin Key Laboratory of Process Measurement and Control, School of Electrical and Information Engineering, Tianjin University, Tianjin, China
| | - Meili Lu
- School of Information Technology Engineering, Tianjin University of Technology and Education, Tianjin, 300222, China
| | - Jiang Wang
- Tianjin Key Laboratory of Process Measurement and Control, School of Electrical and Information Engineering, Tianjin University, Tianjin, China
| | - Guosheng Yi
- Tianjin Key Laboratory of Process Measurement and Control, School of Electrical and Information Engineering, Tianjin University, Tianjin, China.
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2
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Prakash C, Rabidas SS, Tyagi J, Sharma D. Dehydroepiandrosterone Attenuates Astroglial Activation, Neuronal Loss and Dendritic Degeneration in Iron-Induced Post-Traumatic Epilepsy. Brain Sci 2023; 13:brainsci13040563. [PMID: 37190528 DOI: 10.3390/brainsci13040563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/22/2023] [Accepted: 03/25/2023] [Indexed: 03/29/2023] Open
Abstract
Iron-induced experimental epilepsy in rodents reproduces features of post-traumatic epilepsy (PTE) in humans. The neural network of the brain seems to be highly affected during the course of epileptogenesis and determines the occurrence of sudden and recurrent seizures. The aim of the current study was to evaluate astroglial and neuronal response as well as dendritic arborization, and the spine density of pyramidal neurons in the cortex and hippocampus of epileptic rats. We also evaluated the effect of exogenous administration of a neuroactive steroid, dehydroepiandrosterone (DHEA), in epileptic rats. To induce epilepsy, male Wistar rats were given an intracortical injection of 100 mM solution (5 µL) of iron chloride (FeCl3). After 20 days, DHEA was administered intraperitoneally for 21 consecutive days. Results showed epileptic seizures and hippocampal Mossy Fibers (MFs) sprouting in epileptic rats, while DHEA treatment significantly reduced the MFs’ sprouting. Astroglial activation and neuronal loss were subdued in rats that received DHEA compared to epileptic rats. Dendritic arborization and spine density of pyramidal neurons was diminished in epileptic rats, while DHEA treatment partially restored their normal morphology in the cortex and hippocampus regions of the brain. Overall, these findings suggest that DHEA’s antiepileptic effects may contribute to alleviating astroglial activation and neuronal loss along with enhancing dendritic arborization and spine density in PTE.
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3
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Schiapparelli LM, Xie Y, Sharma P, McClatchy DB, Ma Y, Yates JR, Maximov A, Cline HT. Activity-Induced Cortical Glutamatergic Neuron Nascent Proteins. J Neurosci 2022; 42:7900-7920. [PMID: 36261270 PMCID: PMC9617616 DOI: 10.1523/jneurosci.0707-22.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 08/26/2022] [Accepted: 08/30/2022] [Indexed: 11/21/2022] Open
Abstract
Neuronal activity initiates signaling cascades that culminate in diverse outcomes including structural and functional neuronal plasticity, and metabolic changes. While studies have revealed activity-dependent neuronal cell type-specific transcriptional changes, unbiased quantitative analysis of cell-specific activity-induced dynamics in newly synthesized proteins (NSPs) synthesis in vivo has been complicated by cellular heterogeneity and a relatively low abundance of NSPs within the proteome in the brain. Here we combined targeted expression of mutant MetRS (methionine tRNA synthetase) in genetically defined cortical glutamatergic neurons with tight temporal control of treatment with the noncanonical amino acid, azidonorleucine, to biotinylate NSPs within a short period after pharmacologically induced seizure in male and female mice. By purifying peptides tagged with heavy or light biotin-alkynes and using direct tandem mass spectrometry detection of biotinylated peptides, we quantified activity-induced changes in cortical glutamatergic neuron NSPs. Seizure triggered significant changes in ∼300 NSPs, 33% of which were decreased by seizure. Proteins mediating excitatory and inhibitory synaptic plasticity, including SynGAP1, Pak3, GEPH1, Copine-6, and collybistin, and DNA and chromatin remodeling proteins, including Rad21, Smarca2, and Ddb1, are differentially synthesized in response to activity. Proteins likely to play homeostatic roles in response to activity, such as regulators of proteastasis, intracellular ion control, and cytoskeleton remodeling proteins, are activity induced. Conversely, seizure decreased newly synthetized NCAM, among others, suggesting that seizure induced degradation. Overall, we identified quantitative changes in the activity-induced nascent proteome from genetically defined cortical glutamatergic neurons as a strategy to discover downstream mediators of neuronal plasticity and generate hypotheses regarding their function.SIGNIFICANCE STATEMENT Activity-induced neuronal and synaptic plasticity are mediated by changes in the protein landscape, including changes in the activity-induced newly synthesized proteins; however, identifying neuronal cell type-specific nascent proteome dynamics in the intact brain has been technically challenging. We conducted an unbiased proteomic screen from which we identified significant activity-induced changes in ∼300 newly synthesized proteins in genetically defined cortical glutamatergic neurons within 20 h after pharmacologically induced seizure. Bioinformatic analysis of the dynamic nascent proteome indicates that the newly synthesized proteins play diverse roles in excitatory and inhibitory synaptic plasticity, chromatin remodeling, homeostatic mechanisms, and proteasomal and metabolic functions, extending our understanding of the diversity of plasticity mechanisms.
