The Review of Laser Engineering
Online ISSN : 1349-6603
Print ISSN : 0387-0200
ISSN-L : 0387-0200
Volume 40 , Issue 4
Special Issue on Neurophotonics: Lasers and Photonics in Neuroscience and Neurosurgery
Showing 1-16 articles out of 16 articles from the selected issue
Special Issue on Neurophotonics: Lasers and Photonics in Neuroscience and Neurosurgery
Special Issue
Laser Review
  • Shunichi SATO
    2012 Volume 40 Issue 4 Pages 221-
    Published: 2012
    Released: July 16, 2020
    JOURNALS FREE ACCESS
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  • Mutsuo NURIYA
    2012 Volume 40 Issue 4 Pages 224-
    Published: 2012
    Released: July 16, 2020
    JOURNALS FREE ACCESS
    Neurons perform fast information processing in the form of membrane potential dynamics. Therefore, detailed examinations of membrane potential dynamics in neurons are crucial to the understanding of neuronal information processing and brain functions. However, attempts to characterize membrane potential dynamics in neurons have been hampered by the small size and the complexity of neurites, such as dendritic spines and axons, where conventional electrophysiological techniques have limited access. Furthermore, while optical imaging techniques provide better access to these structures, fluorescence-based imaging techniques are not suitable for quantitative membrane potential measurements. Second harmonic generation (SHG) imaging, which can overcome these problems, can be utilized for quantitative membrane potential imaging. Here, I review the basic principles and applications of SHG imaging in neuroscience researches and discuss the potential of this technique.
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  • Kazuto MASAMOTO, Iwao KANNO
    2012 Volume 40 Issue 4 Pages 230-
    Published: 2012
    Released: July 16, 2020
    JOURNALS FREE ACCESS
    We reviewed recent animal studies of neurovascular coupling with in vivo two-photon excitation laser scanning fluorescence microscopy (two-photon microscopy). Two-photon microscopy was introduced into the field of biomedical imaging by Denk et al. in 1990. Since then, the technique has enabled us to directly observe the cell-to-cell interactions involved in neurovascular coupling in in vivo animal brains. Recent studies have shown that neurovascular coupling is accompanied by two microvascular events, (i) an increase of red blood cell speed in brain capillaries at the region of evoked neural activity, and (ii) vasodilation of the upstream pre-capillary and penetrating arterioles. However, the physiological mechanism regulating these microvascular responses and their consequences for central nervous system function remain incompletely understood. Future studies with in vivo two-photon imaging must address these issues with multiple live cell imaging approach. A deeper understanding of neurovascular coupling mechanism will have broad implications for the study of neurodegenerative disorders and brain aging.
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  • Satoko KAWAUCHI
    2012 Volume 40 Issue 4 Pages 236-
    Published: 2012
    Released: July 16, 2020
    JOURNALS FREE ACCESS
    Light-scattering signal, which is sensitive to cellular/subcellular structural integrity, is a potential indicator of brain tissue viability, because metabolic energy is used in part to maintain the structure of cells in the brain. First, we examined how light scattering changed during viability loss of the brain without hemoglobins, for which diffuse reflectance measurements were performed for a rat global ischemic brain model made by perfusing the whole blood. After oxygen/glucose deprivation, we observed a unique triphasic scattering change (TSC), which almost coincided with cerebral ATP decrease in the brain. Secondly, we showed that TSC can be detected even in the presence of blood by using NIR light in a rat hypoxic brain model. The brain recovered when oxygen was restored during the TSC. These results suggest the usefulness of light-scattering signals for monitoring brain tissue reversibility after serious brain diseases and injuries including acute ischemic stroke and traumatic brain injury.
