151
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Göbel W, Kampa BM, Helmchen F. Imaging cellular network dynamics in three dimensions using fast 3D laser scanning. Nat Methods 2006; 4:73-9. [PMID: 17143280 DOI: 10.1038/nmeth989] [Citation(s) in RCA: 223] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2006] [Accepted: 11/01/2006] [Indexed: 11/09/2022]
Abstract
Spatiotemporal activity patterns in three-dimensionally organized cellular networks are fundamental to the function of the nervous system. Despite advances in functional imaging of cell populations, a method to resolve local network activity in three dimensions has been lacking. Here we introduce a three-dimensional (3D) line-scan technology for two-photon microscopy that permits fast fluorescence measurements from several hundred cells distributed in 3D space. We combined sinusoidal vibration of the microscope objective at 10 Hz with 'smart' movements of galvanometric x-y scanners to repeatedly scan the laser focus along a closed 3D trajectory. More than 90% of cell somata were sampled by the scan line within volumes of 250 microm side length. Using bulk-loading of calcium indicator, we applied this method to reveal spatiotemporal activity patterns in neuronal and astrocytic networks in the rat neocortex in vivo. Two-photon population imaging using 3D scanning opens the field for comprehensive studies of local network dynamics in intact tissue.
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Affiliation(s)
- Werner Göbel
- Department of Neurophysiology, Brain Research Institute, University of Zurich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland
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152
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Firth SI, Feller MB. Dissociated GABAergic retinal interneurons exhibit spontaneous increases in intracellular calcium. Vis Neurosci 2006; 23:807-14. [PMID: 17020635 DOI: 10.1017/s095252380623013x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Accepted: 06/13/2006] [Indexed: 11/06/2022]
Abstract
Early in development, before the retina is responsive to light, neurons exhibit spontaneous activity. Recently it was demonstrated that starburst amacrine cells, a unique class of neurons that secretes both GABA and acetylcholine, spontaneously depolarize. Networks comprised of spontaneously active starburst cells initiate correlated bursts of action potentials that propagate across the developing retina with a periodicity on the order minutes. To determine whether other retinal interneurons have similar “pacemaking” properties, we have utilized cultures of dissociated neurons from the rat retina. In the presence of antagonists for fast neurotransmitter receptors, distinct populations of neurons exhibited spontaneous, uncorrelated increases in intracellular calcium concentration. These increases in intracellular calcium concentration were sensitive to tetrodotoxin, indicating they are mediated by spontaneous membrane depolarizations. By combining immunofluorescence and calcium imaging, we found that 44% of spontaneously active neurons were GABAergic and included starburst amacrine cells. Whole cell voltage clamp recordings in the absence of antagonists for fast neurotransmitters revealed that after 7 days in culture, individual retinal neurons receive bursts of GABA-A receptor mediated synaptic input with a periodicity similar to that measured in spontaneously active GABAergic neurons. Low concentrations of GABA-A receptor antagonists did not alter the inter-burst interval despite significant reduction of post-synaptic current amplitude, indicating that pacemaker activity of GABAergic neurons was not influenced by network interactions. Together, these findings indicate that spiking GABAergic interneurons can function as pacemakers in the developing retina.
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Affiliation(s)
- Sally I Firth
- Neurobiology Section, Division of Biological Sciences, University of California at San Diego, San Diego, California, USA
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153
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Nakatani H, van Leeuwen C. Transient synchrony of distant brain areas and perceptual switching in ambiguous figures. BIOLOGICAL CYBERNETICS 2006; 94:445-57. [PMID: 16532332 DOI: 10.1007/s00422-006-0057-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Accepted: 02/01/2006] [Indexed: 05/07/2023]
Abstract
We studied the relationship between perceptual switching in the Necker cube and long-distance transient phase synchronization in EEG. Transient periods of response related synchrony between parietal and frontal areas were observed. They start 800-600, ms prior to the switch response and occur in pairs. Four types of pairs could be distinguished, two of which are accompanied by transient alpha band activity in the occipital area. The results indicate that perceptual switching processes involve parietal and frontal areas; these are the ones that are normally associated with various cognitive processes. Sensory information in the visual areas is involved in some, but not in all, of switching processes. The intrinsic variability, as well as the participating areas, points to the role of strategic cognitive processes in perceptual switching.
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Affiliation(s)
- Hironori Nakatani
- Laboratory for Perceptual Dynamics, RIKEN Brain Science Institute 2-1, Hirosawa, Wako-shi, Saitama, 351-0198, Japan.
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154
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Abstract
We present a minimal spiking network that can polychronize, that is, exhibit reproducible time-locked but not synchronous firing patterns with millisecond precision, as in synfire braids. The network consists of cortical spiking neurons with axonal conduction delays and spike-timing-dependent plasticity (STDP); a ready-to-use MATLAB code is included. It exhibits sleeplike oscillations, gamma (40 Hz) rhythms, conversion of firing rates to spike timings, and other interesting regimes. Due to the interplay between the delays and STDP, the spiking neurons spontaneously self-organize into groups and generate patterns of stereotypical polychronous activity. To our surprise, the number of coexisting polychronous groups far exceeds the number of neurons in the network, resulting in an unprecedented memory capacity of the system. We speculate on the significance of polychrony to the theory of neuronal group selection (TNGS, neural Darwinism), cognitive neural computations, binding and gamma rhythm, mechanisms of attention, and consciousness as “attention to memories.”
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Affiliation(s)
- Eugene M Izhikevich
- The Neurosciences Institute, 10640 John Jay Hopkins Drive, San Diego, CA 92121, USA.
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155
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Knöpfel T, Díez-García J, Akemann W. Optical probing of neuronal circuit dynamics: genetically encoded versus classical fluorescent sensors. Trends Neurosci 2006; 29:160-6. [PMID: 16443289 DOI: 10.1016/j.tins.2006.01.004] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2005] [Revised: 11/17/2005] [Accepted: 01/12/2006] [Indexed: 11/25/2022]
Abstract
During the past few decades, optical methods for imaging activity in networks composed of thousands of neurons have been developed. These techniques rely mainly on organic-chemistry-based dyes as indicators of Ca(2+) and membrane potential. However, recently a new generation of probes, genetically encoded fluorescent protein sensors, has emerged for use by physiologists studying the operation of neuronal circuits. We critically review the development of these new probes, and analyze objectives and experimental conditions in which classical probes are likely to prevail and where the fluorescent protein sensors will open paths to previously unexplored territories of functional neuroimaging.
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Affiliation(s)
- Thomas Knöpfel
- Laboratory for Neuronal Circuit Dynamics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 Japan.
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156
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Chen TW, Lin BJ, Brunner E, Schild D. In situ background estimation in quantitative fluorescence imaging. Biophys J 2005; 90:2534-47. [PMID: 16387783 PMCID: PMC1403198 DOI: 10.1529/biophysj.105.070854] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fluorescence imaging of bulk-stained tissue is a popular technique for monitoring the activities in a large population of cells. However, a precise quantification of such experiments is often compromised by an ambiguity of background estimation. Although, in single-cell-staining experiments, background can be measured from a neighboring nonstained region, such a region often does not exist in bulk-stained tissue. Here we describe a novel method that overcomes this problem. In contrast to previous methods, we determined the background of a given region of interest (ROI) using the information contained in the temporal dynamics of its individual pixels. Since no information outside the ROI is needed, the method can be used regardless of the staining profile in the surrounding tissue. Moreover, we extend the method to deal with background inhomogeneities within a single ROI, a problem not yet solved by any of the currently available tools. We performed computer simulations to demonstrate the accuracy of our method and give example applications in ratiometric calcium imaging of bulk-stained olfactory bulb slices. Converting the fluorescence signals into [Ca2+] gives resting values consistent with earlier single-cell staining results, and odorant-induced [Ca2+] transients can be quantitatively compared in different cells. Using these examples we show that inaccurate background subtraction introduces large errors (easily in the range of 100%) in the assessment of both resting [Ca2+] and [Ca2+] dynamics. The proposed method allows us to avoid such errors.
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Affiliation(s)
- Tsai-Wen Chen
- Institute of Physiology, and Department of Medical Statistics, University of Göttingen, Göttingen, Germany
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157
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Compte A. Computational and in vitro studies of persistent activity: edging towards cellular and synaptic mechanisms of working memory. Neuroscience 2005; 139:135-51. [PMID: 16337341 DOI: 10.1016/j.neuroscience.2005.06.011] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Revised: 05/29/2005] [Accepted: 06/03/2005] [Indexed: 11/17/2022]
Abstract
Persistent neural activity selective to features of an extinct stimulus has been identified as the neural correlate of working memory processes. The precise nature of the physiological substrate for this self-sustained activity is still unknown. In the last few years, this problem has gathered experimental together with computational neuroscientists in a quest to identify the cellular and network mechanisms involved. I introduce here the attractor theory framework within which current persistent activity computational models are built, and I then review the main physiological mechanisms that have been linked thereby to persistent activity and working memory. Open computational and physiological issues with these models are discussed, together with their potential experimental validation in current in vitro models of persistent activity.
