{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,17]],"date-time":"2026-07-17T06:08:31Z","timestamp":1784268511531,"version":"3.55.0"},"reference-count":56,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,7,17]],"date-time":"2026-07-17T00:00:00Z","timestamp":1784246400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Aging Neurosci."],"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>Mild cognitive impairment (MCI) is frequently accompanied by impairments in postural control and trunk muscle function. Although gamma\u2013theta rhythmic stimulation has been reported to modulate neural oscillatory activity, its influence on brain\u2013muscle interactions in individuals with MCI remains poorly understood. This exploratory pilot study investigated whether changes in EEG connectivity following gamma\u2013theta stimulation were associated with alterations in trunk muscle electromyographic (EMG) activity in older adults with MCI.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Nine older adults with MCI underwent two separate 10-min sessions of combined 40 Hz visual flicker and theta-frequency mechanical stimulation. Resting-state EEG and trunk muscle EMG were assessed before and after stimulation. EEG connectivity changes were calculated using Spearman correlations between predefined electrode pairs. Supplementary analyses using phase-lag index (PLI) and imaginary coherence (iCoh) were performed to address potential volume conduction effects. EMG activity was recorded bilaterally from the multifidus and lumbar paraspinal muscles during trunk extension tasks. Correlation analyses examined associations between EEG connectivity changes and EMG changes in RMS amplitude, mean frequency, and spectral power measures.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Although no predefined EEG connectivity pair demonstrated significant group-level change following stimulation, several EEG connectivity change scores were significantly associated with concurrent EMG changes. The most robust associations involved left multifidus activity: FC5\u2013F3 connectivity changes were associated with left multifidus RMS amplitude (\n                      <jats:italic>\u03c1<\/jats:italic>\n                      = +0.800,\n                      <jats:italic>p<\/jats:italic>\n                      = 0.010), and T7\u2013T8 connectivity changes were associated with left multifidus mid-frequency spectral power (\n                      <jats:italic>\u03c1<\/jats:italic>\n                      = \u22120.800,\n                      <jats:italic>p<\/jats:italic>\n                      = 0.010). Leave-one-out sensitivity analyses indicated that both associations remained statistically significant in all nine subsets. Supplementary phase-based connectivity analyses provided limited convergent support for the primary findings. Although several contralateral EEG\u2013EMG associations were identified, the overall pattern was characterized by a predominance of ipsilateral associations.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Discussion<\/jats:title>\n                    <jats:p>These findings suggest that gamma\u2013theta stimulation may influence coordinated brain\u2013muscle responses in older adults with MCI, with a predominance of left-hemisphere EEG\u2013EMG associations indicating relative hemispheric predominance rather than strict hemispheric exclusivity. Associations involving broader measures of muscle activation and spectral distribution were more robust than those involving specific spectral indices. Given the small sample size, absence of sham control, non-simultaneous EEG\u2013EMG recording, and exploratory statistical approach, these findings should be interpreted as hypothesis-generating and require confirmation in larger controlled studies.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fnagi.2026.1882681","type":"journal-article","created":{"date-parts":[[2026,7,17]],"date-time":"2026-07-17T05:43:42Z","timestamp":1784267022000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Predominantly left-lateralized EEG\u2013EMG associations following gamma\u2013theta stimulation in older adults with mild cognitive impairment"],"prefix":"10.3389","volume":"18","author":[{"given":"Runhong","family":"Yao","sequence":"first","affiliation":[{"name":"Faculty of Health Sciences, Nihon Institute of Medical Science, Irumagun","place":["Saitama, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kouji","family":"Yamada","sequence":"additional","affiliation":[{"name":"Graduate School of Health Sciences, Fujita Health University","place":["Toyoake, Aichi, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Masahiro","family":"Kudo","sequence":"additional","affiliation":[{"name":"Faculty of Health Sciences, Nihon Institute of Medical Science, Irumagun","place":["Saitama, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Duojin","family":"Wang","sequence":"additional","affiliation":[{"name":"Institute of Rehabilitation Engineering and Technology, University of Shanghai for Science and Technology","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,7,17]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"929","DOI":"10.1016\/j.neuron.2019.04.011","article-title":"Gamma entrainment binds higher-order brain regions and offers neuroprotection","volume":"102","author":"Adaikkan","year":"2019","journal-title":"Neuron"},{"key":"ref2","doi-asserted-by":"publisher","first-page":"270","DOI":"10.1016\/j.jalz.2011.03.008","article-title":"The diagnosis of mild cognitive impairment due to Alzheimer\u2019s disease: recommendations from the National Institute on Aging-Alzheimer\u2019s association workgroups on diagnostic guidelines for Alzheimer\u2019s disease","volume":"7","author":"Albert","year":"2011","journal-title":"Alzheimers Dement."},{"key":"ref3","doi-asserted-by":"publisher","first-page":"649","DOI":"10.1016\/j.conb.2008.01.007","article-title":"Oscillatory interactions between sensorimotor cortex and the periphery","volume":"17","author":"Baker","year":"2007","journal-title":"Curr. 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