scholarly journals Computational modeling of the photon transport, tissue heating, and cytochrome C oxidase absorption during transcranial near-infrared stimulation

2019 ◽  
Author(s):  
Mahasweta Bhattacharya ◽  
Anirban Dutta
Keyword(s):  
Cytochrome C Oxidase ◽  
Brain Tissue ◽  
Spectral Region ◽  
Temperature Increase ◽  
Near Infrared ◽  
Cortical Excitability ◽  
Tissue Heating ◽  
Photothermal Effects ◽  
The Brain ◽  
Stimulation Of

AbstractTranscranial near-infrared stimulation (tNIRS) has been proposed as a tool to modulate cortical excitability. However, the underlying mechanisms are not clear where the heating effects on the brain tissue needs investigation due to increased near-infrared (NIR) absorption by water and fat. Moreover, the risk of localized heating of tissues (including the skin) during optical stimulation of the brain tissue is a concern. The challenge in estimating localized tissue heating is due to the light interaction with the tissues’ constituents, which is dependent on the combination ratio of the scattering and absorption properties of the constituent. Here, apart from tissue heating that can modulate the cortical excitability (“photothermal effects”); the other mechanism reported in the literature is the stimulation of the mitochondria in the cells which are active in the adenosine triphosphate (ATP) synthesis. In the mitochondrial respiratory chain, the complex IV, also named as the cytochrome c oxidase(CCO), is the unit four with three copper atoms. The absorption peaks of CCO are in the visible (420-450nm and 600-700nm) and the near-infrared (760-980nm) spectral region which have been shown to be promising for low level light therapy (LLLT), also known as “photobiomodulation”. While much higher CCO absorption peaks in the visible spectrum can be used for the photobiomodulation of the skin, 810nm has been proposed for the non-invasive brain stimulation (using tNIRS) due to the optical window in the NIR spectral region. In this article, we applied a computational approach to delineate the “photothermal effects” from the “photobiomodulation,” i.e., to estimate the amount of light absorbed individually by each chromophore in the brain tissue (with constant scattering) and the related tissue heating. Photon migration simulations were performed for motor cortex tNIRS based on a prior work that used a 500mW cm−2 light source placed on the scalp. We simulated photon migration at 630nm and 700nm (red spectral region) and 810nm (near-infrared spectral region). We found a temperature increase in the scalp below 0.25 ° C and a minimal temperature increase in the gray matter less than 0.04 ° C at 810nm. Similar heating was found for 630nm and 700nm used for LLLT, so photothermal effects are postulated to be unlikely in the brain tissue.

scholarly journals Computational Modeling of the Photon Transport, Tissue Heating, and Cytochrome C Oxidase Absorption during Transcranial Near-Infrared Stimulation

2019 ◽  
Vol 9 (8) ◽  
pp. 179 ◽  
Author(s):  
Mahasweta Bhattacharya ◽  
Anirban Dutta
Keyword(s):  
Cytochrome C Oxidase ◽  
Brain Tissue ◽  
Spectral Region ◽  
Temperature Increase ◽  
Near Infrared ◽  
Cortical Excitability ◽  
Tissue Heating ◽  
Photothermal Effects ◽  
The Brain ◽  
Stimulation Of

Transcranial near-infrared stimulation (tNIRS) has been proposed as a tool to modulate cortical excitability. However, the underlying mechanisms are not clear where the heating effects on the brain tissue needs investigation due to increased near-infrared (NIR) absorption by water and fat. Moreover, the risk of localized heating of tissues (including the skin) during optical stimulation of the brain tissue is a concern. The challenge in estimating localized tissue heating is due to the light interaction with the tissues’ constituents, which is dependent on the combination ratio of the scattering and absorption properties of the constituent. Here, apart from tissue heating that can modulate the cortical excitability (“photothermal effects”); the other mechanism reported in the literature is the stimulation of the mitochondria in the cells which are active in the adenosine triphosphate (ATP) synthesis. In the mitochondrial respiratory chain, Complex IV, also known as the cytochrome c oxidase (CCO), is the unit four with three copper atoms. The absorption peaks of CCO are in the visible (420–450 nm and 600–700 nm) and the near-infrared (760–980 nm) spectral regions, which have been shown to be promising for low-level light therapy (LLLT), also known as “photobiomodulation”. While much higher CCO absorption peaks in the visible spectrum can be used for the photobiomodulation of the skin, 810 nm has been proposed for the non-invasive brain stimulation (using tNIRS) due to the optical window in the NIR spectral region. In this article, we applied a computational approach to delineate the “photothermal effects” from the “photobiomodulation”, i.e., to estimate the amount of light absorbed individually by each chromophore in the brain tissue (with constant scattering) and the related tissue heating. Photon migration simulations were performed for motor cortex tNIRS based on a prior work that used a 500 mW cm − 2 light source placed on the scalp. We simulated photon migration at 630 nm and 700 nm (red spectral region) and 810 nm (near-infrared spectral region). We found a temperature increase in the scalp below 0.25 °C and a minimal temperature increase in the gray matter less than 0.04 °C at 810 nm. Similar heating was found for 630 nm and 700 nm used for LLLT, so photothermal effects are postulated to be unlikely in the brain tissue.