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Affiliation(s)
- Lucio M Schiapparelli
- Neuroscience Department and Dorris Neuroscience Center, Scripps Research Institute, La Jolla, California 92037
| | - Yi Xie
- Neuroscience Department and Dorris Neuroscience Center, Scripps Research Institute, La Jolla, California 92037
- Skaggs Graduate School, Scripps Research Institute, La Jolla, California 92037
| | - Pranav Sharma
- Neuroscience Department and Dorris Neuroscience Center, Scripps Research Institute, La Jolla, California 92037
- Xosomix, San Diego, California 92121
| | - Daniel B McClatchy
- Department of Molecular Medicine, Scripps Research Institute, La Jolla, California 92037
| | - Yuanhui Ma
- Department of Molecular Medicine, Scripps Research Institute, La Jolla, California 92037
| | - John R Yates
- Department of Molecular Medicine, Scripps Research Institute, La Jolla, California 92037
| | - Anton Maximov
- Neuroscience Department and Dorris Neuroscience Center, Scripps Research Institute, La Jolla, California 92037
| | - Hollis T Cline
- Neuroscience Department and Dorris Neuroscience Center, Scripps Research Institute, La Jolla, California 92037
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4
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Zamudio SR, Pichardo-Macías LA, Díaz-Villegas V, Flores-Navarrete IL, Guzmán-Velázquez S. Subchronic cerebrolysin treatment alleviates cognitive impairments and dendritic arborization alterations of granular neurons in the hippocampal dentate gyrus of rats with temporal lobe epilepsy. Epilepsy Behav 2019; 97:96-104. [PMID: 31207446 DOI: 10.1016/j.yebeh.2019.05.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 05/17/2019] [Accepted: 05/17/2019] [Indexed: 11/15/2022]
Abstract
Temporal lobe epilepsy (TLE) is one of the most frequent forms of focal epilepsy; patients with this condition, in addition to exhibiting complex seizures, also exhibit cognitive deficits. In the temporal lobe, the hippocampus, a structure relevant to learning and memory processes, is particularly affected by epilepsy. In animal models of TLE induced by pilocarpine, learning and memory deficiencies associated with changes in synaptic plasticity of the hippocampus have been reported. Cerebrolysin (CBL) is a biologically active mixture of low molecular weight peptides with neuroprotective and neurotrophic effects. The objective of the present study was to determine whether subchronic CBL treatment of rats in the chronic phase of TLE reduces the number and intensity of seizures, and whether CBL treatment can improve cognitive deficits (learning and spatial memory) and dendritic morphology in granular dentate neurons of the hippocampus. Temporal lobe epilepsy (lithium-pilocarpine model) was induced in male Wistar rats (weight, 250-300 g). Two epileptic groups were studied, in which CBL (538 mg/kg) or vehicle was administered intraperitoneally for 5 consecutive days per week for 3 weeks. Respective controls were also included in the study. At the end of treatment, the Barnes maze test (BMT) was used to assess spatial navigational learning and memory. The dendritic morphology of the dentate gyrus was also evaluated using the Golgi-Cox staining method. Results of this study did not support an antiepileptic effect of CBL. Epileptic animals treated with this agent exhibited secondarily generalized seizures similar in frequency and intensity to those of epileptic animals treated only with vehicle. However, when analyzing dendritic morphology of hippocampal granular neurons in these animals, CBL appeared to attenuate dendritic deterioration caused by epilepsy, which was associated with improved cognitive performance of the CBL-treated animals in the BMT compared with vehicle-treated epileptic rats. In conclusion, although CBL did not exert an anticonvulsant effect against secondarily generalized seizures, it can be proposed for use as an add-on therapy in epilepsy management to prevent neuronal alterations, and to improve memory and learning processes.