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  • Atsushi MAKI, Takeshi OGINO, Masashi KIGUCHI
    2012 Volume 40 Issue 4 Pages 241-
    Published: 2012
    Released: July 16, 2020
    JOURNALS FREE ACCESS
    The human brain function measurement by light that applies near-infrared spectroscopy (NIRS) has accomplished rapid development in these 30 years. We developed the optical topography (OT) method to make an image of the brain activity by the multipoint measurement simultaneously based on NIRS (1995). OT has several features. 1) It can measure brain activity in the daily life naturally. 2) It can measure the brain activity only by putting on the optical fiber cap. 3) It can measure the neonatal brain function because light level is safe for the baby brain. 4) The measurement signal can be used to know the autonomic nervous system. We have achieved the application to neurosurgery; the diagnosis of the epileptic focus and the dominant hemisphere for language. Moreover, we have found neonatal brain function concerning the language and sleep. Now, everyone can measure the brain function anytime and anywhere. It is expected to become an effective tool to the approach of a different research field and a new brain imaging. We need understanding of the meaning of the measurem
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  • Manabu SATO, Izumi NISHIDATE
    2012 Volume 40 Issue 4 Pages 248-
    Published: 2012
    Released: July 16, 2020
    JOURNALS FREE ACCESS
    The application of optical coherence tomography (OCT) to neuroscience has been reviewed. In imaging of structures in brain tissues, morphological information and scattering coeffi cients have been obtained using ultrahigh resolution OCT. The combinations of drug delivery, electrocoagulation and local block in tissues with OCT have been also reported. In functional imaging, responses at somatosensory or visual cortex by stimulus have been measured using optical intrinsic signal associated with neuronal activities. Further, the application of OCT to monitoring of viability in brain has been studied to show increases of OCT signal before cardiac arrest and negative correlations between OCT signal intensity and temperature.
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  • Toru ISHIZUKA, Hiromu YAWO
    2012 Volume 40 Issue 4 Pages 254-
    Published: 2012
    Released: July 16, 2020
    JOURNALS FREE ACCESS
    The neuronal circuits in the brain of animals consist of diverse types of neurons that are interconnected with each other at synaptic sites. Electrical stimulation has been conventionally used for the direct stimulation of neurons in neurophysiological studies, although the limited spatial and temporal precision inherent in the method has left neuroscientists eager for alternatives. The advent of single-component light-activated cation channels from unicellular green algae, channelrhodopsins, has opened new opportunities in neuroscience for the temporally and spatially precise control of neurons with light. The experimental utility of the photostimulation method, which is called optogenetics, would revolutionize basic neuroscience and the gene therapy of such neuronal disorders as Parkinson’s disease, neuropsychiatric diseases, and vision malfunctions.
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  • Takahiro ANDO, Shunichi SATO, Hiroshi NAWASHIRO, Minoru OBARA
    2012 Volume 40 Issue 4 Pages 259-
    Published: 2012
    Released: July 16, 2020
    JOURNALS FREE ACCESS
    Even though spinal cord injury (SCI) is a major cause of disability in humans, no effective treatment has been established yet. In this review, we describe gene therapy for SCI by photomechanical waves (PMWs) that are generated by irradiating a laser-absorbing material with nanosecond laser pulses. PMWs can alter the cell membranes, allowing exogenous genes to enter the cells in the target tissue. Our treatment strategy delivers small interfering RNAs (siRNAs) to silence the expression of intermediate fi laments, which suppress axonal regeneration, into the injured spinal tissues. We delivered the relevant siRNAs into the lesion in a rat SCI model by applying PMWs, and examined the histologies and the locomotive function. Signifi cant functional recovery was observed in the rats, demonstrating the effi cacy of our PMW-mediated gene therapy for SCI.
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  • Hiroshi NAWASHIRO, Kojiro WADA, Youichi UOZUMI, Hiroaki KOBAYASHI, Sat ...
