{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,29]],"date-time":"2026-06-29T13:15:57Z","timestamp":1782738957813,"version":"3.54.5"},"reference-count":59,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2019,1,18]],"date-time":"2019-01-18T00:00:00Z","timestamp":1547769600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Acupuncture is a practice of treatment based on influencing specific points on the body by inserting needles. According to traditional Chinese medicine, the aim of acupuncture treatment for pain management is to use specific acupoints to relieve excess, activate qi (or vital energy), and improve blood circulation. In this context, the Hegu point is one of the most widely-used acupoints for this purpose, and it has been linked to having an analgesic effect. However, there exists considerable debate as to its scientific validity. In this pilot study, we aim to identify the functional connectivity related to the three main types of acupuncture manipulations and also identify an analgesic effect based on the hemodynamic response as measured by functional near-infrared spectroscopy (fNIRS). The cortical response of eleven healthy subjects was obtained using fNIRS during an acupuncture procedure. A multiscale analysis based on wavelet transform coherence was employed to assess the functional connectivity of corresponding channel pairs within the left and right somatosensory region. The wavelet analysis was focused on the very-low frequency oscillations (VLFO, 0.01\u20130.08 Hz) and the low frequency oscillations (LFO, 0.08\u20130.15 Hz). A mixed model analysis of variance was used to appraise statistical differences in the wavelet domain for the different acupuncture stimuli. The hemodynamic response after the acupuncture manipulations exhibited strong activations and distinctive cortical networks in each stimulus. The results of the statistical analysis showed significant differences (    p &lt; 0.05    ) between the tasks in both frequency bands. These results suggest the existence of different stimuli-specific cortical networks in both frequency bands and the anaesthetic effect of the Hegu point as measured by fNIRS.<\/jats:p>","DOI":"10.3390\/s19020394","type":"journal-article","created":{"date-parts":[[2019,1,18]],"date-time":"2019-01-18T11:26:55Z","timestamp":1547810815000},"page":"394","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":59,"title":["Cortical Network Response to Acupuncture and the Effect of the Hegu Point: An fNIRS Study"],"prefix":"10.3390","volume":"19","author":[{"given":"Raul","family":"Fernandez Rojas","sequence":"first","affiliation":[{"name":"Human-Centred Technology Research Centre, Faculty of Science and Technology, University of Canberra, Canberra 2617, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mingyu","family":"Liao","sequence":"additional","affiliation":[{"name":"Department of Industrial Engineering and Management, National Kaohsiung University of Science and Technology, Kaohsiung 80778, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Julio","family":"Romero","sequence":"additional","affiliation":[{"name":"Human-Centred Technology Research Centre, Faculty of Science and Technology, University of Canberra, Canberra 2617, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xu","family":"Huang","sequence":"additional","affiliation":[{"name":"Human-Centred Technology Research Centre, Faculty of Science and Technology, University of Canberra, Canberra 2617, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Keng-Liang","family":"Ou","sequence":"additional","affiliation":[{"name":"Department of Dentistry, Taipei Medical University Hospital, Taipei 110, Taiwan"},{"name":"Department of Dentistry, Taipei Medical University-Shuang Ho Hospital, New Taipei City 235, Taiwan"},{"name":"School of Dentistry, Health Sciences University of Hokkaido, Hokkaido 061-0293, Japan"},{"name":"Department of Prosthodontics, Faculty of Dentistry, Hasanuddin University, Makassar 90245, Indonesia"},{"name":"Department of Prosthodontics, Faculty of Dentistry, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia"},{"name":"Department of Oral Hygiene Care, Ching Kuo Institute of Management and Health, Keelung 203, Taiwan"},{"name":"3D Global Biotech Inc., New Taipei City 221, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,1,18]]},"reference":[{"key":"ref_1","first-page":"S215","article-title":"Pain terms: A current list with definitions and notes on usage","volume":"3","author":"Lindblom","year":"1986","journal-title":"Pain Suppl."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"457","DOI":"10.2147\/JPR.S105892","article-title":"A review of chronic pain impact on patients, their social environment and the health care system","volume":"9","author":"Ojeda","year":"2016","journal-title":"J. Pain Res."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1444","DOI":"10.1001\/archinternmed.2012.3654","article-title":"Acupuncture for chronic pain: Individual patient data meta-analysis","volume":"172","author":"Vickers","year":"2012","journal-title":"Arch. Intern. Med."