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Affiliation(s)
- Sergio R Zamudio
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico.
| | - Luz A Pichardo-Macías
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
| | - Verónica Díaz-Villegas
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
| | - Itzel L Flores-Navarrete
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
| | - Sonia Guzmán-Velázquez
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
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Beining M, Jungenitz T, Radic T, Deller T, Cuntz H, Jedlicka P, Schwarzacher SW. Adult-born dentate granule cells show a critical period of dendritic reorganization and are distinct from developmentally born cells. Brain Struct Funct 2016; 222:1427-1446. [PMID: 27514866 DOI: 10.1007/s00429-016-1285-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 08/02/2016] [Indexed: 02/05/2023]
Abstract
Adult-born dentate granule cells (abGCs) exhibit a critical developmental phase during function integration. The time window of this phase is debated and whether abGCs become indistinguishable from developmentally born mature granule cells (mGCs) is uncertain. We analyzed complete dendritic reconstructions from abGCs and mGCs using viral labeling. AbGCs from 21-77 days post intrahippocampal injection (dpi) exhibited comparable dendritic arbors, suggesting that structural maturation precedes functional integration. In contrast, significant structural differences were found compared to mGCs: AbGCs had more curved dendrites, more short terminal segments, a different branching pattern, and more proximal terminal branches. Morphological modeling attributed these differences to developmental dendritic pruning and postnatal growth of the dentate gyrus. We further correlated GC morphologies with the responsiveness to unilateral medial perforant path stimulation using the immediate-early gene Arc as a marker of synaptic activation. Only abGCs at 28 and 35 dpi but neither old abGCs nor mGCs responded to stimulation with a remodeling of their dendritic arbor. Summarized, abGCs stay distinct from mGCs and their dendritic arbor can be shaped by afferent activity during a narrow critical time window.
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Affiliation(s)
- Marcel Beining
- Institute of Clinical Neuroanatomy, Goethe University, 60528, Frankfurt am Main, Germany. .,Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Deutschordenstr. 46, 60528, Frankfurt am Main, Germany. .,Frankfurt Institute for Advanced Studies (FIAS), 60438, Frankfurt am Main, Germany.
| | - Tassilo Jungenitz
- Institute of Clinical Neuroanatomy, Goethe University, 60528, Frankfurt am Main, Germany
| | - Tijana Radic
- Institute of Clinical Neuroanatomy, Goethe University, 60528, Frankfurt am Main, Germany
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Goethe University, 60528, Frankfurt am Main, Germany
| | - Hermann Cuntz
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Deutschordenstr. 46, 60528, Frankfurt am Main, Germany.,Frankfurt Institute for Advanced Studies (FIAS), 60438, Frankfurt am Main, Germany
| | - Peter Jedlicka
- Institute of Clinical Neuroanatomy, Goethe University, 60528, Frankfurt am Main, Germany
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Miltner WHR. Plasticity and Reorganization in the Rehabilitation of Stroke. ZEITSCHRIFT FUR PSYCHOLOGIE-JOURNAL OF PSYCHOLOGY 2016. [DOI: 10.1027/2151-2604/a000243] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Abstract. This paper outlines some actual developments in the behavioral treatment and rehabilitation of stroke and other brain injuries in post-acute and chronic conditions of brain lesion. It points to a number of processes that demonstrate the enormous plasticity and reorganization capacity of the human brain following brain lesion. It also highlights a series of behavioral and neuroscientific studies that indicate that successful behavioral rehabilitation is paralleled by plastic changes of brain structures and by cortical reorganization and that the amount of such plastic changes is obviously significantly determining the overall outcome of rehabilitation.
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Affiliation(s)
- Wolfgang H. R. Miltner
- Department of Biological and Clinical Psychology, Friedrich Schiller University, Jena, Germany
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7
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Targeted pruning of a neuron's dendritic tree via femtosecond laser dendrotomy. Sci Rep 2016; 6:19078. [PMID: 26739126 PMCID: PMC4703956 DOI: 10.1038/srep19078] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 12/04/2015] [Indexed: 12/25/2022] Open
Abstract
Neurons are classified according to action potential firing in response to current injection. While such firing patterns are shaped by the composition and distribution of ion channels, modelling studies suggest that the geometry of dendritic branches also influences temporal firing patterns. Verifying this link is crucial to understanding how neurons transform their inputs to output but has so far been technically challenging. Here, we investigate branching-dependent firing by pruning the dendritic tree of pyramidal neurons. We use a focused ultrafast laser to achieve highly localized and minimally invasive cutting of dendrites, thus keeping the rest of the dendritic tree intact and the neuron functional. We verify successful dendrotomy via two-photon uncaging of neurotransmitters before and after dendrotomy at sites around the cut region and via biocytin staining. Our results show that significantly altering the dendritic arborisation, such as by severing the apical trunk, enhances excitability in layer V cortical pyramidal neurons as predicted by simulations. This method may be applied to the analysis of specific relationships between dendritic structure and neuronal function. The capacity to dynamically manipulate dendritic topology or isolate inputs from various dendritic domains can provide a fresh perspective on the roles they play in shaping neuronal output.