Redox changes in cat brain cytochrome-c oxidase after blood-fluorocarbon exchange

1990 ◽  
Vol 258 (6) ◽  
pp. H1706-H1713 ◽  
Author(s):  
M. Ferrari ◽  
D. F. Hanley ◽  
D. A. Wilson ◽  
R. J. Traystman
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Spectral Region ◽  
Near Infrared ◽  
Circulatory Arrest ◽  
Difference Spectra ◽  
Broad Absorption Band ◽  
Cat Brain

Rapid scanning near-infrared spectroscopy (730-960 nm) was utilized to determine cat brain cytochrome-c oxidase copper band by blood-perfluorochemical emulsion (Oxypherol) exchange. Spectra were carried out before, during, and after the exchange transfusion on animals with preserved somatosensory-evoked potentials and microsphere-determined cerebral blood flow. Remaining hemoglobin (less than 4% of control) was converted to carboxyhemoglobin that does not absorb in this spectral region. Difference spectra, between an hypercapnic status (8% CO2-92% O2) and postmortem, demonstrated the presence of a broad absorption band centered around 820-845 nm that could be attributed to the oxidized low potential copper ion (CuA) of cytochrome-c oxidase. However, we were unable to further oxidize this band by adding CO2 to the inspired gas mixture, but this inconsistency may be due to the near-maximal cerebral blood flow levels present in this preparation. Cytochrome oxidation by CO2 is normally attributed to increased O2 delivery to the tissue, secondary to an increased cerebral perfusion. We were unable to induce further increases in cerebral blood flow. In contrast, the cytochrome band could be reduced both by lowering fractional O2 concentration and by inducing circulatory arrest. The spectral data support the hypothesis that it is possible to quantify the cytochrome-c oxidase copper band in the near-infrared spectral region.

Application of time-gated CCD camera with image intensifier in contactless detection of absorbing inclusions buried in optically turbid medium which mimics local changes in oxygenation of the brain tissue

2012 ◽  
Vol 20 (4) ◽  
Author(s):  
P. Sawosz ◽  
N. Zolek ◽  
M. Kacprzak ◽  
R. Maniewski ◽  
A. Liebert
Keyword(s):  
Infrared Spectroscopy ◽  
Brain Tissue ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Image Intensifier ◽  
Ccd Camera ◽  
Turbid Medium ◽  
The Brain ◽  
Contactless Measurements

AbstractThe near infrared spectroscopy may be implemented using various optoelectronic techniques, however, most of them do not allow to carry out measurements at short source-detector separation. We propose a method, based on time-gated intensified CCD camera, which allows for contactless measurements and can be carried out at short source-detector separation. This technique was tested on a phantom with absorbing inclusions buried in an optically turbid medium which mimics local changes in oxygenation of the brain tissue.

scholarly journals Imaging Striatal Dopamine Release Using a Non-Genetically Encoded Near-Infrared Fluorescent Catecholamine Nanosensor

2018 ◽  
Author(s):  
Abraham G. Beyene ◽  
Kristen Delevich ◽  
Jackson Travis Del Bonis-O’Donnell ◽  
David J. Piekarski ◽  
Wan Chen Lin ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Near Infrared ◽  
Critical Role ◽  
Brain Slices ◽  
Biological Tissues ◽  
Single Wall Carbon Nanotubes ◽  
Fluorescence Signal ◽  
Optogenetic Stimulation ◽  
Optical Tools ◽  
Stimulation Of

AbstractNeuromodulation plays a critical role in brain function in both health and disease. New optical tools, and their validation in biological tissues, are needed that can image neuromodulation with high spatial and temporal resolution, which will add an important new dimension of information to neuroscience research. Here, we demonstrate the use of a catecholamine nanosensor with fluorescent emission in the 1000-1300 nm near-infrared window to measure dopamine transmission in ex vivo brain slices. These near-infrared catecholamine nanosensors (nIRCats) represent a broader class of nanosensors that can be synthesized from non-covalent conjugation of single wall carbon nanotubes (SWNT) with single strand oligonucleotides. We show that nIRCats can be used to detect catecholamine efflux in brain tissue driven by both electrical stimulation or optogenetic stimulation. Spatial analysis of electrically-evoked signals revealed dynamic regions of interest approximately 2 microns in size in which transients scaled with simulation intensity. Optogenetic stimulation of dopaminergic terminals produced similar transients, whereas optogenetic stimulation of glutamatergic terminals showed no effect on nIRCat signal. Bath application of nomifensine prolonged nIRCat fluorescence signal, consistent with reuptake blockade of dopamine. We further show that the chemically synthetic molecular recognition elements of nIRCats permit measurement of dopamine dynamics in the presence of dopamine receptor agonists and antagonists. These nIRCat nanosensors may be advantageous for future use because i) they do not require virus delivery, gene delivery, or protein expression, ii) their near-infrared fluorescence facilitates imaging in optically scattering brain tissue and is compatible for use in conjunction with other optical neuroscience tool sets, iii) the broad availability of unique near-infrared colors have the potential for simultaneous detection of multiple neurochemical signals, and iv) they are compatible with pharmacology. Together, these data suggest nIRCats and other nanosensors of this class can serve as versatile new optical tools to report dynamics of extracellular neuromodulation in the brain.