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Dung, H. (2013). Acupuncture: An Anatomical Approach, Routledge.","DOI":"10.1201\/b15609"},{"key":"ref_5","unstructured":"Hopwood, V. (2004). Acupuncture in Physiotherapy: Key Concepts and Evidence-Based Practice, Elsevier Butterworth-Heinemann."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"675","DOI":"10.1038\/273675a0","article-title":"CXBK mice deficient in opiate receptors show poor electroacupuncture analgesia","volume":"273","author":"Peets","year":"1978","journal-title":"Nature"},{"key":"ref_7","unstructured":"Rojas, R.F., Huang, X., and Ou, K.L. (2016, January 17\u201319). Bilateral connectivity in the somatosensory region using near-infrared spectroscopy (NIRS) by wavelet coherence. Proceedings of the SPIE BioPhotonics Australasia, Adelaide, Australia."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"50","DOI":"10.1016\/j.neulet.2003.09.080","article-title":"Evidence from brain imaging with fMRI supporting functional specificity of acupoints in humans","volume":"354","author":"Zhang","year":"2004","journal-title":"Neurosci. Lett."},{"key":"ref_9","first-page":"97","article-title":"Electroacupuncture anaesthesia in oral surgery: A preliminary report","volume":"80","author":"Sheng","year":"1960","journal-title":"Chin. Med. J."},{"key":"ref_10","unstructured":"Sun, P. (2010). The Treatment of Pain with Chinese Herbs and Acupuncture E-Book, Elsevier Health Sciences."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"585493","DOI":"10.1155\/2015\/585493","article-title":"Specific correlation between the Hegu point (LI4) and the orofacial part: Evidence from an fMRI study","volume":"2015","author":"Kong","year":"2015","journal-title":"Evid. Based Complement. Altern. Med."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1007\/s11655-007-0010-3","article-title":"Study on the regulatory effect of electro-acupuncture on hegu point (LI4) in cerebral response with functional magnetic resonance imaging","volume":"13","author":"Wang","year":"2007","journal-title":"Chin. J. Integr. Med."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"388","DOI":"10.1038\/sj.neo.7900118","article-title":"Developments Toward Diagnostic Breast Cancer Imaging Using Near-Infrared Optical Measurements and Fluorescent Contrast Agents 1","volume":"2","author":"Hawrysz","year":"2000","journal-title":"Neoplasia"},{"key":"ref_14","first-page":"254","article-title":"Optical brain imaging reveals general auditory and language-specific processing in early infant development","volume":"21","author":"Ramus","year":"2010","journal-title":"Cereb. Cortex"},{"key":"ref_15","first-page":"1","article-title":"Toward a functional near-infrared spectroscopy-based monitoring of pain assessment for nonverbal patients","volume":"22","author":"Rojas","year":"2017","journal-title":"J. Biomed. Opt."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Rojas, R.F., Huang, X., Romero, J., and Ou, K.L. (2017, January 14\u201318). fNIRS Approach to Pain Assessment for Non-verbal Patients. Proceedings of the International Conference on Neural Information Processing, Guangzhou, China.","DOI":"10.1007\/978-3-319-70093-9_83"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"881","DOI":"10.1002\/gps.4074","article-title":"The effects of combine treatment of memantine and donepezil on Alzheimer\u2019s Disease patients and its relationship with cerebral blood flow in the prefrontal area","volume":"29","author":"Araki","year":"2014","journal-title":"Int. J. Geriatr. Psychiatry"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"463","DOI":"10.1016\/j.ejpain.2004.11.001","article-title":"Human brain mechanisms of pain perception and regulation in health and disease","volume":"9","author":"Apkarian","year":"2005","journal-title":"Eur. J. Pain"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"74","DOI":"10.1016\/j.neulet.2014.05.040","article-title":"Experimental pain in the gingiva and its impact on prefrontal cortical hemodynamics: A functional near-infrared spectroscopy study","volume":"575","author":"Sakuma","year":"2014","journal-title":"Neurosci. Lett."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Kussman, B.D., Aasted, C.M., Y\u00fccel, M.A., Steele, S.C., Alexander, M.E., Boas, D.A., Borsook, D., and Becerra, L. (2016). Capturing pain in the cortex during general anaesthesia: Near infrared spectroscopy measures in patients undergoing catheter ablation of arrhythmias. PLoS ONE, 11.","DOI":"10.1371\/journal.pone.0158975"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"463","DOI":"10.1139\/h04-031","article-title":"Principles, techniques, and limitations of near infrared spectroscopy","volume":"29","author":"Ferrari","year":"2004","journal-title":"Can. J. Appl. Physiol."