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Affiliation(s)
- Albert Compte
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, 03550 Sant Joan d'Alacant, Spain.
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158
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Rattenborg NC. Evolution of slow-wave sleep and palliopallial connectivity in mammals and birds: a hypothesis. Brain Res Bull 2005; 69:20-9. [PMID: 16464681 DOI: 10.1016/j.brainresbull.2005.11.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2005] [Revised: 11/01/2005] [Accepted: 11/02/2005] [Indexed: 11/29/2022]
Abstract
Mammals and birds are the only animals that exhibit rapid eye-movement (REM) sleep and slow-wave sleep (SWS). Whereas the electroencephalogram (EEG) during REM sleep resembles the low-amplitude, high-frequency EEG of wakefulness, the EEG during SWS displays high-amplitude, slow-waves (1-4Hz). The absence of similar slow-waves (SWs) in sleeping reptiles suggests that the neuroanatomical and neurophysiological traits necessary for the genesis of SWs evolved independently in the mammalian and avian ancestors. Advances in our understanding of comparative neuroanatomy and the genesis of mammalian SWs suggest that the absence of SWs in reptiles is due to limited connectivity within the pallium, the dorsal portion of the telencephalon that includes the mammalian neocortex, reptilian dorsal cortex and avian Wulst (hyperpallium), as well as the dorsal ventricular ridge in birds and reptiles and the mammalian claustrum and pallial amygdala. In mammals, the slow oscillation (<1Hz) of cortical neurons acts through reciprocal corticothalamic loops and corticocortical connections to synchronize the 1-4Hz activity of thalamocortical neurons in a manner sufficient to generate SWs detectable in the EEG. Given the role that corticocortical (or palliopallial) connections play in the genesis of SWs in mammals, the degree of palliopallial connectivity might explain why birds show SWs and reptiles do not. Indeed, whereas the mammalian neocortex and avian pallium show extensive palliopallial connectivity, the reptilian pallium exhibits limited intrapallial connections. I thus propose that the evolution of SWs is linked to the independent evolution of extensive palliopallial connectivity in mammals and birds. As suggested by experiments functionally linking SWs to performance enhancements, the palliopallial connections that give rise to SWs might also depend on SWs to maintain their efficacy.
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Affiliation(s)
- Niels C Rattenborg
- Max Planck Institute for Ornithology, Seewiesen, Postfach 1564, Starnberg D-82305, Germany.
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159
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Sirota A, Buzsáki G. Interaction between neocortical and hippocampal networks via slow oscillations. THALAMUS & RELATED SYSTEMS 2005; 3:245-259. [PMID: 18185848 PMCID: PMC2180396 DOI: 10.1017/s1472928807000258] [Citation(s) in RCA: 187] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Both the thalamocortical and limbic systems generate a variety of brain state-dependent rhythms but the relationship between the oscillatory families is not well understood. Transfer of information across structures can be controlled by the offset oscillations. We suggest that slow oscillation of the neocortex, which was discovered by Mircea Steriade, temporally coordinates the self-organized oscillations in the neocortex, entorhinal cortex, subiculum and hippocampus. Transient coupling between rhythms can guide bidirectional information transfer among these structures and might serve to consolidate memory traces.
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Affiliation(s)
- Anton Sirota
- Center for Molecular and Behavioral Neuroscience Rutgers, The State University of New Jersey 197 University Avenue, Newark, USA
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160
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MacLean JN, Watson BO, Aaron GB, Yuste R. Internal Dynamics Determine the Cortical Response to Thalamic Stimulation. Neuron 2005; 48:811-23. [PMID: 16337918 DOI: 10.1016/j.neuron.2005.09.035] [Citation(s) in RCA: 267] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2005] [Revised: 05/17/2005] [Accepted: 09/30/2005] [Indexed: 12/20/2022]
Abstract
Although spontaneous activity occurs throughout the neocortex, its relation to the activity produced by external or sensory inputs remains unclear. To address this, we used calcium imaging of mouse thalamocortical slices to reconstruct, with single-cell resolution, the spatiotemporal dynamics of activity of layer 4 in the presence or absence of thalamic stimulation. We found spontaneous neuronal coactivations corresponded to intracellular UP states. Thalamic stimulation of sufficient frequency (>10 Hz) triggered cortical activity, and UP states, indistinguishable from those arising spontaneously. Moreover, neurons were activated in identical and precise spatiotemporal patterns in thalamically triggered and spontaneous events. The similarities between cortical activations indicate that intracortical connectivity plays the dominant role in the cortical response to thalamic inputs. Our data demonstrate that precise spatiotemporal activity patterns can be triggered by thalamic inputs and indicate that the thalamus serves to release intrinsic cortical dynamics.
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Affiliation(s)
- Jason N MacLean
- Howard Hughes Medical Institute, Department of Biological Sciences, Columbia University, New York, New York 10027, USA.
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161
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Cossart R, Ikegaya Y, Yuste R. Calcium imaging of cortical networks dynamics. Cell Calcium 2005; 37:451-7. [PMID: 15820393 DOI: 10.1016/j.ceca.2005.01.013] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2004] [Accepted: 01/06/2005] [Indexed: 12/17/2022]
Abstract
Studies relating spontaneous network activities to cognitive processes and/or brain disorders constitute a recently expanding field of investigation. They are mostly based either on cellular recordings--usually performed in pharmacologically induced oscillations in brain slices--or on multi-cellular recordings using tetrodes or multiple electrodes. However, these research strategies cannot link the electrical recordings with morphological characterization of the neurons. The progress made in imaging techniques allows for the first time to have simultaneously a dynamic and global characterization of network activity and to determine the single-cell properties of the unitary microcircuits involved in this activity.
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Affiliation(s)
- Rosa Cossart
- INMED, INSERM U29, Parc Scientifique de Luminy, BP.13, 13273 Marseille, Cedex 9, France
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162
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Mazor O, Laurent G. Transient Dynamics versus Fixed Points in Odor Representations by Locust Antennal Lobe Projection Neurons. Neuron 2005; 48:661-73. [PMID: 16301181 DOI: 10.1016/j.neuron.2005.09.032] [Citation(s) in RCA: 329] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2005] [Revised: 09/20/2005] [Accepted: 09/28/2005] [Indexed: 11/21/2022]
Abstract
Projection neurons (PNs) in the locust antennal lobe exhibit odor-specific dynamic responses. We studied a PN population, stimulated with five odorants and pulse durations between 0.3 and 10 s. Odor representations were characterized as time series of vectors of PN activity, constructed from the firing rates of all PNs in successive 50 ms time bins. Odor representations by the PN population can be described as trajectories in PN state space with three main phases: an on transient, lasting 1-2 s; a fixed point, stable for at least 8 s; and an off transient, lasting a few seconds as activity returns to baseline. Whereas all three phases are odor specific, optimal stimulus separation occurred during the transients rather than the fixed points. In addition, the PNs' own target neurons respond least when their PN-population input stabilized at a fixed point. Steady-state measures of activity thus seem inappropriate to understand the neural code in this system.
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Affiliation(s)
- Ofer Mazor
- Computation and Neural Systems Program, Division of Biology, California Institute of Technology, Pasadena, California 91125, USA
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163
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Grinvald A. Imaging input and output dynamics of neocortical networks in vivo: exciting times ahead. Proc Natl Acad Sci U S A 2005; 102:14125-6. [PMID: 16189023 PMCID: PMC1242320 DOI: 10.1073/pnas.0506755102] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Amiram Grinvald
- Department of Neurobiology, The Weizmann Institute of Science, 76100 Rehovot, Israel.
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164
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Fujisawa S, Matsuki N, Ikegaya Y. Single neurons can induce phase transitions of cortical recurrent networks with multiple internal States. ACTA ACUST UNITED AC 2005; 16:639-54. [PMID: 16093564 DOI: 10.1093/cercor/bhj010] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Fluctuations of membrane potential of cortical neurons, referred to here as internal states, are essential for brain function, but little is known about how these internal states emerge and are maintained, or what determines transitions between these states. We performed intracellular recordings from hippocampal CA3 pyramidal cells ex vivo and found that neurons display multiple and hierarchical internal states, which are linked to cholinergic activity and are characterized by several power law structures in membrane potential dynamics. Multiple recordings from adjacent neurons revealed that the internal states were coherent between neurons, indicating that the internal state of any given cell in a local network could represent the network activity state. Repeated stimulation of single neurons led over time to transitions to different internal states in both the stimulated neuron and neighboring neurons. Thus, single-cell activation is sufficient to shift the state of the entire local network. As the states shift to more active levels, theta- and gamma-frequency components developed in the form of subthreshold oscillations. State transitions were associated with changes in membrane conductance but were not accompanied by a change in reversal potential. These data suggest that the recurrent network organizes the internal states of individual neurons into synchronization through network activity with balanced excitation and inhibition, and that this organization is discrete, heterogeneous and dynamic in nature. Thus, neuronal states reflect the 'phase' of an active network, a novel demonstration of the dynamics and flexibility of cortical microcircuitry.