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8
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Psarrou M, Stefanou SS, Papoutsi A, Tzilivaki A, Cutsuridis V, Poirazi P. A simulation study on the effects of dendritic morphology on layer V prefrontal pyramidal cell firing behavior. Front Cell Neurosci 2014; 8:287. [PMID: 25278837 PMCID: PMC4165233 DOI: 10.3389/fncel.2014.00287] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 08/29/2014] [Indexed: 11/13/2022] Open
Abstract
Pyramidal cells, the most abundant neurons in neocortex, exhibit significant structural variability across different brain areas and layers in different species. Moreover, in response to a somatic step current, these cells display a range of firing behaviors, the most common being (1) repetitive action potentials (Regular Spiking-RS), and (2) an initial cluster of 2-5 action potentials with short interspike interval (ISIs) followed by single spikes (Intrinsic Bursting-IB). A correlation between firing behavior and dendritic morphology has recently been reported. In this work we use computational modeling to investigate quantitatively the effects of the basal dendritic tree morphology on the firing behavior of 112 three-dimensional reconstructions of layer V PFC rat pyramidal cells. Particularly, we focus on how different morphological (diameter, total length, volume, and branch number) and passive [Mean Electrotonic Path length (MEP)] features of basal dendritic trees shape somatic firing when the spatial distribution of ionic mechanisms in the basal dendritic trees is uniform or non-uniform. Our results suggest that total length, volume and branch number are the best morphological parameters to discriminate the cells as RS or IB, regardless of the distribution of ionic mechanisms in basal trees. The discriminatory power of total length, volume, and branch number remains high in the presence of different apical dendrites. These results suggest that morphological variations in the basal dendritic trees of layer V pyramidal neurons in the PFC influence their firing patterns in a predictive manner and may in turn influence the information processing capabilities of these neurons.
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Affiliation(s)
- Maria Psarrou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas Heraklion, Greece ; Centre for Computer Science and Informatics Research, Science and Technology Institute, University of Hertfordshire Hatfield, UK ; School of Computer Science, University of Hertfordshire Hatfield, UK
| | - Stefanos S Stefanou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas Heraklion, Greece ; Department of Biology, University of Crete Heraklion, Greece
| | - Athanasia Papoutsi
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas Heraklion, Greece
| | - Alexandra Tzilivaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas Heraklion, Greece ; Department of Biology, University of Crete Heraklion, Greece
| | - Vassilis Cutsuridis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas Heraklion, Greece
| | - Panayiota Poirazi
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas Heraklion, Greece
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9
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Kim H, Jones KE, Heckman CJ. Asymmetry in signal propagation between the soma and dendrites plays a key role in determining dendritic excitability in motoneurons. PLoS One 2014; 9:e95454. [PMID: 25083794 PMCID: PMC4118843 DOI: 10.1371/journal.pone.0095454] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Accepted: 03/27/2014] [Indexed: 12/31/2022] Open
Abstract
It is widely recognized that propagation of electrophysiological signals between the soma and dendrites of neurons differs depending on direction, i.e. it is asymmetric. How this asymmetry influences the activation of voltage-gated dendritic channels, and consequent neuronal behavior, remains unclear. Based on the analysis of asymmetry in several types of motoneurons, we extended our previous methodology for reducing a fully reconstructed motoneuron model to a two-compartment representation that preserved asymmetric signal propagation. The reduced models accurately replicated the dendritic excitability and the dynamics of the anatomical model involving a persistent inward current (PIC) dispersed over the dendrites. The relationship between asymmetric signal propagation and dendritic excitability was investigated using the reduced models while varying the asymmetry in signal propagation between the soma and the dendrite with PIC density constant. We found that increases in signal attenuation from soma to dendrites increased the activation threshold of a PIC (hypo-excitability), whereas increases in signal attenuation from dendrites to soma decreased the activation threshold of a PIC (hyper-excitability). These effects were so strong that reversing the asymmetry in the soma-to-dendrite vs. dendrite-to-soma attenuation, reversed the correlation between PIC threshold and distance of this current source from the soma. We propose the tight relation of the asymmetric signal propagation to the input resistance in the dendrites as a mechanism underlying the influence of the asymmetric signal propagation on the dendritic excitability. All these results emphasize the importance of maintaining the physiological asymmetry in dendritic signaling not only for normal function of the cells but also for biophysically realistic simulations of dendritic excitability.
