Papers - Okada, Eiji

Magnetic resonance imaging appropriate for construction of subject-specific head models for diffuse optical tomography

Kazuki Kurihara, Hiroshi Kawaguchi, Takayuki Obata, Hiroshi Ito, and Eiji Okada

Biomedical Optics Express 6 ( 9 ) 3197 - 3209 2015.09

Research paper (scientific journal), Joint Work, Accepted

Numerical modeling of photon migration in the cerebral cortex of the living rat using the radiative transport equation

Hiroyuki Fujii, Shinpei Okawa, Ken Nadamoto, Eiji Okada, Yukio Yamada, Yoko Hoshi, and Masao Watanabe

Proceedings of SPIE for the Biomedical Applications of Light Scattering IX 9333   1 - 6 2015

Research paper (international conference proceedings), Accepted

Peal arteries respond earlier than penetrating arterioles to neural activation in the somatosensory cortex in awake mice exposed to chromic hypoxia; an additional mechanism to proximal integration signaling?

OKADA EIJI

Journal of Cerebral Blood Flow & Metabolism 34 ( 11 ) 1761 - 1770 2014.11

Joint Work, Accepted,  ISSN  0271-678X

　View Summary

The pial and penetrating arteries have a crucial role in regulating cerebral blood flow (CBF) to meet neural demand in the cortex. Here, we examined the longitudinal effects of chronic hypoxia on the arterial diameter responses to single whisker stimulation in the awake mouse cortex, where activity-induced responses of CBF were gradually attenuated. The vasodilation responses to whisker stimulation under prehypoxia normal conditions were 8.1% and 12% relative to their baselines in the pial arteries and penetrating arterioles, respectively. After 3 weeks of hypoxia, however, these responses were significantly reduced to 5.5% and 4.1%, respectively. The CBF response, measured using laser-Doppler flowmetry (LDF), induced by the same whisker stimulation was also attenuated (14% to 2.6%). A close linear correlation was found for the responses between the penetrating arteriolar diameter and LDF, and their temporal dynamics. After 3 weeks of chronic hypoxia, the initiation of vasodilation in the penetrating arterioles was significantly extended, but the pial artery responses remained unchanged. These results show that vasodilation of the penetrating arterioles followed the pial artery responses, which are not explainable in terms of proximal integration signaling. The findings therefore indicate an additional mechanism for triggering pial artery dilation in the neurovascular coupling.

Quantitative evaluation of deep and shallow tissue layers' contribution to fNIRS signal using multi-distance optodes and independent component analysis

OKADA EIJI

Neuroimage 85   150 - 165 2014.01

Research paper (scientific journal), Joint Work, Accepted

The influence of frontal sinus in brain activation measurements by near-infrared spectroscopy analyzed by realistic head models

OKADA EIJI

Biomedical Optics Express 3 ( 9 ) 2121-2130 2012.08

Research paper (scientific journal), Joint Work, Accepted

Dynamic phantom with two stage-driven absorbers for mimicking hemoglobin changes in superficial and deep tissues

OKADA EIJI

Journal of Biomedical Optics 17 ( 4 ) 047001/1-10 2012.04

Research paper (scientific journal), Joint Work

Optical scanning system for light-absorption measuerment of deep biological tissue

TSUKASA FUNANE, HIROKAZU ATSUMORI, MASASHI KIGUCHI, YUKARI TANIKAWA, OKADA EIJI

Review of Scientific Instruments 82   093101/1-8 2011.09

Research paper (scientific journal), Joint Work

Reproducibility and variance of a stimulation-induced hemodynamic response in barrel cortex of awake behaving mice

OKADA EIJI

Brain Research 1369   103-111 2011

Research paper (scientific journal), Single Work

Effect of spatial variation of skull and cerebrospinal fluid layers on optical mapping of brain activity

OKADA EIJI

Optical Review 17 ( 4 ) 410-420 2010

Research paper (scientific journal), Joint Work, Accepted

光脳機能イメージングの原理

OKADA EIJI

映像情報Medical (産業開発機構)  41 ( 9 ) 886-891 2009.08

Research paper (scientific journal), Single Work

近赤外分光法による脳機能計測

OKADA EIJI

光技術コンタクト (日本オプトメカトロニクス協会)  47 ( 1 ) 14-19 2009.01

Research paper (scientific journal), Single Work

Theoretical and experimental investigation of the influence of frontal sinus on the sensitivity of the NIRS signal in the adult head

OKADA EIJI

Advance in Experimental Medicine and Biology 662   231-236 2009

Research paper (scientific journal), Single Work, Accepted

Influence of a skull cranial window on the measurement of haemoglobin concentration in cortical tissue by multi-spectral imaging analysis

KOICHIRO SAKAGUCHI, SHUNSUKE FURUKAWA, SATOSHI MATSUO, NAOTAKA SAKASHITA, TAKUSHIGE KATSURA, KYOKO YAMAZAKI, HIDEO KAWAGUCHI, ATSUSHI MAKI, OKADA EIJI

Optical Review (応用物理学会日本光学会)  16 ( 2 ) 74-80 2009

Research paper (scientific journal), Joint Work, Accepted

Validation of practical diffusion approximation for virtual near infrared spectroscopy using a digital head phantom

YOSUKE OKI, HIROSHI KAWAGUCHI, OKADA EIJI

Optical Review (応用物理学会日本光学会)  16 ( 2 ) 153-159 2009

Research paper (scientific journal), Joint Work, Accepted

生体光伝播シミュレーションの近赤外線分光法への応用

OKADA EIJI

脈管学 (日本脈管学会)  49 ( 2 ) 113-119 2009

Research paper (scientific journal), Joint Work

近赤外光を用いた脳機能イメージング

OKADA EIJI

OplusE (アドコム・メディア)  30 ( 6 ) 595-598 2008.06

Research paper (scientific journal), Joint Work

Theoretical analysis of crosstalk between oxygenated and deoxygenated haemoglobin in focal brain-activation measurements by near-infrared spectroscopy

HIROSHI KAWAGUCHI, NOBUHIRO OKUI, KOICHIRO SAKAGUCHI, OKADA EIJI

Opto-electronics review (Springer)  16 ( 4 ) 404-412 2008

Research paper (scientific journal), Joint Work, Accepted

頭部組織の光伝播シミュレーションと脳機能計測

OKADA EIJI

光学 (応用物理学会日本光学会)  36 ( 12 ) 686-692 2007.12

Research paper (scientific journal), Joint Work

Experimental prediction of the wavelength-dependent path-length factor for optical intrinsic signal analysis

KOICHIRO SAKAGUCHI, TOMOYA TACHIBANA, SHUNSUKE FURUKAWA, TAKUSHIGE KATSURA, KYOKO YAMAZAKI, HIDEO KAWAGUCHI, ATSUSHI MAKI, OKADA EIJI

Applied Optics (Optical Society of America)  46 ( 14 ) 2769-2777 2007.05

Research paper (scientific journal), Joint Work, Accepted

Effect of probe arrangement on reproducibility of images by near-infrared topography evaluated by a virtual head phantom

HIROSHI KAWAGUCHI, TATSUYA KOYAMA, OKADA EIJI

Applied Optics (Optical Society of America)  46 ( 10 ) 1658-1668 2007.04

Research paper (scientific journal), Joint Work, Accepted