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Affiliation(s)
- Shigeyoshi Fujisawa
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
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165
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Nelson AB, Gittis AH, du Lac S. Decreases in CaMKII activity trigger persistent potentiation of intrinsic excitability in spontaneously firing vestibular nucleus neurons. Neuron 2005; 46:623-31. [PMID: 15944130 DOI: 10.1016/j.neuron.2005.04.009] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2004] [Revised: 01/20/2005] [Accepted: 04/13/2005] [Indexed: 11/16/2022]
Abstract
Calcium/calmodulin-dependent protein kinase II (CaMKII) has been described as a biochemical switch that is turned on by increases in intracellular calcium to mediate synaptic plasticity. Here, we show that reductions in CaMKII activity trigger persistent increases in intrinsic excitability. In spontaneously firing vestibular nucleus neurons, CaMKII activity is near maximal, and blockade of CaMKII activity increases excitability by reducing BK-type calcium-activated potassium currents. Firing rate potentiation, a form of plasticity in which synaptic inhibition induces long-lasting increases in excitability, is occluded by prior blockade of CaMKII and blocked by addition of constitutively active CaMKII. Reductions in CaMKII activity are necessary and sufficient to induce firing rate potentiation and may contribute to motor learning in the vestibulo-ocular reflex.
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Affiliation(s)
- Alexandra B Nelson
- Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
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166
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Grinstein G, Linsker R. Synchronous neural activity in scale-free network models versus random network models. Proc Natl Acad Sci U S A 2005; 102:9948-53. [PMID: 15998732 PMCID: PMC1175007 DOI: 10.1073/pnas.0504127102] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Synchronous firing peaks at levels greatly exceeding background activity have recently been reported in neocortical tissue. A small subset of neurons is dominant in a large fraction of the peaks. To investigate whether this striking behavior can emerge from a simple model, we constructed and studied a model neural network that uses a modified Hopfield-type dynamical rule. We find that networks having a power-law ("scale-free") node degree distribution readily generate extremely large synchronous firing peaks dominated by a small subset of nodes, whereas random (Erdös-Rényi) networks do not. This finding suggests that network topology may play an important role in determining the nature and magnitude of synchronous neural activity.
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Affiliation(s)
- Geoffrey Grinstein
- IBM Thomas J. Watson Research Center, 1101 Kitchawan Road & Route 134, PO Box 218, Yorktown Heights, NY 10598, USA
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167
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Abstract
Vertebrate spinal cord and brainstem central pattern generator (CPG) circuits share profound similarities with neocortical circuits. CPGs can produce meaningful functional output in the absence of sensory inputs. Neocortical circuits could be considered analogous to CPGs as they have rich spontaneous dynamics that, similar to CPGs, are powerfully modulated or engaged by sensory inputs, but can also generate output in their absence. We find compelling evidence for this argument at the anatomical, biophysical, developmental, dynamic and pathological levels of analysis. Although it is possible that cortical circuits are particularly plastic types of CPG ('learning CPGs'), we argue that present knowledge about CPGs is likely to foretell the basic principles of the organization and dynamic function of cortical circuits.
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Affiliation(s)
- Rafael Yuste
- Department of Biological Sciences, Columbia University, 1212 Amsterdam Avenue, Box 2435, New York 10027, USA.
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168
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Carmona MA, Pozas E, Martínez A, Espinosa-Parrilla JF, Soriano E, Aguado F. Age-dependent Spontaneous Hyperexcitability and Impairment of GABAergic Function in the Hippocampus of Mice Lacking trkB. Cereb Cortex 2005; 16:47-63. [PMID: 15829735 DOI: 10.1093/cercor/bhi083] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Patterned intrinsic network activity plays a central role in shaping immature neuronal networks into functional circuits. However, the long-lasting signals that regulate spontaneous activity of developing circuits have not been identified. Here we study the net impact of TrkB signaling on early network activity of identified neuronal populations by analyzing postnatal hippocampi from trkB null mice. Ca2+ imaging showed that pyramidal neurons of trkB-/- mice displayed a decrease in intrinsic synchronous activity in neonatal animals but an increase in juveniles. Strikingly, alterations in network activity in trkB-/- hippocampus were associated with an aberrant induction of the transcription factor Fos. In contrast to pyramidal neurons, spontaneous [Ca2+]i oscillations in trkB-/- interneurons were consistently impaired throughout postnatal development. Moreover, the number of GABAergic synapses and the expression levels of GAD65 and KCC2 were decreased in mutant hippocampi, indicating that pre- and post-synaptic GABAergic components were impaired in trkB-/- mice. Finally, the partial blockade of GABA(A) receptor in postnatal slices revealed that mutant hippocampi displayed an increased susceptibility to network hyperexcitability. These results indicate that the lack of TrkB signaling during development impairs GABAergic neurotransmission, thereby leading to an age-dependent decrease followed by an increase in the intrinsic excitability of neuronal circuits. Furthermore, the present study indicates that long-lasting TrkB signaling may contribute to the construction of CNS circuits by modulating patterns of spontaneous [Ca2+]i oscillations.
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Affiliation(s)
- Maria A Carmona
- Department of Cell Biology and IRBB-Barcelona Science Park, University of Barcelona, Barcelona E-08028, Spain
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169
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Ikegaya Y, Le Bon-Jego M, Yuste R. Large-scale imaging of cortical network activity with calcium indicators. Neurosci Res 2005; 52:132-8. [PMID: 15893573 DOI: 10.1016/j.neures.2005.02.004] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Accepted: 02/21/2005] [Indexed: 12/23/2022]
Abstract
Bulk loading of calcium indicators has provided a unique opportunity to reconstruct the activity of cortical networks with single-cell resolution. Here we describe the detailed methods of bulk loading of AM dyes we developed and have been improving for imaging with a spinning disk confocal microscope.
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Affiliation(s)
- Yuji Ikegaya
- Department of Biological Sciences, Columbia University, 1002 Fairchild Center, M.C. 2435 New York, NY 10027, USA.
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170
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Song S, Sjöström PJ, Reigl M, Nelson S, Chklovskii DB. Highly nonrandom features of synaptic connectivity in local cortical circuits. PLoS Biol 2005; 3:e68. [PMID: 15737062 PMCID: PMC1054880 DOI: 10.1371/journal.pbio.0030068] [Citation(s) in RCA: 900] [Impact Index Per Article: 47.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2004] [Accepted: 12/17/2004] [Indexed: 11/20/2022] Open
Abstract
How different is local cortical circuitry from a random network? To answer this question, we probed synaptic connections with several hundred simultaneous quadruple whole-cell recordings from layer 5 pyramidal neurons in the rat visual cortex. Analysis of this dataset revealed several nonrandom features in synaptic connectivity. We confirmed previous reports that bidirectional connections are more common than expected in a random network. We found that several highly clustered three-neuron connectivity patterns are overrepresented, suggesting that connections tend to cluster together. We also analyzed synaptic connection strength as defined by the peak excitatory postsynaptic potential amplitude. We found that the distribution of synaptic connection strength differs significantly from the Poisson distribution and can be fitted by a lognormal distribution. Such a distribution has a heavier tail and implies that synaptic weight is concentrated among few synaptic connections. In addition, the strengths of synaptic connections sharing pre- or postsynaptic neurons are correlated, implying that strong connections are even more clustered than the weak ones. Therefore, the local cortical network structure can be viewed as a skeleton of stronger connections in a sea of weaker ones. Such a skeleton is likely to play an important role in network dynamics and should be investigated further. A dataset of hundreds of recordings in which four neurons were simultaneously monitored reveals clustered connectivity patterns among cortical neurons
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Affiliation(s)
- Sen Song
- 1Cold Spring Harbor Laboratory, Cold Spring HarborNew YorkUnited States of America
| | - Per Jesper Sjöström
- 2Department of Biology and Volen National Center for Complex Systems, Brandeis UniversityWaltham, MassachusettsUnited States of America
- 3Wolfson Institute for Biomedical Research and Department of Physiology, University CollegeLondonUnited Kingdom
| | - Markus Reigl
- 1Cold Spring Harbor Laboratory, Cold Spring HarborNew YorkUnited States of America
| | - Sacha Nelson
- 2Department of Biology and Volen National Center for Complex Systems, Brandeis UniversityWaltham, MassachusettsUnited States of America
| | - Dmitri B Chklovskii
- 1Cold Spring Harbor Laboratory, Cold Spring HarborNew YorkUnited States of America
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171
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Abstract
When the brain goes from wakefulness to sleep, cortical neurons begin to undergo slow oscillations in their membrane potential that are synchronized by thalamocortical circuits and reflected in EEG slow waves. To provide a self-consistent account of the transition from wakefulness to sleep and of the generation of sleep slow waves, we have constructed a large-scale computer model that encompasses portions of two visual areas and associated thalamic and reticular thalamic nuclei. Thousands of model neurons, incorporating several intrinsic currents, are interconnected with millions of thalamocortical, corticothalamic, and both intra- and interareal corticocortical connections. In the waking mode, the model exhibits irregular spontaneous firing and selective responses to visual stimuli. In the sleep mode, neuromodulatory changes lead to slow oscillations that closely resemble those observed in vivo and in vitro. A systematic exploration of the effects of intrinsic currents and network parameters on the initiation, maintenance, and termination of slow oscillations shows the following. 1) An increase in potassium leak conductances is sufficient to trigger the transition from wakefulness to sleep. 2) The activation of persistent sodium currents is sufficient to initiate the up-state of the slow oscillation. 3) A combination of intrinsic and synaptic currents is sufficient to maintain the up-state. 4) Depolarization-activated potassium currents and synaptic depression terminate the up-state. 5) Corticocortical connections synchronize the slow oscillation. The model is the first to integrate intrinsic neuronal properties with detailed thalamocortical anatomy and reproduce neural activity patterns in both wakefulness and sleep, thereby providing a powerful tool to investigate the role of sleep in information transmission and plasticity.
