Automated detection of intercellular signaling in astrocyte networks using the converging squares algorithm

Hashemi, Mahboubeh; Buibas, Marius; Silva, Gabriel A.

doi:10.1016/j.jneumeth.2008.01.013

Cited by 7 publications

(4 citation statements)

References 37 publications

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“…One of the functions of NAAG is that of a dynamic neurotransmitter, specifically targeted to the astrocytic surface metabotropic glutamate receptor 3 (GRM3), activation of which initiates intracellular calcium transients [22] and secondary astrocyte-astrocyte and astrocyte-vascular system signals that increase focal blood flow [23,24]. A timely increase in focal blood perfusion is necessary in order to remove neuronal waste products including metabolic water, and to rapidly supply additional energy and oxygen as needed in response to neurostimulation.…”

Section: Naa and Naag Are Released To Ecf By Stimulated Neuronsmentioning

confidence: 99%

Are Astrocytes the Missing Link Between Lack of Brain Aspartoacylase Activity and the Spongiform Leukodystrophy in Canavan Disease?

Baslow

Guilfoyle

2009

Neurochem Res

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Canavan disease (CD) is a genetic degenerative brain disorder associated with mutations of the gene encoding aspartoacylase (ASPA). In humans, the CD syndrome is marked by early onset, hydrocephalus, macroencephaly, psychomotor retardation, and spongiform myelin sheath vacuolization with progressive leukodystrophy. Metabolic hallmarks of the disease include elevated N-acetylaspartate (NAA) levels in brain, plasma and CSF, along with daily excretion of large amounts of NAA and its anabolic metabolite, N-acetylaspartylglutamate (NAAG). Of the observed neuropathies, the most important appears to be the extensive demyelination that interferes with normal neuronal signaling. However, finding the links between the lacks of ASPA activity in oligodendrocytes, the buildup of NAA in white matter (WM) and the mechanisms underlying the edematous spongiform leukodystrophy have remained elusive. In this analytical review we consider what those links might be and propose that in CD, the pathological buildup of NAA in limited WM extracellular fluid (ECF) is responsible for increased ECF osmotic-hydrostatic pressure and initiation of the demyelination process. We also hypothesize that NAA is not directly liberated by neurons in WM as it is in gray matter, and that its source in WM ECF is solely as a product of the catabolism of axon-released NAAG at nodes of Ranvier by astrocyte NAAG peptidase after it has docked with the astrocyte surface metabotropic glutamate receptor 3. This hypothesis ascribes for the first time a possible key role played by astrocytes in CD, linking the lack of ASPA activity in myelinating oligodendrocytes, the pathological buildup of NAA in WM ECF, and the spongiform demyelination process. It also offers new perspectives on the cause of the leukodystrophy in CD, and on possible treatment strategies for this inherited metabolic disease.

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Section: Naa and Naag Are Released To Ecf By Stimulated Neuronsmentioning

confidence: 99%

Are Astrocytes the Missing Link Between Lack of Brain Aspartoacylase Activity and the Spongiform Leukodystrophy in Canavan Disease?

Baslow

Guilfoyle

2009

Neurochem Res

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“…81) Online signal processing is also important in fMCI studies. Several studies proposed automatic signal processing algorithms to select the regions of interest 19,82,83) and to detect spike events from time series of a calcium trace. 18,25,84) Realtime closed-loop systems 85) are useful for further development of online analyses, such as experiments with eventdriven stimulation.…”

Section: Fmci Application In Brain Slicesmentioning

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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“…Benesova et al (2009) employed edge-detection algorithms for computing GFAP+ cell areas, followed by manual selection of astrocyte soma. One of the first automated methods was presented by Hashemi et al (2008). Their method is based on the converging squares algorithm for analyzing intracellular signaling in astrocytes.…”

Section: Introductionmentioning

confidence: 99%

Quantitative 3-D analysis of GFAP labeled astrocytes from fluorescence confocal images

Kulkarni

Barton

Savelonas

et al. 2015

Journal of Neuroscience Methods

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Automated detection of intercellular signaling in astrocyte networks using the converging squares algorithm

Cited by 7 publications

References 37 publications

Are Astrocytes the Missing Link Between Lack of Brain Aspartoacylase Activity and the Spongiform Leukodystrophy in Canavan Disease?

Are Astrocytes the Missing Link Between Lack of Brain Aspartoacylase Activity and the Spongiform Leukodystrophy in Canavan Disease?

Current Application and Technology of Functional Multineuron Calcium Imaging

Quantitative 3-D analysis of GFAP labeled astrocytes from fluorescence confocal images

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