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Affiliation(s)
- Hojeong Kim
- Division of Robotics Research, Daegu Gyeongbuk Institute of Science & Technology, Daegu, Korea
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, United States of America
- * E-mail:
| | - Kelvin E. Jones
- Centre for Neuroscience and Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Canada
| | - C. J. Heckman
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, United States of America
- Department of Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, United States of America
- Department of Physical Therapy and Human Movement Science, Northwestern University Feinberg School of Medicine, Chicago, United States of America
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10
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Kolb B, Muhammad A. Harnessing the power of neuroplasticity for intervention. Front Hum Neurosci 2014; 8:377. [PMID: 25018713 PMCID: PMC4072970 DOI: 10.3389/fnhum.2014.00377] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 05/14/2014] [Indexed: 01/06/2023] Open
Abstract
A fundamental property of the brain is its capacity to change with a wide variety of experiences, including injury. Although there are spontaneous reparative changes following injury, these changes are rarely sufficient to support significant functional recovery. Research on the basic principles of brain plasticity is leading to new approaches to treating the injured brain. We review factors that affect synaptic organization in the normal brain, evidence of spontaneous neuroplasticity after injury, and the evidence that factors including postinjury experience, pharmacotherapy, and cell-based therapies, can form the basis of rehabilitation strategies after brain injuries early in life and in adulthood.
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Affiliation(s)
- Bryan Kolb
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge Lethbridge, AB, Canada
| | - Arif Muhammad
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge Lethbridge, AB, Canada
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11
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Kolb B, Gibb R. Searching for the principles of brain plasticity and behavior. Cortex 2013; 58:251-60. [PMID: 24457097 DOI: 10.1016/j.cortex.2013.11.012] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 11/28/2013] [Accepted: 11/28/2013] [Indexed: 01/30/2023]
Abstract
An important development in behavioral neuroscience in the past 25 years has been the demonstration that the brain is far more flexible in structure and function than was previously believed. Studies of laboratory animals have provided an important tool for understanding the nature of brain plasticity and behavior at many levels ranging from detailed behavioral paradigms, electrophysiology, neuronal morphology, protein chemistry, and epigenetics. Here we seek a synthesis of the multidisciplinary work on brain plasticity and behavior to identify some general principles on how the brain changes in response to a wide range of experiences over the lifetime.
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Affiliation(s)
- Bryan Kolb
- Department of Neuroscience, University of Lethbridge, Lethbridge, AB, Canada.
| | - Robbin Gibb
- Department of Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
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12
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Epileptic baboons have lower numbers of neurons in specific areas of cortex. Proc Natl Acad Sci U S A 2013; 110:19107-12. [PMID: 24191031 DOI: 10.1073/pnas.1318894110] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Epilepsy is characterized by recurrent seizure activity that can induce pathological reorganization and alter normal function in neocortical networks. In the present study, we determined the numbers of cells and neurons across the complete extent of the cortex for two epileptic baboons with naturally occurring seizures and two baboons without epilepsy. Overall, the two epileptic baboons had a 37% average reduction in the number of cortical neurons compared with the two nonepileptic baboons. The loss of neurons was variable across cortical areas, with the most pronounced loss in the primary motor cortex, especially in lateral primary motor cortex, representing the hand and face. Less-pronounced reductions of neurons were found in other parts of the frontal cortex and in somatosensory cortex, but no reduction was apparent in the primary visual cortex and little in other visual areas. The results provide clear evidence that epilepsy in the baboon is associated with considerable reduction in the numbers of cortical neurons, especially in frontal areas of the cortex related to motor functions. Whether or not the reduction of neurons is a cause or an effect of seizures needs further investigation.
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13
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Singh SP, He X, McNamara JO, Danzer SC. Morphological changes among hippocampal dentate granule cells exposed to early kindling-epileptogenesis. Hippocampus 2013; 23:1309-20. [PMID: 23893783 DOI: 10.1002/hipo.22169] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2013] [Indexed: 11/10/2022]
Abstract
Temporal lobe epilepsy is associated with changes in the morphology of hippocampal dentate granule cells. These changes are evident in numerous models that are associated with substantial neuron loss and spontaneous recurrent seizures. By contrast, previous studies have shown that in the kindling model, it is possible to administer a limited number of stimulations sufficient to produce a lifelong enhanced sensitivity to stimulus evoked seizures without associated spontaneous seizures and minimal neuronal loss. Here we examined whether stimulation of the amygdala sufficient to evoke five convulsive seizures (class IV or greater on Racine's scale) produce morphological changes similar to those observed in models of epilepsy associated with substantial cell loss. The morphology of GFP-expressing granule cells from Thy-1 GFP mice was examined either 1 day or 1 month after the last evoked seizure. Interestingly, significant reductions in dendritic spine density were evident 1 day after the last seizure, the magnitude of which had diminished by 1 month. Further, there was an increase in the thickness of the granule cell layer 1 day after the last evoked seizure, which was absent a month later. We also observed an increase in the area of the proximal axon, which again returned to control levels a month later. No differences in the number of basal dendrites were detected at either time point. These findings demonstrate that the early stages of kindling epileptogenesis produce transient changes in the granule cell body layer thickness, molecular layer spine density, and axon proximal area, but do not produce striking rearrangements of granule cell structure.