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Affiliation(s)
- Sean Hill
- Department of Psychiatry, University of Wisconsin-Madison, 6001 Research Park Boulevard, Madison, WI 53719-1176, USA.
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172
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Karpuk NN, Vorob'ev VV. The role of the electrophysiological properties of neurons in the mechanisms grouping their discharges in the cerebral cortex. ACTA ACUST UNITED AC 2005; 34:881-8. [PMID: 15686133 DOI: 10.1023/b:neab.0000042572.67704.f5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Studies using intracellular recording in living slices of rat sensorimotor cortex addressed the interaction between the properties of neuron spike activity (n = 80) and the membrane potentials of the neurons. Spike sequences containing discharges with regularly increasing and decreasing interspike intervals were analyzed. Parameters were identified which were closely associated with the mean neuron discharge frequency: the number of spikes in sequences (5-30% of the total number of spikes recorded), the amplitude of oscillations in the afterhyperpolarization potential (0-1.5 mV), etc. There was a biphasic relationship in changes in the number of spikes in sequences with a critical mean discharge frequency over the range 5-7 Hz. Groups of cells without and with a depolarization component in conditions of afterhyperpolarization had different morphological and electrophysiological properties, though the relationships between their parameter and mean discharge frequency were similar. The possible roles of spike sequences and these regular features in the formation of rhythmic processes in the neocortex are discussed.
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Affiliation(s)
- N N Karpuk
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino.
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173
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Wyart C, Cocco S, Bourdieu L, Léger JF, Herr C, Chatenay D. Dynamics of excitatory synaptic components in sustained firing at low rates. J Neurophysiol 2005; 93:3370-80. [PMID: 15673554 DOI: 10.1152/jn.00530.2004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sustained firing is necessary for the persistent activity associated with working memory. The relative contributions of the reverberation of excitation and of the temporal dynamics of the excitatory postsynaptic potential (EPSP) to the maintenance of activity are difficult to evaluate in classical preparations. We used simplified models of synchronous excitatory networks, hippocampal autapses and pairs, to study the synaptic mechanisms underlying firing at low rates. Calcium imaging and cell attached recordings showed that these neurons spontaneously fired bursts of action potentials that lasted for seconds over a wide range of frequencies. In 2-wk-old cells, the median firing frequency was low (11 +/- 8.8 Hz), whereas in 3- to 4-wk-old cells, it decreased to a very low value (2 +/- 1.3 Hz). In both cases, we have shown that the slowest synaptic component supported firing. In 2-wk-old autapses, antagonists of N-methyl-d-aspartate receptors (NMDARs) induced rare isolated spikes showing that the NMDA component of the EPSP was essential for bursts at low frequency. In 3- to 4-wk-old neurons, the very low frequency firing was maintained without the NMDAR activation. However EGTA-AM or alpha-methyl-4-carboxyphenylglycine (MCPG) removed the very slow depolarizing component of the EPSP and prevented the sustained firing at very low rate. A metabotropic glutamate receptor (mGluR)-activated calcium sensitive conductance is therefore responsible for a very slow synaptic component associated with firing at very low rate. In addition, our observations suggested that the asynchronous release of glutamate might participate also in the recurring bursting.
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Affiliation(s)
- Claire Wyart
- Laboratoire de Dynamique des Fluides Complexes, Unité 7506 Centre National de la Recherche Scientifique, Université Louis Pasteur, Institut de Physique, Strasbourg, France
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174
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Ohki K, Chung S, Ch'ng YH, Kara P, Reid RC. Functional imaging with cellular resolution reveals precise micro-architecture in visual cortex. Nature 2005; 433:597-603. [PMID: 15660108 DOI: 10.1038/nature03274] [Citation(s) in RCA: 784] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2004] [Accepted: 12/14/2004] [Indexed: 11/09/2022]
Abstract
Neurons in the cerebral cortex are organized into anatomical columns, with ensembles of cells arranged from the surface to the white matter. Within a column, neurons often share functional properties, such as selectivity for stimulus orientation; columns with distinct properties, such as different preferred orientations, tile the cortical surface in orderly patterns. This functional architecture was discovered with the relatively sparse sampling of microelectrode recordings. Optical imaging of membrane voltage or metabolic activity elucidated the overall geometry of functional maps, but is averaged over many cells (resolution >100 microm). Consequently, the purity of functional domains and the precision of the borders between them could not be resolved. Here, we labelled thousands of neurons of the visual cortex with a calcium-sensitive indicator in vivo. We then imaged the activity of neuronal populations at single-cell resolution with two-photon microscopy up to a depth of 400 microm. In rat primary visual cortex, neurons had robust orientation selectivity but there was no discernible local structure; neighbouring neurons often responded to different orientations. In area 18 of cat visual cortex, functional maps were organized at a fine scale. Neurons with opposite preferences for stimulus direction were segregated with extraordinary spatial precision in three dimensions, with columnar borders one to two cells wide. These results indicate that cortical maps can be built with single-cell precision.
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Affiliation(s)
- Kenichi Ohki
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115, USA
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175
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Menendez de la Prida L, Gal B. Synaptic contributions to focal and widespread spatiotemporal dynamics in the isolated rat subiculum in vitro. J Neurosci 2004; 24:5525-36. [PMID: 15201325 PMCID: PMC6729319 DOI: 10.1523/jneurosci.0309-04.2004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The subiculum, which has a strategic position in controlling hippocampal activity, is receiving significant attention in epilepsy research. However, the functional organization of subicular circuits remains unknown. Here, we combined different recording and analytical methods to study focal and widespread population activity in the isolated subiculum in zero Mg2+ media. Patch and field recordings were combined to examine the contribution of different cell types to population activity. The properties of cells leading field activity were examined. Predictive factors for a cell to behave as leader included exhibiting the bursting phenotype, displaying a low firing threshold, and having more distal apical dendrites. A subset of bursting cells constituted the first glutamatergic type that led a recruitment process that subsequently activated additional excitatory as well as inhibitory cells. This defined a sequence of synaptic excitation and inhibition that was studied by measuring the associated conductance changes and the evolution of the composite reversal potential. It is shown that inhibition was time-locked to excitation, which shunted excitatory inputs and suppressed firing during focal activity. This was recorded extracellularly as a multi-unit ensemble of active cells, the spatial boundaries of which were controlled by inhibition in contrast to widespread epileptiform activity. Focal activity was not dependent on the preparation or the developmental state because it was also recorded under 5 mm [K+]o and in adult tissue. Our data indicate that the subicular networks can be spontaneously organized as leader-follower local circuits in which excitation is mainly driven by a subset of bursting cells and inhibition controls spatiotemporal firing.
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Affiliation(s)
- L Menendez de la Prida
- Departamento de Neurobiología-Investigación, Hospital Ramón y Cajal, Madrid 28034, Spain.
