Our previous studies have shown that water immersion (WI) changes sensorimotor processing and cortical excitability in the sensorimotor regions of the brain. The present study examined the site specificity of the brain activation during WI using functional near infrared spectroscopy (fNIRS). Cortical oxyhaemoglobin (O2Hb) levels in the anterior and posterior parts of the supplementary motor area (pre-SMA and SMA), primary motor cortex (M1), primary somatosensory cortex (S1), and posterior parietal cortex (PPC) were recorded using fNIRS (OMM-3000; Shimadzu Co.) before, during, and after WI in nine healthy participants. The cortical O2Hb levels in SMA, M1, S1, and PPC significantly increased during the WI and increased gradually along with the filling of the WI tank. These changes were not seen in the pre-SMA. The results show that WI-induced increases in cortical O2Hb levels are at least somewhat site specific: there was little brain activation in response to somatosensory input in the pre-SMA, but robust activation in other areas.
Water immersion Oxyhaemoglobin concentration Site specificity Sensorimotor fNIRS
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This study was supported by JSPS KAKENHI 15 K12712 and a Grant-in-Aid for Exploratory Research from Niigata University of Health and Welfare.
Sato D, Seko C, Hashitomi T et al (2015) Differential effects of water-based exercise on the cognitive function in independent elderly adults. Aging Clin Exp Res 27(2):149–159CrossRefPubMedGoogle Scholar
Sato D, Onishi H, Yamashiro K et al (2012) Water immersion to the femur level affects cerebral cortical activity in humans: functional near-infrared spectroscopy study. Brain Topogr 25(2):220–227CrossRefPubMedGoogle Scholar
Boas DA, Gaudette T, Strangman G et al (2001) The accuracy of near infrared spectroscopy and imaging during focal changes in cerebral hemodynamics. NeuroImage 13(1):76–90CrossRefPubMedGoogle Scholar
Tanji J (1985) Comparison of neuronal activities in the monkey supplementary and precentral motor areas. Behav Brain Res 18(2):137–142CrossRefPubMedGoogle Scholar
Miyai I, Tanabe HC, Sase I et al (2001) Cortical mapping of gait in humans: a near-infrared spectroscopic topography study. NeuroImage 14(5):1186–1192CrossRefPubMedGoogle Scholar
Niederhauser BD, Rosenbaum BP, Gore JC et al (2008) A functional near-infrared spectroscopy study to detect activation of somatosensory cortex by peripheral nerve stimulation. Neurocrit Care 9(1):31–36CrossRefPubMedGoogle Scholar
Suzuki M, Miyai I, Ono T et al (2008) Activities in the frontal cortex and gait performance are modulated by preparation. An fNIRS study. NeuroImage 39(2):600–607CrossRefPubMedGoogle Scholar
Suzuki M, Miyai I, Ono T et al (2004) Prefrontal and premotor cortices are involved in adapting walking and running speed on the treadmill: an optical imaging study. NeuroImage 23(3):1020–1026CrossRefPubMedGoogle Scholar
Hari R, Forss N (1999) Magnetoencephalography in the study of human somatosensory cortical processing. Philos Trans R Soc Lond Ser B Biol Sci 354(1387):1145–1154CrossRefGoogle Scholar
Deuchert M, Ruben J, Schwiemann J et al (2002) Event-related fMRI of the somatosensory system using electrical finger stimulation. Neuroreport 13(3):365–369CrossRefPubMedGoogle Scholar
Fox PT, Burton H, Raichle ME (1987) Mapping human somatosensory cortex with positron emission tomography. J Neurosurg 67(1):34–43CrossRefPubMedGoogle Scholar
Numminen J, Schurmann M, Hiltunen J et al (2004) Cortical activation during a spatiotemporal tactile comparison task. NeuroImage 22(2):815–821CrossRefPubMedGoogle Scholar
Bodegard A, Geyer S, Herath P et al (2003) Somatosensory areas engaged during discrimination of steady pressure, spring strength, and kinesthesia. Hum Brain Mapp 20(2):103–115CrossRefPubMedGoogle Scholar