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Affiliation(s)
- Shatrunjai P Singh
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Molecular and Developmental Biology Graduate Program, University of Cincinnati, Cincinnati, Ohio
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14
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Ma Y, Ramachandran A, Ford N, Parada I, Prince DA. Remodeling of dendrites and spines in the C1q knockout model of genetic epilepsy. Epilepsia 2013; 54:1232-9. [PMID: 23621154 DOI: 10.1111/epi.12195] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2013] [Indexed: 12/24/2022]
Abstract
PURPOSE To determine whether developmental synaptic pruning defects in epileptic C1q-knockout (KO) mice are accompanied by postsynaptic abnormalities in dendrites and/or spines. METHODS Immunofluorescence staining was performed on biocytin-filled layer Vb pyramidal neurons in sensorimotor cortex. Basal dendritic arbors and their spines were reconstructed with NEUROLUCIDA software, and their morphologic characteristics were quantitated in Neuroexplorer. KEY FINDINGS Seven to nine completely filled pyramidal neurons were analyzed from the wild-type (WT) and C1q KO groups. Compared to WT controls, KO mice showed significant structural modifications in their basal dendrites including (1) higher density of dendritic spines (0.60 ± 0.03/μm vs. 0.49 ± 0.03/μm dendritic length in WT, p < 0.05); (2) remarkably increased occurrence of thin spines (0.26 ± 0.02/μm vs. 0.14 ± 0.02/μm dendritic length in control, p < 0.01); (3) longer dendritic length (2,680 ± 159 μm vs. 2,119 ± 108 μm in control); and (4) increased branching (22.6 ± 1.9 vs. 16.2 ± 1.3 in WT at 80 μm from soma center, p < 0.05; 12.4 ± 1.4 vs. 8.2 ± 0.6 in WT at 120 μm from soma center, respectively, p < 0.05). Dual immunolabeling demonstrated the expression of putative glutamate receptor 2 (GluR2) on some thin spines. These dendritic alterations are likely postsynaptic structural consequences of failure of synaptic pruning in the C1q KO mice. SIGNIFICANCE Failure to prune excessive excitatory synapses in C1q KO mice is a likely mechanism underlying abnormalities in postsynaptic dendrites, including increased branching and alterations in spine type and density. It is also possible that seizure activity contributes to these abnormalities. These structural abnormalities, together with increased numbers of excitatory synapses, likely contribute to epileptogenesis in C1q KO mice.
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Affiliation(s)
- Yunyong Ma
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California 94305-5122, USA
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15
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Ferri SL, Flanagan-Cato LM. Oxytocin and dendrite remodeling in the hypothalamus. Horm Behav 2012; 61:251-8. [PMID: 22326383 PMCID: PMC3312999 DOI: 10.1016/j.yhbeh.2012.01.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 01/13/2012] [Accepted: 01/14/2012] [Indexed: 10/14/2022]
Abstract
For most people, their quality of life depends on their successful interdependence with others, which requires sophisticated social cognition, communication, and emotional bonds. Across the lifespan, new bonds must be forged and maintained, and conspecific menaces must be managed. The dynamic nature of the human social landscape suggests ongoing specific alterations in neural circuitry across several brain systems to subserve social behavior. To discover the biological mechanisms that contribute to normal social activities, animal models of social behavior have been developed. One valuable model system has been female rat sexual behavior, which is governed by cyclic variation of ovarian hormones. This behavior is modulated by the neuropeptide oxytocin (OT) through its actions in the hypothalamic ventromedial nucleus (VMH). The fluctuation of this behavior is associated with dendrite remodeling, like several other examples of behavioral plasticity. This review compares hormone-induced plasticity in the VMH with other examples of dendrite plasticity across the mammalian nervous system, namely the neurobehavioral paradigms of environmental enrichment, chronic stress, and incentive sensitization, which affect the neocortex, hippocampal formation, and ventral striatum, respectively. This comparison suggests that the effects of ovarian hormones on VMH neurons in rats, given the simple dendritic arbor and short time course for dendrite remodeling, provide a dual opportunity for mechanistic and functional studies that will shed light on i) the neural actions of OT that regulate social behavior and, ii) behaviorally relevant dendrite regulation in a variety of brain structures. This article is part of a Special Issue entitled Oxytocin, Vasopressin, and Social Behavior.
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Affiliation(s)
- Sarah L Ferri
- Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Kolb B, Muhammad A, Gibb R. Searching for factors underlying cerebral plasticity in the normal and injured brain. JOURNAL OF COMMUNICATION DISORDERS 2011; 44:503-514. [PMID: 21621219 DOI: 10.1016/j.jcomdis.2011.04.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
UNLABELLED Brain plasticity refers to the capacity of the nervous system to change its structure and ultimately its function over a lifetime. There have been major advances in our understanding of the principles of brain plasticity and behavior in laboratory animals and humans. Over the past decade there have been advances in the application of these principles to brain-injured laboratory animals. To date, there have been few major applications of this knowledge to establish postinjury interventions in humans. A significant challenge for the next 20 years will be the translation of this work to improve the outcome from brain injury and disease in humans. The goal of this review is to synthesize the multidisciplinary laboratory work on brain plasticity and behavior in the injured brain to inform the development of rehabilitation programs. LEARNING OUTCOMES Readers will be able to: (a) identify principles of brain plasticity, (b) review the application of these principles to the treatment of brain-injured laboratory animals, and (c) consider the translation of the new treatments to brain-injured humans.