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176
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de Lecea L. Reverse Genetics and the Study of Sleep-Wake Cycle. Sleep 2004. [DOI: 10.1201/9780203496732.ch6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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177
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Sachdev RNS, Ebner FF, Wilson CJ. Effect of subthreshold up and down states on the whisker-evoked response in somatosensory cortex. J Neurophysiol 2004; 92:3511-21. [PMID: 15254074 DOI: 10.1152/jn.00347.2004] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Changes in spontaneous activity within the cortex recognized by subthreshold fluctuations of the membrane potential of cortical neurons modified the response of cortical neurons to sensory stimuli. Sensory stimuli occurring in the hyperpolarized "down" state evoked a larger depolarization and were more effective in evoking action potentials than stimuli occurring in the depolarized "up" state. Direct electrical stimulation of the thalamus showed the same dependence on the cell's state at the time of the stimulus, ruling out a strictly thalamic mechanism. Stimuli were more effective at triggering action potentials in the down state even during moderate de- or hyperpolarization of the somatic membrane potential. The postsynaptic potential (PSP) evoked from the down state was larger than the up state PSP but achieved about the same peak membrane potential, which was also near the reversal potential of the PSP (about -51 mV). Chloride loading shifted the reversal potentials of both the up state and the whisker-evoked PSP toward a more depolarized membrane potential. In addition, the threshold for action potentials evoked from the down state was lower than for spikes evoked in the up state. Thus the larger PSP from the down state may be caused by its larger driving force, and the state dependence of action potential generation in response to whisker stimulation may in part be related to a shift in threshold. Different mechanisms are therefore responsible for the state-dependence of PSP amplitude and the spike frequency response to the whisker stimulus.
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Affiliation(s)
- Robert N S Sachdev
- Department of Biology, University of Texas, San Antonio 78249-0662, USA.
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178
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Abstract
When a cortical neuron is repeatedly injected with the same fluctuating current stimulus (frozen noise) the timing of the spikes is highly precise from trial to trial and the spike pattern appears to be unique. We show here that the same repeated stimulus can produce more than one reliable temporal pattern of spikes. A new method is introduced to find these patterns in raw multitrial data and is tested on surrogate data sets. Using it, multiple coexisting spike patterns were discovered in pyramidal cells recorded from rat prefrontal cortex in vitro, in data obtained in vivo from the middle temporal area of the monkey (Buracas et al., 1998) and from the cat lateral geniculate nucleus (Reinagel and Reid, 2002). The spike patterns lasted from a few tens of milliseconds in vitro to several seconds in vivo. We conclude that the prestimulus history of a neuron may influence the precise timing of the spikes in response to a stimulus over a wide range of time scales.
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Affiliation(s)
- Jean-Marc Fellous
- Computational Neurobiology Laboratory, Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, California 92037, USA.
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179
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Ikegaya Y, Aaron G, Cossart R, Aronov D, Lampl I, Ferster D, Yuste R. Synfire Chains and Cortical Songs: Temporal Modules of Cortical Activity. Science 2004; 304:559-64. [PMID: 15105494 DOI: 10.1126/science.1093173] [Citation(s) in RCA: 532] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
How can neural activity propagate through cortical networks built with weak, stochastic synapses? We find precise repetitions of spontaneous patterns of synaptic inputs in neocortical neurons in vivo and in vitro. These patterns repeat after minutes, maintaining millisecond accuracy. Calcium imaging of slices reveals reactivation of sequences of cells during the occurrence of repeated intracellular synaptic patterns. The spontaneous activity drifts with time, engaging different cells. Sequences of active neurons have distinct spatial structures and are repeated in the same order over tens of seconds, revealing modular temporal dynamics. Higher order sequences are replayed with compressed timing.
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Affiliation(s)
- Yuji Ikegaya
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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180
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Kang S, Kitano K, Fukai T. Self-organized two-state membrane potential transitions in a network of realistically modeled cortical neurons. Neural Netw 2004; 17:307-12. [PMID: 15037349 DOI: 10.1016/j.neunet.2003.11.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2003] [Revised: 11/07/2003] [Accepted: 11/07/2003] [Indexed: 10/26/2022]
Abstract
Recent studies have revealed that in vivo cortical neurons show spontaneous transitions between two subthreshold levels of the membrane potentials, 'up' and 'down' states. The neural mechanism of generating those spontaneous states transitions, however, remains unclear. Recent electrophysiological studies have suggested that those state transitions may occur through activation of a hyperpolarization-activated cation current (H-current), possibly by inhibitory synaptic inputs. Here, we demonstrate that two-state membrane potential fluctuations similar to those exhibited by in vivo neurons can be generated through a spike-timing-dependent self-organizing process in a network of inhibitory neurons and excitatory neurons expressing the H-current.
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Affiliation(s)
- Siu Kang
- Department of Information-Communication Engineering, Tamagawa University, 6-1-1 Machidashi, Tamagawa-gakuen, Tokyo, Japan.
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181
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Murray KD, Isackson PJ, Jones EG. N-methyl-D-aspartate receptor dependent transcriptional regulation of two calcium/calmodulin-dependent protein kinase type II isoforms in rodent cerebral cortex. Neuroscience 2004; 122:407-20. [PMID: 14614906 DOI: 10.1016/j.neuroscience.2003.07.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Alpha Calcium/calmodulin-dependent protein kinase type II (CaMKII-alpha) expression is regulated in an activity-dependent manner, but it is not known whether other CaMKII isoforms (beta, delta, and gamma) are similarly regulated. We examined the activity-dependent regulation of these CaMKII isoforms in vivo, using a model of generalized seizures caused by i.p. injection of kainic acid. Following seizure induction, CaMKII-alpha expression was downregulated and CaMKII-delta expression upregulated while CaMKII-beta and CaMKII-gamma expression was unaffected. A transient downregulation in CaMKII-alpha and a transient increase in CaMKII-delta occurred throughout neocortex in the same temporal order. Although CaMKII-alpha mRNA was decreased by seizure activity, the less abundant, alternatively spliced, CaMKII-alpha33 mRNA was unaffected. Organotypic cortical slice cultures treated with bicuculline and 4-aminopyridine to induce seizure activity also showed a downregulation of CaMKII-alpha mRNA and an upregulation of CaMKII-delta mRNA. Prior exposure to tetrodotoxin prevented the changes in CaMKII-alpha and CaMKII-delta mRNA regulation and this was mimicked by D-L-2-amino-5-phosphonovaleric acid, but not by 6-cyano-2,3-dihydroxy-7-nitro-quinoxaline, suggesting that CaMKII-alpha and CaMKII-delta mRNA expression is regulated in an N-methyl-D-aspartate receptor-dependent manner. Regulation was also transcription dependent. Blocking transcription with actinomycin-D prevented activity-dependent changes in CaMKII-alpha and CaMKII-delta mRNA, but produced opposite effects on basal transcription, resulting in more stabilized CaMKII-alpha mRNA and less stabilized CaMKII-delta mRNA. These results reveal unique patterns of seizure-induced alterations in CaMKII mRNAs. Activity-dependent changes in subunit composition could, therefore, differentially influence the functional attributes of the CaMKII holoenzyme.
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Affiliation(s)
- K D Murray
- Center for Neuroscience, University of California, Davis, 1544 Newton Court, Davis, CA 95616, USA
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182
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Maravall M, Stern EA, Svoboda K. Development of intrinsic properties and excitability of layer 2/3 pyramidal neurons during a critical period for sensory maps in rat barrel cortex. J Neurophysiol 2004; 92:144-56. [PMID: 14973314 DOI: 10.1152/jn.00598.2003] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The development of layer 2/3 sensory maps in rat barrel cortex (BC) is experience dependent with a critical period around postnatal days (PND) 10-14. The role of intrinsic response properties of neurons in this plasticity has not been investigated. Here we characterize the development of BC layer 2/3 intrinsic responses to identify possible sites of plasticity. Whole cell recordings were performed on pyramidal cells in acute BC slices from control and deprived rats, over ages spanning the critical period (PND 12, 14, and 17). Vibrissa trimming began at PND 9. Spiking behavior changed from phasic (more spike frequency adaptation) to regular (less adaptation) with age, such that the number of action potentials per stimulus increased. Changes in spiking properties were related to the strength of a slow Ca(2+)-dependent afterhyperpolarization. Maturation of the spiking properties of layer 2/3 pyramidal neurons coincided with the close of the critical period and was delayed by deprivation. Other measures of excitability, including I-f curves and passive membrane properties, were affected by development but unaffected by whisker deprivation.
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Affiliation(s)
- Miguel Maravall
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA.