    2012 Volume 40 Issue 4 Pages 265-
    Published: 2012
    Released: July 16, 2020
    JOURNALS FREE ACCESS
    Positive behavioral improvement has been observed following transcranial near-infrared light therapy in humans with chronic traumatic brain injury and acute stroke. We first examined the effect of 808 nm laser diode irradiation on regional cerebral blood flow (rCBF) in mice. An 808 nm CW diode laser was applied to the hemisphere transcranially. Transcranial near-infrared laser irradiation increased rCBF by 30% compared to control value in mice. Near-infrared laser irradiation also provoked a significant increase in cerebral nitric oxide concentration. In the clinical setting, transcranial near-infrared lightemitting diode irradiation to the forehead in a patient with persistent vegetative state following head injury was done. rCBF showed focal increase of 20%, compared to the pre-treatment value. The patient showed some improvement in his neurological condition after light-emitting diode therapy. Transcranial near-infrared irradiation might increase rCBF with some improvement of neurological condition in patients. Further study is warranted.
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  • Jiro AKIMOTO
    2012 Volume 40 Issue 4 Pages 269-
    Published: 2012
    Released: July 16, 2020
    JOURNALS FREE ACCESS
    We employed second-generation photosensitizer, Talaporfin sodium, for the intra-operative photodynamic diagnosis (PDD) and photodynamic therapy (PDT) for glioblastoma patients. 22 consecutive patients with glioblastoma (16 newly diagnosed and 6 recurrence) received intravenous dosed of Talaporfin sodium (40 mg/m2) 24 hours prior to craniotomy. Intra-operatively, tumor fluorescence was visualized using modified diode laser (664 nm) mounted surgical microscope. Fluorescence-guided resection of tumor tissue was performed, and additional PDT (150 mW/cm2, 27 J/cm2) was performed to 11 cases on invading tissues in eloquent area. A clear fluorescence signal was demonstrated in the tumor bulk and peritumoral zone, and the satisfactory resection of contrastenhancing tumor was confirmed and achieved 9 months of median survival time. Mild liver dysfunction was occurred in 11.6% of cases, and skin photosensitivity was occurred in 1 case. The clinical experience in this study indicates the clinical feasibility of Talaporfin-induced PDD and PDT for glioblastoma patients.
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Laser Original
  • Masashi KUSANO, Haruka NAKAYAMA, Kazuto MASAMOTO, Iwao KANNO, Eiji OKA ...
    2012 Volume 40 Issue 4 Pages 274-
    Published: 2012
    Released: July 16, 2020
    JOURNALS FREE ACCESS
    We measured the cerebral blood flow (CBF) of mice by laser speckle flowgraphy (LSFG) and laser Doppler fl owmetry(LDF). In LSFG, two parameters that indicate CBF, mean blur rate (MBR) and the reciprocal of correlation time (CT), are calculated from speckle patterns. MBR is calculated from 2 × 2 pixels in successive three frames, but CT is calculated from 7 × 7 pixels in one frame. The CBF change is caused by the brain activation evoked by whisker stimulation, and the MBR and CT time courses measured by LSFG were compared with the time course by LDF to validate the temporal resolution of LSFG. Both MBR and CT time courses were highly correlated with the LDF results. The spatial resolution of the MBR map is higher than that of the CT map and MBR is less infl uenced by the noise.
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  • Kosuke HASHIMOTO, Suguru KUDOH, Hidetoshi SATO
    2012 Volume 40 Issue 4 Pages 280-
    Published: 2012
    Released: July 16, 2020
    JOURNALS FREE ACCESS
    We applied Raman spectroscopy to monitor the molecular compositional changes during the maturation of cultured neural cells. Since the Raman spectra of the nucleus and cytoplasm of neural cells are slightly different, we employed the Raman spectra of the nucleus for further analysis. We analyzed with PLS regression the spectra of live neural cells measured after 2, 8, 15, and 60 days of culturing. Our results suggest that functional progress and maturation are related with molecular compositional changes in the cell and demonstrate the high potential of Raman spectroscopy in monitoring functions of live neural cells without labeling.