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Affiliation(s)
- Bryan Kolb
- Department of Neuroscience, University of Lethbridge, Lethbridge, AB, Canada T1K 3M4.
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17
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Corcoran ME, Kroes RA, Burgdorf JS, Moskal JR. Regional changes in gene expression after limbic kindling. Cell Mol Neurobiol 2011; 31:819-34. [PMID: 21424270 DOI: 10.1007/s10571-011-9672-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 03/02/2011] [Indexed: 11/24/2022]
Abstract
Repeated electrical stimulation results in development of seizures and a permanent increase in seizure susceptibility (kindling). The permanence of kindling suggests that chronic changes in gene expression are involved. Kindling at different sites produces specific effects on interictal behaviors such as spatial cognition and anxiety, suggesting that causal changes in gene expression might be restricted to the stimulated site. We employed focused microarray analysis to characterize changes in gene expression associated with amygdaloid and hippocampal kindling. Male Long-Evans rats received 1 s trains of electrical stimulation to either the amygdala or hippocampus once daily until five generalized seizures had been kindled. Yoked control rats carried electrodes but were not stimulated. Rats were euthanized 14 days after the last seizures, both amygdala and hippocampus dissected, and transcriptome profiles compared. Of the 1,200 rat brain-associated genes evaluated, 39 genes exhibited statistically significant expression differences between the kindled and non-kindled amygdala and 106 genes exhibited statistically significant differences between the kindled and non-kindled hippocampus. In the amygdala, subsequent ontological analyses using the GOMiner algorithm demonstrated significant enrichment in categories related to cytoskeletal reorganization and cation transport, as well as in gene families related to synaptic transmission and neurogenesis. In the hippocampus, significant enrichment in gene expression within categories related to cytoskeletal reorganization and cation transport was similarly observed. Furthermore, unique to the hippocampus, enrichment in transcription factor activity and GTPase-mediated signal transduction was identified. Overall, these data identify specific and unique neurochemical pathways chronically altered following kindling in the two sites, and provide a platform for defining the molecular basis for the differential behaviors observed in the interictal period.
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Affiliation(s)
- M E Corcoran
- Neural Systems and Plasticity Research Group and Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK S7N 3R2, Canada.
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18
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Kolb B, Teskey GC. Age, experience, injury, and the changing brain. Dev Psychobiol 2010; 54:311-25. [DOI: 10.1002/dev.20515] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Accepted: 10/04/2010] [Indexed: 01/27/2023]
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van Elburg RAJ, van Ooyen A. Impact of dendritic size and dendritic topology on burst firing in pyramidal cells. PLoS Comput Biol 2010; 6:e1000781. [PMID: 20485556 PMCID: PMC2869305 DOI: 10.1371/journal.pcbi.1000781] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Accepted: 04/09/2010] [Indexed: 11/19/2022] Open
Abstract
Neurons display a wide range of intrinsic firing patterns. A particularly relevant pattern for neuronal signaling and synaptic plasticity is burst firing, the generation of clusters of action potentials with short interspike intervals. Besides ion-channel composition, dendritic morphology appears to be an important factor modulating firing pattern. However, the underlying mechanisms are poorly understood, and the impact of morphology on burst firing remains insufficiently known. Dendritic morphology is not fixed but can undergo significant changes in many pathological conditions. Using computational models of neocortical pyramidal cells, we here show that not only the total length of the apical dendrite but also the topological structure of its branching pattern markedly influences inter- and intraburst spike intervals and even determines whether or not a cell exhibits burst firing. We found that there is only a range of dendritic sizes that supports burst firing, and that this range is modulated by dendritic topology. Either reducing or enlarging the dendritic tree, or merely modifying its topological structure without changing total dendritic length, can transform a cell's firing pattern from bursting to tonic firing. Interestingly, the results are largely independent of whether the cells are stimulated by current injection at the soma or by synapses distributed over the dendritic tree. By means of a novel measure called mean electrotonic path length, we show that the influence of dendritic morphology on burst firing is attributable to the effect both dendritic size and dendritic topology have, not on somatic input conductance, but on the average spatial extent of the dendritic tree and the spatiotemporal dynamics of the dendritic membrane potential. Our results suggest that alterations in size or topology of pyramidal cell morphology, such as observed in Alzheimer's disease, mental retardation, epilepsy, and chronic stress, could change neuronal burst firing and thus ultimately affect information processing and cognition.