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183
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Legrand JC, Darbon P, Streit J. Contributions of NMDA receptors to network recruitment and rhythm generation in spinal cord cultures. Eur J Neurosci 2004; 19:521-32. [PMID: 14984403 DOI: 10.1111/j.0953-816x.2003.03143.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
N-methyl-d-aspartic acid (NMDA) receptors are implicated in fictive locomotion; however, their precise role there is not clear. In cultures of dissociated cells from foetal rat spinal cord, synchronous bursting (but not fictive locomotion) can be induced by disinhibition, which is produced by blocking glycinergic and gamma-aminobutyric acid (GABA)A-dependent synaptic conductances. In this study, we investigate the role of NMDA-R in rhythm generation during disinhibition with multielectrode arrays and patch-clamp. We previously determined that bursting activity is generated by repetitive recruitment of a network through recurrent excitation. Blocking NMDA-R with d(-)-2-amino-5-phosphonopentanoic acid (APV) decreased the burst duration, suggesting a role of such receptors in the maintenance of high network activity during the bursts. In addition, APV reduced burst rate in about a third of the experiments, suggesting a contribution of NMDA-R in network recruitment. When (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid hydrate (AMPA)/kainate receptors were blocked with 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) in the presence of disinhibition, the burst rate was reduced and burst onset was slowed in two-thirds of the experiments. In the remaining experiments, bursting ceased completely with CNQX. Neither APV nor CNQX changed the spatial patterns of activity in the network, suggesting a co-operation of both receptors in rhythm generation. While NMDA alone was not able to create a rhythm, it accelerated bursting in the presence of disinhibition, made it more regular and slowed down network recruitment. These effects were most likely due to the depolarization of the interneurons in the network. We conclude that NMDA-R contribute to rhythm generation in spinal cultures by supporting recurrent excitation and network recruitment and by depolarizing the network.
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184
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Béïque JC, Chapin-Penick EM, Mladenovic L, Andrade R. Serotonergic facilitation of synaptic activity in the developing rat prefrontal cortex. J Physiol 2004; 556:739-54. [PMID: 14742723 PMCID: PMC1665004 DOI: 10.1113/jphysiol.2003.051284] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Previous studies have outlined an important role for serotonin (5-HT) in the development of synaptic connectivity and function in the cerebral cortex. In this study, we have examined the effects of 5-HT on synaptic function in prefrontal cortex at a time of intense synapse formation and remodelling. Whole-cell recordings in slices derived from animals aged postnatal (P) days 16-20 showed that administration of 5-HT induced a robust increase in synaptic activity that was blocked by CNQX but not by bicuculline. This 5-HT-induced increase in glutamate-mediated synaptic activity was pharmacologically heterogeneous as it was differentially inhibited by the receptor subtype-selective antagonists SB-269970, MDL 100907 and GR 113808 and thus involved 5-HT(7), 5-HT(2A) and 5-HT(4) receptors. These results, obtained in juvenile cortex, contrast with those seen in adults where the increase in spontaneous excitatory postsynaptic currents (sEPSCs) was mediated solely by 5-HT(2A) receptors. In developing cortex, activation of 5-HT(7), but not 5-HT(2A) or 5-HT(4) receptors, elicited a robust inward current. However, the facilitation of synaptic activity mediated by all three of these receptors involved increases in both the amplitude and frequency of sEPSCs and was blocked by TTX. These results are best interpreted as indicating that all three receptor subtypes increase synaptic activity by exciting neuronal elements within the slice. No evidence was found for a postsynaptic facilitation of synaptic currents by 5-HT. Together, these results show that the repertoire of electrophysiologically active 5-HT receptors in prefrontal cortex is developmentally regulated, and that 5-HT(7) and 5-HT(4) receptors play a previously unsuspected role in regulating synaptic activity in this region.
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MESH Headings
- 6-Cyano-7-nitroquinoxaline-2,3-dione/pharmacology
- Amphetamines/pharmacology
- Animals
- Bicuculline/pharmacology
- Fluorobenzenes/pharmacology
- GABA-A Receptor Antagonists
- Glutamic Acid/pharmacology
- Indoles/pharmacology
- Lidocaine/analogs & derivatives
- Lidocaine/pharmacology
- Male
- Patch-Clamp Techniques
- Phenols/pharmacology
- Pindolol/analogs & derivatives
- Pindolol/pharmacology
- Piperidines/pharmacology
- Prefrontal Cortex/cytology
- Prefrontal Cortex/drug effects
- Prefrontal Cortex/physiology
- Pyramidal Cells/drug effects
- Pyramidal Cells/physiology
- Rats
- Rats, Sprague-Dawley
- Receptor, Serotonin, 5-HT2A/physiology
- Receptors, AMPA/antagonists & inhibitors
- Receptors, AMPA/physiology
- Receptors, Metabotropic Glutamate/antagonists & inhibitors
- Receptors, Serotonin/physiology
- Receptors, Serotonin, 5-HT4/physiology
- Serotonin/pharmacology
- Serotonin/physiology
- Serotonin 5-HT1 Receptor Antagonists
- Serotonin 5-HT2 Receptor Antagonists
- Serotonin 5-HT4 Receptor Antagonists
- Serotonin Antagonists/pharmacology
- Sodium Channel Blockers/pharmacology
- Sulfonamides/pharmacology
- Synapses/drug effects
- Synapses/physiology
- Tetrodotoxin/pharmacology
- Time Factors
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Affiliation(s)
- Jean-Claude Béïque
- Department of Psychiatry and Behavioural Neurosciences, Wayne State University School of Medicine, 540 E. Canfield, Rm 2309 Scott Hall, Detroit, MI 48201, USA.
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185
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Mizutani K, Shimoi T, Kitamura Y, Ogawa H, Oka K. Identification of two types of synaptic activity in the earthworm nervous system during locomotion. Neuroscience 2003; 121:473-8. [PMID: 14522005 DOI: 10.1016/s0306-4522(03)00492-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the ventral nervous system of the earthworm, a central pattern generator and motor neurons are activated during locomotion. We have previously reported that bath application of octopamine (OA) induces fictive locomotion in the earthworm, and the burst frequency of electrical activity from the first lateral nerves increases with OA concentration. However, there are no reports concerning locomotor neural networks in the earthworm. To identify neural networks involved in fictive locomotion, we optically monitored activity-dependent fluorescent staining in the earthworm ventral nerve cord (VNC) with a styryl dye, N-(3-triethylammoniumpropyl)-4-(4-(dibutylamino)styryl)pyridinium dibromide (FM1-43), and a confocal laser scanning microscope. OA induces FM1-43 fluorescence in a dose-dependent manner, with bright fluorescent spots of 3-10 microm in diameter observed to be localized around specified neurons in the segmental ganglion of the VNC. We compared OA dose-response curves for FM1-43 fluorescence with the bursting frequency for fictive locomotion, and found that two types of curves could be identified: one fluorescence response shows a similar dose-dependency to that of the burst frequency, while another response has a higher sensitivity to OA. From these results, we suggest that OA acts as one of the neuromodulators for the earthworm locomotion. This is the first attempt to record motor and inter-neuronal activities simultaneously in a locomotor network in the earthworm.
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Affiliation(s)
- K Mizutani
- Center for Life Science and Technology, School of Fundamental Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
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186
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Fellous JM, Sejnowski TJ. Regulation of persistent activity by background inhibition in an in vitro model of a cortical microcircuit. ACTA ACUST UNITED AC 2003; 13:1232-41. [PMID: 14576214 PMCID: PMC2928820 DOI: 10.1093/cercor/bhg098] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We combined in vitro intracellular recording from prefrontal cortical neurons with simulated synaptic activity of a layer 5 prefrontal microcircuit using a dynamic clamp. During simulated in vivo background conditions, the cell responded to a brief depolarization with a sequence of spikes that outlasted the depolarization, mimicking the activity of a cell recorded during the delay period of a working memory task in the behaving monkey. The onset of sustained activity depended on the number of action potentials elicited by the cue-like depolarization. Too few spikes failed to provide enough NMDA drive to elicit sustained reverberations; too many spikes activated a slow intrinsic hyperpolarization current that prevented spiking; an intermediate number of spikes produced sustained activity. When high dopamine levels were simulated by depolarizing the cell and by increasing the amount of NMDA current, the cell exhibited spontaneous 'up-states' that terminated by the activation of a slow intrinsic hyperpolarizing current. The firing rate during the delay period could be effectively modulated by the standard deviation of the inhibitory background synaptic noise without significant changes in the background firing rate before cue onset. These results suggest that the balance between fast feedback inhibition and slower AMPA and NMDA feedback excitation is critical in initiating persistent activity and that the maintenance of persistent activity may be regulated by the amount of correlated background inhibition.
