{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,31]],"date-time":"2026-10-31T21:51:20Z","timestamp":1793483480730,"version":"4.5.0"},"reference-count":43,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2025,10,2]],"date-time":"2025-10-02T00:00:00Z","timestamp":1759363200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Japan Society for the Promotion of Science (JSPS) KAKENHI Grant-in-Aid for Research Activity Start-up","award":["24K23043"],"award-info":[{"award-number":["24K23043"]}]}],"content-domain":{"domain":["www.mdpi.com"],"crossmark-restriction":true},"short-container-title":["Brain Sciences"],"abstract":"<jats:p>Background\/Objectives: Stroke often results in lasting upper limb deficits. Mirror visual feedback (MVF) supports motor recovery, and electromyography-triggered electrical stimulation (ES) could enhance engagement. However, the effects in healthy older adults, age-matched to typical patient cohorts, remain insufficiently understood. We tested MVF and MVF + ES using functional near-infrared spectroscopy. Methods: Seventeen right-handed older adults performed left-wrist flexion under three visual conditions: circle fixation, viewing the right hand at rest, and mirror viewing, with\/without electrical stimulation to the right-wrist flexors time-locked to left-forearm electromyography. Oxygenated hemoglobin (oxy-Hb) was recorded over the bilateral inferior frontal gyrus (IFG), precentral gyrus (PrG), postcentral gyrus (PoG), supramarginal gyrus (SMG), superior parietal lobule (SPL), and supplementary motor area. Effects were assessed with linear mixed-effects models (stimulation \u00d7 visual condition); pairwise comparisons of estimated marginal means used Fisher\u2019s least significant difference. Left-forearm electromyography verified comparable effort across conditions. Results: Linear mixed-effects models revealed left-lateralized increases in oxy-Hb, most prominently under mirror viewing with stimulation. Post hoc tests showed high oxy-Hb in the left IFG, PrG, PoG, SMG, and SMA. The left EMG did not differ. Conclusions: In healthy older adults, MVF paired with EMG-triggered ES enhances frontoparietal\u2013motor engagement beyond MVF alone, with recruitment shaped by visuo\u2013proprioceptive congruence. These findings support mechanistic plausibility and motivate dose\u2013response optimization and patient-focused trials testing behavioral transfer in stroke.<\/jats:p>","DOI":"10.3390\/brainsci15101074","type":"journal-article","created":{"date-parts":[[2025,10,2]],"date-time":"2025-10-02T08:20:28Z","timestamp":1759393228000},"page":"1074","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Topography of Cortical Activation with Mirror Visual Feedback and Electromyography-Triggered Electrical Stimulation: A Functional Near-Infrared Spectroscopy Study in Healthy Older Adults"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0009-0006-0408-2658","authenticated-orcid":false,"given":"Yuji","family":"Inagaki","sequence":"first","affiliation":[{"name":"Department of Rehabilitation Science, Faculty of Health Sciences, Hokkaido University, Sapporo 060-0812, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Miku","family":"Nakatsuka","sequence":"additional","affiliation":[{"name":"Graduate School of Health Sciences, Hokkaido University, Sapporo 060-0812, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yumene","family":"Naito","sequence":"additional","affiliation":[{"name":"Department of Rehabilitation Science, Faculty of Health Sciences, Kobe University, Kobe 654-0142, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3180-3474","authenticated-orcid":false,"given":"Daisuke","family":"Sawamura","sequence":"additional","affiliation":[{"name":"Department of Rehabilitation Science, Faculty of Health Sciences, Hokkaido University, Sapporo 060-0812, Japan"},{"name":"Department of Physiotherapy, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, VIC 3053, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,10,2]]},"reference":[{"key":"ref_1","unstructured":"GBD 2021 Stroke Risk Factor Collaborators (2024). Global, regional, and national burden of stroke and its risk factors, 1990\u20132021: A systematic analysis for the Global Burden of Disease Study 2021. Lancet Neurol., 23, 973\u20131003."