Bouchard MB, Chen BR, Burgess SA, Hillman EMCUltra-fast multispectral optical imaging of cortical oxygenation, blood flow, and intracellular calcium dynamics. Opt Express 17:15670-15678

Laboratory for Functional Optical Imaging, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA.
Optics Express (Impact Factor: 3.49). 09/2009; 17(18):15670-8. DOI: 10.1364/OE.17.015670
Source: PubMed


Camera-based optical imaging of the exposed brain allows cortical hemodynamic responses to stimulation to be examined. Typical multispectral imaging systems utilize a camera and illumination at several wavelengths, allowing discrimination between changes in oxy- and deoxyhemoglobin concentration. However, most multispectral imaging systems utilize white light sources and mechanical filter wheels to multiplex illumination wavelengths, which are slow and difficult to synchronize at high frame rates. We present a new LED-based system capable of high-resolution multispectral imaging at frame rates exceeding 220 Hz. This improved performance enables simultaneous visualization of hemoglobin oxygenation dynamics within single vessels, changes in vessel diameters, blood flow dynamics from the motion of erythrocytes, and dynamically changing fluorescence.

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Available from: Elizabeth M Hillman, Apr 06, 2014
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    • "IOS and laser Doppler flowmetry (LDF) data were collected using custom-written software in LabView 8.6 (National Instruments). For IOS imaging, four 530 nm LEDs (Thorlabs, M530L2-C1) (Bouchard et al., 2009) passed through a ± 10 nm filter (Thorlabs, FB530-10) were used to uniformly illuminate the cortical surface. A CCD camera (Dalsa, Pantera 1 M60) was used to acquire 12-bit images (Drew and Feldman, 2009). "
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    ABSTRACT: Voluntary locomotion is accompanied by large increases in cortical activity and localized increases in cerebral blood volume (CBV). We sought to quantitatively determine the spatial and temporal dynamics of voluntary locomotion-evoked cerebral hemodynamic changes. We measured single vessel dilations using two-photon microscopy and cortex-wide changes in CBV-related signal using intrinsic optical signal (IOS) imaging in head-fixed mice freely locomoting on a spherical treadmill. During bouts of locomotion, arteries dilated rapidly, while veins distended slightly and recovered slowly. The dynamics of diameter changes of both vessel types could be captured using a simple linear convolution model. Using these single vessel measurements, we developed a novel analysis approach to separate out spatially and temporally distinct arterial and venous components of the location-specific hemodynamic response functions (HRF) for IOS. The HRF of each pixel of was well fit by a sum of a fast arterial and a slow venous component. The HRFs of pixels in the limb representations of somatosensory cortex had a large arterial contribution, while in the frontal cortex the arterial contribution to the HRF was negligible. The venous contribution was much less localized, and was substantial in the frontal cortex. The spatial pattern and amplitude of these HRFs in response to locomotion in the cortex were robust across imaging sessions. Separating the more localized, the arterial component from the diffuse venous signals will be useful for dealing with the dynamic signals generated by naturalistic stimuli. Copyright © 2014. Published by Elsevier Inc.
    NeuroImage 10/2014; 105. DOI:10.1016/j.neuroimage.2014.10.030 · 6.36 Impact Factor
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    • "Moreover, Bouchard et al. proposed an LSCI system with a lower overall cost compared with the LSCI system currently employed in laboratory settings. This low-cost LSCI system enables simultaneous visualization of HbT, HbO2 and Hb dynamics within single vessels in response to forepaw stimulation [75]. LSCI has proven to be an important tool for neuroscience research, presenting excellent spatial and temporal resolutions and capabilities that extend beyond the visualization of cerebral functional and structural hemodynamic patterns. "
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    ABSTRACT: Optical imaging techniques reflect different biochemical processes in the brain, which is closely related with neural activity. Scientists and clinicians employ a variety of optical imaging technologies to visualize and study the relationship between neurons, glial cells and blood vessels. In this paper, we present an overview of the current optical approaches used for the in vivo imaging of neurovascular coupling events in small animal models. These techniques include 2-photon microscopy, laser speckle contrast imaging (LSCI), voltage-sensitive dye imaging (VSDi), functional photoacoustic microscopy (fPAM), functional near-infrared spectroscopy imaging (fNIRS) and multimodal imaging techniques. The basic principles of each technique are described in detail, followed by examples of current applications from cutting-edge studies of cerebral neurovascular coupling functions and metabolic. Moreover, we provide a glimpse of the possible ways in which these techniques might be translated to human studies for clinical investigations of pathophysiology and disease. In vivo optical imaging techniques continue to expand and evolve, allowing us to discover fundamental basis of neurovascular coupling roles in cerebral physiology and pathophysiology.
    BioMedical Engineering OnLine 04/2013; 12(1):38. DOI:10.1186/1475-925X-12-38 · 1.43 Impact Factor
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    • "as a response to the needs of real-time diagnosis of oral disease. Combined applications of biomedicine, spectroscopy, and illumination engineering have been undertaken in recent years to overcome these drawbacks [1] [2] [3] [4] [5] [6] [7]. The multi-spectral imaging (MSI) technique shows the most potential among these applications because of its real-time properties. "
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    ABSTRACT: Color reproduction systems based on the multi-spectral imaging technique (MSI) for both direct estimating reflection spectra and direct visualization from oral tissues by using various light sources are proposed. Images from three oral cancer patients were taken as the experimental samples, and spectrum differences between precancerous and normal oral mucosal tissues, were calculated during three times of the 5-Aminolevulinic acid photodynamic therapy (ALA-PDT) to analyze whether they were consistent with disease processes. For checking the successful treatment of oral cancer with ALA-PDT, the oral cavity images by swept-source optical coherence tomography (SS-OCT) are demonstrated. This system can also reproduced images under different light sources. For precancerous detection, the oral images after second ALA-PDT are assigned as the target samples. By using RGB LEDs with various correlated color temperatures (CCTs) for color difference comparison, the light source with CCT of about 4500 K was found that it has the best ability to enhance the color difference between precancerous and normal oral mucosal tissues in oral cavity. Compared with the fluorescent lighting commonly used today, the color difference can be improved by 39.2% from 16.5270 to 23.0023. Hence, this light source and spectral analysis increase the efficiency of the medical diagnosis of oral cancer and aids the patients to receive early treatment.
    Journal of optics 03/2013; 15(5):055301. DOI:10.1088/2040-8978/15/5/055301 · 2.06 Impact Factor
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