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Affiliation(s)
- Jean-Marc Fellous
- Computational Neurobiology Laboratory, Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
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187
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Dent EW, Tang F, Kalil K. Axon guidance by growth cones and branches: common cytoskeletal and signaling mechanisms. Neuroscientist 2003; 9:343-53. [PMID: 14580119 DOI: 10.1177/1073858403252683] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Growing axons are guided to appropriate targets by responses of their motile growth cones to environmental cues. Interstitial axon branching is also an important form of axon guidance in the mammalian CNS. Visualization of growing axons in cortical slices and in dissociated cortical cultures showed that growth cone pausing behaviors demarcate sites of future axon branching. Studies of vertebrate and invertebrate growth cones suggest common mechanisms that regulate growth cone behaviors and axon branching. These include reorganization of the actin and microtubule cytoskeleton, dynamic interactions between microtubules and actin filaments, effects of axon guidance molecules, actions of actin regulatory proteins, and dynamic changes in intracellular calcium signaling. Future challenges will be to extend high-resolution imaging of single neurons to studies of intracellular events in the intact nervous system and to apply knowledge of developmental mechanisms to the promotion of axon sprouting after injury in the adult CNS.
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Affiliation(s)
- Erik W Dent
- Department of Anatomy, University of Wisconsin, Madison 53706, USA
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188
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Csicsvari J, Henze DA, Jamieson B, Harris KD, Sirota A, Barthó P, Wise KD, Buzsáki G. Massively parallel recording of unit and local field potentials with silicon-based electrodes. J Neurophysiol 2003; 90:1314-23. [PMID: 12904510 DOI: 10.1152/jn.00116.2003] [Citation(s) in RCA: 253] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Parallel recording of neuronal activity in the behaving animal is a prerequisite for our understanding of neuronal representation and storage of information. Here we describe the development of micro-machined silicon microelectrode arrays for unit and local field recordings. The two-dimensional probes with 96 or 64 recording sites provided high-density recording of unit and field activity with minimal tissue displacement or damage. The on-chip active circuit eliminated movement and other artifacts and greatly reduced the weight of the headgear. The precise geometry of the recording tips allowed for the estimation of the spatial location of the recorded neurons and for high-resolution estimation of extracellular current source density. Action potentials could be simultaneously recorded from the soma and dendrites of the same neurons. Silicon technology is a promising approach for high-density, high-resolution sampling of neuronal activity in both basic research and prosthetic devices.
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Affiliation(s)
- Jozsef Csicsvari
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, Newark, New Jersey 07102, USA
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189
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Stosiek C, Garaschuk O, Holthoff K, Konnerth A. In vivo two-photon calcium imaging of neuronal networks. Proc Natl Acad Sci U S A 2003; 100:7319-24. [PMID: 12777621 PMCID: PMC165873 DOI: 10.1073/pnas.1232232100] [Citation(s) in RCA: 905] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two-photon calcium imaging is a powerful means for monitoring the activity of distinct neurons in brain tissue in vivo. In the mammalian brain, such imaging studies have been restricted largely to calcium recordings from neurons that were individually dye-loaded through microelectrodes. Previous attempts to use membrane-permeant forms of fluorometric calcium indicators to load populations of neurons have yielded satisfactory results only in cell cultures or in slices of immature brain tissue. Here we introduce a versatile approach for loading membrane-permeant fluorescent indicator dyes in large populations of cells. We established a pressure ejection-based local dye delivery protocol that can be used for a large spectrum of membrane-permeant indicator dyes, including calcium green-1 acetoxymethyl (AM) ester, Fura-2 AM, Fluo-4 AM, and Indo-1 AM. We applied this dye-loading protocol successfully in mouse brain tissue at any developmental stage from newborn to adult in vivo and in vitro. In vivo two-photon Ca2+ recordings, obtained by imaging through the intact skull, indicated that whisker deflection-evoked Ca2+ transients occur in a subset of layer 2/3 neurons of the barrel cortex. Thus, our results demonstrate the suitability of this technique for real-time analyses of intact neuronal circuits with the resolution of individual cells.
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Affiliation(s)
- Christoph Stosiek
- Physiologisches Institut, Ludwig-Maximilians Universität München, Pettenkoferstrasse 12, 80336 Munich, Germany
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190
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Abstract
Properties of neuronal discharges and their interrelationship with mean evoked firing rate (MF) were investigated in detail in the rat somatosensory cortex in vitro. Firing was evoked by 1-min depolarizing current injection (0.1-1.0 nA) into pyramidal neurons (n=93) of layers II/III and V. Spike sequence patterns (SSPs) with consecutive increasing or decreasing interspike intervals were analyzed. SSP rate (change of pattern, 2-50 min(-1)) and the deviations of afterhyperpolarizing potentials (up to 1.5 mV) associated with the SSPs were significantly correlated with MF. The number of transitions in spike frequency was dependent on the MF and showed a biphasic interrelation with a reversible point at 5-8 Hz. All neurons analysed were subdivided into two groups: with depolarizing potential after single spike and without such afterdepolarizing potential. It was found that despite significant differences in electrophysiological properties of the cells from these groups, similar dependency in patterns of their discharges upon MF was observed. A possible role of spike sequence patterns in neocortical rhythmical processes is discussed.
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Affiliation(s)
- Nikolai Karpuk
- Institute of Cell Biophysics, Russian Academy of Sciences, 142290 Pushchino, Russia.
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191
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Shu Y, Hasenstaub A, McCormick DA. Turning on and off recurrent balanced cortical activity. Nature 2003; 423:288-93. [PMID: 12748642 DOI: 10.1038/nature01616] [Citation(s) in RCA: 726] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2002] [Accepted: 03/28/2003] [Indexed: 11/09/2022]
Abstract
The vast majority of synaptic connections onto neurons in the cerebral cortex arise from other cortical neurons, both excitatory and inhibitory, forming local and distant 'recurrent' networks. Although this is a basic theme of cortical organization, its study has been limited largely to theoretical investigations, which predict that local recurrent networks show a proportionality or balance between recurrent excitation and inhibition, allowing the generation of stable periods of activity. This recurrent activity might underlie such diverse operations as short-term memory, the modulation of neuronal excitability with attention, and the generation of spontaneous activity during sleep. Here we show that local cortical circuits do indeed operate through a proportional balance of excitation and inhibition generated through local recurrent connections, and that the operation of such circuits can generate self-sustaining activity that can be turned on and off by synaptic inputs. These results confirm the long-hypothesized role of recurrent activity as a basic operation of the cerebral cortex.
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Affiliation(s)
- Yousheng Shu
- Department of Neurobiology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06510, USA
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192
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Cossart R, Aronov D, Yuste R. Attractor dynamics of network UP states in the neocortex. Nature 2003; 423:283-8. [PMID: 12748641 DOI: 10.1038/nature01614] [Citation(s) in RCA: 416] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2002] [Accepted: 03/25/2003] [Indexed: 11/08/2022]
Abstract
The cerebral cortex receives input from lower brain regions, and its function is traditionally considered to be processing that input through successive stages to reach an appropriate output. However, the cortical circuit contains many interconnections, including those feeding back from higher centres, and is continuously active even in the absence of sensory inputs. Such spontaneous firing has a structure that reflects the coordinated activity of specific groups of neurons. Moreover, the membrane potential of cortical neurons fluctuates spontaneously between a resting (DOWN) and a depolarized (UP) state, which may also be coordinated. The elevated firing rate in the UP state follows sensory stimulation and provides a substrate for persistent activity, a network state that might mediate working memory. Using two-photon calcium imaging, we reconstructed the dynamics of spontaneous activity of up to 1,400 neurons in slices of mouse visual cortex. Here we report the occurrence of synchronized UP state transitions ('cortical flashes') that occur in spatially organized ensembles involving small numbers of neurons. Because of their stereotyped spatiotemporal dynamics, we conclude that network UP states are circuit attractors--emergent features of feedback neural networks that could implement memory states or solutions to computational problems.
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Affiliation(s)
- Rosa Cossart
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA.