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Rojas, R.F., Huang, X., Ou, K.L., and Lopez-Aparicio, J. (2016). Cross correlation analysis of multi-channel near infrared spectroscopy. Comput. Sci. Inf. Technol., 23\u201333.","DOI":"10.5121\/csit.2016.60303"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1080\/20445911.2015.1102919","article-title":"Past and future of near-infrared spectroscopy in studies of emotion and social neuroscience","volume":"28","author":"Balconi","year":"2016","journal-title":"J. Cogn. Psychol."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Crivelli, D., and Balconi, M. (2017). Near-infrared spectroscopy applied to complex systems and human hyperscanning networking. Appl. Sci., 7.","DOI":"10.3390\/app7090922"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"813","DOI":"10.3389\/fnhum.2013.00813","article-title":"A new methodical approach in neuroscience: Assessing inter-personal brain coupling using functional near-infrared imaging (fNIRI) hyperscanning","volume":"7","author":"Scholkmann","year":"2013","journal-title":"Front. Hum. Neurosci."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3727\/036012902816026103","article-title":"Scientific bases of acupuncture analgesia","volume":"27","author":"Cao","year":"2002","journal-title":"Acupunct. Electro-Ther. Res."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1142\/S0192415X80000311","article-title":"Central neurotransmitters and acupuncture analgesia","volume":"8","author":"Han","year":"1980","journal-title":"Am. J. Chin. Med."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"511","DOI":"10.1016\/j.pain.2005.02.011","article-title":"Acupuncture analgesia during surgery: A systematic review","volume":"114","author":"Lee","year":"2005","journal-title":"Pain"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"376","DOI":"10.1016\/0013-4694(87)90206-9","article-title":"Cerebral location of international 10\u201320 system electrode placement","volume":"66","author":"Homan","year":"1987","journal-title":"Electroencephalogr. Clin. Neurophysiol."},{"key":"ref_30","first-page":"1","article-title":"Spatiotemporal Analysis of Brain Activity Response Using Near Infrared Spectroscopy","volume":"5","author":"Rojas","year":"2016","journal-title":"Int. J. Pharma Med. Biol. Sci."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1038\/aps.2008.14","article-title":"Cerebral cortex modulation of pain","volume":"30","author":"Xie","year":"2009","journal-title":"Acta Pharmacol. Sin."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"334","DOI":"10.1016\/j.pain.2012.10.021","article-title":"Role of primary somatosensory cortex in the coding of pain","volume":"154","author":"Vierck","year":"2013","journal-title":"PAIN\u00ae"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1554","DOI":"10.1016\/j.neuroimage.2003.12.017","article-title":"Practicality of wavelength selection to improve signal-to-noise ratio in near-infrared spectroscopy","volume":"21","author":"Sato","year":"2004","journal-title":"Neuroimage"},{"key":"ref_34","unstructured":"Rojas, R.F., Huang, X., Hernandez-Juarez, J., and Ou, K.L. (2017, January 11\u201315). Physiological fluctuations show frequency-specific networks in fNIRS signals during resting state. Proceedings of the 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), Seogwipo, Korea."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"210120","DOI":"10.1155\/2015\/210120","article-title":"Brain network response to acupuncture stimuli in experimental acute low back pain: An fMRI study","volume":"2015","author":"Shi","year":"2015","journal-title":"Evid. Based Complement. Altern. Med."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"011014","DOI":"10.1117\/1.1852552","article-title":"Eigenvector-based spatial filtering for reduction of physiological interference in diffuse optical imaging","volume":"10","author":"Zhang","year":"2005","journal-title":"J. Biomed. Opt."},{"key":"ref_37","unstructured":"Cloud, M.A. (2013). Reliable Frontal Cortex Activity For An Oral Stroop Task Using Functional Near Infrared Spectroscopy. [Master\u2019s Thesis, The University of Texas]."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"61","DOI":"10.1175\/1520-0477(1998)079<0061:APGTWA>2.0.CO;2","article-title":"A practical guide to wavelet analysis","volume":"79","author":"Torrence","year":"1998","journal-title":"Bull. Am. Meteorol. Soc."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Mallat, S. (1999). A Wavelet Tour of Signal Processing, Academic Press.","DOI":"10.1016\/B978-012466606-1\/50008-8"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"395","DOI":"10.1146\/annurev.fl.24.010192.002143","article-title":"Wavelet transforms and their applications to turbulence","volume":"24","author":"Farge","year":"1992","journal-title":"Annu. Rev. Fluid Mech."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"561","DOI":"10.5194\/npg-11-561-2004","article-title":"Application of the cross wavelet transform and wavelet coherence to geophysical time series","volume":"11","author":"Grinsted","year":"2004","journal-title":"Nonlinear Process. Geophys."