Spontaneous Plasticity of Multineuronal Activity Patterns in Activated Hippocampal Networks

Usami, Atsushi; Matsuki, Norio; Ikegaya, Yuji

doi:10.1155/2008/108969

Cited by 14 publications

(12 citation statements)

References 41 publications

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“…EC therefore receives input from all sensory modalities and is believed to play a greater role in the processing and integration of contextual information than of object information (Suzuki et al, 1997). EC does, however, receive object information from PrC and passes that information along to the hippocampus; most generally, the EC is considered to mediate much of the informational input to the hippocampus (Canto et al, 2008). Relative to other regions of MTL, less is known about the exact function of EC, but we can offer several possibilities.…”

Section: The Creation and Retrieval Of Unitizationsmentioning

confidence: 99%

A Review of the Neural and Behavioral Consequences for Unitizing Emotional and Neutral Information

Murray¹,

Kensinger²

2013

Front. Behav. Neurosci.

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A special type of association, called a “unitization,” is formed when pieces of information are encoded as a single representation in memory (e.g., “shirt” and “blue” are encoded as a “blue shirt”; Graf and Schacter, 1989) and typically are later reactivated in memory as a single unit, allowing access to the features of multiple related stimuli at once (Bader et al., 2010; Diana et al., 2011). This review examines the neural processes supporting memory for unitizations and how the emotional content of the material may influence unitization. Although associative binding is typically reliant on hippocampal processes and supported by recollection, the first part of this review will present evidence to suggest that when two items are unitized into a single representation, memory for those bound items may be accomplished on the basis of familiarity and without reliance on the hippocampus. The second part of this review discusses how emotion may affect the processes that give rise to unitizations. Emotional information typically receives a mnemonic benefit over neutral information, but the literature is mixed on whether the presence of emotional information impedes or enhances the associative binding of neutral information (reviewed by Mather, 2007). It has been suggested that the way the emotional and neutral details are related together may be critical to whether the neutral details are enhanced or impeded (Mather, 2007; Mather and Sutherland, 2011). We focus on whether emotional arousal aids or inhibits the creation of a unitized representation, presenting preliminary data, and future directions to test empirically the effects of forming and retrieving emotional and neutral unitizations.

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Section: The Creation and Retrieval Of Unitizationsmentioning

confidence: 99%

A Review of the Neural and Behavioral Consequences for Unitizing Emotional and Neutral Information

Murray¹,

Kensinger²

2013

Front. Behav. Neurosci.

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“…SI was normalized to the highest (SI max ) and the lowest (SI min ) value, which were obtained by rearranging all events in the dataset. 12) We then defined the "asynchrony index" as (SIϪ SI min )/(SI max ϪSI min ). This normalization is required to compare data across specimens with varying numbers of neurons.…”

Section: Organotypic Hippocampal Slice Cultures and Recording Solutionsmentioning

confidence: 99%

“…12,15) But for this particular state we focused on, there is a possibility that we may have overlooked a slight difference in synchrony that this parameter was not sensitive enough to capture.…”

Section: Asynchronous Neuronal Activity Observed Under Ogdmentioning

confidence: 99%

Asynchronously Enhanced Spiking Activity of Ischemic Neuronal Networks

Ujita

Mizunuma

Matsuki

et al. 2011

Biological & Pharmaceutical Bulletin

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Cerebral ischemia drawn by stroke, cardiac arrest, and other circulatory disorders induces complex neuronal responses leading to irreversible dysfunction and cell death. The mechanisms of these responses and their consequences have been investigated widely both in vivo and in vitro, including changes in neurotransmitter release, uptake, and degradation, [1][2][3][4][5] receptor alteration, 1,6,7) enhancement of proteolysis, 8,9) and mitochondrial metabolic aberration. 9,10) But these studies are conducted only at a single-cell level, and how the whole neuronal network reacts to energy deprivation has not been assessed. This point of view is important, because the activity of each cell is summed up in a network, producing complex responses to environment changes.Here we simulated ex vivo ischemia by applying oxygenglucose deprivation (OGD) to rat hippocampal organotypic slice cultures and captured the activity of an assembly of CA1 neurons using functional multineuron calcium imaging (fMCI), an optical technique that records suprathreshold activities en masse from large neuron populations with single cell resolution. We discovered that the network shows enhanced neuronal activity but maintains the same asynchrony level as control, as confirmed by two mathematically irrelevant parameters. This is distinct from other well known pathological states in which the network excitability rises with synchrony. This previously unknown network alteration brought by energy deprivation should open a novel strategy toward therapeutic and pharmaceutical approach to ischemia. MATERIALS AND METHODS Organotypic Hippocampal Slice Cultures and Recording SolutionsAll experiments were performed with the approval of the animal experiment ethics committee at the University of Tokyo according to the University of Tokyo guidelines for the care and use of laboratory animals. Hippocampal slices (300 mm) were prepared from postnatal day 7 Wistar/ST rats (SLC, Shizuoka, Japan), embedded on an Omnipore membrane filter with culture media, and incubated in 5% CO 2 at 35°C. 11) The slice cultures used in the experiments were maintained 7 to 14 d in vitro after preparation. For the experiments, slice cultures were transferred to a heated recording chamber (29-33°C) and continuously perfused with carbonated (95% O 2 , 5% CO 2 ) artificial cerebrospinal fluid (aCSF) containing 126 mM NaCl, 26 mM NaHCO 3 , 3.5 mM KCl, 1.25 mM NaH 2 PO 4 , 1.3 mM MgSO 4 , 2.0 mM CaCl 2 , and 10 mM glucose. For OGD, the extracellular solution was switched to aCSF without glucose, bubbled with 95% N 2 -5% CO 2 .Electrophysiology Cell-attached recordings were taken from the soma of CA1 cells with Axopatch 700B amplifier (Molecular Devices, Union City, CA, U.S.A.). Patch pipettes (4-9 MW) were filled with normal aCSF.Functional Multineuron Calcium Imaging (fMCI) Slices were incubated for 45 min at 35°C with 0.0005% Oregon Green 488 BAPTA 1-AM (Invitrogen), 0.01% Pluronic F-127 (Invitrogen), and 0.005% Cremophor EL (SigmaAldrich, St. Louis, MO, U.S.A.) and then recovered in...