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"399","DOI":"10.1016\/S0003-9993(95)80567-2","article-title":"Outcome and time course of recovery in stroke. Part I: Outcome. The Copenhagen Stroke Study","volume":"76","author":"Nakayama","year":"1995","journal-title":"Arch. Phys. Med. Rehabil."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1279","DOI":"10.1161\/01.STR.32.6.1279","article-title":"Estimates of the prevalence of acute stroke impairments and disability in a multiethnic population","volume":"32","author":"Lawrence","year":"2001","journal-title":"Stroke"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Bernardo-Filho, M., Bemben, M.G., Taiar, R., Sa\u00f1udo, B., Furness, T., and Clark, B.C. (2020). Editorial: Interventional strategies for enhancing quality of life and health span in older adults. Front. Aging Neurosci., 12.","DOI":"10.3389\/fnagi.2020.00253"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Xue, S., Zhou, X., Yang, Z.H., Si, X.K., and Sun, X. (2023). Stroke-induced damage on the blood-brain barrier. Front. Neurol., 14.","DOI":"10.3389\/fneur.2023.1248970"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"785","DOI":"10.1007\/s11910-023-01308-9","article-title":"Post-stroke everything","volume":"23","author":"Lekoubou","year":"2023","journal-title":"Curr. Neurol. Neurosci. Rep."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"377","DOI":"10.1098\/rspb.1996.0058","article-title":"Synaesthesia in phantom limbs induced with mirrors","volume":"263","author":"Ramachandran","year":"1996","journal-title":"Proc. Biol. Sci."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2035","DOI":"10.1016\/S0140-6736(99)00920-4","article-title":"Rehabilitation of hemiparesis after stroke with a mirror","volume":"353","author":"Altschuler","year":"1999","journal-title":"Lancet"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Kim, H., Lee, E., Jung, J., and Lee, S. (2023). Utilization of mirror visual feedback for upper limb function in poststroke patients: A systematic review and meta-analysis. Vision, 7.","DOI":"10.3390\/vision7040075"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"8","DOI":"10.2340\/16501977-2287","article-title":"Mirror therapy for motor function of the upper extremity in patients with stroke: A meta-analysis","volume":"50","author":"Zeng","year":"2017","journal-title":"J. Rehabil. Med."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1478","DOI":"10.1002\/pmrj.12964","article-title":"Effects of mirror therapy on spasticity and sensory impairment after stroke: Systematic review and meta-analysis","volume":"15","year":"2023","journal-title":"PM R"},{"key":"ref_12","first-page":"6159","article-title":"Effects of contralateral controlled functional electrical stimulation combined with mirror therapy on motor recovery and negative mood in stroke patients","volume":"15","author":"Wei","year":"2023","journal-title":"Am. J. Transl. Res."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Qian, J., Liang, C., Liu, R., Yu, J., Yang, T., and Bai, D. (2025). Combination of robot-assisted glove and mirror therapy improves upper limb motor function in subacute stroke patients: A randomized controlled pilot study. Front. Neurol., 16.","DOI":"10.3389\/fneur.2025.1602896"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"3271","DOI":"10.12659\/MSM.914095","article-title":"Mirror therapy using gesture recognition for upper limb function, neck discomfort, and quality of life after chronic stroke: A single-blind randomized controlled trial","volume":"25","author":"Choi","year":"2019","journal-title":"Med. Sci. Monit."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"7266263","DOI":"10.1155\/2021\/7266263","article-title":"Associated mirror therapy enhances motor recovery of the upper extremity and daily function after stroke: A randomized control study","volume":"2021","author":"Zhuang","year":"2021","journal-title":"Neural Plast."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2501","DOI":"10.1589\/jpts.28.2501","article-title":"Effect of mirror therapy on upper extremity motor function in stroke patients: A randomized controlled trial","volume":"28","author":"Gurbuz","year":"2016","journal-title":"J. Phys. Ther. Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"393","DOI":"10.1016\/j.apmr.2007.08.162","article-title":"Mirror therapy improves hand function in subacute stroke: A randomized controlled trial","volume":"89","author":"Yavuzer","year":"2008","journal-title":"Arch. Phys. Med. Rehabil."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"675","DOI":"10.1016\/j.apmr.2008.09.571","article-title":"Mirror-induced visual illusion of hand movements: A functional magnetic resonance imaging study","volume":"90","author":"Matthys","year":"2009","journal-title":"Arch. Phys. Med. Rehabil."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"e00320","DOI":"10.1016\/j.neurot.2024.e00320","article-title":"Evidence of mirror therapy for recruitment of ipsilateral motor pathways in stroke recovery: A resting fMRI study","volume":"21","author":"Zhang","year":"2024","journal-title":"Neurotherapeutics"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2321045","DOI":"10.1155\/2018\/2321045","article-title":"The activation of the mirror neuron system during action observation and action execution with mirror visual feedback in stroke: A systematic review","volume":"2018","author":"Zhang","year":"2018","journal-title":"Neural Plast."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"5660","DOI":"10.1080\/09638288.2024.2310757","article-title":"Effects of mirror therapy with electrical stimulation for upper limb recovery in people with stroke: A systematic review and meta-analysis","volume":"46","author":"Pan","year":"2024","journal-title":"Disabil. Rehabil."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Inagaki, Y., Seki, K., Makino, H., Matsuo, Y., Miyamoto, T., and Ikoma, K. (2019). Exploring hemodynamic responses using mirror visual feedback with electromyogram-triggered stimulation and functional near-infrared spectroscopy. Front. Hum. Neurosci., 13.","DOI":"10.3389\/fnhum.2019.00060"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"85","DOI":"10.1037\/0882-7974.17.1.85","article-title":"Hemispheric asymmetry reduction in older adults: The HAROLD model","volume":"17","author":"Cabeza","year":"2002","journal-title":"Psychol. Aging"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1016\/j.bbr.2012.10.038","article-title":"Age-related changes in the somatosensory processing of tactile stimulation: An fMRI study","volume":"238","author":"Brodoehl","year":"2013","journal-title":"Behav. Brain Res."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1016\/0278-2626(87)90118-7","article-title":"The measurement of handedness","volume":"6","author":"Chapman","year":"1987","journal-title":"Brain Cogn."},{"key":"ref_26","unstructured":"Futami, R., Seki, K., Kawanishi, T., Sugiyama, T., Cikajlo, I., and Handa, Y. (2005, January 5\u20138). Application of local EMG-driven FES to incompletely paralyzed lower extremities. Proceedings of the 10th Annual Conference of IFESS, Montreal, QC, Canada. Available online: https:\/\/pdfs.semanticscholar.org\/b536\/c9db3b7a319eb3dab7d76d3ae799efb2c634.pdf."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1506","DOI":"10.1016\/j.neuroimage.2006.10.043","article-title":"Virtual spatial registration of stand-alone fNIRS data to MNI space","volume":"34","author":"Tsuzuki","year":"2007","journal-title":"NeuroImage"},{"key":"ref_28","first-page":"371","article-title":"The ten\u2013twenty electrode system of the International Federation","volume":"10","author":"Jasper","year":"1958","journal-title":"Electroencephalogr. Clin. Neurophysiol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"428","DOI":"10.1016\/j.neuroimage.2008.08.036","article-title":"NIRS-SPM: Statistical parametric mapping for near-infrared spectroscopy","volume":"44","author":"Ye","year":"2009","journal-title":"NeuroImage"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"315","DOI":"10.3171\/jns.1992.76.2.0315","article-title":"Intracerebral penetration of infrared light","volume":"76","author":"McCormick","year":"1992","journal-title":"J. Neurosurg."