},{"key":"ref_42","first-page":"864","article-title":"Identifying and quantifying main components of physiological noise in functional near infrared spectroscopy on the prefrontal cortex","volume":"7","author":"Kirilina","year":"2013","journal-title":"Front. Hum. Neurosci."},{"key":"ref_43","unstructured":"Rojas, R.F., Huang, X., Ou, K.L., and Hernandez-Juarez, J. (2017, January 11\u201316). Exploring the use of optical flow for the study of functional NIRS signals. Proceedings of the SPIE Medical Imaging, Orlando, FL, USA."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"137","DOI":"10.1016\/j.brainres.2009.10.046","article-title":"How do infants perceive scrambled face?: A near-infrared spectroscopic study","volume":"1308","author":"Honda","year":"2010","journal-title":"Brain Res."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"100","DOI":"10.1016\/j.neuroimage.2007.01.045","article-title":"The oxygenation response to functional stimulation: Is there a physiological meaning to the lag between parameters?","volume":"36","author":"Boden","year":"2007","journal-title":"Neuroimage"},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Rojas, R.F., Huang, X., Ou, K.L., Tran, D., and Islam, S.M. (arXiv, 2015). Analysis of pain hemodynamic response using near-infrared spectroscopy (nirs), arXiv.","DOI":"10.5121\/ijma.2015.7203"},{"key":"ref_47","unstructured":"Mayers, A. (2013). Introduction to Statistics and SPSS in Psychology, Pearson."},{"key":"ref_48","unstructured":"Marieb, E.N. (1989). Human Anatomy & Physiology, Benjamin-Cummings Publishing Company."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1255\/jnirs.1239","article-title":"Region of interest detection and evaluation in functional near infrared spectroscopy","volume":"24","author":"Rojas","year":"2016","journal-title":"J. Near Infrared Spectrosc."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"S41","DOI":"10.1016\/j.pain.2010.10.012","article-title":"Acupuncture analgesia: Areas of consensus and controversy","volume":"152","author":"Han","year":"2011","journal-title":"Pain"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1142\/S0192415X04001825","article-title":"The soreness and numbness effect of acupuncture on skin blood flow","volume":"32","author":"Kuo","year":"2004","journal-title":"Am. J. Chin. Med."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"186","DOI":"10.1016\/j.jams.2014.02.008","article-title":"Significance of \u201cDeqi\u201d response in acupuncture treatment: Myth or reality","volume":"7","author":"Zhou","year":"2014","journal-title":"J. Acupunct. Meridian Stud."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"319734","DOI":"10.1155\/2013\/319734","article-title":"Characterization of deqi sensation and acupuncture effect","volume":"2013","author":"Yang","year":"2013","journal-title":"Evid. Based Complement. Altern. Med."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1142\/S0192415X75000177","article-title":"Effect of acupuncture on pain threshold and pain tolerance determined by electrical stimulation of the skin: A controlled study","volume":"3","author":"Stacher","year":"1975","journal-title":"Am. J. Chin. Med."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1016\/0304-3959(95)00030-V","article-title":"Analgesic effects induced by TENS and electroacupuncture with different types of stimulating electrodes on deep tissues in human subjects","volume":"63","author":"Ishimaru","year":"1995","journal-title":"PAIN\u00ae"},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"172","DOI":"10.1097\/AJP.0b013e31824909f9","article-title":"Acupuncture for acute low back pain: A systematic review","volume":"29","author":"Lee","year":"2013","journal-title":"Clin. J. Pain"},{"key":"ref_57","doi-asserted-by":"crossref","unstructured":"Baeumler, P.I., Fleckenstein, J., Takayama, S., Simang, M., Seki, T., and Irnich, D. (2014). Effects of acupuncture on sensory perception: A systematic review and meta-analysis. PLoS ONE, 9.","DOI":"10.1371\/journal.pone.0113731"},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"031405","DOI":"10.1117\/1.NPh.3.3.031405","article-title":"False positives and false negatives in functional near-infrared spectroscopy: Issues, challenges, and the way forward","volume":"3","author":"Tachtsidis","year":"2016","journal-title":"Neurophotonics"},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"109","DOI":"10.1016\/j.neuroimage.2017.03.041","article-title":"Expectation violation and attention to pain jointly modulate neural gain in somatosensory cortex","volume":"153","author":"Fardo","year":"2017","journal-title":"Neuroimage"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/2\/394\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:27:12Z","timestamp":1760185632000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/2\/394"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,1,18]]},"references-count":59,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2019,1]]}},"alternative-id":["s19020394"],"URL":"https:\/\/doi.org\/10.3390\/s19020394","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,1,18]]}}}