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Affiliation(s)
- Ronald A. J. van Elburg
- Department of Artificial Intelligence, Faculty of Mathematics and Natural Sciences, University of Groningen, Groningen, The Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, The Netherlands
| | - Arjen van Ooyen
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, The Netherlands
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Henry LC, Goertzen CD, Lee A, Teskey GC. Repeated seizures lead to altered skilled behaviour and are associated with more highly efficacious excitatory synapses. Eur J Neurosci 2008; 27:2165-76. [PMID: 18412634 DOI: 10.1111/j.1460-9568.2008.06153.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
People with epilepsy have a high incidence of interictal behavioural problems that appear to be related to the location of their seizure focus. This study investigated a novel test of the hypotheses that repeated seizures result in behavioural deficits and altered performance during the interictal state, and that those behaviours are related to the presence of more highly efficacious excitatory synapses. We tested these hypotheses by first repeatedly eliciting seizures with electric current through indwelling electrodes in the corpus callosum at the level of the caudal forelimb area of sensorimotor neocortex in the rat. We then assessed learned skilled behaviours that primarily utilize the forelimbs on tasks that are sensitive to the functional integrity of that structure. We observed both behavioural deficits and altered kinematic performance in rats that experienced repeated neocortical seizures relative to an electrode-implanted control group. From a separate set of rats, tissue was prepared for quantification of thickness and excitatory synaptic subtypes from neocortical layer V. We observed significantly increased numbers of perforated synapses that make their connections directly onto the dendritic shaft at 3 weeks following the last seizure. Altered reaching behaviours are likely due to neural reorganization in the neocortex including more efficacious synapses.
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Affiliation(s)
- Luke C Henry
- Behavioural Neuroscience Research Group, Department of Psychology, Epilepsy and Brain Circuits Program, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada T2N 1N4
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Whishaw IQ, Alaverdashvili M, Kolb B. The problem of relating plasticity and skilled reaching after motor cortex stroke in the rat. Behav Brain Res 2008; 192:124-36. [PMID: 18282620 DOI: 10.1016/j.bbr.2007.12.026] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Revised: 12/20/2007] [Accepted: 12/22/2007] [Indexed: 11/17/2022]
Abstract
The plasticity of the nervous system is illustrated in the many new neuronal connections that are formed during the acquisition of behavioral skills, loss of function after brain injury, and subsequent recovery of function. The present review describes the acquisition of skilled reaching, the act of reaching for food with a forelimb, and the changes that take place in skilled reaching following motor cortex stroke. The review then discusses the difficulty in associating plastic changes with specific aspects of behavioral change. Skilled reaching behavior is complex and consists of a number of oppositions (stimulus response relationships), between the rat and the food target, a number of forelimb gestures (non-weight supporting movements), which are performed to obtain food, and a complex series of segmental movements (of the limb, head, and trunk), all of which influence the success of the act. Measures of these four aspects of skilled reaching behavior following motor cortex stroke reveal that there are a number of learned changes that take place at different times, including learned nonuse, learned bad-use, and forgetting. The widespread dendritic proliferation, axonal growth, and synaptic formation that take place both before and after stroke are difficult to precisely relate to these behavioral changes. Whereas plasticity is usually proposed to be associated with improved performance it is suggested that future work should attempt to better relate plastic changes to the details of behavioral changes.
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Affiliation(s)
- Ian Q Whishaw
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada.
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Zsombok A, Jacobs KM. Postsynaptic currents prior to onset of epileptiform activity in rat microgyria. J Neurophysiol 2007; 98:178-86. [PMID: 17475719 DOI: 10.1152/jn.00106.2007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Structural malformations of the cortex, arising as a result of genetic mutation or injury during development are associated with dyslexia, epilepsy, and other neurological deficits. We have used a rat model of a microgyral malformation to examine mechanisms of epileptogenesis. Our previous studies showed that the frequency of miniature excitatory postsynaptic currents (mEPSCs) recorded in neocortical layer V pyramidal neurons is increased in malformed cortex at a time when field potential epileptiform events can be evoked. Here we show that the increase occurs at an age before onset of cortical epileptiform activity and at a time when the frequency of mEPSCs in control layer V pyramidal neurons is stable. An increase in the frequency of spontaneous (s)EPSCs in layer V pyramidal neurons of malformed cortex occurs earlier than that for mEPSCs, suggesting that there may additionally be alterations in intrinsic properties that increase the excitability of the cortical afferents. Frequencies of EPSC bursts and late evoked activity were also increased in malformed cortex. These results suggest that a hyperinnervation of layer V pyramidal neurons by excitatory afferents occurs as an active process likely contributing to subsequent development of field epileptiform events.
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Affiliation(s)
- A Zsombok
- Dept of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA 23298, USA
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