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"182","DOI":"10.1136\/jnnp.73.2.182","article-title":"Increase in focal concentration of deoxyhaemoglobin during neuronal activity in cerebral ischaemic patients","volume":"73","author":"Murata","year":"2002","journal-title":"J. Neurol. Neurosurg. Psychiatry"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"i3","DOI":"10.1093\/bja\/aep299","article-title":"Near-infrared spectroscopy as an index of brain and tissue oxygenation","volume":"103","author":"Murkin","year":"2009","journal-title":"Br. J. Anaesth."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1464","DOI":"10.1016\/j.neuroimage.2003.10.042","article-title":"Evoked-cerebral blood oxygenation changes in false-negative activations in BOLD contrast functional MRI of patients with brain tumors","volume":"21","author":"Fujiwara","year":"2004","journal-title":"NeuroImage"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1204","DOI":"10.1016\/j.neuroimage.2003.12.002","article-title":"Circulatory basis of fMRI signals: Relationship between changes in the hemodynamic parameters and BOLD signal intensity","volume":"21","author":"Seiyama","year":"2004","journal-title":"NeuroImage"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"341","DOI":"10.1016\/j.neuroimage.2003.12.041","article-title":"Shortening intertrial intervals in event-related cognitive studies with near-infrared spectroscopy","volume":"22","author":"Schroeter","year":"2004","journal-title":"NeuroImage"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1487","DOI":"10.1097\/00001756-200005150-00026","article-title":"fMRI shows multiple somatotopic digit representations in human primary somatosensory cortex","volume":"11","author":"Kurth","year":"2000","journal-title":"Neuroreport"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1101","DOI":"10.1097\/00001756-200507130-00014","article-title":"Seeing the hand being touched modulates the primary somatosensory cortex","volume":"16","author":"Schaefer","year":"2005","journal-title":"Neuroreport"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1243","DOI":"10.1093\/cercor\/bhi007","article-title":"Action observation and acquired motor skills: An fMRI study with expert dancers","volume":"15","author":"Glaser","year":"2005","journal-title":"Cereb. Cortex"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"114","DOI":"10.1162\/089892904322755601","article-title":"Neural circuits involved in the recognition of actions performed by nonconspecifics: An fMRI study","volume":"16","author":"Buccino","year":"2004","journal-title":"J. Cogn. Neurosci."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1016\/j.cortex.2022.11.007","article-title":"Evidence of Motor Resonance in Stroke Patients with Severe Upper Limb Function Impairments","volume":"159","author":"Craighero","year":"2023","journal-title":"Cortex"},{"key":"ref_41","first-page":"8763","article-title":"Mirror therapy versus action observation therapy: Effects on excitability of the cerebral cortex in patients after strokes","volume":"12","author":"Zhang","year":"2019","journal-title":"Int. J. Clin. Exp. Med."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Cui, Y., Cong, F., Huang, F., Zeng, M., and Yan, R. (2023). Cortical activation of neuromuscular electrical stimulation synchronized mirror neuron rehabilitation strategies: An fNIRS study. Front. Neurol., 14.","DOI":"10.3389\/fneur.2023.1232436"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1016\/j.pmrj.2014.07.004","article-title":"Sensory and motor thresholds of transcutaneous electrical stimulation are influenced by gender and age","volume":"7","author":"Guirro","year":"2015","journal-title":"PM R"}],"container-title":["Brain Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-3425\/15\/10\/1074\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,2]],"date-time":"2025-10-02T08:38:25Z","timestamp":1759394305000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-3425\/15\/10\/1074"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,10,2]]},"references-count":43,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2025,10]]}},"alternative-id":["brainsci15101074"],"URL":"https:\/\/doi.org\/10.3390\/brainsci15101074","relation":{},"ISSN":["2076-3425"],"issn-type":[{"value":"2076-3425","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,10,2]]}}}