@article{362f14acfd954732ae77e7c7ed195ed4,
title = "A NIRS-fMRI investigation of prefrontal cortex activity during a working memory task",
abstract = "Near-infrared spectroscopy (NIRS) is commonly used for studying human brain function. However, several studies have shown that superficial hemodynamic changes such as skin blood flow can affect the prefrontal NIRS hemoglobin (Hb) signals. To examine the criterion-related validity of prefrontal NIRS-Hb signals, we focused on the functional signals during a working memory (WM) task and investigated their similarity with blood-oxygen-level-dependent (BOLD) signals simultaneously measured by functional magnetic resonance imaging (fMRI). We also measured the skin blood flow with a laser Doppler flowmeter (LDF) at the same time to examine the effect of superficial hemodynamic changes on the NIRS-Hb signals. Correlation analysis demonstrated that temporal changes in the prefrontal NIRS-Hb signals in the activation area were significantly correlated with the BOLD signals in the gray matter rather than those in the soft tissue or the LDF signals. While care must be taken when comparing the NIRS-Hb signal with the extracranial BOLD or LDF signals, these results suggest that the NIRS-Hb signal mainly reflects hemodynamic changes in the gray matter. Moreover, the amplitudes of the task-related responses of the NIRS-Hb signals were significantly correlated with the BOLD signals in the gray matter across participants, which means participants with a stronger NIRS-Hb response showed a stronger BOLD response. These results thus provide supportive evidence that NIRS can be used to measure hemodynamic signals originating from prefrontal cortex activation.",
keywords = "Blood oxygenation level dependent (BOLD), Finger tapping, Functional magnetic resonance imaging (fMRI), Hemoglobin, Near-infrared spectroscopy (NIRS), Optical topography, Prefrontal cortex, Simultaneous measurement, Working memory",
author = "Hiroki Sato and Noriaki Yahata and Tsukasa Funane and Ryu Takizawa and Takusige Katura and Hirokazu Atsumori and Yukika Nishimura and Akihide Kinoshita and Masashi Kiguchi and Hideaki Koizumi and Masato Fukuda and Kiyoto Kasai",
note = "Funding Information: We thank Mr. Tsuyoshi Miyashita, Dr. Hirokazu Tanaka, and Dr. Eisuke Sakakibara for their assistance with the experiments, Dr. Daisuke Suzuki, Mr. Michiyuki Fujiwara, and Mr. Shingo Kawasaki for providing technical assistance, and Dr. Akiko Obata and Dr. Ryuta Aoki for their helpful comments on the experimental design. This study was supported by Grants-in-Aid for Scientific Research on Innovative Areas (nos. 23118001 & 23118004 [Adolescent Mind & Self-Regulation] to KK, no. 32118003 to MF, and Comprehensive Brain Science Network to KK), a Grant-in-Aid for Young Scientists (B) (no. 23791309 ) to RT, a Grant-in-Aid for Scientific Research (B) (no. 23390286 ) to MF, and a Grant-in-Aid for Challenging Exploratory Research (no. 22659209 ) to MF from the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT) . A part of this study was also the result of the “Development of biomarker candidates for social behavior” interdisciplinary project carried out under the Strategic Research Program for Brain Sciences by MEXT. This study was also supported in part by Health and Labor Sciences Research Grants for Comprehensive Research on Disability Health and Welfare ( H23-seishin-ippan-002 ) to RT, YN, and MF. ",
year = "2013",
month = dec,
doi = "10.1016/j.neuroimage.2013.06.043",
language = "English",
volume = "83",
pages = "158--173",
journal = "NeuroImage",
issn = "1053-8119",
publisher = "Academic Press Inc.",
}