Analysis of optical properties of the mouse cranium—Implications for in vivo multi photon laser scanning microscopy

Helm, P. Johannes; Ottersen, Ole Petter; Nase, Gabriele

doi:10.1016/j.jneumeth.2008.12.032

Cited by 22 publications

(14 citation statements)

References 18 publications

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“…First, in our experience, it is faster and easier to replace the dorsal skull with glass than to try and thin uniformly the entire dorsal skull without rupturing it. Second, the optical quality of the Crystal Skull window is commercial optical grade; by comparison, the optical quality of a thinned skull preparation is limited by the intrinsic material variations and surface roughness of a thinned skull bone (Helm et al, 2009; Yang et al, 2010). Third, the Crystal Skull preparation is stable over months (Figure 1B), whereas skull re-growth generally alters the optical quality of a thinned skull preparation.…”

Section: Resultsmentioning

confidence: 99%

Long-Term Optical Access to an Estimated One Million Neurons in the Live Mouse Cortex

et al. 2016

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SUMMARY A major technological goal in neuroscience is to enable the interrogation of individual cells across the live brain. By creating a curved glass replacement to the dorsal cranium and surgical methods for its installation, we developed a chronic mouse preparation providing optical access to an estimated 800,000–1,100,000 individual neurons across the dorsal surface of neocortex. Post-surgical histological studies revealed comparable glial activation as in control mice. In behaving mice expressing a Ca2+ indicator in cortical pyramidal neurons, we performed Ca2+ imaging across neocortex using an epi-fluorescence macroscope and estimated that 25,000–50,000 individual neurons were accessible per mouse across multiple focal planes. Two-photon microscopy revealed dendritic morphologies throughout neocortex, allowed time-lapse imaging of individual cells, and yielded estimates of >1 million accessible neurons per mouse by serial tiling. This approach supports a variety of optical techniques and enables studies of cells across >30 neocortical areas in behaving mice.

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Section: Resultsmentioning

confidence: 99%

Long-Term Optical Access to an Estimated One Million Neurons in the Live Mouse Cortex

et al. 2016

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“…19 It has been demonstrated that light is able to penetrate the cranium and reach the brain. 78 This effect is being used for the development of optical imaging techniques using nearinfrared light in humans. 79 Although light attenuation occurs when light travels through bone, this attenuation is not of a strong magnitude.…”

Section: Transcranial Effectsmentioning

confidence: 99%

“…78 Photons at wavelengths between 630 nm and 800 nm have been shown to travel up to 28 mm even in layers of tissues with relatively low transparencies such as skin, connective tissue, muscle, bone, and spinal cord, with about 6% of the total energy density being detectable at the ventral surface of a living rat. 42,80 In gray matter, red and near-infrared light penetration is governed by Beer -Lambert law, with the optical power decaying up to 80% at 1 mm from the surface.…”

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confidence: 99%

Low-level light therapy of the eye and brain

Rojas¹,

González-Lima²

2011

117

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Low-level light therapy (LLLT) using red to near-infrared light energy has gained attention in recent years as a new scientific approach with therapeutic applications in ophthalmology, neurology, and psychiatry. The ongoing therapeutic revolution spearheaded by LLLT is largely propelled by progress in the basic science fields of photobiology and bioenergetics. This paper describes the mechanisms of action of LLLT at the molecular, cellular, and nervous tissue levels. Photoneuromodulation of cytochrome oxidase activity is the most important primary mechanism of action of LLLT. Cytochrome oxidase is the primary photoacceptor of light in the red to near-infrared region of the electromagnetic spectrum. It is also a key mitochondrial enzyme for cellular bioenergetics, especially for nerve cells in the retina and the brain. Evidence shows that LLLT can secondarily enhance neural metabolism by regulating mitochondrial function, intraneuronal signaling systems, and redox states. Current knowledge about LLLT dosimetry relevant for its hormetic effects on nervous tissue, including noninvasive in vivo retinal and transcranial effects, is also presented. Recent research is reviewed that supports LLLT potential benefits in retinal disease, stroke, neurotrauma, neurodegeneration, and memory and mood disorders. Since mitochondrial dysfunction plays a key role in neurodegeneration, LLLT has potential significant applications against retinal and brain damage by counteracting the consequences of mitochondrial failure. Upon transcranial delivery in vivo, LLLT induces brain metabolic and antioxidant beneficial effects, as measured by increases in cytochrome oxidase and superoxide dismutase activities. Increases in cerebral blood flow and cognitive functions induced by LLLT have also been observed in humans. Importantly, LLLT given at energy densities that exert beneficial effects does not induce adverse effects. This highlights the value of LLLT as a novel paradigm to treat visual, neurological, and psychological conditions, and supports that neuronal energy metabolism could constitute a major target for neurotherapeutics of the eye and brain.

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“…Other considerations in choosing optical window type are desired imaging depth, spatial resolution, and cortical area to be monitored. Compared to an open skull preparation, the thinned skull window provides somewhat lower spatial resolution and depth penetration into tissue (Helm et al 2009). The extent to which these parameters are affected depends on the thickness and texture of the bone remaining after the thinning procedure.…”

Section: Choosing An Optical Window Typementioning

confidence: 99%

“…Most texture and thickness irregularities can be eliminated by careful scraping with dedicated surgical blades. Remaining irregularities in skull thickness can lead to image distortions (Helm et al 2009), some of which may be diminished, for example, using adaptive wave-front correction (Rueckel et al 2006). However, because the risk of causing bone cracks increases with skull area to be thinned, imaging of large contiguous cortical areas (several millimeters in diameter) has been challenging.…”

Section: Choosing An Optical Window Typementioning

confidence: 99%

Two-Photon Imaging of Microglia in the Mouse Cortex In Vivo

Nimmerjahn¹

2012

Cold Spring Harb Protoc

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Microglia are the primary immune effector cells of the brain parenchyma. They are distributed throughout the brain at various densities. Two-photon fluorescence microscopy, together with expression of fluorescent proteins in microglia, has enabled study of these fascinating cells in vivo. Imaging studies have shown, for example, that microglia continually survey their cellular environment and immediately respond to injury. However, we still know very little about their roles in various parts of the developing and adult brain or their diverse effector functions in aging and different disease states. Experimental procedures have been developed for minimally invasive short- and long-term two-photon imaging of microglial cells in cortical regions of the intact mouse brain. This protocol describes two-photon imaging of microglia in the mouse cortex in vivo, using mice which have had a head plate implanted and have been prepared with either a thinned skull or optical window. Technical pitfalls, limitations, and alternative approaches are also discussed.

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Analysis of optical properties of the mouse cranium—Implications for in vivo multi photon laser scanning microscopy

Cited by 22 publications

References 18 publications

Long-Term Optical Access to an Estimated One Million Neurons in the Live Mouse Cortex

Long-Term Optical Access to an Estimated One Million Neurons in the Live Mouse Cortex

Low-level light therapy of the eye and brain

Two-Photon Imaging of Microglia in the Mouse Cortex In Vivo

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