scholarly journals THE CAUSAL LINK BETWEEN VACCINATION ADJUVANTS AND AUTISM

2019 ◽  
Vol 7 (6) ◽  
pp. 288-295
Author(s):  
Thomas Prevenslik
Keyword(s):  
Immune System ◽  
Brain Tissue ◽  
Causal Link ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cytokine Levels ◽  
Patient Will ◽  
Solar Uv ◽  
Planck Law ◽  
The Brain ◽  
Stimulation Of

Adjuvants essential in vaccines to stimulate activation of the immune system comprise submicron (< 100 nm) nanoparticles (NPs) of aluminum hydroxide that upon vaccine injection cross the blood-brain-barrier (BBB) and because of their low solubility may remain in the brain for an extended time. Despite over a century of use, the mechanism underlying the stimulation of the immune system by adjuvants has not been understood. Solar UV can optically stimulate most immune systems in the skin, but solar UV is not available inside the brain. By the process of simple QED, the NPs lacking heat capacity by the Planck law conserve heat from brain tissue by emitting UV radiation instead of increasing in temperature. Hence, the causal link between vaccination adjuvants and autism is UV stimulation of the immune system from constituent NPs that cross the BBB. But the UV also damages the DNA of brain tissue and increases the pro-inflammatory interleukin (IL-6) cytokine levels common in autism patients. Pre-vaccination enzyme-linked immunosorbent assay (ELISA) tests of IL-6 level including UV blood irradiation (UBI common in immune-modulating therapy are suggested to determine if a patient will have an adverse vaccination response. Patients having high IL-6 levels are not recommended for vaccination.

scholarly journals Assessing cerebral blood flow, oxygenation and cytochrome c oxidase stability in preterm infants during the first 3 days after birth

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Ajay Rajaram ◽  
Daniel Milej ◽  
Marianne Suwalski ◽  
Lilian Kebaya ◽  
Matthew Kewin ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Injury ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Preterm Infants ◽  
Near Infrared ◽  
Correlation Spectroscopy ◽  
The Impact ◽  
The Brain

AbstractA major concern with preterm birth is the risk of neurodevelopmental disability. Poor cerebral circulation leading to periods of hypoxia is believed to play a significant role in the etiology of preterm brain injury, with the first three days of life considered the period when the brain is most vulnerable. This study focused on monitoring cerebral perfusion and metabolism during the first 72 h after birth in preterm infants weighing less than 1500 g. Brain monitoring was performed by combining hyperspectral near-infrared spectroscopy to assess oxygen saturation and the oxidation state of cytochrome c oxidase (oxCCO), with diffuse correlation spectroscopy to monitor cerebral blood flow (CBF). In seven of eight patients, oxCCO remained independent of CBF, indicating adequate oxygen delivery despite any fluctuations in cerebral hemodynamics. In the remaining infant, a significant correlation between CBF and oxCCO was found during the monitoring periods on days 1 and 3. This infant also had the lowest baseline CBF, suggesting the impact of CBF instabilities on metabolism depends on the level of blood supply to the brain. In summary, this study demonstrated for the first time how continuous perfusion and metabolic monitoring can be achieved, opening the possibility to investigate if CBF/oxCCO monitoring could help identify preterm infants at risk of brain injury.

scholarly journals Voltage-sensitive dye delivery through the blood brain barrier using adenosine receptor agonist Regadenoson

2018 ◽  
Author(s):  
Rebecca W. Pak ◽  
Jeeun Kang ◽  
Heather Valentine ◽  
Leslie M. Loew ◽  
Daniel L.J. Thorek ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Blood Brain Barrier ◽  
Near Infrared ◽  
Brain Activity ◽  
Brain Barrier ◽  
Fluorescence Signal ◽  
Voltage Sensitive Dye ◽  
Blood Brain ◽  
Adenosine Receptor Agonist ◽  
The Brain

AbstractOptical imaging of brain activity has mostly employed genetically manipulated mice, which cannot be translated to clinical human usage. Observation of brain activity directly is challenging due to difficulty in delivering dyes and other agents through the blood brain barrier (BBB). Using fluorescence imaging, we have demonstrated the feasibility of delivering the near-infrared voltage-sensitive dye (VSD) IR-780 perchlorate to the brain tissue through pharmacological techniques, via an adenosine agonist (Regadenoson). Comparison of VSD fluorescence of mouse brains without and with Regadenoson showed significantly increased residence time of the fluorescence signal in the latter case, indicative of VSD diffusion into the brain tissue. Dose and timing of Regadenoson were varied to optimize BBB permeability for VSD delivery.

Chemical Stimulation of the Brain Makes Stimulating Reading

1975 ◽  
Vol 20 (12) ◽  
pp. 923-924
Author(s):  
MADGE E. SCHEIBEL ◽  
ARNOLD B. SCHEIBEL
Keyword(s):  
Chemical Stimulation ◽  
The Brain ◽  
Stimulation Of
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