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  • Mitsuaki KOMATSU, Masato MURATA, Shinichi KOGURE
    2012 Volume 40 Issue 4 Pages 285-
    Published: 2012
    Released: July 16, 2020
    JOURNALS FREE ACCESS
    This study clarifies the effect of low-power laser irradiation (LLI) on the muscle contraction of frog gastrocnemius and provides further insights into the possibility of clinical applications at the mammal level. When we used continuous wave LLI on the muscle contraction of frog gastrocnemius, the retardation of tension attenuation was obtained by near-infrared LLI (808 nm, 100 mW). However, we could not determine whether such retardation was based on the thermal or the photochemical effect of LLI. Since a pulsed laser has the potential to discriminate such effects, we conducted the present experiments. As a result, the pulsed LLI induced neither temperature increments nor retarded muscle fatigue. Although a thermal effect on the retardation of muscle fatigue cannot be excluded, we conclude that the photochemical action is dominant if the optical absorption and the temperature change of living tissue are considered.
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  • Teruo NOZAKI, Shinichi INOMOTO, Seiichi ARAI, Hiroko TAKAHARA, Masahir ...
    2012 Volume 40 Issue 4 Pages 292-
    Published: 2012
    Released: July 16, 2020
    JOURNALS FREE ACCESS
    Based on our hypothesis that low-power laser irradiation (LLI) influences a hyperpolarization-activated cation current (Ih), we examined the effects of LLI on cardiac automatism of the frog heart because the Ih was firstly identified in the rabbit heart as a pacemaker channel. ECG was directly recorded. In control group, the heart rate gradually decreased and stopped with an average survival time of 14.9 ± 3.4 h (mean ± SD). 532 nm LLI induced a transient tachycardia and resulted in a prolongation of survival time, whereas 808 nm LLI did bradycardia and a reduction of survival time. An Ih blocker, ZD7288 application induced bradycardia as well as reduction of survival time. The simultaneous application of LLI and ZD7288 put out the LLI effect but remained the blocker effect. It is concluded that LLI effects on cardiac automatism are induced by a certain process of activation or inactivation in pace-making channels.
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  • Izumi NISHIDATE, Keiichiro YOSHIDA, Satoko KAWAUCHI, Shunichi SATO, Ma ...
    2012 Volume 40 Issue 4 Pages 299-
    Published: 2012
    Released: July 16, 2020
    JOURNALS FREE ACCESS
    In this study, we present a method to determine the reduced scattering coefficients μs’ (λ ) and the absorption coeffi cients μa (λ ) of in vivo cerebral cortex based on the diffuse refl ectance spectroscopy using single reflectance fiber probe with two source-collector geometries. In order to confirm the possibility of the method to evaluate changes in the optical properties of biological tissue, we performed in vivo experiments for exposed brain of rats during cortical spreading depression (CSD). The time courses of μa (λ ) and SO2 after the stimulation indicated the hemodynamic change in cerebral cortex, whereas variations of μs’(λ ) implied the changes in light scattering by tissue and red blood cells.
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Regular Paper
Laser Original
  • Akiko KITAYABU, Katsunori ISHII, Norihiro HONDA, Kunio AWAZU
    2012 Volume 40 Issue 4 Pages 305-
    Published: 2012
    Released: July 16, 2020
    JOURNALS FREE ACCESS
    The diagnosis of atherosclerosis in the early phase is difficult. In this study, we focused on a hyperspectral imaging (HSI) technology to detect atherosclerotic plaques. HSI is one method of spectroscopic imaging. Near-infrared (NIR) HSI can show the distribution of chemical compounds by vibrational information and provide the diagnostic imaging of plaques which consists of a lipid-rich tissues. The object of this study is to detect an atherosclerosis phantom using NIR-HSI. An HSI system was constructed by an NIR super continuum light source and an InGaAs CCD camera. We measured the diffuse refl ectance of an atherosclerosis phantom, constructed hyperspectral images with a spectral angle mapper algorithm in the 1150-1320 nm wavelength and detected the absorption spectra of bovine fat under an optical arterial tissue phantom with thicknesses of 0.5 and 1.0 mm. These results support the possibility of NIR-HSI as a new and noninvasive arteriosclerosis diagnostic modality.
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