A portable optical fiber probe for in vivo brain temperature measurements

Musolino, Stefan; Schartner, Erik P.; Tsiminis, Georgios; Salem, Abdallah; Monro, Tanya M.; Hutchinson, Mark R.

doi:10.1117/12.2242831

Cited by 6 publications

(7 citation statements)

References 18 publications

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“…Further, we demonstrate straightforward combinations of fiber photometry with optogenetics in the same device. Similar approaches for light delivery and collection have previously been used for optical coherence tomography (Lee et al, 2013; Lorenser et al, 2013), endoscopy (Lemire-Renaud et al, 2010; Lorenser et al, 2013), temperature sensing (Musolino et al, 2016), and monitoring of opsin-eGFP expression (Diester et al, 2011), but they have not been applied to infer and manipulate neuronal activity. Notably, application of the FFP system is not limited to neuroscientific research, but it can also be employed for other excitable cells: For example, tools for simultaneous delivery and collection of light are requested for all-optical readout and control of cardiac activity (Entcheva, 2013; Entcheva & Bub, 2016; Entcheva & Kay, 2021; O’Shea et al, 2019) and skeletal muscles (Gundelach et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

A flexible and versatile system for multicolor fiber photometry and optogenetic manipulation

Formozov¹,

Dieter²

2022

Preprint

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Fiber photometry is a technique of growing popularity in neuroscientific research. It is widely used to infer brain activity by recording calcium dynamics in genetically defined populations of neurons. Aside from the wide variety of calcium indicators, other genetically encoded biosensors have recently been engineered to measure membrane potential, neurotransmitter release, pH, or various cellular metabolites, such as ATP or cAMP. Due to the spectral characteristics of these molecular tools, different assemblies of optical hardware are usually needed to reveal the full potential of different biosensors. In addition, the combination of multiple biosensors in one experiment often requires the investment in more complex equipment, which limits the flexibility of the experimental design. Such constraints often hamper a straightforward implementation of new molecular tools, evaluation of their performance in vivo, and design of new experimental paradigms - especially if the financial budget is a limiting factor. Here, we propose a novel approach for fiber photometry recordings, based on a multimode optical fused-fiber coupler (FFC) for both light delivery and collection. Recordings can readily be combined with optogenetic manipulations in a single device without the requirement for dichroic beam-splitters. In combination with a multi-color light source and appropriate emission filters, our approach offers remarkable flexibility in experimental design and facilitates the implication of new molecular tools in vivo at minimal cost. The ease of assembly, operation, characterization, and customization of this platform holds the potential to foster the development of experimental strategies for multicolor fused fiber photometry (FFP) combined with optogenetics far beyond its current state.

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Section: Discussionmentioning

confidence: 99%

A flexible and versatile system for multicolor fiber photometry and optogenetic manipulation

Formozov¹,

Dieter²

2022

Preprint

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“…The main source of bias in temperature estimation in our approach might be introduced by the user dependence in the curve-fitting process carried out by jMRUI. Nonetheless, the accuracy of noninvasive human MR thermometry is still surprising when compared with invasive probe insertion, the current gold-standard of brain temperature monitoring, only providing an accuracy of 0.1-0.3°C as reported (Schartner and Monro, 2014;Musolino et al, 2016;Fekete et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

Magnetic Resonance Spectroscopy Thermometry at 3 Tesla: Importance of Calibration Measurements

Verius

Frank

Gizewski

et al. 2019

Therapeutic Hypothermia and Temperature Management

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To demonstrate the importance of calibration measurements in 3 Tesla proton magnetic resonance (MR) spectroscopy (1 H-MRS) thermometry for human brain temperature estimation for routine clinical applications. In vitro proton MR spectroscopy to obtain calibration constants of the water-chemical shift was conducted at 3 Tesla with a temperature-controlled phantom, containing a pH-buffered aqueous solution of N-acetyl aspartate (NAA), creatine (Cr), methylene protons of Cr (Cr2), dimethyl silapentane sulfonic acid (DSS), and sodium formate (NaFor). Estimations of absolute human brain temperature were performed utilizing the correlation of temperature to the water-chemical shift for the resonances of NAA, Cr, and Cr2. Data for calibration of the metabolites' chemical shift differences and in vivo temperature estimations were acquired with single-voxel point-resolved spectroscopy (PRESS) sequences (repetition time/echo time = 2000/30 ms; voxel size 2 • 2 • 2 cm 3). Spectroscopy data were quantified in the time-domain, and a Pearson correlation analysis was performed to estimate the correlation between the chemical shift of metabolites and measured temperatures. The correlation coefficients (r) of our calibration measurements were NAA 0.9975 (-0.0609), Cr-0.9979 (-0.0621), Cr2-0.9973 (-0.0577), DSS-0.9976 (-0.0615), and NaFor-0.8132 (-2.348). The mean calculated brain temperature was 37.78-1.447°C, and the mean tympanic temperature was 36.83-0.2456°C. Calculated temperatures derived from Cr and Cr2 provided significant (p = 0.0241 and p = 0.0210, respectively) correlations with measured temperatures (r = 0.4108 and r =-0.4194, respectively). Calibration measurements are vital for 1 H-MRS thermometry. Small numeric differences in measured signal and data preprocessing without any calibration measurements reduce accuracy of temperature calculations, which indicates that calculated temperatures should be interpreted with caution. Application of this method for clinical purposes warrants further investigation and a more practical approach.

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“…These studies used a ratiometric approach to fluorescence temperature sensing in fibre based probes as a means to sense changes in temperature at discrete points in space with high sensitivity. The flexibilty of using fibres as temperature probes has also been demonstrated by monitoring intracranial temperature of a rat [16], highlighting the biocompatibility of tellurite composites for biological applications. Here we present a non-standard approach to temperature sensing by using scanning confocal microscopy (SCM) to monitor the temperature sensitive upconversion fluorescence of a rare-earth doped glass.…”

Section: Introductionmentioning

confidence: 95%

“…Previously Er 3+ :Yb 3+ co doped tellurite glass (EYT) has been used for monitoring temperature in biological systems with high sensitivity (≈ 10 −3 /K) at temperature ranges of importance to biological processes [15][16][17]. These studies used a ratiometric approach to fluorescence temperature sensing in fibre based probes as a means to sense changes in temperature at discrete points in space with high sensitivity.…”

Section: Introductionmentioning

confidence: 99%

Micron scale thermometry using lanthanide doped tellurite glass

Stavrevski

Schartner

Abraham

et al. 2019

AOS Australian Conference on Optical Fibre Technology (ACOFT) and Australian Conference on Optics, Lasers, and Spectroscopy (AC

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Quantifying temperature variations at the micron scale can provide new opportunities in optical sensing. In this paper, we present a novel approach using the temperature-dependent variations in fluorescence of rare-earth doped tellurite glass to provide a micron-scale image of temperature variations over a 200 micrometre field of view. We demonstrate the system by monitoring the evaporation of a water droplet and report a net temperature change of 7.04 K with a sensitivity of at least 0.12 K. These results establish the practicality of this confocal-based approach to provide high-resolution marker-free optical temperature sensing.

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A portable optical fiber probe for in vivo brain temperature measurements

Cited by 6 publications

References 18 publications

A flexible and versatile system for multicolor fiber photometry and optogenetic manipulation

A flexible and versatile system for multicolor fiber photometry and optogenetic manipulation

Magnetic Resonance Spectroscopy Thermometry at 3 Tesla: Importance of Calibration Measurements

Micron scale thermometry using lanthanide doped tellurite glass

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