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193
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Aguado F, Carmona MA, Pozas E, Aguiló A, Martínez-Guijarro FJ, Alcantara S, Borrell V, Yuste R, Ibañez CF, Soriano E. BDNF regulates spontaneous correlated activity at early developmental stages by increasing synaptogenesis and expression of the K+/Cl- co-transporter KCC2. Development 2003; 130:1267-80. [PMID: 12588844 DOI: 10.1242/dev.00351] [Citation(s) in RCA: 216] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Spontaneous neural activity is a basic property of the developing brain, which regulates key developmental processes, including migration, neural differentiation and formation and refinement of connections. The mechanisms regulating spontaneous activity are not known. By using transgenic embryos that overexpress BDNF under the control of the nestin promoter, we show here that BDNF controls the emergence and robustness of spontaneous activity in embryonic hippocampal slices. Further, BDNF dramatically increases spontaneous co-active network activity, which is believed to synchronize gene expression and synaptogenesis in vast numbers of neurons. In fact, BDNF raises the spontaneous activity of E18 hippocampal neurons to levels that are typical of postnatal slices. We also show that BDNF overexpression increases the number of synapses at much earlier stages (E18) than those reported previously. Most of these synapses were GABAergic, and GABAergic interneurons showed hypertrophy and a 3-fold increase in GAD expression. Interestingly, whereas BDNF does not alter the expression of GABA and glutamate ionotropic receptors, it does raise the expression of the recently cloned K(+)/Cl(-) KCC2 co-transporter, which is responsible for the conversion of GABA responses from depolarizing to inhibitory, through the control of the Cl(-) potential. Together, results indicate that both the presynaptic and postsynaptic machineries of GABAergic circuits may be essential targets of BDNF actions to control spontaneous activity. The data indicate that BDNF is a potent regulator of spontaneous activity and co-active networks, which is a new level of regulation of neurotrophins. Given that BDNF itself is regulated by neuronal activity, we suggest that BDNF acts as a homeostatic factor controlling the emergence, complexity and networking properties of spontaneous networks.
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Affiliation(s)
- Fernando Aguado
- Department of Cell Biology Faculty of Biology, and Barcelona Science Park, University of Barcelona, Barcelona 08028, Spain
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194
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Abstract
Growth cones of cortical axons pause for many hours in preparation for axon branching. They become large and complex compared with small advancing growth cones. We wanted to investigate whether calcium transients regulate the advance of mammalian CNS growth cones. We found that spontaneous calcium transients in developing cortical neurons have characteristic patterns, frequencies, and amplitudes. Importantly, neurons with large paused growth cones exhibit high-frequency spontaneous calcium transients, which are rare in those with small advancing growth cones. The incidence, frequencies, and amplitudes of calcium transients are inversely related to rates of axon outgrowth. The transients are mediated primarily by L-type voltage-gated calcium channels, and silencing them with channel blockers promotes axon outgrowth. Thus calcium transients regulate growth cone advance by direct effects on the growth cone.
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195
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Ludwig A, Budde T, Stieber J, Moosmang S, Wahl C, Holthoff K, Langebartels A, Wotjak C, Munsch T, Zong X, Feil S, Feil R, Lancel M, Chien KR, Konnerth A, Pape HC, Biel M, Hofmann F. Absence epilepsy and sinus dysrhythmia in mice lacking the pacemaker channel HCN2. EMBO J 2003; 22:216-24. [PMID: 12514127 PMCID: PMC140107 DOI: 10.1093/emboj/cdg032] [Citation(s) in RCA: 409] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Hyperpolarization-activated cation (HCN) channels are believed to be involved in the generation of cardiac pacemaker depolarizations as well as in the control of neuronal excitability and plasticity. The contributions of the four individual HCN channel isoforms (HCN1-4) to these diverse functions are not known. Here we show that HCN2-deficient mice exhibit spontaneous absence seizures. The thalamocortical relay neurons of these mice displayed a near complete loss of the HCN current, resulting in a pronounced hyperpolarizing shift of the resting membrane potential, an altered response to depolarizing inputs and an increased susceptibility for oscillations. HCN2-null mice also displayed cardiac sinus dysrhythmia, a reduction of the sinoatrial HCN current and a shift of the maximum diastolic potential to hyperpolarized values. Mice with cardiomyocyte- specific deletion of HCN2 displayed the same dysrhythmia as mice lacking HCN2 globally, indicating that the dysrhythmia is indeed caused by sinoatrial dysfunction. Our results define the physiological role of the HCN2 subunit as a major determinant of membrane resting potential that is required for regular cardiac and neuronal rhythmicity.
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Affiliation(s)
- Andreas Ludwig
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
| | - Thomas Budde
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
| | - Juliane Stieber
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
| | - Sven Moosmang
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
| | - Christian Wahl
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
| | - Knut Holthoff
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
| | - Anke Langebartels
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
| | - Carsten Wotjak
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
| | - Thomas Munsch
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
| | - Xiangang Zong
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
| | - Susanne Feil
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
| | - Robert Feil
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
| | - Marike Lancel
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
| | - Kenneth R. Chien
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
| | - Arthur Konnerth
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
| | - Hans-Christian Pape
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
| | - Martin Biel
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
| | - Franz Hofmann
- Institut für Pharmakologie und Toxikologie, Technische Universität München, D-80802 München, Institut für Physiologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Department für Pharmazie, Ludwig-Maximilians Universität, D-81377 München, Institut für Physiologie, Ludwig-Maximilians Universität, D-80336 München, Schlafpharmakologie and Mausverhalten/Neuronale Plastizität, Max-Planck-Institut für Psychiatrie, D-80804 München, Germany and UCSD Institute of Molecular Medicine, La Jolla, CA 92093, USA Corresponding author e-mail:
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196
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Abstract
Voltage-clamp recordings from layer II neurones in somatosensory cortex of rats aged between 12 and 17 days showed a high frequency of spontaneous postsynaptic currents (sPSCs), which on average was 33 +/- 13 Hz (s.d.). sPSCs were mediated largely by glutamatergic AMPA receptors. Their rates and amplitudes were independent of blocking sodium channels with 1 microM tetrodotoxin (TTX). Most of them, therefore, represent genuine miniature excitatory postsynaptic currents (mEPSCs). The rise time of the fastest (10 %) mEPSCs was 288 +/- 86 micros (10-90 %) and the half-width was 1073 +/- 532 micros. The amplitude was -5.9 +/- 1.1 pA with a coefficient of variation (CV) of 0.44 +/- 0.14. The rate of mEPSCs was very temperature sensitive with a Q(10) (33-37 degrees C) of 8.9 +/- 0.9. Due to this temperature sensitivity, we estimated that the microscope lamp contributed an increase in temperature of about 4 degrees C to the tissue in the focal volume of the condenser. Cell-type differences in the rate of mEPSCs were found between pyramidal/multipolar and bipolar cells. The latter had a frequency of about a third of that seen in the other cell groups. Recordings in layer II are ideally suited to investigate mechanisms of spontaneous transmitter release.
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Affiliation(s)
- Christopher R L Simkus
- Institute of Neuroinformatics, University of Zürich and Federal Institute of Technology (ETH), Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
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197
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Affiliation(s)
- Sacha Nelson
- Department of Biology and Volen Center for Complex Systems, Brandeis University, Waltham, MA 02454, USA.
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198
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Redmond L, Kashani AH, Ghosh A. Calcium regulation of dendritic growth via CaM kinase IV and CREB-mediated transcription. Neuron 2002; 34:999-1010. [PMID: 12086646 DOI: 10.1016/s0896-6273(02)00737-7] [Citation(s) in RCA: 362] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We report that CaM kinase IV and CREB play a critical role in mediating calcium-induced dendritic growth in cortical neurons. Calcium-dependent dendritic growth is suppressed by CaM kinase inhibitors, a constitutively active form of CaM kinase IV induces dendritic growth in the absence of extracellular stimulation, and a kinase-dead form of CaM kinase IV suppresses dendritic growth induced by calcium influx. CaM kinase IV activates the transcription factor CREB, and expression of a dominant negative form of CREB blocks calcium- and CaM kinase IV-induced dendritic growth. In cortical slice cultures, dendritic growth is attenuated by inhibitors of voltage-sensitive calcium channels and by dominant negative CREB. These experiments indicate that calcium-induced dendritic growth is regulated by activation of a transcriptional program that involves CaM kinase IV and CREB-mediated signaling to the nucleus.
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Affiliation(s)
- Lori Redmond
- Department of Neuroscience, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA
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199
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Migliore M, Shepherd GM. Emerging rules for the distributions of active dendritic conductances. Nat Rev Neurosci 2002; 3:362-70. [PMID: 11988775 DOI: 10.1038/nrn810] [Citation(s) in RCA: 234] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A key goal in neuroscience is to explain how the operations of a neuron emerge from sets of active channels with specific dendritic distributions. If general principles can be identified for these distributions, dendritic channels should reflect the computational role of a given cell type within its functional neural circuit. Here, we discuss insights from experimental and computational data on the distribution of voltage-gated channels in dendrites, and attempt to derive rules for how their interactions implement different dendritic functions. We propose that this type of analysis will be important for understanding behavioural processes in terms of single-neuron properties, and that it constitutes a step towards a 'functional proteomics' of nerve cells, which will be essential for defining neuronal phenotypes.
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Affiliation(s)
- Michele Migliore
- Department of Neurobiology, Yale University School of Medicine, New Haven, Connecticut 06520-8001, USA
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