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“…In past years, we have exploited this technique and analyzed neural circuit dynamics. 20,[22][23][24][25][26][27][28][29][30] In this review, we focus on recent applications of fMCI and technical advancements in optics and engineering which are supporting further development of the fMCI.…”

Section: Introductionmentioning

confidence: 99%

Current Application and Technology of Functional Multineuron Calcium Imaging

Namiki

Ikegaya

2009

Biological & Pharmaceutical Bulletin

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Here we describe recent applications and technical advancements of functional multineuron calcium imaging (fMCI), which monitors the firing activity of more than a thousand neurons through their somatic Ca 2؉ signals. fMCI is used for analysis of various neural circuits under normal and pathological conditions. In vitro fMCI is made more sophisticated by using multipoint illumination and scanning technology with spinning-disk and low-laser-intensity imaging, electron-multiplying charge-coupled device cameras, etc. In vivo fMCI is still developing. We review optical technologies for fast scanning imaging, deep tissue imaging, and recording from moving animals.Key words calcium imaging; functional multineuron calcium imaging; large-scale recording; scanning; spinning disk Review January 2009 1 Biol. Pharm. Bull. 32(1) 1-9 (2009) © 2009 Pharmaceutical Society of Japan * To whom correspondence should be addressed. e-mail: ikegaya@mol.f.u-tokyo.ac.jp tation is removed with a small aperture called a pinhole which functions as a spatial filter 31) ; that is, light emitted from the focal spot efficiently passes through the pinhole, while the vast majority of emission light arising from the outside area is physically blocked. To acquire a two-dimensional or three-dimensional image of a specimen, the focal spot is moved with servomotor-controlled mirrors called Galvano-mirrors, servomotor-controlled stages, etc. Scanned emission light is detected by a photomultiplier tube (PMT). PMT detects a photon via a photoelectric effect and amplifies the signal 10 5 -10 8 times through multiple charged cathodes, in which an incoming photoelectron produces secondary electrons. The amplified electrons are converted into electric currents by an anode.Nipkow Spinning Disk Confocal Microscopy: Spinning Disk with Multi-Pinholes The second implementation is the use of multi-point illumination with many pinholes on a spinning plate termed a Nipkow disk. A rotating spinning disk has multiple pinholes through which laser lines embody multisite focal illumination and detection. The commercially available apparatus, Yokogawa's spinning disk, is further sophisticated. The system uses an additional spinning disk that contains a ca. 20000 microlens array for light convergence on the corresponding pinholes on a Nipkow disk.32) The light focusing also helps reduce scattering light, improving the signal-to-noise ratio. In addition, pinholes are strategically aligned in space to achieve uniform illumination over the field of view. 33,34) The latest version of Yokogawa's spinning disk, CSU-X1, is more improved in terms of the light use efficiency, about two-fold higher than the previous version, CSU-10. In CSU-X1, reduction of mechanical noise from its disk-driving part allows realization of 10000 revolutions per minute. Because the helical pinhole distribution covers the whole field of view every 30°of disk rotation, CSU-X1 enables the maximum sampling rate of 2000 Hz.Charge-Coupled Device Technology Spinning disk confocal microscopy simultaneously...

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Spontaneous Plasticity of Multineuronal Activity Patterns in Activated Hippocampal Networks

Cited by 14 publications

References 41 publications

A Review of the Neural and Behavioral Consequences for Unitizing Emotional and Neutral Information

A Review of the Neural and Behavioral Consequences for Unitizing Emotional and Neutral Information

Asynchronously Enhanced Spiking Activity of Ischemic Neuronal Networks

Current Application and Technology of Functional Multineuron Calcium Imaging

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